RTCA SC-214/EUROCAE WG-78 - DOC

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					                             RTCA SC-214/EUROCAE WG-78
                Air Traffic Services Safety and Interoperability Requirements
                                                   General Information

Position Paper Number [assigned by Pub]:             Version: e.g. 1, 1.1   Date: e.g. 11 Nov 94     Comments Due to Author:

                                                          H (Input for           03/02/2010
FANS 1/A - Advanced                                       Validation)
Services - INTEROP                                   (Validation Input)
                                                              V1.3

Position Paper Title:                                                       Editor /email address:

FUTURE AIR NAVIGATION SYSTEM 1/A                                            Chris Collings /
ACCOMODATION FOR ADVANCED                                                   chris.collings@harris.com
SERVICES IN THE ATN ENVIRONMENT
INTEROPERABILITY STANDARD
Status:

                 New Material Review                                          Publication Integration

Abstract and Proposed Actions:

This new material provides the mature draft for INTEROP document ―Interoperability Requirements
Standard For FANS 1/A-ATN Advanced ATS Data Communication‖.
It is representing the state of the work after SG-3 telecon (27 May 08), the SG-3 meeting at Plenary 4
(June 2008), the SG-3 telecon (July 2008), the SG-3 meeting in Munich (August 2008), Plenary 5
(September 2008), Melbourne SG-3 Meeting (October 2008), SG-3 telecon (November 2008), Plenary
6 (December 2008), Toulouse, France, SG-3 telecon (February 2009) and Plenary 7 (March 2009),
Scottsdale. Additional changes to the work package 1 baseline were made at the SG-3 Meeting (June
2009) Maastricht, SG-3 Meeting (August 2009) Frankfurt, Plenary 8 (September 2009) Toulouse, SG-3
Meeting (October 2009) Seattle, and Plenary 9 (December 2009) Albuquerque.
It contains the INTEROP requirements for the advanced ATS services (DLIC, ACL, ACM, DCL, and
AMC) and provide INTEROP guidance for ADS-S based services.
Coordinator and supporters are continuing to work on the document before releasing it for integration.

Key word(s) (optional):



                                                   Web site information
Web site location:                         Filename(s):

www.faa.gov/go/sc214                       FANS INTEROP Standard_(03FEB10)-H.doc
ii



Special posting instructions:
                                       Distribution

Name                                  Org             Email Address

All RTCA SC-214/ EUROCAE WG-78 SG-3   RTCA/EUROCAE    sg3-dcs@eurocontrol.int
members

All RTCA SC-214/ EUROCAE WG-78        RTCA/EUROCAE    plenary @eurocontrol.int

DATACOMM Program                      FAA             Gregg.Anderson@faa.gov
iv




        FUTURE AIR NAVIGATION SYSTEM 1/A
 ACCOMODATION FOR ADVANCED SERVICES IN THE ATN
    ENVIRONMENT INTEROPERABILITY STANDARD
        (FANS 1/A — ATS INTEROP STANDARD)




                 Version
          H (Input for Validation)
                   03/02/2010
EUROCAE ED-XXX/RTCA DO-XXX                   Prepared by:
Date: 03/02/2010             RTCA SC-214/EUROCAE WG-78
vi




                                                                TABLE OF CONTENTS

1      INTRODUCTION ................................................................................................. 1-13

1.1        Purpose ...................................................................................................................................................... 1-13

1.2        Scope .......................................................................................................................................................... 1-13

1.3        Relationships to other Documents ........................................................................................................... 1-14

1.4     Description of this Document .................................................................................................................. 1-16
   1.4.1 Document Conventions .......................................................................................................................... 1-16
   1.4.2 Document Organization ......................................................................................................................... 1-17
   1.4.3 Acronyms and Glossary of Terms .......................................................................................................... 1-17

1.5        References ................................................................................................................................................. 1-19


2      DESCRIPTION AND OPERATIONAL CONSIDERATIONS ............................... 2-20

2.1     Data Link Initiation Capability ............................................................................................................... 2-21
   2.1.1 ATN CM Application ............................................................................................................................ 2-21
   2.1.2 FANS 1/A AFN Application .................................................................................................................. 2-21

2.2     CPDLC Application ................................................................................................................................. 2-21
   2.2.1 ATN CPDLC Application ...................................................................................................................... 2-21
   2.2.2 FANS 1/A CPDLC Application ............................................................................................................. 2-22

2.3     ADS-C Application Description .............................................................................................................. 2-22
   2.3.1 ATN ADS-C Application ....................................................................................................................... 2-22
   2.3.2 FANS 1/A ADS Application .................................................................................................................. 2-22


3      COMMUNICATION REQUIREMENTS ................................................................ 3-23

4      REQUIREMENTS FOR DATA LINK APPLICATIONS ....................................... 4-25

4.1     CM/AFN Application Requirements ...................................................................................................... 4-25
   4.1.1 ATN CM and FANS 1/A AFN Primitives ............................................................................................. 4-25
   4.1.2 ATN and FANS 1/A Primitive Parameters ............................................................................................ 4-26
   4.1.3 ATN CM and FANS 1/A AFN Variables .............................................................................................. 4-29
   4.1.4 Timers .................................................................................................................................................... 4-32

4.2     CPDLC Application Requirements......................................................................................................... 4-33
   4.2.1 Time, Timestamp and Message Latency ................................................................................................ 4-33
   4.2.2 ATN CPDLC Constructs and FANS 1/A ACARS IMIs ........................................................................ 4-38
   4.2.3 High-Level Data Structures .................................................................................................................... 4-46
   4.2.4 Message Attributes ................................................................................................................................. 4-46
   4.2.5 LACK ..................................................................................................................................................... 4-49
    4.2.6       CPDLC Disabling/Enabling ................................................................................................................... 4-52
    4.2.7       Message Header ..................................................................................................................................... 4-53
    4.2.8       Uplink Message Elements ...................................................................................................................... 4-54
    4.2.9       Downlink Message Elements ............................................................................................................... 4-113
    4.2.10        Concatenating Messages Elements .................................................................................................. 4-125
    4.2.11        Error Information ............................................................................................................................. 4-128
    4.2.12        Message Element Parameters and Data Type .................................................................................. 4-142
    4.2.13        ATN and FANS 1/A Message Element Pairing ............................................................................... 4-176
    4.2.14        ATN UM with W/U resp and Corresponding FANS 1/A Messages with R resp ............................ 4-212
    4.2.15        Timers .............................................................................................................................................. 4-213


5       DYNAMIC FUNCTIONS/OPERATIONS OF DATA LINK SERVICES .............. 5-214

5.1     DLIC ........................................................................................................................................................ 5-214
   5.1.1 Scope and Objective ............................................................................................................................. 5-214
   5.1.2 DLIC Contact Function ........................................................................................................................ 5-217

5.2      CPDLC .................................................................................................................................................... 5-220
   5.2.1 Timers in CPDLC-based services ........................................................................................................ 5-220
   5.2.2 ATC Communication Management (ACM) Service ............................................................................ 5-224
   5.2.3 Handling CPDLC connections ............................................................................................................. 5-238
   5.2.4 Transfer from T-ATSU to R-ATSU with simultaneous transfer of data and frequency ...................... 5-239
   5.2.5 Transfer from a not CPDLC-equipped T-ATSU to a CPDLC-equipped R-ATSU .............................. 5-242
   5.2.6 Transfer from a CPDLC-equipped T-ATSU to a not CPDLC-equipped R-ATSU with simultaneous
   transfer of data and frequency communications ................................................................................................ 5-243
   5.2.7 Transfer from T-sector to R-sector both using CPDLC ....................................................................... 5-245
   5.2.8 Transfer from T-ATSU to R-ATSU with independent transfer of data and frequency communications (by
   data link or voice) .............................................................................................................................................. 5-247
   5.2.9 Transfer from a CPDLC-equipped T-ATSU to a non-CPDLC equipped R-ATSU with independent
   transfer of data and frequency communications ................................................................................................ 5-248
   5.2.10      C-ATSU Ends CPDLC Connection ................................................................................................. 5-249
   5.2.11      Change of Frequency Requested by the Flight Crew....................................................................... 5-249
   5.2.12      Deferred instruction to change frequency ........................................................................................ 5-250

5.3         ATC Traffic Clearance (ACL) Service ................................................................................................. 5-251

5.4     Departure Clearance (DCL) Service ..................................................................................................... 5-252
   5.4.1 Accommodation of the Departure Clearnace Service .......................................................................... 5-252
   5.4.2 Departure Clearance Revsions ............................................................................................................. 5-253
   5.4.3 Departure Clearance Request ............................................................................................................... 5-253

5.5         ATC Microphone Check (AMC) Service.............................................................................................. 5-253

5.6     4DTRAD Service .................................................................................................................................... 5-253
   5.6.1 ITBO Service ....................................................................................................................................... 5-253


6 GUIDELINES FOR ATN GROUND SYSTEM USE OF FANS 1/A ADS-C
APPLICATION ......................................................................................................... 6-254

6.1         ADS-C Contracts .................................................................................................................................... 6-254

6.2     Uplink Functions .................................................................................................................................... 6-255
   6.2.1 ADS Uplink Messages ......................................................................................................................... 6-255
viii


   6.2.2       ADS Demand Contract Request ........................................................................................................... 6-257
   6.2.3       ADS Periodic Contract Request ........................................................................................................... 6-260
   6.2.4       ADS Event Contract Request ............................................................................................................... 6-263

6.3     Downlink Functions................................................................................................................................ 6-269
   6.3.1 ADS Downlink Messages .................................................................................................................... 6-269
   6.3.2 ADS Report .......................................................................................................................................... 6-271
   6.3.3 ADS ATN Reject / FANS Negative Ack ............................................................................................. 6-279
   6.3.4 ADS ATN Cancel Positive Ack / FANS Positive Ack ........................................................................ 6-281
   6.3.5 ADS ATN Cancel Negative Ack / FANS Negative Ack ..................................................................... 6-281
   6.3.6 ADS Positive Acknowledgement ......................................................................................................... 6-282
   6.3.7 ADS Non-Compliance Notification ..................................................................................................... 6-282

6.4        Parameter Range and Resolution.......................................................................................................... 6-285

6.5        Timers ...................................................................................................................................................... 6-290
                                                      APPENDICES
Appendix A    MEMBERSHIP
Appendix B    HISTORY AND TERMS OF REFERENCE OF SC-214/WG-78
Appendix C    IMPROVEMENT SUGGESTION FORM
Appendix D    Interoperability Requirements Traceability Table


                                                  LIST OF FIGURES
Figure 1-1    Mixed technology environments.................................................................................... 1-15


                                                   LIST OF TABLES
Table 2-1     Advanced Services data link services and applications ................................................. 2-20
Table 3-1     SMI Downlink and Uplink relationship for FANS 1/A AFN, and CPDLC .................. 3-24
Table 3-2     Valid label/sub-label/MFI/IMI/SMI combinations for FANS 1/A CPDLC uplink ....... 3-24
Table 3-3     Valid label/sub-label/MFI/IMI/SMI combinations for FANS 1/A AFN uplink ............ 3-24
Table 4-1     ATN CM and FANS 1/A AFN primitives ..................................................................... 4-25
Table 4-2     Mapping of parameters into ATN CM primitives and FANS 1/A AFN primitives ...... 4-26
Table 4-3     ATN CM and FANS 1/A AFN variables ....................................................................... 4-29
Table 4-4     ATN CM and FANS 1/A AFN timers ........................................................................... 4-32
Table 4-5     ATN and FANS 1/A CPDLC requirements for time source ......................................... 4-33
Table 4-6     ATN and FANS 1/A CPDLC requirements for timestamp generation.......................... 4-34
Table 4-7     ATN and FANS 1/A CPDLC requirements for message latency .................................. 4-35
Table 4-8     ATN CPDLC constructs and FANS 1/A CPDLC ACARS IMIs .................................. 4-38
Table 4-9     ATN and FANS 1/A CPDLC high-level data structures ............................................... 4-46
Table 4-10    ATN and FANS 1/A CPDLC message response attributes ........................................... 4-47
Table 4-11:   LACK on Downlink Messages ...................................................................................... 4-50
Table 4-12:   LACK on Downlink Messages ...................................................................................... 4-50
Table 4-13    CPDLC Disabling/Enabling Functionality .................................................................... 4-52
Table 4-14    ATN and FANS 1/A CPDLC message headers ............................................................. 4-53
Table 4-15    ATN and FANS 1/A CPDLC uplink message elements................................................ 4-54
Table 4-16    ATN and FANS 1/A CPDLC downlink message elements ......................................... 4-113
Table 4-17    FANS 1/A CPDLC emergency message elements ...................................................... 4-125
Table 4-18    High Level Concatenation Requirements .................................................................... 4-125
Table 4-19    ATN and FANS 1/A CPDLC responses to concatenated messages ............................ 4-127
Table 4-20    ATN and FANS 1/A ERROR information requirements ............................................ 4-129
Table 4-21    ATN and FANS 1/A uplink [errorinformation] parameter .......................................... 4-131
Table 4-22    ATN and FANS 1/A downlink [errorinformation] parameter ..................................... 4-133
Table 4-23    ATN and FANS 1/A DOWNLINK error information ................................................. 4-135
Table 4-24    ATN LevelType and FANS 1/A altitude ..................................................................... 4-143
Table 4-25    ATN and FANS 1/A position data type ....................................................................... 4-144
Table 4-26    ATN and FANS 1/A speed data type ........................................................................... 4-145
Table 4-27    ATN specified distance and FANS 1/A distance offset data type ............................... 4-149
Table 4-28    ATN Timesec and FANS 1/A Time data type ............................................................. 4-150
Table 4-29    ATN and FANS 1/A vertical rate parameter ............................................................... 4-151
Table 4-30    ATN facility parameter ................................................................................................ 4-152
Table 4-31    ATN facility designation and FANS 1/A ICAO facility designation data type ........... 4-153
Table 4-32    ATN unit name and FANS 1/A ICAO unit name data type ........................................ 4-154
Table 4-33    ATN and FANS 1/A route clearance data type............................................................ 4-155
x


Table 4-34     ATN and FANS 1/A published identifier data type ..................................................... 4-157
Table 4-35     ATN and FANS 1/A place bearing distance data type ................................................ 4-158
Table 4-36     ATN and FANS 1/A leg type data type ....................................................................... 4-158
Table 4-37     ATN and FANS 1/A latitude/longitude data type ........................................................ 4-159
Table 4-38     ATN and FANS 1/A frequency data type .................................................................... 4-162
Table 4-39     ATN and FANS 1/A code data type ............................................................................ 4-163
Table 4-40     ATN and FANS 1/A Departure Clearance Parameter ................................................. 4-164
Table 4-41     ATN and FANS 1/A Procedure Name Parameter ....................................................... 4-168
Table 4-42     ATN and FANS 1/A Altimeter Parameter ................................................................... 4-169
Table 4-43     ATN and FANS 1/A Atis Code Parameter .................................................................. 4-170
Table 4-44     ATN and FANS 1/A To/From Parameter .................................................................... 4-170
Table 4-45     ATN and FANS 1/A position report parameter ........................................................... 4-170
Table 4-46     ATN and FANS 1/A Remaining Fuel Parameter......................................................... 4-172
Table 4-47     ATN and FANS 1/A Persons on Board Parameter ...................................................... 4-173
Table 4-48     ATN and FANS 1/A Version Number Parameter ....................................................... 4-173
Table 4-49     ATN and FANS 1/A temperature data type ................................................................. 4-173
Table 4-50     ATN and FANS 1/A Vertical Change Parameter ........................................................ 4-174
Table 4-51     ATN and FANS 1/A Vertical Direction Parameter ..................................................... 4-175
Table 4-52     ATN and FANS 1/A vertical rate data type ................................................................. 4-175
Table 4-53     ATN downlink message elements with Y response attribute ...................................... 4-177
Table 4-54     ATN uplink message elements with Y response attribute ........................................... 4-199
Table 4-55     ATN UM with W/U Resp and Corresponding FANS Messages with R Resp ............ 4-212
Table 4-56     ATN and FANS 1/A CPDLC timers ........................................................................... 4-213
Table 5-1      DLIC initiation using ATN CM and FANS 1/A AFN ................................................. 5-215
Table 5-2      DLIC contact using ATN CM and FANS 1/A AFN.................................................... 5-217
Table 5-3      tr Timers....................................................................................................................... 5-220
Table 5-4      ttr Timers...................................................................................................................... 5-221
Table 5-5      tts Timers ..................................................................................................................... 5-223
Table 5-6      t-CPDLC-end Timer .................................................................................................... 5-224
Table 5-7 ACM General Requirements ................................................................................................. 5-225
Table 5-8 Requirements on UM160 NEXT DATA AUTHORITY ....................................................... 5-226
Table 5-9      Transfer of Data Communications with Open Dialogues (with change of the
               CPLDC connection) ..................................................................................................... 5-227
Table 5-10 Transfer of Data Communications with Open Dialogues (with change of the CPLDC
               connection)................................................................................................................... 5-229
Table 5-11 Sending the VCI .................................................................................................................. 5-229
Table 5-12 Acknowledging the VCI ...................................................................................................... 5-230
Table 5-13 Sending the CDA ................................................................................................................. 5-232
Table 5-14 Notifying CPDLC is OFF .................................................................................................... 5-232
Table 5-15 Notifying LACK is prohibited ............................................................................................. 5-233
Table 5-16 Enabling CPDLC ................................................................................................................. 5-234
Table 5-17 Disabling LACK .................................................................................................................. 5-236
Table 5-18 Sending LACK .................................................................................................................... 5-237
Table 5-19 Connection Establishment ................................................................................................... 5-238
Table 5-20 Connection Termination ...................................................................................................... 5-238
Table 5-21     Transfer from T-ATSU to R-ATSU with simultaneous transfer of data and
               frequency ..................................................................................................................... 5-239
Table 5-22     Transfer from a not CPDLC-equipped T-ATSU to a CPDLC-equipped R-ATSU ..... 5-242
Table 5-23     Transfer from a CPDLC-equipped T-ATSU to a not CPDLC-equipped R-ATSU
               with simultaneous transfer of data and frequency communications ............................ 5-243
Table 5-24     Transfer from T-sector to R-sector both using CPDLC ............................................... 5-245
Table 5-25 Transfer from T-ATSU to R-ATSU with independent transfer of data and frequency
               communications (by data link or voice)....................................................................... 5-247
Table 5-26     Transfer from a CPDLC-equipped T-ATSU to a non-CPDLC equipped R-ATSU
               with independent transfer of data and frequency communications .............................. 5-248
Table 5-27     C-ATSU ends CPDLC connection .............................................................................. 5-249
Table 5-28     Change of Frequency Requested by the Flight Crew .................................................. 5-249
Table 5-29     Deferred instruction to change frequency .................................................................... 5-250
Table 6-1      ATN and FANS 1/A ADS-C Contracts ....................................................................... 6-254
Table 6-2      ATN and FANS 1/A ADS uplink messages ................................................................ 6-255
Table 6-3      ATN and FANS 1/A ADS-C Demand Contract Request variables ............................. 6-257
Table 6-4      ATN and FANS 1/A ADS Periodic Contract Request variables ................................. 6-260
Table 6-5      Lateral Deviation Change Event .................................................................................. 6-265
Table 6-6      Vertical Rate Change Event ......................................................................................... 6-266
Table 6-7      Level/Altitude Range Event ......................................................................................... 6-267
Table 6-8      Way-point Event .......................................................................................................... 6-268
Table 6-9      ATN and FANS 1/A ADS downlink messages ........................................................... 6-269
Table 6-10     ATN and FANS 1/A ADS reports ............................................................................... 6-271
Table 6-11     Basic Data Block / Basic ADS Group ......................................................................... 6-274
Table 6-12     Ground Vector / Earth Reference ................................................................................ 6-274
Table 6-13     Air Vector / Air Reference ........................................................................................... 6-275
Table 6-14     Projected Profile data block / Predicted Route ............................................................ 6-275
Table 6-15     Extended Projected Profile data block / Predicted route Group .................................. 6-276
Table 6-16     Extended Projected Profile data block / Intermediate Projected Intent Group ............ 6-277
Table 6-17     ATN Ground Vector / Earth Reference ....................................................................... 6-278
Table 6-18     ATN ADS Reject / FANS 1/A Negative Ack .............................................................. 6-279
Table 6-19     ATN ATN Cancel Negative Ack / FANS 1/A Positive Ack ....................................... 6-281
Table 6-20     ATN ATN Cancel Negative Ack / FANS 1/A Negative Ack...................................... 6-281
Table 6-21     ATN and FANS 1/A ADS positive acknowledgement ................................................ 6-282
Table 6-22     ATN and FANS 1/A ADS non-compliance notification ............................................. 6-282
Table 6-23     ATN and FANS 1/A ADS variables with range and resolution .................................. 6-285
xii




      This page intentionally left blank.
1     INTRODUCTION
      This standard was developed to enable air traffic service providers (ATSPs) to
      interoperate with FANS 1/A data link equipped aircraft. The standard is intended to
      support the goal of converging oceanic and continental data link applications.

1.1   Purpose
      This document provides the interoperability requirements for an aeronautical
      telecommunication network for advanced ATS data communication services (ATN)
      ground system that provides air traffic data link services to future air navigation system
      1/A (FANS 1/A) aircraft in continental airspace.
      Note:     Based on DO-264/ED-78A, INTEROP and SPR standards provide
                recommendations intended for government organizations, conference of
                governments, or agencies having statutory jurisdiction over the use and
                provision of air traffic services supported by data communications. These
                recommendations are for use by such government organizations to enunciate
                official policy, related to such matters, in aeronautical information publications
                (AIPs), notices to airmen (NOTAMs), airplane flight manuals (AFMs), and
                operator specifications.

1.2   Scope
      This standard provides interoperability requirements for the ATN ground system to
      provide FANS 1/A aircraft data link services, as defined by the Standard for Advanced
      ATS Data Communications SPR, taking into consideration ICAO material listed in
      paragraph 1.5. The following continental data link services are considered for the
      FANS 1/A aircraft:
         Data Link Initiation Capability (DLIC),
         ATC Communications Management (ACM),
         ATC Clearance (ACL),
         ATC Microphone Check (AMC),
         Departure Clearance (DCL).
      This standard also considers the FANS 1/A aircraft emergency data communication
      capability.
      The requirements for the ATN ground system to provide FANS 1/A aircraft data link
      services applies to both the continental and oceanic and remote areas airspace. The
      advanced ATS data communications SPR includes the oceanic and remote areas data link
      services. The following oceanic and remote areas data link sercices are considered for the
      FANS 1/A aircraft:
             Data Link Initiation Capability (DLIC),
             Connection Establishment (CE),
             Connection Termination (CT),
             Transfer of Communication (TC),
1-14


              Clearance Request and Delivery (CRD),
              Information Exchange and Reporting (IER), and
              Position Reporting (PR).
       Note 1: This standard considers message elements of the CPDLC application that are
               included in the “version 2” message set as defined by the ATS INTEROP
               Standard to support advanced data link services and the FANS 1/A aircraft
               emergency data communication capability. See paragraph 4.2.8 for the uplink
               CPDLC message elements and paragraph 4.2.9 for the downlink CPDLC
               message elements considered within the scope of this document.
       Note 2: This standard considers all the message element parameters and data types of
               the CPDLC application that are included in the ATS INTEROP Standard for
               the message elements in the “version 2” message set. See paragraph 4.2.12 for
               message element parameters and data types.
       Note 3: This standard does not consider the D-TAXI as defined in the Standard for
               Advanced ATS Data Communications SPR.
       Note 4: This standard does not consider the Flight Information Service (FIS)
               application (e.g. D-OTIS).
       Note 5: The scope of this document has been determined based on the need at the time
               this standard was developed. This standard may be revised at a later time as
               experience is gained, and to expand the scope as the need arises to include, for
               example, the interoperability requirements to provide continental data link
               services to aircraft in a mixed technology environment, and the interoperability
               requirements for the FANS 1/A ground system to provide oceanic data link
               services to ATN aircraft.
       This standard addresses ADS-C by identifying the differences between the ATN and
       FANS1/A ADS-C protocols from the perspective of a Ground System willing to provide
       ADS-C services to both types of aircraft.

1.3    Relationships to other Documents
       Figure 1-1 is used to illustrate the relationships between the standards. In addition to
       ICAO material, this standard is intended for use in conjunction with the following
       RTCA/EUROCAE documents:
          DO-XXX/ED-XXX, ATS SPR (Safety and Performance Requirements Standard for
           Advanced ATS Data Communications) [ref d.], which provides the definition of the
           term, ―advanced data link services,‖ as used in this document.
          DO-258A/ED-100A, FANS 1/A Interoperability (INTEROP) Standard [ref. c],
           which provides the definition of the terms, ―FANS 1/A aircraft‖ and ―FANS 1/A
           ground system,‖ as used in this document.
          DO-XXX/ED-XXX, ATS INTEROP Standard [ref. b], which provides the
           definition of the terms, ―ATN ground system‖ and ―ATN aircraft,‖ as used in this
           document.
                                                                                                              1-15


   DO-264/ED-78A, Guidelines for the Provision and Use of Air Traffic Services
    Supported by Data Communications [ref. a], for provides guidance material for
    implementation and approval of air traffic data link services.




                                    FANS Overview
                                           Aircraft Systems


                                                                 DO-306/ED-122
                                                                   FANS 1/A
                                                                 Continental &
                                                                Oceanic Services




      DO-258A                                               DO-258A                      Interoperability &
      ED-100A                                               ED-100A                       Accommodation
      FANS ACC      ED-YYY                DO-280            DO-305                    DO-258A
        Interop     Interop               ED-110B           ED-154                    ED-100A
       Scope of
      INTEROP




                 DO/ED-YYY             DO-290/ED-120                                DO-306/ED-122
                Y3 (Over ATN)          ATN Baseline 1                                 FANS 1/A
                  Oceanic &          Continental Services                          Oceanic Services
             Continental Services
                                          Ground Systems


                              Figure 1-1 Mixed technology environments


This INTEROP standard is developed in accordance with the guidelines of
DO-264/ED-78A taking into account experience gained from the production of other
INTEROP Standards. For the ATN ground system intending to provide continental data
link services to FANS 1/A aircraft, this INTEROP standard can be used as evidence of
the interoperability assessment using a mixture of FANS 1/A and ATN Advanced
Services Data Link technologies.
This evidence provides the basis for qualifying implementations to the interoperability
requirements for elements of the CNS/ATM system, taking into consideration the
operational, safety, and performance requirements provided by the Standard for
Advanced ATS Data Communications and relevant ICAO material. It is noted that this
document alone does not satisfy all the requirements for approval and implementation.
For example, a specific implementation will need to ensure compliance with the
operational, safety, and performance requirements, provided in the Standard for
Advanced ATS Data Communications, and other requirements stated by the appropriate
regulatory authority. Applicants will have to show for approval that this INTEROP
standard is viable for the relevant SPR standards as per Sections 5 and 6 of
DO-264/ED-78A.
1-16


        Note:    When this INTEROP standard is recognized in AIPs, NOTAMs, AFMs, and
                 operator‟s specifications, such recognition and other unique characteristics
                 affecting interoperability for a specific air traffic service provision, aircraft
                 type design, or operator‟s operation can be found in the respective documents.

1.4     Description of this Document
1.4.1   Document Conventions
        The following conventions are used in this document:
        This document provides mandated criteria, i.e. the criteria are mandatory and no
        alternative may be applied to the ATN ground system providing advanced data link
        services to FANS 1/A aircraft. The mandated criteria take the form of interoperability
        requirements. Each requirement is prefaced with the nomenclature, IR-[x], where [x] is a
        sequential number. In some cases, the word ―shall‖ appears in a statement that was taken
        from another document, e.g., the ATS INTEROP Standard or ICAO Doc 9880. These
        criteria are considered mandatory by their respective reference.
        Note:    In an approval context, the “shalls” are considered a mandated criterion if the:
                  Applicant defines this standard, in conjunction with relevant INTEROP
                   standards, and any adaptation (Refer to RTCA DO-264/EUROCAE
                   ED-78A, paragraph 1.3.3), as the approval basis, and
                  Approval authority accepts this approval basis.
                 The approval basis defines the criteria for compliance. “Shoulds” are typically
                 used to describe guidelines for the processes used to produce elements of the
                 system or for meeting the mandated criterion.
        The use of the word ―should‖ is not used in this document in any particular context other
        than normal use. Text that appears in this standard that is not prefaced by IR-[x] can
        have the following meaning:
            1)   To aid in the understanding of the mandatory criterion or as guidance material;
                 and
            2)   In cases where ―No additional interoperability requirement‖ is stated in a table
                 row, no additional interoperability requirements are necessary for specific item
                 described in the row. It is noted, however, that the interoperability
                 requirements provided in the cross-referenced paragraphs for that item are
                 applicable.
        This document normally refers to the Standard for Advanced ATS Data Communications,
        the ATS Advanced Services INTEROP Standard (ATS INTEROP), and the FANS 1/A
        INTEROP Standard. In some cases, where these standards do not provide sufficient
        detail to describe the interoperability requirements, reference will be made to other
        documents. For example, in some cases direct reference is made to ICAO Doc 9880. In
        these cases, the reference is ICAO Doc 9880, as modified by the resolutions to the
        Problem Defect Reports (PDRs) provided in the ATS INTEROP Standard.
        This document refers to FANS 1/A+ as defined in DO-258A/ED-100A throughout the
        document as FANS 1/A.
                                                                                             1-17


1.4.2   Document Organization
             Section 1 – Provides an introduction to the Interoperability Requirements Standard
              for FANS-ATN systems.
             Section 2 – Provides FANS-ATN system description and operational considerations.
             Section 3 – Defines the interoperability requirements for the FANS-ATN system
              Communication requirements.
             Section 4 – Defines the interoperability requirements for the FANS-ATN system
              requirements for Data Link Applications.
             Section 5 – Defines the interoperability requirements for the FANS-ATN system
              dynamic functions/operations of Data Link services.
             Section 6 – Provides interoperability guidelines for the FANS-ATN system
              providing ADS-C based Data Link services.
             Section 7 – Addresses interoperability issues for specific services.
             Appendix A – Lists the members of RTCA SC-214/EUROCAE WG-78.
             Appendix B – Provides the history of this document and its relationship to the terms
              of reference of SC-214/WG-78.
             Appendix C – Is an improvement suggestion form for this document.
             Appendix D – Contains the traceability between DO-305 and this Standard.
1.4.3   Acronyms and Glossary of Terms
        The following acronyms and terms are consistent with those used in the
        DO-264/ED-78A, the SPR Standards, and the INTEROP Standards referenced in this
        document.
        ACRONYMS
        Acronym          Description
        ACL              ATC Clearance (service)
        ACM              ATC Communication Management (service)
        ADS              Automatic Dependent Surveillance
        AFN              ATC Facility Notification
        AMC              ATC Microphone Check (service)
        ATC              Air Traffic Control
        ATIS             Automatic Terminal Information Service
        ATN              Aeronautical Telecommunication Network
        ATS              Air Traffic Services
        ATSP             Air Traffic Service Provider
        ATSU             Air Traffic Service Unit
1-18


       Acronym        Description
       C-ATSU         Current/Controlling Air Traffic Service Unit
       CDA            Current Data Authority
       CM             Context Management
       CNS/ATM        Communication, Navigation, and Surveillance/Air Traffic Management
       CPDLC          Controller Pilot Data Link Communication
       CSP            Communication Service Provider
       D-ATIS         Data link Automatic Terminal Information Service
       DCL            Departure Clearance (service)
       DLIC           Data Link Initiation Capability (service)
       DM             Downlink Message
       DSC            Downstream Clearance (service)
       EOBT           Estimated Off Block Time
       ETD            Estimated Time of Departure
       FIS            Flight Information Service
       FMS            Fight Management System
       FOM            Figure Of Merit
       ICAO           International Civil Aviation Organization
       IMI            Imbedded Message Identifier
       INTEROP        Interoperability Requirement Standard
       Standard
       LACK           Logical Acknowledgement
       MAS            Message Assurance
       MFI            Message Format Identifier
       NDA            Next Data Authority
       OSD            Operational Service Description
       PDU            Protocol Data Unit
       R-ATSU         Receiving Air Traffic Service Unit
       SMI            Standard Message Identifier
       SPR Standard   Safety and Performance Requirements Standard
       T-ATSU         Transferring Air Traffic Service Unit
       UM             Uplink Message
       VCI            Voice Contact Information
       VHF            Very High Frequency
                                                                                      1-19


      Acronym        Description
      WILCO          Will Comply



      GLOSSARY OF TERMS
      The terms used in this document specifically for Interoperability are defined below.
      Generic terms are defined in the SPR [ref. d].


1.5   References
      The references cited in this INTEROP standard are listed below:
      a)   RTCA DO-264/EUROCAE ED-78A, Guidelines for Approval of the Provision and
           Use of Air Traffic Services Supported by Data Communications;
      b)   RTCA DO-XXX/EUROCAE ED-XXX, Interoperability Requirements Standard for
           Advanced ATS Data Communications (ATS INTEROP Standard);
      c)   RTCA DO-258A/EUROCAE ED-100A, Interoperability Requirements Standard for
           FANS1/A (FANS 1/A INTEROP Standard);
      d)   RTCA DO-XXX/EUROCAE ED-XXX, Safety and Performance Requirements
           Standard for Advanced ATS Data Communications;
      e)   ICAO Annex 2 — Rules of the Air;
      f)   ICAO Annex 10 — Aeronautical Telecommunications                 -   Volume    II
           (Communications Procedures including those with PANS status);
      g)   ICAO Annex 11 — Air Traffic Services;
      h)   ICAO Doc 4444, Edition 15 – Procedures for Air Navigation Services – Air Traffic
           Management; and
      i)   ICAO Doc 9880 – Manual of Technical Provisions for the Aeronautical
           Telecommunications Network (ATN).
2-20



2      DESCRIPTION AND OPERATIONAL CONSIDERATIONS
       This section provides a description and operational considerations for the ATN ground
       system providing FANS 1/A aircraft the advanced services data link services as defined
       in the Standard for Advanced ATS Data Communications and as limited by the scope of
       this document provided in paragraph 1.2.
       Table 2-1 presents a mapping between advanced services data link services, the ATN
       applications, and the FANS 1/A applications. The table includes references to the
       paragraphs in this document that provide interoperability requirements for the ATN
       ground system providing continental data link services to FANS 1/A aircraft.
                Table 2-1      Advanced Services data link services and applications

       Advanced Data      ATN Application     FANS 1/A           Reference
       Link Service                           Application
       DLIC               CM                  AFN                Paragraphs 4.1, 5.1
       ACM                CPDLC               CPDLC              Paragraphs 4.2, 0
       ACL                CPDLC               CPDLC              Paragraphs 4.2, 5.2.11
       AMC                CPDLC               CPDLC              Paragraphs 4.2, 5.5
       DCL                CPDLC               CPDLC              Paragraphs 4.2, 5.4



       The ATN applications for the ground system and the aircraft are defined using Context
       Management (CM) and CPDLC applications, as defined in the ATS INTEROP Standard.
       The ATS INTEROP Standard provides a mapping to the continental and oceanic data
       link services.
       The FANS 1/A applications for the ground system and the aircraft are defined in terms of
       the definition of the ATC Facility Notification (AFN) and CPDLC applications, as
       defined in the FANS 1/A INTEROP Standard. This document provides a mapping of
       these complete definitions to sequence of operations for the continental and oceanic data
       link services using either the ATN or FANS 1/A technology. There are many similarities
       even though the nomenclatures are different. Both the ATN and the FANS 1/A
       technologies use similar methods for defining dynamic operation.
                                                                                                2-21


2.1     Data Link Initiation Capability
        The data link initiation capability is accomplished using CM by ATN aircraft, and using
        AFN by the FANS 1/A aircraft.
2.1.1   ATN CM Application
        The CM application enables an ATN ground system to become aware of an aircraft‘s data
        link capabilities. The CM application does not establish communication between the
        airborne and ground peers of data link applications; this is done by the applications
        themselves. ATN aircraft provide the application name, address, and version number for
        each supported ground-initiated application. In addition, an ATN ground system requires
        that the aircraft provide flight plan association data. This information includes the airport
        departure (required), airport destination (required), and the estimated time of departure (if
        available). The ground system responds by providing the flight identification, application
        name and version number for each ground-initiated application that is used to provide a
        continental data link service.
        In addition to application name and version number, the ATN ground system provides the
        address information (for air-initiated applications) in the CM logon response.
        The ATN ground system and ATN aircraft use only the CM Logon, CM Contact, and
        CM Update operational functions and the CM Abort (user and provider) functions.
2.1.2   FANS 1/A AFN Application
        The ATS Facilities Notification (AFN) application enables an ATS ground system to
        become aware of an aircraft‘s data link capabilities. The AFN does not establish
        communications between the airborne and ground peers of data link applications; this is
        done by the applications themselves. Airborne systems provide the flight identification,
        application name and version number for each supported application. AFN consists of an
        AFN Contact and a Contact Advisory function.

2.2     CPDLC Application
        The CPDLC application enables pilots and controllers to exchange messages via data
        link. The CPDLC application includes a set of clearance/information/request message
        elements used for air traffic control.
2.2.1   ATN CPDLC Application
        The ATN CPDLC application includes the message elements defined in the Advanced
        Service SPR.
        The ATN CPDLC message elements encompass level assignments, crossing constraints,
        route modifications and clearances, speed assignments, radio frequency assignments, and
        various requests for information. The pilot is provided with the capability to respond to
        messages, to request some types of clearances and information, and to report information.
        An uplink "free text" capability is also provided to exchange information not conforming
        to defined formats and to append information explaining error reasons. A downlink "free
        text" capability is also provided to only to append information explaining error reasons.
2-22


2.2.2   FANS 1/A CPDLC Application
        The FANS 1/A INTEROP Standard specifies a set of message elements, similar to the
        defined CPDLC message elements set in Doc 4444. FANS 1/A CPDLC message
        elements encompass altitude assignments, crossing constraints, lateral offset deviations,
        route modifications and clearances, speed assignments, radio frequency assignments, and
        various requests for information. The pilot is provided with the capability to respond to
        messages, to request clearances and information, to report information, and to
        declare/cancel an emergency. A "free text" capability is also provided to exchange
        information not conforming to defined formats.

2.3     ADS-C Application Description
        This appendix provides guidance for determining the interoperability requirements for the
        ATN ground system to use the FANS 1/A+ aircraft Automatic Dependent Surveillance
        (ADS-C) application.
        The ADS-C application is an air-ground ATS data link application, in which airborne
        systems transmit automatically data derived from onboard navigation and flight
        management systems in response to ground-initiated contract request. As a minimum, the
        data include three-dimensional position, the corresponding estimated time for the position
        data, and a Figure of Merit (FOM).
2.3.1   ATN ADS-C Application
        As defined in document the ATN INTEROP Standard, three contract types may be used:
        demand, event and periodic.
        The ADS report contains basic information (three-dimensional position, the
        corresponding estimated time for the position data, and a Figure of Merit). Additional
        data can be included: aircraft address and identification, air and ground vectors,
        projected and extended projected profiles, meteorological data, emergency/urgency
        status.
        All three contract types can be used in the ATN INTEROP Standard.
2.3.2   FANS 1/A ADS Application
        The FANS 1/A INTEROP Standard defines three contract types: Event, Periodic and
        Demand.
        FANS 1/A aircraft use two contract tag types: event and periodic. The FANS 1/A
        demand contract is a periodic contract with reporting rate set to 0.
        As a minimum, the ADS report consists of the basic group (three-dimensional position,
        the corresponding estimated time for the position data, and a Figure of Merit). Additional
        data can be included: flight and airframe identification, ground and air vectors,
        meteorological data, predicted route, fixed and intermediaite projected intent.
                                                                                        3-23



3   COMMUNICATION REQUIREMENTS
    This section provides interoperability requirements for the FANS 1/A communication
    protocols and application addressing. These requirements are additional to those
    provided in the FANS 1/A INTEROP Standard or the ATS INTEROP Standard either
    specifically or by reference.
    IR-1The ATN ground system shall support ACARS based Air-Ground communication
    protocols, as per the FANS 1/A Interoperability Standard.
    IR-2The ATN ground system shall keep track of the SMI used and apply the
    corresponding uplink SMI (Ref [f]) for all uplinks to the FANS 1/A aircraft as shown in
    Table 3-1.
    IR-3When the FANS 1/A aircraft does not use an MFI in downlink messages, the ATN
    ground system shall use the appropriate uplink SMI (Ref [f]) for each application as
    given in Table 3-1.
    IR-4When the FANS 1/A aircraft uses an MFI in downlink messages, the ATN ground
    system shall use the appropriate uplink SMI (Ref [f])/MFI for each uplink message as
    given in Table 3-2 and Table 3-3.


    The following notes apply to Table 3-1, Table 3-2, Table 3-3.
    Note 1: For SMI uplink, „x‟ may take the value D, L, R, or 3.
    Note 2: For SMI downlink, „y‟ may take the value L, R, or 3.
    Note 3: For label/sub-label, „z‟ may take the value 1, 2, or 3.
    Note 4: The SMI of the AFN Contact (FN_CON) message can be used to determine the
            appropriate addressing method for a particular aircraft.
    Note 5: ACARS uplink messages use a combination of label and sub-label to identify
            the avionics device to which the message is being sent. The communication
            service provider converts the Standard Message Identifier (SMI) contained in
            the ground-ground message to the appropriate label/sub-label (and MFI)
            combination to allow the avionics to route the message to the appropriate
            airborne end-system.
3-24


          Table 3-1     SMI Downlink and Uplink relationship for FANS 1/A AFN, and
                                                 CPDLC

       End System       AFN SMI                      CPDLC SMI                ADS SMI
       Type
                        Uplink       Downlink        Uplink       Downlink    Uplink    Downlink


       ACARS            AFU          AFD             ATC          ATC         RAR       PAR
       management
       function (MU)
       Flight           FMx          FMy             FMx          FMy         FMx       FMy
       management
       system



          Table 3-2     Valid label/sub-label/MFI/IMI/SMI combinations for FANS 1/A
                                                CPDLC uplink

       End System       CPDLC                                     ADS
       Type
                        Label/        MFI         IMI      SMI    Label/      MFI      IMI    SMI
                        Sub-label                                 Sub-label

       ACARS            AA            (none)      AT1      ATC    A6          (none)   ADS    RAR
       management                                 CR1
       function (MU)                              DR1
                                                  CC1
       Flight           H1/Mz         AA          AT1      FMx    H1/Mz       A6       ADS    FMx
       management                                 CR1
       system                                     DR1



       Table 3-3    Valid label/sub-label/MFI/IMI/SMI combinations for FANS 1/A AFN
                    uplink

        End System           AFN
        Type
                             Label/         MFI         IMI      SMI
                             Sub-label

        ACARS                A0             (none)      AFN      AFU
        management
        function (MU)
        Flight               H1/MD          A0          AFN      FMx
        management
        system
                                                                                                  4-25



4              REQUIREMENTS FOR DATA LINK APPLICATIONS
               This section provides the interoperability requirements to enable FANS 1/A applications
               on aircraft to use data link services provided by the ATN ground system.
               IR-5 The ATN ground system shall implement an ACARS compatible system (ACS) that
               will enable the ACARS network to support ATS applications (ACS provides
               formatting/addressing, cyclic redundancy check (CRC) integrity check and bit-to-
               hexadecimal conversion process), as per the FANS 1/A Interoperability Standard.

4.1            CM/AFN Application Requirements
4.1.1          ATN CM and FANS 1/A AFN Primitives
               Table 4-1 lists the ATN CM primitives along with the comparable FANS 1/A AFN
               primitives.


                               Table 4-1   ATN CM and FANS 1/A AFN primitives

        ATN CM Primitives       FANS 1/A AFN Primitives         Interoperability Requirement

        CM Logon Request        AFN Contact                     None.

        CM Logon Response       AFN Acknowledge                 None.

        CM Update               No equivalent.                  The ATN ground system cannot issue an
                                                                update to the FANS 1/A aircraft.

        CM Contact Request      AFN Contact Advisory            None.

        CM Contact Response     AFN Response + AFN Complete     IR-6 When expecting a CM Contact
                                                                response, the ATN ground system
                                                                shall be able to process the sequence
                                                                of the reception of AFN response and
                                                                AFN Complete.
                                                                Reception of the AFN Response followed
                                                                by AFN Complete is functionally
                                                                equivalent to the CM Contact Response.
                                                                When the AFN Complete is received, a
                                                                subsequent AFN Response can be
                                                                ignored.

        CM Abort                No equivalent.                  The ATN ground system cannot issue an
                                                                abort to the FANS 1/A aircraft. Both
                                                                sides may time-out.
4-26


4.1.2   ATN and FANS 1/A Primitive Parameters
        Table 4-2 maps ATN CM primitive parameters to FANS 1/A AFN primitive parameters.


         Table 4-2   Mapping of parameters into ATN CM primitives and FANS 1/A AFN
                                                 primitives

        ATN CM Primitive            FANS 1/A AFN                  Interoperability Requirement
        Parameters                  Primitives Parameters
        CMLogonRequest:             AFN Message header:           IR-7 The ATN ground system
         Facility Designation         Flight ID                   shall use the Flight ID and the
         Aircraft Address (24-bit     Aircraft Registration       Aircraft Registration to perform
         address)                     24-bit aircraft address     the flight plan association.
         Logon Request                (optional)                  The FANS 1/A aircraft does not
         Aircraft Flight            Note: Some aircraft may       provide the Departure Airport and
         Identification             provide the 24-bit aircraft   the Destination Airport used for the
                                    address.                      flight plan association when required.
         CM Long TSAP(Aircraft
         CM application address)      Timestamp                   The ATN ground system does not
                                                                  use the class of communication.
         Ground-initiated           AFN Contact:
         application                                              The FANS 1/A aircraft does not
                                      Aircraft Position           provide the Air-only-initiated
         Information (for all         Active Flag                 application information.
         supported applications):
                                      Application Name (for
           Application name,          all supported
           Application address,       applications)
           Application version        Version Number (for all
           number                     supported applications)
         Air-only-initiated
         application
         Information (for all
         supported applications):
           Application name,
           Application version
           number
         Facility Designation
         (optional)
         Departure Airport
         Destination Airport
         ETD (optional)
         Class of Communication
         (optional)
                                                                                            4-27


ATN CM Primitive             FANS 1/A AFN                  Interoperability Requirement
Parameters                   Primitives Parameters
CMLogonResponse              AFN Message header:           IR-8 The ATN ground system
(successful):                  Flight ID                   shall generate the AFN
List of Application            Aircraft Registration       acknowledge containing an
Information:                                               overall reason code fixed to (0) as
                               24-bit aircraft address
Application name               (optional)                  a successful CM logon response.
Application version          Note: Some aircraft may       The airborne system uses facility
number                       provide the 24-bit aircraft   designation or the ATC centre
Application address          address.                      address to associate the AFN
                                                           acknowledge.
Note: Application address      Timestamp
is only given for air-                                     The application version number
                             AFN Acknowledge
initiated applications                                     cannot be provided in the AFN
                             (positive):
                                                           acknowledge. A positive AFN
                               Overall Reason Code (0)     Acknowledgement is only sent when
                               Facility Designation        the ground system can support the
                             Optional variables:           application version number given in
                                                           the AFN Contact.
                               Application Name(s)
                                                           See paragraph 4.1.3 for use of name
                               Reason Code                 variable.
                             Originating ATC Centre
                             Address (optional)
Or                           Or
CMLogonResponse (not        AFN Message header:            IR-9 The ATN ground system
successful):                  Flight ID                    shall generate the AFN
Note: In this case, the ATN   Aircraft Registration        acknowledge containing an
ground system does not                                     overall reason code fixed to (non-
                              24-bit aircraft address
provide ground                                             0) as an unsuccessful CM logon
                              (optional)
application information.                                   response.
                            Note: Some aircraft may
                            provide the 24-bit aircraft    In this case, the ATN ground system
                            address.                       does not provide application name
                                                           variables in a negative AFN
                              Timestamp
                                                           acknowledge.
                            AFN Acknowledge
                            (negative)
                              Overall Reason Code
                              (non 0)
                              Facility Designation
                            Optional variables:
                              Application Name(s)
                              Reason Code
                              Originating ATC Centre
                              Address
4-28


       ATN CM Primitive             FANS 1/A AFN                  Interoperability Requirement
       Parameters                   Primitives Parameters
       CMContactRequest:            AFN Message header:           IR-10  When requesting a
        Aircraft Address              Flight ID                   CMContactRequest, the ATN
        Facility Designation          Aircraft Registration       ground system shall send the
        Facility Designation (the     24-bit aircraft address     AFN Contact Advisory.
        next centre to be             (optional)                  See paragraph 4.1.3 for use of
        contacted)                  Note: Some aircraft may       variables.
        address (CM application     provide the 24-bit aircraft
        address representing the    address.
        next ATC centre to be         Timestamp
        contacted)
                                    AFN Contact Advisory:
        Class of
                                      Next Centre Address
        Communications
        (optional)                    Active Flag

       CMContactResponse            Positive indication:          IR-11    The ATN ground system
       (successful):                AFN Message header:           shall process the reception of an
       - Response (0)                 Flight ID                   AFN Complete (regardless of the
                                      Aircraft Registration       reason code value) as the
                                                                  reception of a successful CM
                                      24-bit aircraft address
                                      (optional)
                                                                  Contact Response.
                                                                  The ATN ground system may ignore
                                    Note: Some aircraft may
                                                                  the reception of positive AFN
                                    provide the 24-bit aircraft
                                                                  Response.
                                    address.
                                                                  In the FANS 1/A INTEROP
                                      Timestamp
                                                                  Standard, the AFN Complete
                                    AFN response                  indicates the result of the AFN
                                      Reason Code (0)             Logon with the next Centre. In the
                                                                  ATS INTEROP Standard, a
                                                                  successful CM Contact Response
                                    And:
                                                                  indicates that the CM Logon has
                                                                  been performed without any
                                    AFN Message header:           information on the logon response.
                                      Flight ID                   The ATN ground system may ignore
                                      Aircraft Registration       the next Centre address parameter
                                                                  contained in the AFN Complete
                                      24-bit aircraft address
                                                                  message.
                                      (optional)
                                    Note: Some aircraft may
                                    provide the 24-bit aircraft
                                    address.
                                      Timestamp
                                    AFN Complete
                                      Next Centre Address
                                      Reason Code
                                                                                                  4-29


        ATN CM Primitive             FANS 1/A AFN                  Interoperability Requirement
        Parameters                   Primitives Parameters
        CMContactResponse            Negative indication:          IR-12    The ATN ground system
        (unsuccessful):              AFN Message header:           shall process the reception of a
        - Response (1)                 Flight ID                   negative AFN Response like the
                                       Aircraft Registration       reception of a negative CM
                                                                   Contact Response.
                                       24-bit aircraft address
                                       (optional)
                                     Note: Some aircraft may
                                     provide the 24-bit aircraft
                                     address.
                                       Timestamp
                                     AFN response
                                       Reason Code (non-0)



4.1.3   ATN CM and FANS 1/A AFN Variables
        Table 4-3 maps the ATN CM variables to the comparable FANS 1/A AFN variables.


                         Table 4-3      ATN CM and FANS 1/A AFN variables

        ATN CM Variables             FANS 1/A AFN                  Interoperability Requirement
                                     Variables
        Address (LongTSAP of         Next Centre Address           IR-13    The ATN ground system
        Next Centre)                                               shall map the CM-address of the
                                                                   next ATC Centre to the next ATC
                                                                   Centre Address.
                                                                   IR-14    The ATN ground system
                                                                   shall process the address as the
                                                                   Next Centre address.
        No equivalent.               Originating ATC Centre        IR-15    When providing the
                                     address                       originating ATC centre address in
                                                                   the positive AFN
                                                                   acknowledgement, the ATN
                                                                   ground system shall set it as the
                                                                   same value as the ATC centre
                                                                   address received in the ACARS
                                                                   header of the AFN Contact.
4-30


       ATN CM Variables            FANS 1/A AFN              Interoperability Requirement
                                   Variables
       AP Address                  No equivalent.            None.
                                                             Information is available in the
                                                             ACARS Header.
                                                             The Aircraft Registration and the
                                                             SMI (representing MFI or label) and
                                                             IMI serve as the application address
                                                             for all applications (i.e. AFN, ADS
                                                             and CPDLC).
       AE Qualifier                AP_name                   IR-16    The ATN ground system
       (0)                         ADS                       shall process the ADS application
       (22)                        ATC                       name as an AE qualifier (0).
                                                             IR-17    The ATN ground system
                                                             shall process the ATC application
                                                             name as an AE qualifier (22).
       AP Version                  Vers                      None.
       Aircraft Address (24-bit    24-bit aircraft address   None.
       ICAO aircraft address)      (optional)                Some FANS 1/A aircraft may
                                                             provide the 24-bit aircraft address.
                                                             The 24-bit aircraft address may be
                                                             used locally, but not for FANS 1/A
                                                             aircraft addressing.
       AircraftFlightIdentification Flight ID                None.
       No equivalent.              Active Flag               IR-18    The ATN ground system
                                                             shall set the active flag to 1.
                                                             Active Flag is sent, but not used.
       No equivalent.              Aircraft Position         The ATN ground system may use
                                                             locally the aircraft position.
       Class of Communications     No equivalent.            None.
       No equivalent.              Overall Reason Code       See Table 4-2.
       Response                    Reason Code               See Table 4-2.
       DepartureAirport            No equivalent.            None.
       DepartureTime               No equivalent.            None.
                                                                                      4-31


ATN CM Variables          FANS 1/A AFN              Interoperability Requirement
                          Variables
DestinationAirport        No equivalent.            None.
FacilityDesignation (in the ICAO Facility Designation IR-19   The ATN ground system
logon request header) (4 to (4 Character ICAO Code) shall use the facility designation
8 Character ICAO Code)                                only with size 4 using the first
                                                    four letters.
FacilityDesignation       No equivalent.            IR-20   The ATN ground system
(Optional in the logon                              shall omit the Facility
request primitive)                                  Designation in the
                                                    CMLogonRequest.
LongTSAP                  No equivalent.            None.
                                                    Information is available in the
                                                    ACARS Header and message
                                                    Header.
                                                    The Aircraft Registration and the
                                                    SMI (representing MFI or label) and
                                                    IMI serve as the application address
                                                    for all applications (i.e. AFN, ADS
                                                    and CPDLC).
No equivalent.            Timestamp                 The ATN ground system may use
                                                    locally the timestamp.
4-32


4.1.4   Timers
        Table 4-4 lists the ATN CM timer along with the comparable FANS 1/A AFN timer.


                            Table 4-4      ATN CM and FANS 1/A AFN timers

        ATN CM Timer                    FANS 1/A AFN Timer              Interoperability Requirement

        tts Termination timer           ATST1 is used by the            None.
        (sender) used to indicate the   FANS 1/A aircraft to detect     The ATST1 timer is an airborne
        absence of a CM Logon           the absence of the              timer and is functionally
        response from the ground        AFN_ACK in response to          equivalent to the ‗tts‘ timer.
        system in an acceptable         an AFN Contact.
                                                                        ATST1 timer is set at 10 minutes,
        period of time
                                                                        being less stringent for the
        When the tts is                                                 FANS 1/A aircraft than for the
        implemented, the value for                                      ATN aircraft.
        the timer shall be greater
        than or equal to 60 sec.

        tts Termination timer           ATST2 is used to detect the     IR-21    When using the ‗tts‘
        (sender) used to indicate the   absence of the AFN              timer, the ATN ground system
        absence of a CM Contact         Response in response to an      shall set the value for ‗tts‘ as
        response from the aircraft in   AFN Contact Advisory.           specified in the ATS
        an acceptable period of time    When it is used, it should be
                                                                        INTEROP Standard, paragraph
        When the tts is                 set to 5mn.
                                                                        4.1.1.2.2.
        implemented, the value for      ATST3 is used to detect the
        the timer shall be greater      absence of the AFN              The ‗tts‘ timer is functionally
        than or equal to 120 sec.       Complete in response to an      equivalent to ATST2+ATST3.
                                        AFN Contact Advisory. It is     For domestic airspace, the ATN
                                        set on the reception of an      value is used.
                                        AFN Response positive.
                                        When it is used, it should be
                                        set to 15mn.
                                                                                                                    4-33



4.2                 CPDLC Application Requirements
                    IR-22    The ATN ground system shall have the capability to encode and decode message
                    elements addressed to or received from the FANS 1/A aircraft following the ASN.1
                    definitions as given in the ATS INTEROP Standard.
4.2.1               Time, Timestamp and Message Latency
        4.2.1.1             Time
                    Table 4-5 presents the operational requirement and comparable FANS 1/A CPDLC
                    requirements for time.


                             Table 4-5    ATN and FANS 1/A CPDLC requirements for time source

           ATN                            FANS 1/A                             Interoperability Requirement
           CPC-OR-1: The time used        4.6.3.3 b). All downlink CPDLC       IR-23    The ATN ground system
           for ATN messages shall be      messages shall contain the           shall only accept the FANS 1/A
           in accordance with the         timestamp which indicates the        aircraft that follows the requirements
           requirements of ICAO           originators send time and should     of ICAO-Annex 2. (See the Note in
           Annex 2 for the aircraft and   use a time source which is
                                                                               column 2).
           Annex 11 for the ATS           referenced to UTC.
           provider.                      4.6.3.3 c). All uplink messages      IR-24    The ATN ground system
                                          shall contain a timestamp which      shall comply with the OSD
                                          indicates the originator send time   requirement CPC-OR-1.
                                          to an accuracy of +/- one second,    Before providing data link services to the
                                          and shall use a time source which    FANS 1/A aircraft, the ATS provider has
                                          is synchronized to UTC within        to confirm with the operator that the
                                          one second.                          aircraft(s) conform to the ICAO-Annex 2
                                          Note: In the FANS 1/A                requirement.
                                          INTEROP Standard, the                Uplink CPDLC messages are
                                          timestamp synchronization to         functionally identical.
                                          UTC is a recommendation, but at
                                          the writing of this document it is
                                          assumed that the majority of
                                          aircraft are compliant to ICAO
                                          Annex 2.
4-34


       4.2.1.2          Timestamp Generation
                  Table 4-6 presents the operational requirement and comparable FANS 1/A CPDLC
                  requirements for timestamp generation.


                    Table 4-6     ATN and FANS 1/A CPDLC requirements for timestamp generation

          ATN                                  FANS 1/A                       Interoperability Requirement
          CPC-OR-46: The timestamp shall        No requirement contained in   None.
          indicate the time that the message is the FANS 1/A INTEROP          ATN ground system implementers
          released by the controller, by the    Standard.                     must be aware that the FANS 1/A
          pilot, or by a system without human                                 aircraft may generate the
          intervention, for onward                                            timestamp according to local
          transmission.                                                       implementation.
          Note 1: When the pilot or controller
          sends a CPDLC message, the
          timestamp will be the time at which
          he/she authorizes the transmission of
          the CPDLC message (e.g. by
          pressing an “ENTER” key or by
          activation of a message release
          function in an interactive display).
          Note 2: For CPDLC messages
          generated by a system without
          human intervention, the timestamp
          will be the time when the CPDLC
          application releases the completed
          CPDLC message to the
          communications system.
                                                                                                          4-35


4.2.1.3          Message Latency
           Table 4-7 presents the ATN and comparable FANS 1/A CPDLC requirements for
           message latency.
                 Table 4-7    ATN and FANS 1/A CPDLC requirements for message latency

   ATN                                          FANS 1/A                       Interoperability Requirement
   Aircraft requirements                        Aircraft requirements          IR-25   The ATN ground
                                                4.6.6.9 Message Latency        system shall decode
                                                a. When a CPDLC                ErrorInformation value (10)
                                                timestamp is present in a      + FREETEXT from the
                                                received message, and the      FANS 1/A aircraft, which is
                                                difference between the         represented by
                                                timestamp and UTC              ErrorInformation (3) +FREE
                                                exceeds the ―late message‖     TEXT in the ATS INTEROP
                                                value, the aircraft shall      Standard.
                                                either provide an applicable
                                                notification to the aircrew    When processing the Urgency
                                                or discard the message and     and/or Alert attributes, the ATN
                                                notify the originator with     ground system must take care
                                                an ERROR + FREE TEXT           of the differences between the
                                                message. The                   FANS 1/A INTEROP Standard
                                                [errorinformation]             and ATS INTEROP Standard
                                                contained in such an           definitions; DM62 (URG U,
                                                ERROR message shall be         Alert L) in the FANS 1/A
                                                assigned a value of ―          aircraft and DM67 (no attribute)
                                                invalidData‖ (10).             in the ATN ground system. See
                                                                               also paragraph 4.2.4 about
                                                                               message attributes.
   CPC-IR-23: When the Aircraft system          b. In aircraft that reject a   None.
   discards a received CPDLC message            late uplink message and
   because it contains a timestamp indicating   send an ERROR response,
   a difference between the timestamp and       the avionics shall add free
   reception time of more than the latency      text DM67 containing the
   value, it shall send a CPDLC downlink        text ―UPLINK DELAYED
   message containing the concatenation of      IN NETWORK AND
   message element DM62 (ERROR (error           REJECTED - RESEND
   information)) with the choice (2) followed   OR CONTACT BY
   by message element DM98 (UPLINK              VOICE― to the ERROR
   DELAYED IN NETWORK AND                       response.
   REJECTED. RESEND OR CONTACT BY
   VOICE).
4-36


       ATN                                           FANS 1/A                         Interoperability Requirement
       CPC-IR-19: If the ATSU or Aircraft            No equivalent.                   None.
       System receives a message containing a        c. Prior to the establishment    The FANS 1/A aircraft does not
       timestamp that indicates a future time        of the first CPDLC               detect timestamps with a value
       greater than 2 seconds from the current       connection during any            greater than 2 seconds from the
       time, the the ATSU or Aircraft system shall   flight, the ―late message‖       reception time.
       abort the CPDLC connection with reason        value shall be set to a
       [time-out-of-synchronisation].                default value or the latency
                                                     check shall be cancelled.
                                                     The message latency value
                                                     shall be cancelled or reset
                                                     to the default value no later
                                                     than at the end of the flight,
                                                     and may be cancelled or
                                                     reset at the end of any
                                                     CPDLC connection.
                                                     The aircraft shall provide a
                                                     capability to modify the
                                                     ―late message‖ value
                                                     during flight.
                                                     Note: This statement is not
                                                     intended to preclude
                                                     automated reset of the
                                                     “late message” value,
                                                     based on e.g. ground
                                                     uplinks or database values.
                                                     d. (see ground
                                                     requirements)
       Ground Requirements                           Ground requirements              IR-26   The ATN ground
       CPC-IR 24: When the ATSU System               d. When a ground system          system shall generate the
       discards a received CPDLC message             enables a CPDLC                  FANS 1/A UM169 message
       because it contains a timestamp indicating    connection with an aircraft,     element [SET MAX
       a difference between the timestamp and        the ground system shall          UPLINK DELAY VALUE
       reception time of more than the ground        uplink CPDLC message             TO ―xx‖ SEC].
       latency value, it shall send a CPDLC uplink   UM169[SET MAX
       message containing the concatenation of       UPLINK DELAY VALUE               ―xx‖ is set to the value specified
       message element UM159 (ERROR (error           TO XXX SEC], XXX                 in the SPR.
       information)) with the choice (2) followed    being the ―late message‖         Setting and handling of the
       by message element UM183 (DOWNLINK            value expressed in seconds.      timers and handling of the
       DELAYED AND REJECTED RESEND                   Note 1: “Enabling” a             Response are a local matter.
       OR CONTACT BY VOICE).                         CPDLC connection refers          The ATN ground system sets
       CPC-IR 19 If the ATSU or Aircraft System      to the point at which a          the max uplink delay value as
       receives a message containing a timestamp     ground system makes the          specified in the SPR.
       that indicates a future time greater than 2   CPDLC connection                 The free text message element
       seconds from the current time, the the        available for operational        UM183 is not in the FANS 1/A
       ATSU or Aircraft system shall abort the       exchanges. It is based on        message set. See paragraph
       CPDLC connection with reason [time-out-       automated restrictions in        4.2.8 for use of free text
       of-synchronisation].                          the ATSU that ensure             message element.
                                                     operational CPDLC
                                                             4-37


ATN   FANS 1/A                       Interoperability Requirement
      messages are only sent to
      an aircraft under the
      operational control of one
      of its ATC sectors. The
      UM169 message needs to
      be sent after the
      “enabling” point to reduce
      the risk that the message is
      routinely rejected by the
      avionics because the
      transmitting ground system
      is not yet the CDA for that
      aircraft at the time the
      system is designed to send
      it.
      Note 2: Uplink of the
      um169 late value
      confirmation message
      needs to take place any
      time a new link is
      „enabled‟. The ground
      system therefore needs to
      include the uplink in the
      case of reconnection logic
      for re-establishing lost
      CPDLC connections, etc.
      Note 3: Treatment of the
      subsequent DM3
      („ROGER‟) response to the
      UM169 is a local matter.
4.2.2           ATN CPDLC Constructs and FANS 1/A ACARS IMIs
                Table 4-8 presents the ATN CPDLC constructs and comparable FANS 1/A ACARS
                IMIs.


                     Table 4-8    ATN CPDLC constructs and FANS 1/A CPDLC ACARS IMIs

        ATN Constructs                 FANS 1/A ACARS IMIs             Interoperability Requirement
        Ground Initiated CPDLC-start   IMI CR1 UM163                   IR-27    When establishing a CPDLC
        service (req/ind) (no UM       [icaofacilitydesignation]       connection, the ATN ground system
        included)                      [tp4table]                      shall send an IMI CR1 including
        CPC-IR-95 The ATSU System      From 4.6.2.1                    FANS 1/A message element UM163.
        shall not include a CPDLC      Note 1: Only the ATS            The ASN1 definition of UM163 is different
        Message when invoking the      provider system can initiate    in the ATS INTEROP Standard and the
        CPDLC-start service request    connections.                    FANS 1/A INTEROP Standard. See this
        primit                                                         document, paragraph 4.2, for general
                                       Note 2: A valid tp4table must
                                       be supplied although            requirements.
                                       ATCComm ignores it.             The value for the [tp4table] parameter should
                                                                       be set to enumerated 0 or 1 by the ATN
                                                                       ground system.
                                                                       The FANS 1/A aircraft will reject the
                                                                       connection initiation if no or another
                                                                       message element other than UM163 is
                                                                       contained.
        Ground Initiated CPDLC-start   IMI CC1 DM73                    IR-28    The ATN ground system shall
        service (rsp/cnf)              [versionnumber]                 convert IMI CC1 into a positive
                                                                       CPDLC-start confirmirmation.
                                       Or                              IR-29    The ATN ground system shall
                                                                       not provide data link services to
                                       IMI DR1 DM62 (optional)         FANS 1/A aircraft responding with a
                                                                       version number other than 1.
                                       Or                              IR-30    The ATN ground system shall
                                                                       convert the IMI DR1 received in
                                                                       response to the IMI CR1 into a CPDLC-
                                       IMI DR1 DM64 (optional)
                                                                       start confirmation (rejected), except if
                                                                       the DM62 error information, received
                                                                       with DR1, contains the value (invalid
                                                                       data) or (insufficient data).
                                                                       IR-31    When receiving an IMI DR1
                                                                       containing the message element DM64
                                                                       in response to the IMI CR1, the ATN
                                                                       ground system shall convert the
                                                                       FANS 1/A response into a CPDLC-start
                                                                       Confirmation (rejected), setting the
                                                                       Reject Reason parameter to a CPDLC
                                                                       message with the ATN message element
                                                                       DM107 (NOT AUTHORISED NEXT
                                                                                                     4-39



ATN Constructs                   FANS 1/A ACARS IMIs             Interoperability Requirement
                                                                 DATA AUTHORITY).
                                                                 The FANS 1/A aircraft sends the same
                                                                 version number 1.
                                                                 When it has no CPDLC connection
                                                                 established yet, the FANS 1/A aircraft
                                                                 rejects a valid CPDLC connection request if
                                                                 no successful logon has been done before
                                                                 with the ground system having sent the
                                                                 CPDLC connection request.
                                                                 When it has a CPDLC connection
                                                                 established, the FANS 1/A aircraft rejects a
                                                                 valid CPDLC connection request, if it is not
                                                                 coming from the ground system indicated to
                                                                 be the R-ATSU.
CPDLC-message service (any       IMI AT1 (any DM or UM)          IR-32    If no connection is established or
UM or DM)                        4.6.2.1.1 If no connection is   in the process of being established, upon
                                 established or in the process   receipt of any CPDLC message, the
                                 of being established, upon      ATN ground system shall ignore that
                                 receipt of any CPDLC            message.
                                 message, the ATS Provider
                                 system shall ignore that        IR-33    If a "Connect Request"
                                 message.                        (IMI=CR1) is pending, upon receipt of a
                                 4.6.2.1.2 If a "Connect
                                                                 message other than the corresponding
                                 Request" (IMI=CR1) is           "Connect Confirm" (IMI=CC1) or a
                                 pending, upon receipt of a      ―Disconnect Request‖ (IMI=DR1), the
                                 message other than the          ATN ground system shall ignore that
                                 corresponding "Connect          message.
                                 Confirm" (IMI=CC1) or a
                                 ―Disconnect Request‖
                                 (IMI=DR1), the ATS
                                 Provider system shall ignore
                                 that message.
CPDLC-end service (req/ind)      IMI AT1 UM161 END               IR-34    When ending a CPDLC
(UM optional)                    SERVICE + UM (optional)         connection, the ATN ground system
Note: As per paragraph 4.3, UM   Note: See requirements in       shall send IMI AT1 UM161 END
message concatenated with        4.6.2.2.1 and 4.6.2.2.2.        SERVICE + UM (optional) to the
CPDLC-end service in several                                     FANS 1/A aircraft.
ACM cases.
                                                                 For sending to the FANS 1/A aircraft, these
                                                                 optional message elements will be
                                                                 concatenated with UM161 message element.
CPDLC-end service (rsp/cnf)    IMI DR1                           IR-35   When the IMI DR1 is received
(UM optional)                  Note: See requirements in         as response to single element message
Note: As per paragraph 4.3, UM 4.6.2.2.1 and 4.6.2.2.2.          containing UM161, the ATN ground
message concatenated with                                        system shall process it as a CPDLC-end-
CPDLC-end service in several                                     confirmation (accepted).
4-40


       ATN Constructs   FANS 1/A ACARS IMIs   Interoperability Requirement
       ACM cases.                             IR-36    Upon receipt of DM62 in the
                                              Disconnect Request, the ATN ground
                                              system shall not present the message to
                                              controllers.
                                              IR-37    When the IMI DR1 is received
                                              as a response to an uplink message,
                                              containing UM161 message element, if a
                                              DM62 is included in the Disconnect
                                              Request, the ATN ground system shall
                                              ignore the [errorinformation].
                                              IR-38    When the IMI DR1 is received
                                              as response to a multiple-element
                                              message containing UM161 and any
                                              UM, the ATN ground system shall
                                              process it as a CPDLC-end-confirmation
                                              (accepted).
                                              IR-39    The ATN ground system shall
                                              process the operational response(s)
                                              received prior to the IMI DR1.
                                              IR-40    When a DM1 UNABLE is
                                              received prior to the IMI DR1 in
                                              response to a multiple-element message
                                              containing UM161 and any UM, the
                                              ATN ground system shall process it as a
                                              CPDLC-end-confirmation (rejected) .
                                              This results in continued capability to
                                              exchange operational messages with the T-
                                              ATSU.
                                              The ATN ground system should not process
                                              the IMI DR1 before the reception of the
                                              operational response(s) unless the dialogue
                                              timers expire.
                                              In case that there are pending uplink
                                              messages (see definition of pending uplink
                                              message in the FANS 1/A INTEROP
                                              Standard, paragraph 4.6.6.4), when the
                                              aircraft receives the end service message, the
                                              FANS 1/A aircraft generates a disconnect
                                              request containing DM62, regardless of
                                              whether or not the END SERVICE is
                                              concatenated with another message element.
                                              If negative answer is selected by the crew to
                                              the concatenated UM161 and any UM, no
                                              subsequent IMI DR1 will be sent by the
                                              FANS 1/A aircraft.
                                              See paragraph 0 for the operational
                                                                          4-41



ATN Constructs   FANS 1/A ACARS IMIs   Interoperability Requirement
                                       response(s) to the concatenations of UM161
                                       and any UM.
4-42


       ATN Constructs                  FANS 1/A ACARS IMIs            Interoperability Requirement
       Ground CPDLC-user-abort         4.6.2.2.2                      IR-41   As per the FANS 1/A INTEROP
       service (CPDLCUserAbort)        a) If an END SERVICE           Standard, paragraph 4.6.2.2.2, when
       Including commanded             (uM161) message element is     aborting a CPDLC connection, the ATN
       termination                     received as a component of a   ground system shall send IMI AT1
                                       multiple element message       UM161 END SERVICE concatenated
                                       and a WILCO (dM0)              with UM159 (ERROR) with error
                                       response is not a valid        information set to ‗commanded-
       CPC-IR 3 Aborts that result
                                       response for that message,
       from a pilot or controller
                                       send "Disconnect Request"
                                                                      termination‘.
       explicit action shall use the                                  IR-42   When DM62 is received in the
                                       (IMI=DR1) containing a
       abort reason ―commanded
                                       message with the ERROR         Disconnect Request, the ATN ground
       termination‖.
                                       [errorinformation] (dM62)      system shall not present the message to
       CPC-IR 6 When the Controller message element with the          controllers.
       initiates termination, the ATSU [endServiceWithNoValidRes
       System shall transmit a CPDLC- ponse] value for all            IR-43   When the IMI DR1 and included
       user-abort request using the    connections and discard the    DM62 is received as response to UM161
       ―commanded-termination‖ value message.                         +UM169, the ATN ground system shall
       (5) in the Reason parameter
                                       Note: This procedure should    ignore the message.
                                       be used by the current ATC     As per the FANS 1/A INTEROP Standard,
                                       Data Authority to invoke an    paragraph 4.6.2.2.2, such a combination is
                                       abnormal connection            processed as an abnormal disconnection.
                                       termination. The END           The FANS 1/A INTEROP Standard,
                                       SERVICE (uM161) message        paragraph 5.3.1.2, explains why uplink IMI
                                       element will be sent in        DR1 should not be used to disconnect.
                                       combination with the ERROR
                                       [errorinformation] (uM159)
                                       message element (a
                                       combination for which
                                       WILCO (dM0) is not a valid
                                       response). The suggested
                                       [errorinformation] value is
                                       commandedTermination].
       Air CPDLC-user-abort service    IMI DR1                        IR-44   When the IMI DR1 is received
       (CPDLCUserAbort)                                               unsolicited, ATN ground system shall
                                       Or                             process it like an Air CPDLC-user-abort
                                                                      (undefined).
                                       IMI DR1 DM62 ERROR             IR-45   Upon receipt of DM62 in the
                                       [errorinformation]             Disconnect Request, the ATN ground
                                                                      system shall not present the message to
                                                                      controllers.
                                       Or
                                                                      IR-46   When receiving an IMI AT1
                                                                      DM62 (duplicateMsgIdentification
                                       IMI AT1 DM62 ERROR
                                                                      Number), the ATN ground system shall
                                       (duplicateMsgIdentification
                                       Number)                        send IMI AT1 UM161 END SERVICE
                                                                      concatenated with UM159 (ERROR),
                                                                      with error information set to
                                                                      ‗commanded-termination‘, and internally
                                                                                                            4-43



ATN Constructs                       FANS 1/A ACARS IMIs              Interoperability Requirement
                                                                      process the IMI AT1 DM62 as an Air
                                                                      CPDLC User Abort (duplicate message
                                                                      identification numbers (2)).
                                                                      DR1 is considered unsolicited when it is
                                                                      received while no ground-initiated CPDLC
                                                                      start, end, or abort is in progress.
                                                                      As per Ground CPDLC-user-abort service
                                                                      (CPDLCUserAbort) the response to UM161
                                                                      + UM159 is ignored by the ground system.
CPDLC-provider-abort-service         A DR1 DM62 (invalid data)        IR-47   The ATN ground system shall
(CPDLCProviderAbort)                 is sent by the FANS 1/A          process a DR1 DM62 (invalid data) as a
initiated by the aircraft            aircraft only in response to a   CPDLC Provider abort (invalid PDU).
                                     CR1 (Connection Request)
Doc 9880, 3.5.4.3.1                  when an error is encountered
                                                                      The FANS 1/A aircraft will send an ERROR
If the User Data parameter of a                                       (―invalid data‖) but will not disconnect in the
                                     in the message contained in
D-END confirmation with                                               following cases:
                                     the CR1.
Result parameter is set to the                                        • An invalid coded user data (FANS
abstract value ―rejected‖, or if                                      equivalent to PDU) is found in a AT1 IMI
the User Data parameter of a D-                                       message (ATN equivalent is a provider
START indication, a D-DATA                                            abort);
indication, or a D-END                                                • An error is found during the processing at
indication, does not contain a                                        application level (ATN equivalent also an
valid PDU, the CPDLC- air-                                            ERROR).
ASE shall:
                                                                      The ATN ground system will process the
…                                                                     error (invalid data) received in IMI ATI like
b) Create an AircraftPDUs                                             a CPDLC error message and consequently
APDU with a                                                           remains connected. Refer to paragraph 0 for
CPDLCProviderAbortReason                                              ERROR processing.
[invalid-PDU] APDU message
element,
c) Invoke D-ABORT request
with:
  1) the abstract value ―provider‖
as the D-ABORT Originator
parameter value, and
  2) the APDU as the D-ABORT
User Data parameter value,‖

Doc 9880, 3.5.4.7.1                  IMI DR1 DM62(insufficient        IR-48    The ATN ground system shall
                                     data) is sent by the             process IMI DR1 DM62(insufficient
If the User Data parameter of a      FANS 1/A aircraft when
D-START indication or D-                                              data) received in response to a IMI CR1
                                     insufficient data is received    as a provider-abort (invalid PDU).
DATA indication does not             within a IMI CR1 to decode
contain a PDU, the CPDLC-or          the included message.            IR-49    The ATN ground system shall
air-ASE shall:                                                        process IMI AT1 (insufficient data) as a
                                     The FANS 1/A aircraft will
…                                    downlink IMI AT1 DM62            provider-abort (invalid PDU).
b) Create an AircraftPDUs            (insufficient data) when an      When the FANS 1/A aircraft receives an
APDU with a
4-44


       ATN Constructs                      FANS 1/A ACARS IMIs             Interoperability Requirement
       CPDLCProviderAbortReason            uplink ATI is not correct and   uplink message (IMI AT1) containing a
       [expected-PDU missing] APDU         for the FANS 1/A aircraft in    [routeclearance] parameter and in the
       message element,                    the following case:             [routeinformationadditional] parameter the
       c) Invoke D-ABORT request           ATCComm receives an             optional [waypointspeedaltitude] type with
       with:                               uplink message (IMI AT1)        neither a [speed] type nor an [aTWaltitude]
                                           containing a [routeclearance]   type they also respond with IMI ATI
        1) the abstract value ―provider‖
                                           parameter and in the            (insufficient data). This case is not an issue
       as the D-ABORT Originator
                                           [routeinformationadditional]    as this data combination is not within the
       parameter value, and
                                           parameter the optional          scope of this document provided in
        2) the APDU as the D-ABORT                                         paragraph 1.2.
                                           [waypointspeedaltitude] type
       User Data parameter value‖,
                                           with neither a [speed] type
                                           nor an [aTWaltitude] type.
       CPDLC-provider-abort-service        No equivalent.                  IR-50    When the timer expires, the
       (CPDLCProviderAbort)                                                ATN ground system shall abort the
       initiated by the ground                                             CPDLC connection, sending UM161
       Doc 9880, 3.5.6.1.1                                                 END SERVICE concatenated with
       If a CPDLC-ground ASE                                               UM159 (ERROR) with error
       detects that a timer has expired,                                   information ‘commanded termination‘ to
       that CPDLC- ground ASE shall:                                       the FANS 1/A aircraft.
       …                                                                   IR-51    The ATN ground system shall
       b) Create a GroundPDUs APDU                                         ignore the DR1 that will be received in
       with a                                                              response from the aircraft.
       CPDLCProviderAbortReason                                            IR-52    The ATN ground system shall
       [timer-expired] APDU message                                        issue a provider abort indication to the
       element,                                                            local ground user.
       c) Invoke D-ABORT request
       with:
       1) the abstract value ―provider‖
       as the D-ABORT Originator
       parameter value, and
       2) the APDU as the D-ABORT
       User Data parameter value

       Doc 9880, 3.5.6.3.1                 No equivalent.                  When invalid coded data is detected in a IMI
                                                                           AT1, the ATN ground system should
       If the User Data parameter of a                                     respond with UM159 (ERROR) with error
       D-END confirmation with                                             information ‗invalid data.‘
       Result parameter set to the
       abstract value ―rejected‖, a D-
       START indication, a D-DATA
       indication, or a D-END
       indication, does not
       contain a valid PDU, the
       CPDLC-ground-ASE shall:
       ...
       b) Create a GroundPDUs APDU
       with a
                                                                                                     4-45



ATN Constructs                      FANS 1/A ACARS IMIs         Interoperability Requirement
CPDLCProviderAbortReason
[invalid-PDU]
APDU message element,
c) Invoke D-ABORT request
with:
1) the abstract value ―provider‖
as the D-ABORT Originator
parameter value,
and
2) the APDU as the D-ABORT
User Data parameter value,...
No equivalent.                      IMI CC1 with invalid        When invalid coded data is detected in a IMI
                                    encoded user data           CC1, the ATN ground system should abort
                                                                the connection with UM161 concatenated
                                                                with UM159 (ERROR) with error
                                                                information‚ ‗invalid data.‘

Doc 9880, 3.5.6.7.1                 IMI AT1 without user data   When no user data is detected in a IMI AT1,
                                                                the ATN ground system should respond
If the User Data parameter of a                                 UM159 (ERROR) with error information
D-START indication or a D-                                      ‗insufficient data.‘
DATA indication does not
contain a PDU, the CPDLC-
ground-ASE shall:
…
d) If the CPDLC-ground-user is
an active user, invoke CPDLC-
provider-abort service indication
with the abstract value ―not-
permitted PDU‖ as the CPDLC-
provider-abort Reason
parameter value.
No equivalent.                      Unexpected IMI              When any IMI is received whilst no
                                                                connection is established or in the process of
                                                                being established, the ATN ground system
                                                                should disregard the message.
4.2.3          High-Level Data Structures
               Table 4-9 compares the ATN CPDLC and FANS 1/A high-level data structures.


                       Table 4-9    ATN and FANS 1/A CPDLC high-level data structures

        ATN                          FANS 1/A          Interoperability Requirement
        Applicable GroundPDUs:       ATCuplinkmessag None.
         CPDLCUserAbortReason        e               The FANS 1/A aircraft does not have the user or
         CPDLCProviderAbortReason                    provider abort PDUs. The FANS 1/A error reason
                                                     codes support some of the ATN aborts. The ATN
         ICUplinkMessage
                                                     aborts and comparable FANS 1/A error reasons
                                                     are shown in paragraph 4.3.2.1.
                                                     In both the ATS INTEROP Standard and the
                                                     FANS 1/A INTEROP Standard, the ATC Uplink
                                                     Message PDU contains the uplink message
                                                     elements choices.
        Applicable AircraftPDUs:     ATCdownlinkmes    None.
         CPDLCUserAbortReason        sage              The FANS 1/A aircraft does not have the user or
         CPDLCProviderAbortReason                      provider abort PDUs. The FANS 1/A error reason
                                                       codes support some of the ATN aborts. ATN
         ICDownlinkMessage
                                                       aborts and comparable FANS 1/A error reasons
                                                       are shown in paragraph 4.3.2.1.
                                                       In both the ATS INTEROP Standard and the
                                                       FANS 1/A INTEROP Standard the ATC
                                                       Downlink Message PDU contains the downlink
                                                       message elements choices.



4.2.4          Message Attributes
               In both ATN system and FANS 1/A system for some CPDLC messages, the message
               attributes have changed between the ATN message elements and the FANS 1/A message
               elements.
               Table 4-10 compares the ATN CPDLC and FANS 1/A uplink and downlink message
               response, urgency, and alert attributes.
                                                                                                4-47



                  Table 4-10 ATN and FANS 1/A CPDLC message response attributes

ATN Message Attributes            FANS 1/A Message       Interoperability Requirement
                                  Attributes
Response Attribute – Uplink       Response Attribute -
                                  Uplink
W/U                               W/U                    None.
A/N                               A/N                    None.
R                                 R                      None.
                                                         ATN systems permit UNABLE response
                                                         message to R messages. An UNABLE
                                                         response to R messages is not available in
                                                         FANS 1/A.
                                                         If a ATN ground system uses a message
                                                         element with R response attribute, a
                                                         procedure could be established to ensure that
                                                         the pilot can express rejection of the message
                                                         by voice and that the controller will not be
                                                         mislead by the ROGER received.
                                                         See paragraph 4.2.8, for use of messages
                                                         with R response.
4-48

       ATN Message Attributes                    FANS 1/A Message        Interoperability Requirement
                                                 Attributes
       N                                         NE                      IR-53   The ATN ground system shall
       Note: In the ATS INTEROP Standard,        Note: In the FANS 1/A   be capable of accepting message
       when a message with a N response          INTEROP Standard,       reference numbers in all ERROR
       attribute is received and an error is     when message with a     messages.
       detected then:                            NE response attribute
       - If the message requires a logical       is received and an
                                                 error is detected, an   Note: This is to prevent the ATN ground
       acknowledgement, an ERROR response                                system from rejecting a response ERROR
       is sent with a message reference number   ERROR response is
                                                 sent that may contain   messages containing a reference number for
       (the same as the FANS 1/A message                                 a N message.
       without the logical acknowledgement).     a message reference
                                                 number.
       - If the message does not permit a
       logical acknowledgement, then an
       ERROR message can be sent, but a
       reference number is normally not
       included (exception see note below).
       Thus the ERROR message will normally
       not explicitly refer to the message in
       error.
       From the ATS INTEROP 3.3.2.4
       Note 3: Some aircraft always include a
       reference number matching the
       identification number of the CPDLC
       message to which the ERROR message
       refers. This is not Doc 9880 compliant
       when theCPDLC message in error has
       an “N” response attribute and does not
       require a LACK.
       Y                                         Y                       None.
       Response Attribute -Downlink              Response Attribute -
                                                 Downlink
       Y                                         Y                       None.
       N                                         N                       None.
       Alert Attribute                           Alert Attribute
       H                                         A/D                     None.
                                                                         FANS 1/A does not use the alert attribute.
       M                                         A                       None.
                                                                         FANS 1/A does not use the alert attribute.
       L                                         V                       None.
                                                                         FANS 1/A does not use the alert attribute.
       N                                         N                       None.
                                                                         FANS 1/A does not use the alert attribute.
                                                                                                    4-49



    ATN Message Attributes                FANS 1/A Message    Interoperability Requirement
                                          Attributes
    Urgency Attribute                     Urgency Attribute
    D                                     D                   None.
                                                              The urgency attribute is not used in ATN or
                                                              FANS 1/A.
    U                                     U                   None.
                                                              The urgency attribute is not used in ATN or
                                                              FANS 1/A.
    N                                     N                   None.
                                                              The urgency attribute is not used in ATN or
                                                              FANS 1/A.
    L                                     L                   None.
                                                              The urgency attribute is not used in ATN or
                                                              FANS 1/A.




4.2.5             LACK
                  A ―LACK required‖ indication is not available in the FANS 1/A INTEROP Standard
                  definitions. Logical acknowledgements (LACKs) are not available in the FANS 1/A
                  aircraft.


        4.2.5.1       LACK on Downlink Messages
                  Table 4-11 compares the FANS and ATN management of LACK on Downlink
                  Messages.
4-50

                                          Table 4-11: LACK on Downlink Messages

          ATN                             FANS 1/A                          Interoperability Requirement
                                                                            IR-54   The ATN ground system
                                                                            shall not generate LACK message
                                                                            elements to the FANS 1/A aircraft
                                                                            in response to downlink messages.
                                          Note: As LACKs are not            IR-55   No requirement.
                                          supported by FANS 1/A aircraft,
                                          it is not necessary for an ATN
                                          ground system that does not
                                          support LACK, to send UM233
                                          USE OF LACK PROHIBITED to
                                          FANS 1/A aircraft (see
                                          paragraph 4.2.8).
          CPC-IR 2 When the ATSU          No equivalent.                    IR-56
          System receives a downlink
          message requiring a logical
          acknowledgement where the
          use of logical
          acknowledgement has been
          prohibited, then the ATSU
          System shall send a CPDLC
          message referencing the
          request, containing the
          concatenation of message
          element UM159 (ERROR
          (error information)) with the
          choice (2) followed by
          message element UM183
          (LOGICAL
          ACKNOWLEDGEMENT
          NOT ACCEPTED).



       4.2.5.2          LACK on Uplink Messages
                   Table 4-13 compares the FANS and ATN management of LACK on Downlink
                   Messages.
                                          Table 4-12: LACK on Downlink Messages
                                                                                                     4-51



ATN                              FANS 1/A                           Interoperability Requirement
CPC-IR 1 When a CPDLC            Note: The FANS 1/A aircraft        When sending a message to the
connection is established, the   transmits a Message Assurance      FANS 1/A aircraft, if the ATN ground
avionics shall default to        (MA) to the ground system by the   system uses LACKs, it shall translate
requesting LACK                  data link service provider (DSP)   the positive MA into a CPDLC
                                 when the FANS 1/A aircraft has     downlink message containing the
                                 confirmed to the DSP receipt of    message element DM100 (LACK)
                                 the entire message. This           using the uplink message number as
                                 confirmation is generated prior    message reference number.
                                 to CRC and application level       IR-57 When sending a message to
                                 message checking.               the FANS 1/A aircraft and the ATN
                                 The MA is sent for every uplink ground system does not use
                                 FANS 1/A message for which a    LACKs, it shall discard the positive
                                 confirmation is received.       MA.
                                 Note 1: The FANS 1/A aircraft   IR-58    Upon receipt of a negative
                                 may transmit a MA followed by MA message from a FANS 1/A
                                 an ERROR response for the same aircraft, the ATN ground system
                                 uplink message                  shall translate a negative MA into a
                                                                 CPDLC downlink message
                                                                 containing the concatenation of
                                                                 message element DM62 (ERROR
                                                                 (error information)) with the choice
                                                                 (0) followed by message element
                                                                 DM98 (‗MESSAGE NOT
                                                                 DELIVERED') using the uplink
                                                                 message number as message
                                                                 reference number.

         .
4-52

4.2.6           CPDLC Disabling/Enabling
                Table 4-13 presents the interoperability requirements for CPDLC disabling/enabling
                functionality available in the ATN ground system.


                Table 4-13 CPDLC Disabling/Enabling Functionality

        ATN                                       FANS 1/A         Interoperability Requirement
        3.3.1.4                                  No equivalent.    None.
        Note. Some data link equipped ATSU                         As per the FANS 1/A INTEROP
        Systems allow CPDLC to be turned “In                       Standard, paragraph 4.6.2.2, when
        Use” (i.e. CPDLC in use) and “Not In                       CPDLC has been disabled for the
        Use” (i.e. CPDLC not in use) on an                         whole ATSU, the FANS 1/A ground
        ATSU and/or sector basis. In both cases,                   system sends IMI AT1 UM161 END
        the CPDLC connection is maintained.                        SERVICE concatenated with UM159
        This capability may be used at any time                    (ERROR) with error information
                                                                   ‘commanded-termination‘ to all
                                                                   FANS 1/A aircraft currently
                                                                   connected.
        ACM-IR-26 Upon receipt of DM99            No equivalent.   None.
        CURRENT DATA AUTHORITY and
        CPDLC is not used by the receiving
        sector, the R-ATSU System shall send
        using CPDLC-message request UM287
        (NEW UM-ACM3) CPDLC NOT IN
        USE requiring a LACK for this message.
        ACM-IR 27 Whenever the status of the      No equivalent.   None.
        use of CPDLC changes, the ATSU
        System shall send using CPDLC-
        message request either UM287 (NEW
        UM-ACM3) CPDLC NOT IN USE or
        UM286 (NEW UM-ACM2) CPDLC IN
        USE.
        CPC-IR-11 When the ATSU System            No equivalent.   None.
        receives a CPDLC message (except for
        emergency messages), and discards the
        message because CPDLC is not in use,
        then the ATSU System shall send a
        CPDLC uplink message containing the
        concatenation of message element
        UM159 (ERROR (error information))
        with the choice (2) followed by message
        element UM183 (CPDLC NOT IN USE
        AT THIS TIME - USE VOICE).
                                                                                                        4-53



4.2.7           Message Header
                Table 4-14 compares the ATN and FANS 1/A CPDLC message headers.


                                 Table 4-14 ATN and FANS 1/A CPDLC message headers

        ATN Message Header            FANS 1/A Message Header Interoperability Requirement
        Message Identification        Message Identification      None
        Number                        Number
        Message Reference Number      Message Reference Number    None
        (optional)                    (optional)
        Timestamp consisting of date Timestamp HHMMSS             IR-59    The ATN ground system
        (YYMMDD) and time            (optional)                   shall use its own system date source.
        (HHMMSS)                     Note: The optional item is   Note 1: For downlink CPDLC messages,
                                     always provided by the       the ATN ground system has to take into
                                     FANS 1/A aircraft.           consideration that the date is not
                                                                  available in the FANS 1/A timestamp.
                                                                  Note 2: Around midnight, the ATN
                                                                  ground system has to receive and process
                                                                  time information related to the previous
                                                                  day.
                                                                  Note 3: For uplink CPDLC messages, the
                                                                  ATN ground system cannot provide the
                                                                  date in uplink messages addressed to the
                                                                  FANS 1/A aircraft.
        An indication if logical    No equivalent.                See paragraph 4.2.5 for LACK
        acknowledgement is required                               requirements on downlink and uplink
                                                                  message elements.
4.2.8          Uplink Message Elements
               Table 4-15 lists ATN uplink message elements, the corresponding FANS 1/A uplink
               message elements, and related interoperability requirements.
                        Table 4-15 ATN and FANS 1/A CPDLC uplink message elements

        ATN Message Element          FANS 1/A Message Element     Interoperability Requirement
        UM0 UNABLE                   UM0 UNABLE                   None.
        UM1 STANDBY                  UM1 STANDBY                  None.
        UM2 REQUEST DEFERRED         UM2 REQUEST DEFERRED         None.
        UM3 ROGER                    UM3 ROGER                    None.
        UM4 AFFIRM                   UM4 AFFIRM                   None.
        UM5 NEGATIVE                 UM5 NEGATIVE                 None.
        UM6 EXPECT [level]           UM6 EXPECT [altitude]        See paragraph 4.2.12.1 for use of
                                                                  level/altitude parameter
                                                                  requirements.
        UM7 Replaced by UM245        UM7 EXPECT CLIMB AT          None, ATN message is never sent.
                                     [time]
        UM8 EXPECT CLIMB AT          UM8 EXPECT CLIMB AT          See paragraph 4.2.12.2 for use of
        [position]                   [position]                   position parameter.
        UM9 Replaced by UM246        UM9 EXPECT DESCENT AT        None, ATN message is never sent.
                                     [time]

        UM10 EXPECT DESCENT AT       UM10 EXPECT DESCENT AT       See paragraph 4.2.12.2 for use of
        [position]                   [position]                   position parameter.
        UM11 Replaced by UM247       UM11 EXPECT CRUISE           None, ATN message is never sent.
                                     CLIMB AT [time]
        UM12 EXPECT CRUISE CLIMB UM12 EXPECT CRUISE               See paragraph 4.2.12.2 for use of
        AT [position]            CLIMB AT [position]              position parameter.
        UM13 Reserved                UM 13 AT [time] EXPECT       None, ATN message is never sent.
                                     CLIMB TO [altitude]
        UM14 Reserved                UM14 AT [position] EXPECT    None, ATN message is never sent.
                                     CLIMB TO [altitude]
        UM15 Reserved                UM15 AT [time] EXPECT        None, ATN message is never sent.
                                     DECENT TO [altitude]
        UM16 Reserved                UM16 AT [position] EXPECT    None, ATN message is never sent.
                                     DECENT TO [altitude]
        UM17 Reserved                UM17 AT [time] EXPECT        None, ATN message is never sent.
                                     DECENT TO [altitude]
        UM18 Reserved                UM18 AT [position] EXPECT    None, ATN message is never sent.
                                     DECENT TO [altitude]
                                                                                         4-55


ATN Message Element           FANS 1/A Message Element      Interoperability Requirement
UM19 MAINTAIN [level]         UM19 MAINTAIN [altitude]      IR-60    When using a vertical
                                                            range, the ATN ground system
                              Or                            shall convert the ATN UM19
                                                            message element to FANS 1/A
                                                            UM30 message element.
                              UM30 MAINTAIN BLOCK
                              [altitude] TO [altitude]      IR-61    When using a single
                                                            level, the ATN ground system
                                                            shall use the FANS 1/A UM19
                                                            message element.
                                                            See paragraph 4.2.12.1 for use of
                                                            level/altitude parameter.
UM20 CLIMB TO [level]         UM20 CLIMB TO AND             IR-62    When using a vertical
                              MAINTAIN [altitude]           range, the ATN ground system
                                                            shall convert the ATN UM20
                              Or                            message element to the
                                                            FANS 1/A UM31 message
                              UM31 CLIMB TO AND
                                                            element.
                              MAINTAIN BLOCK [altitude]     IR-63    When using a single
                              TO [altitude]                 level, the ATN ground system
                                                            shall use the FANS 1/A UM20
                                                            message element.
                                                            See paragraph 4.2.12.1 for use of
                                                            level/altitude parameter.
UM21 Replaced by UM248        UM21 AT [time] CLIMB TO       None, ATN message is never sent.
                              AND MAINTAIN [altitude]
UM22 AT [position] CLIMB TO   UM22 AT [position] CLIMB TO   See paragraph 4.2.12.1 for use of
[level]                       AND MAINTAIN [altitude]       level/altitude parameter.
                                                            See paragraph 4.2.12.2 for use of
                                                            position parameter.
UM23 DESCEND TO [level]       UM23 DESCEND TO AND           IR-64    When using a vertical
                              MAINTAIN [altitude]           range, the ATN ground system
                                                            shall convert the ATN UM23
                              Or                            message element to the
                                                            FANS 1/A UM32 message
                              UM32 DESCEND TO AND
                                                            element.
                              MAINTAIN BLOCK [altitude]     IR-65    When using a single
                              TO [altitude]                 level, the ATN ground system
                                                            shall use the FANS 1/A UM23
                                                            message element.
                                                            See paragraph 4.2.12.1 for use of
                                                            level/altitude parameter.
4-56


       ATN Message Element          FANS 1/A Message Element     Interoperability Requirement
       UM24 Replaced by UM249       UM24 AT [time] DESCEND TO    None, ATN message is never sent.
                                    [altitude]
       UM25 AT [position] DESCEND   UM25 AT [position] DESCEND   See paragraph 4.2.12.2 for use of
       TO [level]                   TO [altitude]                position parameter.
                                                                 See paragraph 4.2.12.1 for use of
                                                                 level/altitude parameter.
       UM26 Replaced by UM250       UM26 CLIMB TO REACH          None, ATN message is never sent.
                                    [altitude] BY [time]
       UM27 CLIMB TO REACH          UM27 CLIMB TO REACH          See paragraph 4.2.12.1 for use of
       [level] BY [position]        [altitude] BY [position]     level/altitude parameter.
                                                                 See paragraph 4.2.12.2 for use of
                                                                 position parameter.
       UM28 Replaced by UM251       UM28 DESCEND TO REACH        None, ATN message is never sent.
                                    [altitude] BY [time]
       UM29 DESCEND TO REACH        UM29 DESCEND TO REACH        See paragraph 4.2.12.1 for use of
       [level] BY [position]        [altitude] BY [position]     level/altitude parameter.
                                                                 See paragraph 4.2.12.2 for use of
                                                                 position parameter.
       UM30 Replaced by UM19        UM30 MAINTAIN BLOCK          None, ATN message is never sent.
                                    [altitude] TO [altitude]

       UM31 Replaced by UM20        UM31 CLIMB TO AND            None, ATN message is never sent.
                                    MAINTAIN BLOCK [altitude]
                                    TO [altitude]

       UM32 Replaced by UM23        UM32 DESCENT TO AND          None, ATN message is never sent.
                                    MAINTAIN BLOCK [altitude]
                                    TO [altitude]

       UM33 Reserved                UM33 CRUISE [altitude]       None, ATN message is never sent.

       UM34 CRUISE CLIMB TO         UM34 CRUISE CLIMB TO         See paragraph 4.2.12.1 for use of
       [level]                      [altitude]                   level/altitude parameter.

       UM35 WHEN ABOVE [level]      UM 35 CRUISE CLIMB           See paragraph 4.2.12.1 for use of
       COMMENCE CRUISE CLIMB        ABOVE [altitude]             level/altitude parameter.

       UM36 EXPEDITE CLIMB TO       UM36 EXPEDITE CLIMB TO       See paragraph 4.2.12.1 for use of
       [level]                      [altitude]                   level/altitude parameter.

       UM37 EXPEDITE DESCENT TO UM37 EXPEDITE DESCENT            See paragraph 4.2.12.1 for use of
       [level]                  TO [altitude]                    level/altitude parameter.

       UM38 IMMEDIATELY CLIMB       UM38 IMMEDIATELY CLIMB       See paragraph 4.2.12.1 for use of
       TO [level]                   TO [altitude]                level/altitude parameter.
                                                                                         4-57


ATN Message Element           FANS 1/A Message Element      Interoperability Requirement
UM39 IMMEDIATELY              UM39 IMMEDIATELY              See paragraph 4.2.12.1 for use of
DESCENT TO [level]            DESCENT TO [altitude]         level/altitude parameter.
UM40 Reserved                 UM40 IMMEDIATELY STOP         None, ATN message is never sent.
                              CLIMB AT [altitude]
UM41 Reserved                 UM41 IMMEDIATELY STOP         None, ATN message is never sent.
                              DESCENT AT [altitude]
UM42 Reserved                 UM42 EXPECT TO CROSS          None, ATN message is never sent.
                              [position] AT [altitude]
UM43 Reserved                 UM43 EXPECT TO CROSS          None, ATN message is never sent.
                              [position] AT OR
                              ABOVE[altitude]
UM44 Reserved                 UM44 EXPECT TO CROSS          None, ATN message is never sent.
                              [position] AT OR BELOW
                              [altitude]
UM45 Reserved                 UM45 EXPECT TO CROSS          None, ATN message is never sent.
                              [position] AT AND MAINTAIN
                              [altitude]
UM46 CROSS [position] AT      UM46 CROSS [position] AT      See paragraph 4.2.12.1 for use of
[level]                       [altitude]                    level/altitude parameter.
                                                            See paragraph 4.2.12.2 for use of
                                                            position parameter.
UM47 CROSS [position] AT OR   UM47 CROSS [position] AT OR   See paragraph 4.2.12.1 for use of
ABOVE [level]                 ABOVE [altitude]              level/altitude parameter.
                                                            See paragraph 4.2.12.2 for use of
                                                            position parameter.
UM48 CROSS [position] AT OR   UM48 CROSS [position] AT OR   See paragraph 4.2.12.1 for use of
BELOW [level]                 BELOW [altitude]              level/altitude parameter.
                                                            See paragraph 4.2.12.2 for use of
                                                            position parameter.
UM49 CROSS [position] AT      UM49 CROSS [position] AT      See paragraph 4.2.12.1 for use of
AND MAINTAIN [level]          AND MAINTAIN [altitude]       level/altitude parameter.
                                                            See paragraph 4.2.12.2 for use of
                                                            position parameter.
UM50 CROSS [position]         UM50 CROSS [position]         See paragraph 4.2.12.1 for use of
BETWEEN [level] AND [level]   BETWEEN [altitude] AND        level/altitude parameter.
                              [altitude]                    See paragraph 4.2.12.2 for use of
                                                            position parameter.
UM51 Replaced by UM252        UM51 CROSS [position] AT      None, ATN message is never sent.
                              [time]
UM52 Replaced by UM253        UM52 CROSS [position] AT OR   None, ATN message is never sent.
                              BEFORE [time]
4-58


       ATN Message Element              FANS 1/A Message Element       Interoperability Requirement
       UM53 Replaced by UM254           UM53 CROSS [position] AT OR    None, ATN message is never sent.
                                        AFTER [time]
       UM54 Replaced by UM255           UM54 CROSS [position]          None, ATN message is never sent.
                                        BETWEEN [time] AND [time]
       UM55 CROSS [position] AT         UM55 CROSS [position] AT       See paragraph 4.2.12.2 for use of
       [speed]                          [speed]                        position parameter.
                                                                       See paragraph 4.2.12.3 for use of
                                                                       speed parameter.

       UM56 CROSS [position] AT OR      UM56 CROSS [position] AT OR    See paragraph 4.2.12.2 for use of
       LESS THAN [speed]                LESS THAN [speed]              position parameter.
                                                                       See paragraph 4.2.12.3 for use of
                                                                       speed parameter.
       UM57 CROSS [position] AT OR      UM57 CROSS [position] AT OR    None.
       GREATER THAN [speed]             GREATER THAN [speed]           See paragraph 4.2.12.2 for use of
                                                                       position parameter.
                                                                       See paragraph 4.2.12.3 for use of
                                                                       speed parameter.

       UM58 Replaced by UM256           UM58 CROSS [position] AT       None, ATN message is never sent.
                                        [time] AT [altitude]

       UM59 Replaced by UM257           UM59 CROSS [position] AT OR    None, ATN message is never sent.
                                        BEFORE [time] AT [altitude]

       UM60 Replaced by UM258           UM60 CROSS [position] AT OR    None, ATN message is never sent.
                                        AFTER [time] AT [altitude]
       UM61 CROSS [position] AT         UM61 CROSS [position] AT       See paragraph 4.2.12.1 for use of
       AND MAINTAIN [level] AT          AND MAINTAIN [altitude] AT     level/altitude parameter.
       [speed]                          [speed]                        See paragraph 4.2.12.2 for use of
                                                                       position parameter.
                                                                       See paragraph 4.2.12.3 for use of
                                                                       speed parameter.
       UM62 Replaced by UM259           UM62 AT [time] CROSS           None, ATN message is never sent.
                                        [position] AT AND MAINTAIN
                                        [altitude]
       UM63 Replaced by UM260           UM63 AT [time] CROSS           None, ATN message is never sent.
                                        [position] AT AND MAINTAIN
                                        [altitude] AT [speed]
       UM64 OFFSET [specified           UM64 OFFSET [distanceoffset]   See paragraph 4.2.12.4 for use of
       distance] [direction] OF ROUTE   [direction] OF ROUTE           specified distance parameter.
                                                                                                   4-59


ATN Message Element                 FANS 1/A Message Element          Interoperability Requirement

UM65 AT [position] OFFSET           UM65 AT [position] OFFSET         See paragraph 4.2.12.4 for use of
[specified distance] [direction] OF [distanceoffset] [direction] OF   specified distance parameter.
ROUTE                               ROUTE                             See paragraph 4.2.12.2 for use of
                                                                      position parameter.

UM66 Replaced by UM261              UM66 AT [time] OFFSET             None, ATN message is never sent.
                                    [distanceoffset] [direction] OF
                                    ROUTE

UM67 PROCEED BACK ON                UM67 PROCEED BACK ON              None.
ROUTE                               ROUTE

UM68 REJOIN ROUTE BY                UM68 REJOIN ROUTE BY              See paragraph 4.2.12.2 for use of
[position]                          [position]                        position parameter.

UM69 Replaced by UM262              UM69 REJOIN ROUTE BY              None, ATN message is never sent.
                                    [time]

UM70 EXPECT BACK ON                 UM70 EXPECT BACK ON               See paragraph 4.2.12.2 for use of
ROUTE BY [position]                 ROUTE BY [position]               position parameter.

UM71 Replaced by UM263              UM71 EXPECT BACK ON               None, ATN message is never sent.
                                    ROUTE BY [time]
UM72 RESUME OWN                     UM72 RESUME OWN                   None.
NAVIGATION                          NAVIGATION
UM73 Replaced by UM264              UM73 [predepartureclearance]      None, ATN message is never sent.
UM74 PROCEED DIRECT TO              UM74 PROCEED DIRECT TO            See paragraph 4.2.12.2 for use of
[position]                          [position]                        position parameter.

UM75 WHEN ABLE PROCEED              UM75 WHEN ABLE PROCEED See paragraph 4.2.12.2 for use of
DIRECT TO [position]                DIRECT TO [position]   position parameter.

UM76 Replaced by UM265              UM76 AT [time] PROCEED            None, ATN message is never sent.
                                    DIRECT TO [position]

UM77 AT [position] PROCEED          UM77 AT [position] PROCEED        See paragraph 4.2.12.2 for use of
DIRECT TO [position]                DIRECT TO [position]              position parameter.

UM78 AT [level] PROCEED             UM78 AT [altitude] PROCEED        See paragraph 4.2.12.1 for use of
DIRECT TO [position]                DIRECT TO [position]              level/altitude parameter.
                                                                      See paragraph 4.2.12.2 for use of
                                                                      position parameter.
UM79 Replaced by UM266              UM79 CLEARED TO [position]        None, ATN message is never sent.
                                    VIA [routeclearance]
UM80 Replaced by UM267              UM80 CLEARED                      None, ATN message is never sent.
                                    [routeclearance]
4-60


       ATN Message Element           FANS 1/A Message Element        Interoperability Requirement
       UM81 CLEARED [procedure       UM81 CLEARED                    See paragraph 4.2.12.19 for use of
       name]                         [procedurename]                 procedure name parameter.
       UM82 CLEARED TO DEVIATE       UM82 CLEARED TO DEVIATE See paragraph 4.2.12.4 for use of
       UP TO [specified distance]    UP TO [disanceoffset] [direction] specified distance parameter.
       [direction] OF ROUTE          OF ROUTE
       UM83 Replaced by UM268        UM83 AT [position] CLEARED      None, ATN message is never sent.
                                     [routeclearance]
       UM84 AT [position] CLEARED    UM84 AT [position] CLEARED      See paragraph 4.2.12.2 for use of
       [procedure name]              [procedurename]                 position parameter.
                                                                     See paragraph 4.2.12.19 for use of
                                                                     procedure name parameter.
       UM85 Replaced by UM269        UM85 EXPECT [routeclearance]    None, ATN message is never sent.
       UM86 Replaced by UM270        UM86 AT [position] EXPECT       None, ATN message is never sent.
                                     [routeclearance]
       UM87 EXPECT DIRECT TO         UM87 EXPECT DIRECT TO           See paragraph 4.2.12.2 for use of
       [position]                    [position]                      position parameter.
       UM88 AT [position] EXPECT     UM88 AT [position] EXPECT       See paragraph 4.2.12.2 for use of
       DIRECT TO [position]          DIRECT TO [position]            position parameter.
       UM89 Replaced by UM271        UM89 AT [time] EXPECT           None, ATN message is never sent.
                                     DIRECT TO [position]
       UM90 AT [level] EXPECT        UM90 AT [altitude] EXPECT       See paragraph 4.2.12.1 for use of
       DIRECT TO [position]          DIRECT TO [position]            level/altitude parameter.
                                                                     See paragraph 4.2.12.2 for use of
                                                                     position parameter.
       UM91 HOLD AT [position]       UM91 HOLD AT [position]         See paragraph 4.2.12.1 for use of
       MAINTAIN [level] INBOUND      MAINTAIN [altitude]             level/altitude parameter.
       TRACK [degrees] [direction]   INBOUND TRACK [degrees]         See paragraph 4.2.12.2 for use of
       TURNS [leg type]              [direction] TURNS [legtype]     position parameter.
                                                                     See paragraph 4.2.12.14 for use of
                                                                     leg type parameter.
       UM92 HOLD AT [position] AS    UM92 HOLD AT [position] AS      See paragraph 4.2.12.1 for use of
       PUBLISHED MAINTAIN [level]    PUBLISHED MAINTAIN              level/altitude parameter.
                                     [altitude]                      See paragraph 4.2.12.2 for use of
                                                                     position parameter.
       UM93 Replaced by UM272        UM93 EXPECT FURTHER             None, ATN message is never sent.
                                     CLEARANCE AT [time]
       UM94 TURN [direction]         UM94 TURN [direction]           None.
       HEADING [degrees]             HEADING [degrees]
       UM95 TURN [direction]         UM95 TURN [direction]           None.
       GROUND TRACK [degrees]        GROUND TRACK [degrees]
                                                                                             4-61


ATN Message Element             FANS 1/A Message Element        Interoperability Requirement
UM96 CONTINUE PRESENT           UM96 FLY PRESENT                None.
HEADING                         HEADING
UM97 AT [position] FLY          UM97 AT [position] FLY          See paragraph 4.2.12.2 for use of
HEADING [degrees]               HEADING [degrees]               position parameter.

UM98 IMMEDIATELY TURN           UM98 IMMEDIATELY TURN           None.
[direction] HEADING [degrees]   [direction] HEADING [degrees]

UM99 EXPECT [procedure name] UM99 EXPECT [procedurename] See paragraph 4.2.12.19 for use of
                                                         procedure name parameter.

UM100 Replaced by UM273         UM100 AT [time] EXPECT          None, ATN message is never sent.
                                [speed]

UM101 AT [position] EXPECT      UM101 AT [position] EXPECT      See paragraph 4.2.12.2 for use of
[speed]                         [speed]                         position parameter.
                                                                See paragraph 4.2.12.3 for use of
                                                                speed parameter.

UM102 AT [level] EXPECT         UM102 AT [altitude] EXPECT      See paragraph 4.2.12.1 for use of
[speed]                         [speed]                         level/altitude parameter.
                                                                See paragraph 4.2.12.3 for use of
                                                                speed parameter.

UM103 Replaced by UM274         UM103 AT [time] EXPECT          None, ATN message is never sent.
                                [speed] TO [speed]

UM104 AT [position] EXPECT      UM104 AT [position] EXPECT      See paragraph 4.2.12.2 for use of
[speed] TO [speed]              [speed] TO [speed]              position parameter.
                                                                See paragraph 4.2.12.3 for use of
                                                                speed parameter.
UM105 AT [level] EXPECT         UM105 AT [altitude] EXPECT      See paragraph 4.2.12.1 for use of
[speed] TO [speed]              [speed] TO [speed]              level/altitude parameter.
                                                                See paragraph 4.2.12.3 for use of
                                                                speed parameter.
UM106 MAINTAIN [speed]          UM106 MAINTAIN [speed]          See paragraph 4.2.12.3 for use of
                                                                speed parameter.
UM107 MAINTAIN PRESENT          UM107 MAINTAIN PRESENT          None.
SPEED                           SPEED
UM108 MAINTAIN [speed] OR       UM108 MAINTAIN [speed] OR       See paragraph 4.2.12.3 for use of
GREATER                         GREATER                         speed parameter.
UM109 MAINTAIN [speed] OR       UM109 MAINTAIN [speed] OR       See paragraph 4.2.12.3 for use of
LESS                            LESS                            speed parameter.
UM110 MAINTAIN [speed] TO       UM110 MAINTAIN [speed] TO       See paragraph 4.2.12.3 for use of
[speed]                         [speed]                         speed parameter.
4-62


       ATN Message Element           FANS 1/A Message Element     Interoperability Requirement
       UM111 INCREASE SPEED TO       UM111 INCREASE SPEED TO      See paragraph 4.2.12.3 for use of
       [speed]                       [speed]                      speed parameter.
       UM112 INCREASE SPEED TO       UM112 INCREASE SPEED TO      See paragraph 4.2.12.3 for use of
       [speed] OR GREATER            [speed] OR GREATER           speed parameter.
       UM113 REDUCE SPEED TO         UM113 REDUCE SPEED TO        See paragraph 4.2.12.3 for use of
       [speed]                       [speed]                      speed parameter.
       UM114 REDUCE SPEED TO         UM114 REDUCE SPEED TO        See paragraph 4.2.12.3 for use of
       [speed] OR LESS               [speed] OR LESS              speed parameter.
       UM115 DO NOT EXCEED           UM115 DO NOT EXCEED          See paragraph 4.2.12.3 for use of
       [speed]                       [speed]                      speed parameter.
       UM116 RESUME NORMAL           UM116 RESUME NORMAL          None.
       SPEED                         SPEED
       UM117 CONTACT [unitname]      UM117 CONTACT                See paragraph 4.2.12.9 for use of
       [frequency]UM117              [icaounitname] [frequency]   unit name parameter.
       UM118 AT [position] CONTACT UM118 AT [position]            See paragraph 4.2.12.9 for use of
       [unitname] [frequency]UM118 CONTACT [icaounitname]         unit name parameter.
                                   [frequency]                    See paragraph 4.2.12.2 for use of
                                                                  position parameter.


       UM119 Replaced by UM275       UM119 AT [time] CONTACT      None, ATN message is never sent.
                                     [icaounitname] [frequency]
       UM120 MONITOR [unitname]      UM120 MONITOR                See paragraph 4.2.12.9 for use of
       [frequency]UM120              [icaounitname] [frequency]   unit name parameter.
       UM121 AT [position] MONITOR   UM121 AT [position]          See paragraph 4.2.12.9 for use of
       [unitname] [frequency]        MONITOR [icaounitname]       unit name parameter.
                                     [frequency]                  See paragraph 4.2.12.2 for use of
                                                                  position parameter.
       UM122 Replaced by UM276       UM122 AT [time] MONITOR      None, ATN message is never sent.
                                     [icaounitname] [frequency]
       UM123 SQUAWK [code]           UM123 SQUAWK [beaconcode]    See paragraph 0 for use of unit
                                                                  name parameter.
       UM124 STOP SQUAWK             UM124 STOP SQUAWK            None.
       UM125 SQUAWK MODE             UM125 ALTITUDE CHARLIE       None.
       CHARLIE
       UM126 STOP SQUAWK MODE        UM126 STOP ALTITUDE          None.
       CHARLIE                       CHARLIE
                                                                                 4-63


ATN Message Element      FANS 1/A Message Element   Interoperability Requirement
UM127 REPORT BACK ON     UM127 REPORT BACK ON       Response attribute different: W/U
ROUTE                    ROUTE                      in the ATS INTEROP Standard, R
                                                    in the FANS 1/A INTEROP
                                                    Standard.
                                                    See paragraph 1.1.1 for handling
                                                    of the W/U and R responses.
UM128 REPORT LEAVING     UM128 REPORT LEAVING       See paragraph 4.2.12.1 for use of
[level]                  [altitude]                 level/altitude parameter.
                                                    Response attribute different: W/U
                                                    in the ATS INTEROP Standard, R
                                                    in the FANS 1/A INTEROP
                                                    Standard.
                                                    See paragraph 1.1.1 for handling
                                                    of the W/U and R responses.
UM129 REPORT             UM129 REPORT LEVEL         See paragraph 4.2.12.1 for use of
MAINTAINING [level]      [altitude]                 level/altitude parameter.
                                                    Response attribute different: W/U
                                                    in the ATS INTEROP Standard, R
                                                    in the FANS 1/A INTEROP
                                                    Standard.
                                                    See paragraph 1.1.1 for handling
                                                    of the W/U and R responses.
UM130 REPORT PASSING     UM130 REPORT PASSING       See paragraph 4.2.12.2 for use of
[position]               [position]                 position parameter.
                                                    Response attribute different: W/U
                                                    in the ATS INTEROP Standard, R
                                                    in the FANS 1/A INTEROP
                                                    Standard.
                                                    See paragraph 1.1.1 for handling
                                                    of the W/U and R responses.
UM131 REPORT REMAINING   UM131 REPORT REMAINING     Response attribute different: Y in
FUEL AND PERSONS ON      FUEL AND PERSONS ON        the ATS INTEROP Standard, NE
BOARD                    BOARD                      in the FANS 1/A INTEROP
                                                    Standard.
                                                    See paragraph 4.2.4 for processing
                                                    differences with message element
                                                    attributes.
                                                    See paragraph 4.2.13.2 for
                                                    processing message elements with
                                                    a ―Y‖ response attribute.
4-64


       ATN Message Element               FANS 1/A Message Element   Interoperability Requirement
       UM132 REPORT POSITION             UM132 CONFIRM POSITION     Response attribute different: Y in
                                                                    the ATS INTEROP Standard, NE
                                                                    in the FANS 1/A INTEROP
                                                                    Standard.
                                                                    See paragraph 4.2.4 for processing
                                                                    differences with message element
                                                                    attributes.
                                                                    See paragraph 4.2.13.2 for
                                                                    processing message elements with
                                                                    a ―Y‖ response attribute.
       UM133 REPORT PRESENT              UM133 CONFIRM ALTITUDE     Response attribute different: Y in
       LEVEL                                                        the ATS INTEROP Standard, NE
                                                                    in the FANS 1/A INTEROP
                                                                    Standard.
                                                                    See paragraph 4.2.4 for processing
                                                                    differences with message element
                                                                    attributes.
                                                                    See paragraph 4.2.13.2 for
                                                                    processing message elements with
                                                                    a ―Y‖ response attribute.
       UM134 REPORT [speed type]         UM134 CONFIRM SPEED        Response attribute different: Y in
       [speed type] [speed type] SPEED                              the ATS INTEROP Standard, NE
                                                                    in the FANS 1/A INTEROP
                                                                    Standard.
                                                                    See paragraph 4.2.4 for processing
                                                                    differences with message element
                                                                    attributes.
                                                                    See paragraph 4.2.13.2 for
                                                                    processing message elements with
                                                                    a ―Y‖ response attribute.
                                                                    Note: The response received from
                                                                    a FANS 1/A aircraft may not
                                                                    match the [speed type] requested.
       UM135 CONFIRM ASSIGNED            UM135 CONFIRM ASSIGNED     Response attribute different: Y in
       LEVEL                             ALTITUDE                   the ATS INTEROP Standard, NE
                                                                    in the FANS 1/A INTEROP
                                                                    Standard.
                                                                    See paragraph 4.2.4 for processing
                                                                    differences with message element
                                                                    attributes.
                                                                    See paragraph 4.2.13.2 for
                                                                    processing message elements with
                                                                    a ―Y‖ response attribute.
                                                                                    4-65


ATN Message Element       FANS 1/A Message Element     Interoperability Requirement
UM136 CONFIRM ASSIGNED    UM136 CONFIRM ASSIGNED       Response attribute different: Y in
SPEED                     SPEED                        the ATS INTEROP Standard, NE
                                                       in the FANS 1/A INTEROP
                                                       Standard.
                                                       See paragraph 4.2.4 for processing
                                                       differences with message element
                                                       attributes.
                                                       See paragraph 4.2.13.2 for
                                                       processing message elements with
                                                       a ―Y‖ response attribute.
UM137 CONFIRM ASSIGNED    UM137 CONFIRM ASSIGNED       Response attribute different: Y in
ROUTE                     ROUTE                        the ATS INTEROP Standard, NE
                                                       in the FANS 1/A INTEROP
                                                       Standard.
                                                       See paragraph 4.2.4 for processing
                                                       differences with message element
                                                       attributes.
                                                       See paragraph 4.2.13.2 for
                                                       processing message elements with
                                                       a ―Y‖ response attribute.
UM138 CONFIRM TIME OVER   UM138 CONFIRM TIME OVER Response attribute different: Y in
REPORTED WAYPOINT         REPORTED WAYPOINT       the ATS INTEROP Standard, NE
                                                  in the FANS 1/A INTEROP
                                                  Standard.
                                                  See paragraph 4.2.4 for processing
                                                  differences with message element
                                                  attributes.
                                                  See paragraph 4.2.13.2 for
                                                  processing message elements with
                                                  a ―Y‖ response attribute.
UM139 CONFIRM REPORTED    UM139 CONFIRM REPORTED       Response attribute different: Y in
WAYPOINT                  WAYPOINT                     the ATS INTEROP Standard, NE
                                                       in the FANS 1/A INTEROP
                                                       Standard.
                                                       See paragraph 4.2.4 for processing
                                                       differences with message element
                                                       attributes.
                                                       See paragraph 4.2.13.2 for
                                                       processing message elements with
                                                       a ―Y‖ response attribute.
4-66


       ATN Message Element     FANS 1/A Message Element   Interoperability Requirement
       UM140 CONFIRM NEXT      UM140 CONFIRM NEXT         Response attribute different: Y in
       WAYPOINT                WAYPOINT                   the ATS INTEROP Standard, NE
                                                          in the FANS 1/A INTEROP
                                                          Standard.
                                                          See paragraph 4.2.4 for processing
                                                          differences with message element
                                                          attributes.
                                                          See paragraph 4.2.13.2 for
                                                          processing message elements with
                                                          a ―Y‖ response attribute.
       UM141 CONFIRM NEXT      UM141 CONFIRM NEXT         Response attribute different: Y in
       WAYPOINT ETA            WAYPOINT ETA               the ATS INTEROP Standard, NE
                                                          in the FANS 1/A INTEROP
                                                          Standard.
                                                          See paragraph 4.2.4 for processing
                                                          differences with message element
                                                          attributes.
                                                          See paragraph 4.2.13.2 for
                                                          processing message elements with
                                                          a ―Y‖ response attribute.
       UM142 CONFIRM ENSUING   UM142 CONFIRM ENSUING      Response attribute different: Y in
       WAYPOINT                WAYPOINT                   the ATS INTEROP Standard, NE
                                                          in the FANS 1/A INTEROP
                                                          Standard.
                                                          See paragraph 4.2.4 for processing
                                                          differences with message element
                                                          attributes.
                                                          See paragraph 4.2.13.2 for
                                                          processing message elements with
                                                          a ―Y‖ response attribute.
       UM143 CONFIRM REQUEST   UM143 CONFIRM REQUEST      Response attribute different: Y in
                                                          the ATS INTEROP Standard, NE
                                                          in the FANS 1/A INTEROP
                                                          Standard.
                                                          See paragraph 4.2.4 for processing
                                                          differences with message element
                                                          attributes.
                                                          See paragraph 4.2.13.2 for
                                                          processing message elements with
                                                          a ―Y‖ response attribute.
                                                                                 4-67


ATN Message Element      FANS 1/A Message Element   Interoperability Requirement
UM144 CONFIRM SQUAWK     UM144 CONFIRM SQUAWK       Response attribute different: Y in
                                                    the ATS INTEROP Standard, NE
                                                    in the FANS 1/A INTEROP
                                                    Standard.
                                                    See paragraph 4.2.4 for processing
                                                    differences with message element
                                                    attributes.
                                                    See paragraph 4.2.13.2 for
                                                    processing message elements with
                                                    a ―Y‖ response attribute.
UM145 CONFIRM HEADING    UM145 CONFIRM HEADING      Response attribute different: Y in
                                                    the ATS INTEROP Standard, NE
                                                    in the FANS 1/A INTEROP
                                                    Standard.
                                                    See paragraph 4.2.4 for processing
                                                    differences with message element
                                                    attributes.
                                                    See paragraph 4.2.13.2 for
                                                    processing message elements with
                                                    a ―Y‖ response attribute.
UM146 REPORT GROUND      UM146 CONFIRM GROUND       Response attribute different: Y in
TRACK                    TRACK                      the ATS INTEROP Standard, NE
                                                    in the FANS 1/A INTEROP
                                                    Standard.
                                                    See paragraph 4.2.4 for processing
                                                    differences with message element
                                                    attributes.
                                                    See paragraph 4.2.13.2 for
                                                    processing message elements with
                                                    a ―Y‖ response attribute.
UM147 REQUEST POSITION   UM147 REQUEST POSITION     Response attribute different: Y in
REPORT                   REPORT                     the ATS INTEROP Standard, NE
                                                    in the FANS 1/A INTEROP
                                                    Standard.
                                                    See paragraph 4.2.4 for processing
                                                    differences with message element
                                                    attributes.
                                                    See paragraph 4.2.13.2 for
                                                    processing message elements with
                                                    a ―Y‖ response attribute.
4-68


       ATN Message Element           FANS 1/A Message Element      Interoperability Requirement
       UM148 WHEN CAN YOU            UM148 WHEN CAN YOU            Response attribute is different: Y
       ACCEPT [level]                ACCEPT [altitude]             in the ATS INTEROP Standard,
                                                                   NE in the FANS 1/A INTEROP
                                                                   Standard.
                                                                   See paragraph 4.2.4 for processing
                                                                   differences with message element
                                                                   attributes.
                                                                   See paragraph 4.2.12.1 for use of
                                                                   level/altitude parameter.
                                                                   See paragraph 4.2.13.2 for
                                                                   processing message elements with
                                                                   a ―Y‖ response attribute.
       UM149 CAN YOU ACCEPT          UM149 CAN YOU ACCEPT          None.
       [level] AT [position]         [altitude] AT [position]      See paragraph 4.2.12.1 for use of
                                                                   level/altitude parameter.
                                                                   See paragraph 4.2.12.2 for use of
                                                                   position parameter.
       UM150 Replaced by UM277       UM150 CAN YOU ACCEPT          None, ATN message is never sent.
                                     [altitude] AT [time]
       UM151 WHEN CAN YOU            None.                         None. The required response
       ACCEPT [speed]                                              downlink messages are not
                                                                   available in FANS 1/A.
       UM152 WHEN CAN YOU            UM152 WHEN CAN YOU            See paragraph 4.2.12.4 for use of
       ACCEPT [specified distance]   ACCEPT [distanceoffset]       specified distance parameter.
       [direction] OFFSET            [direction] OFFSET            Response attribute different: Y in
                                                                   the ATS INTEROP Standard, NE
                                                                   in the FANS 1/A INTEROP
                                                                   Standard.
                                                                   See paragraph 4.2.4 for processing
                                                                   differences with message element
                                                                   attributes.
                                                                   See paragraph 4.2.13.2 for
                                                                   processing message elements with
                                                                   a ―Y‖ response attribute.
       UM153 Replaced by UM278       UM153 ALTIMETER [altimeter] None, ATN message is never sent.
       UM154 RADAR SERVICE           UM154 RADAR SERVICE           None.
       TERMINATED                    TERMINATED

       UM155 RADAR CONTACT           UM155 RADAR CONTACT           See paragraph 4.2.12.2 for use of
       [position]                    [position]                    position parameter.
       UM156 RADAR CONTACT           UM156 RADAR CONTACT           None.
       LOST                          LOST
                                                                                               4-69


ATN Message Element              FANS 1/A Message Element        Interoperability Requirement
UM157 Replaced by UM279          UM157 CHECK STUCK               None, ATN message is never sent.
                                 MICROPHONE [frequency]
UM158 ATIS [atis code]           UM158 ATIS [atiscode]           None.
UM159 ERROR [error               UM159 ERROR                     See paragraph 4.2.11.2 for use of
information]                     [errorinformation]              error information parameter.
UM160 NEXT DATA                  UM160 NEXT DATA                 See paragraph 4.2.12.8 for use of
AUTHORITY [facility]             AUTHORITY                       facility parameter.
                                 [icaofacilitydesignation]
UM161 END SERVICE                UM161 END SERVICE               None.
UM162 MESSAGE NOT                UM162 SERVICE                   None.
SUPPORTED BY THIS ATS            UNAVAILABLE
UNIT
UM163 [facility designation]     UM163                           FANS 1/A Aircraft shall set the
                                 [facilitydesignationTP4table]   TP4 table parameter to label A.
                                                                 See paragraph 4.2.12.8.2 for use
                                                                 of facility designation parameter.
                                                                 Note: Only labels A is supported
                                                                 by FANS 1/A aircraft.
UM164 WHEN READY                 UM164 WHEN READY                None.
UM165 THEN                       UM165 THEN                      None.
UM166 DUE TO [traffic type]      UM166 DUE TO TRAFFIC            None.
TRAFFIC                                                          Note: FANS 1/A does not use the
                                                                 [traffic type] parameter.
UM167 DUE TO AIRSPACE            UM167 DUE TO AIRSPACE           None.
RESTRICTION                      RESTRICTION
UM168 DISREGARD                  UM168 DISREGARD                 None.
UM169 [free text]                UM169 [free text]               None.
UM170 [free text]                UM170 [free text]               None.
UM171 CLIMB AT [vertical rate]   UM171 CLIMB AT [vertical        See paragraph 4.2.12.7 for use of
MINIMUM                          rate] MINIMUM                   vertical rate parameter.
UM172 CLIMB AT [vertical rate]   UM172 CLIMB AT [vertical        See paragraph 4.2.12.7 for use of
MAXIMUM                          rate] MAXIMUM                   vertical rate parameter.
UM173 DESCEND AT [vertical       UM173 DESCEND AT [vertical      See paragraph 4.2.12.7 for use of
rate] MINIMUM                    rate] MINIMUM                   vertical rate parameter.
UM174 DESCEND AT [vertical       UM174 DESCEND AT [vertical      See paragraph 4.2.12.7 for use of
rate] MAXIMUM                    rate] MAXIMUM                   vertical rate parameter.
UM175 Reserved                   UM 175 REPORT REACHING          None, ATN message is never sent.
                                 [altitude]
4-70


       ATN Message Element       FANS 1/A Message Element   Interoperability Requirement
       UM 176 MAINTAIN OWN       UM 176 MAINTAIN OWN        None.
       SEPARATION AND VMC        SEPARATION AND VMC
       UM177 AT PILOTS           UM177 AT PILOTS            None.
       DISCRETION                DISCRETION
       UM178 Reserved            UM178 Reserved             None, ATN message is never sent.
       UM179 SQUAWK IDENT        UM179 SQUAWK IDENT         None.
       UM180 Reserved            UM180 REPORT REACHING      None, ATN message is never sent.
                                 BLOCK [level] TO [level]
       UM181 REPORT DISTANCE     UM181 REPORT DISTANCE      See paragraph 4.2.12.2 for use of
       [to/from] [position]      [to/from] [position]       position parameter.
                                                            Response attribute different: Y in
                                                            the ATS INTEROP Standard, NE
                                                            in the FANS 1/A INTEROP
                                                            Standard.
                                                            See paragraph 4.2.4 for processing
                                                            differences with message element
                                                            attributes.
                                                            See paragraph 4.2.13.2 for
                                                            processing message elements with
                                                            a ―Y‖ response attribute.
       UM182 CONFIRM ATIS CODE   UM182 CONFIRM ATIS CODE    Response attribute different: Y in
                                                            the ATS INTEROP Standard, NE
                                                            in the FANS 1/A INTEROP
                                                            Standard.
                                                            See paragraph 4.2.4 for processing
                                                            differences with message element
                                                            attributes.
                                                            See paragraph 4.2.13.2 for
                                                            processing message elements with
                                                            a ―Y‖ response attribute.
                                                                                 4-71


ATN Message Element       FANS 1/A Message Element   Interoperability Requirement
UM183 [free text]         UM169 [freetext]           IR-66   The ATN ground
                                                     system shall convert UM183
                                                     message into UM169.
                                                     IR-67   The ATN ground
                                                     system shall use the same
                                                     character string in UM169 as in
                                                     UM183.
                                                     IR-68   The ATN ground
                                                     system shall ignore the
                                                     ROGER response when
                                                     received as a response to
                                                     UM183.
                                                     Response attribute for UM169 is
                                                     different: N in ATN, R in
                                                     FANS 1/A.
UM184 Replaced by UM280   None.                      None, ATN message is never sent.
UM185 Reserved            None.                      None, ATN message is never sent.
UM186 Reserved            None.                      None, ATN message is never sent.
UM187 [free text]         UM169 [freetext]           IR-69   The ATN ground
                                                     system shall convert UM187
                                                     message into UM169.
                                                     IR-70   The ATN ground
                                                     system shall use the same
                                                     character string in UM169 as in
                                                     UM187.
                                                     IR-71   The ATN ground
                                                     system shall ignore the
                                                     ROGER response when
                                                     received as a response to
                                                     UM187.
                                                     Response attribute for UM169 is
                                                     different: N in ATN, R in
                                                     FANS 1/A.
                                                     Urgency attribute for UM169 is
                                                     different: L in ATN, N in FANS
                                                     1/A.
4-72


       ATN Message Element             FANS 1/A Message Element         Interoperability Requirement
       UM188 AFTER PASSING             None.                            Not viable.
       [position] MAINTAIN [speed]                                      The use of FANS 1/A message
                                                                        element UM169 to use the ATN
                                                                        message UM188 is not considered
                                                                        a valid option in this document
                                                                        (no free text UM with W/U
                                                                        response attribute).
       UM189 ADJUST SPEED TO           None.                            Not viable.
       [speed]                                                          The use of FANS 1/A message
                                                                        element UM169 to use the ATN
                                                                        message UM189 is not considered
                                                                        a valid option in this document
                                                                        (no free text UM with W/U
                                                                        response attribute).
       UM190 FLY HEADING [degrees] UM94 TURN [direction]                IR-72   When the ATN ground
                                   HEADING [degrees] where the          system has current heading
                                   choice for the direction parameter   information and it can
                                   shall be set to [right] or [left]    distinguish the direction of the
                                                                        turn and use the appropriate
                                                                        choices [left] or [right], the
                                                                        ATN ground system shall
                                                                        convert ATN UM190 message
                                                                        element into the FANS 1/A
                                                                        message element UM94.
                                                                        The use of the FANS 1/A message
                                                                        element UM169 to provide the
                                                                        message content of the ATN
                                                                        message element UM190 is not
                                                                        considered as a valid option (no
                                                                        free text UM with W/U response
                                                                        attribute).
                                                                        See paragraph 4.2.12.10 for use of
                                                                        degrees parameter.
       UM191 ALL ATS                   UM169 ‗ALL ATS                   IR-73   The ATN ground
       TERMINATED                      TERMINATED‘                      system shall convert the ATN
                                                                        UM191 message element into
                                                                        FANS 1/A UM169 message
                                                                        element.
                                                                        Alert attribute for UM169 is
                                                                        different than UM191: M in ATN,
                                                                        V in FANS 1/A.
                                                                        See paragraph 4.2.4 for processing
                                                                        differences with message element
                                                                        attributes.
                                                                                   4-73


ATN Message Element       FANS 1/A Message Element   Interoperability Requirement
UM192 Replaced by UM281   None.                      None, ATN message is never sent.


UM193 IDENTIFICATION      UM169 ‗IDENTIFICATION      IR-74   The ATN ground
LOST                      LOST‘                      system shall convert the ATN
                                                     UM193 message element into
                                                     FANS 1/A UM169 message
                                                     element.
                                                     Alert attribute for UM169 is
                                                     different than UM193: M in ATN,
                                                     V in FANS 1/A.
                                                     See paragraph 4.2.4 for processing
                                                     differences with message element
                                                     attributes.
UM194 [free text]         None.                      None, ATN message is never sent.
UM195 [free text]         UM169 [freetext]           IR-75   The ATN ground
                                                     system shall convert UM195
                                                     message into UM169.
                                                     IR-76   The ATN ground
                                                     system shall use the same
                                                     character string in UM169 as in
                                                     UM195.
                                                     Urgency attribute for UM169 is
                                                     different: L in ATN, N in FANS
                                                     1/A.
UM196 [free text]         None                       Not viable.
                                                     The use of FANS 1/A message
                                                     element UM169 to use the ATN
                                                     message element UM196 is not
                                                     considered a valid option in this
                                                     document (no free text UM with
                                                     W/U response attribute).
4-74


       ATN Message Element   FANS 1/A Message Element   Interoperability Requirement

       UM197 [free text]     None                       Not viable.
                                                        IR-77    The use of FANS 1/A
                                                        message element UM169 to
                                                        use the ATN message element
                                                        UM197 is not considered a
                                                        valid option in this document
                                                        (no free text UM with W/U
                                                        response attribute).
       UM198 [free text]     None                       Not viable.The use of FANS 1/A
                                                        message element UM169 to use
                                                        the ATN message element UM198
                                                        is not considered a valid option in
                                                        this document (no free text UM
                                                        with W/U response attribute).

       UM199 [free text]     UM169 [freetext]           IR-78   The ATN ground
                                                        system shall convert UM199
                                                        message into UM169.
                                                        IR-79   The ATN ground
                                                        system shall use the same
                                                        character string in UM169 as in
                                                        UM199.
                                                        IR-80   The ATN ground
                                                        system shall ignore the
                                                        ROGER/ STANDBY response
                                                        when received as a response to
                                                        UM199.
                                                        Response attribute for UM169 is
                                                        different: N in ATN, R in
                                                        FANS 1/A.

       UM200 REPORT          None.                      Not viable.
       MAINTAINING                                      The use of FANS 1/A message
                                                        element UM169 to use the ATN
                                                        message UM200 is not considered
                                                        a valid option in this document
                                                        (no free text UM with W/U
                                                        response attribute).
       UM201 Reserved        None.                      Message Reserved.
       UM202 Reserved        None.                      Message Reserved.
                                                                             4-75


ATN Message Element   FANS 1/A Message Element   Interoperability Requirement
UM203 [free text]     UM169 [freetext]           IR-81   The ATN ground
                                                 system shall convert the
                                                 UM203 message into UM169.
                                                 IR-82   The ATN ground
                                                 system shall use the same
                                                 character string in UM169 as in
                                                 UM203.
UM204 [free text]     None.                      None, ATN message is never sent.
UM205 [free text]     UM169 [free text]          IR-83   The ATN ground
                                                 system shall convert the ATN
                                                 message element UM205 into
                                                 the FANS 1/A message
                                                 element UM169.
                                                 IR-84   The ATN ground
                                                 system shall process the
                                                 ROGER response as a positive
                                                 response to the ATN message
                                                 element UM205.
                                                 Response attribute for UM169 is
                                                 different than UM205: A/N in
                                                 ATN, R in FANS 1/A.
                                                 Processing the pilot‘s UNABLE
                                                 response is a local matter.
UM206 [free text]     None.                      None, ATN message is never sent.
UM207 [free text]     UM169 [freetext]           IR-85   The ATN ground
                                                 system shall convert UM207
                                                 message into UM169.
                                                 IR-86   The ATN ground
                                                 system shall use the same
                                                 character string in UM169 as in
                                                 UM207.
                                                 See paragraph 4.2.13.2 for
                                                 processing message elements with
                                                 a ―Y‖ response attribute.
                                                 Response attribute for UM169 is
                                                 different: Y in ATN, R in
                                                 FANS 1/A.
                                                 Urgency attribute for UM169 is
                                                 different: L in ATN, N in FANS
                                                 1/A.
4-76


       ATN Message Element           FANS 1/A Message Element    Interoperability Requirement
       UM208 [free text]             UM169 [freetext]            IR-87   The ATN ground
                                                                 system shall convert UM208
                                                                 message into UM169.
                                                                 IR-88   The ATN ground
                                                                 system shall use the same
                                                                 character string in UM169 as in
                                                                 UM208.
                                                                 IR-89   The ATN ground
                                                                 system shall ignore the
                                                                 ROGER/ STANDBY response
                                                                 when received as a response to
                                                                 UM208.
                                                                 Response attribute for UM169 is
                                                                 different: N in ATN, R in
                                                                 FANS 1/A.
                                                                 Urgency attribute for UM169 is
                                                                 different: L in ATN, N in FANS
                                                                 1/A.
       UM209 REACH [level] BY        None.                       Not viable.
       [position]                                                The use of FANS 1/A message
                                                                 element UM169 to use the ATN
                                                                 message UM209 is not considered
                                                                 a valid option in this document
                                                                 (no free text UM with W/U
                                                                 response attribute).
       UM210 IDENTIFIED [position]   UM169 ‗IDENTIFIED [xxx]‘    IR-90    The ATN ground
                                     Where [xxx] = [position].   system shall convert the
                                                                 UM210 message into UM169.
                                                                 IR-91    When sending UM210,
                                                                 the ATN ground system shall
                                                                 include the [position]
                                                                 parameter in the free text
                                                                 parameter of UM169 as one of
                                                                 the choices:
                                                                 IR-92     a character string of
                                                                 four letters, representing the
                                                                 location indicator of the facility
                                                                 designation for navid, airport,
                                                                 and fix name
                                                                 IR-93    Place bearing distance
                                                                 and latitude/longitude are not
                                                                 viable options.
                                                                                           4-77


ATN Message Element            FANS 1/A Message Element       Interoperability Requirement
UM211 REQUEST                  UM169 ‗REQUEST                 IR-94   The ATN ground
FORWARDED                      FORWARDED‘                     system shall convert the
                                                              UM211 message into UM169.
                                                              IR-95   When using UM169 to
                                                              convert UM211, the ATN
                                                              ground system shall ignore
                                                              ROGER/ STANDBY response
                                                              when received as answer to
                                                              UM169.
                                                              Response attribute for UM169 is
                                                              different than UM211: N in ATN,
                                                              R in FANS 1/A.
UM212 [facility designation]   UM169 ‗[xxx] ATIS [yyy]        IR-96    The ATN ground
ATIS [atis code] CURRENT       CURRENT‘                       system shall convert the
                               Where [xxx] = [facility        UM212 message into UM169.
                               designation] and [yyy]=[atis   IR-97    When sending UM212,
                               code]
                                                              the ATN ground system shall
                                                              include the [facility
                                                              designation] parameter in the
                                                              free text parameter of UM169
                                                              as a 4 character string.
                                                              IR-98    When sending UM212,
                                                              the ATN ground system shall
                                                              include the [atis code]
                                                              parameter in the free text
                                                              parameter of UM169 as a 1
                                                              character string
UM213 Replaced by UM277.       None.                          None, ATN message is never sent.
UM214 Replaced by UM283.       None.                          None, ATN message is never sent.
UM215 TURN [direction]         None.                          Not viable.
[degrees] DEGREES                                             The use of FANS 1/A message
                                                              element UM169 to use the ATN
                                                              message element UM215 is not
                                                              considered in this document as a
                                                              valid option (no free text UM with
                                                              W/U response attribute).
UM216 REQUEST FLIGHT           None.                          None, ATN message is never sent.
PLAN
4-78


       ATN Message Element           FANS 1/A Message Element   Interoperability Requirement
       UM217 REPORT ARRIVAL          None.                      Not viable.
                                                                The response to ATN message
                                                                UM217 (DM102 LANDING
                                                                REPORT) is not available in
                                                                FANS 1/A.
       UM218 REQUEST ALREADY         UM169 ‗REQUEST ALREADY     IR-99   The ATN ground
       RECEIVED                      RECEIVED‘                  system shall convert the ATN
                                                                UM218 message element into
                                                                FANS 1/A UM169 message
                                                                element.
                                                                IR-100 The ATN ground
                                                                system shall ignore the
                                                                ROGER response for ATN
                                                                message UM218 for a FANS
                                                                1/A aircraft.
                                                                Response attribute for UM169 is
                                                                different than UM218: N in ATN,
                                                                R in FANS 1/A.


       UM219 STOP CLIMB AT [level]   None.                      Not viable.
                                                                The use of FANS 1/A message
                                                                element UM169 to use the ATN
                                                                message UM219 is not considered
                                                                a valid option in this document
                                                                (no free text UM with W/U
                                                                response attribute).
       UM220 STOP DESCENT AT         None.                      Not viable.
       [level]                                                  The use of FANS 1/A message
                                                                element UM169 to use the ATN
                                                                message UM220 is not considered
                                                                a valid option in this document
                                                                (no free text UM with W/U
                                                                response attribute).
       UM221 STOP TURN HEADING       None.                      Not viable.
       [degrees]                                                The use of FANS 1/A message
                                                                element UM169 to use the ATN
                                                                message UM221 is not considered
                                                                a valid option in this document
                                                                (no free text UM with W/U
                                                                response attribute).
                                                                                      4-79


ATN Message Element           FANS 1/A Message Element   Interoperability Requirement
UM222 NO SPEED                UM169 ‗NO SPEED            IR-101  The ATN ground
RESTRICTION                   RESTRICTION‘               system shall convert the ATN
                                                         UM222 message element into
                                                         FANS 1/A UM169 message
                                                         element.
                                                         See this document,
                                                         paragraph 4.2.4 for processing
                                                         message attributes.
UM223 REDUCE TO MINIMUM None.                            Not viable.
APPROACH SPEED                                           The use of FANS 1/A message
                                                         element UM169 to use the ATN
                                                         message UM223 is not considered
                                                         a valid option in this document
                                                         (no free text UM with W/U
                                                         response attribute).
UM224 NO DELAY EXPECTED UM169 ‗NO DELAY                  IR-102  The ATN ground
                        EXPECTED‘                        system shall convert the ATN
                                                         UM224 message element into
                                                         FANS 1/A UM169 message
                                                         element.
UM225 DELAY NOT               UM169 ‗DELAY NOT           IR-103  The ATN ground
DETERMINED                    DETERMINED‘                system shall convert the ATN
                                                         UM225 message element into
                                                         FANS 1/A UM169 message
                                                         element.
UM226 Replaced by UM284       None.                      None, the message is never sent.
UM227 LOGICAL                 None                       See paragraph 4.2.5 for use of
ACKNOWLEDGEMENT                                          LACK.
UM228 REPORT ETA [position]   None.                      Not viable.
                                                         The use of FANS 1/A message
                                                         element UM169 to use the ATN
                                                         message UM228 is not considered
                                                         a valid option in this document.
                                                         The response message DM134
                                                         ETA [position][time] is not
                                                         supported in FANS 1/A.
4-80


       ATN Message Element      FANS 1/A Message Element   Interoperability Requirement
       UM229 REPORT ALTERNATE   None.                      Not viable.
       AERODROME                                           The use of FANS 1/A message
                                                           element UM169 to use the ATN
                                                           message UM229 is not considered
                                                           a valid option in this document.
                                                           The response message DM105
                                                           ALTERNATIVE AERODROME
                                                           [airport] is not supported in FANS
                                                           1/A.
       UM230 IMMEDIATELY        UM 169 ‗IMMEDIATELY‘       IR-104  The ATN ground
                                                           system shall convert the ATN
                                                           UM230 message element into
                                                           FANS 1/A UM169 message
                                                           element only when sent with a
                                                           message element requiring a
                                                           W/U response.
       UM231 STATE PREFERRED    UM169 ‗STATE PREFERRED     IR-105  The ATN ground
       LEVEL                    LEVEL‘                     system shall convert the ATN
                                                           message element UM231 into
                                                           the equivalent FANS 1/A
                                                           message element UM169.
                                                           Response attribute for UM169 is
                                                           different than UM231: Y in ATN,
                                                           R in FANS 1/A.
                                                           See paragraph 4.2.4 for processing
                                                           differences with message element
                                                           attributes.
                                                           See paragraph 4.2.13.2 for
                                                           processing message elements with
                                                           a ―Y‖ response attribute.
       UM232 STATE-TOP-OF-      UM169 ‗STATE TOP OF        IR-106  The ATN ground
       DESCENT                  DESCENT‘                   system shall convert the ATN
                                                           message element UM232 into
                                                           FANS 1/A message element
                                                           UM169.
                                                           Response attribute for UM169 is
                                                           different than UM232: Y in ATN,
                                                           R in FANS 1/A.
                                                           See paragraph 4.2.4 for processing
                                                           differences with message element
                                                           attributes.
                                                           See paragraph 4.2.13.2 for
                                                           processing message elements with
                                                           a ―Y‖ response attribute.
                                                                                    4-81


ATN Message Element      FANS 1/A Message Element   Interoperability Requirement
UM233 USE OF LOGICAL     None                       IR-107   The ATN ground
ACKNOWLEDGEMENT                                     system shall prohibit the use of
PROHIBITED                                          UM233 USE OF LACK
                                                    PROHIBITED for FANS 1/A
                                                    aircraft
                                                    See paragraph 4.2.5 on use of
                                                    LACK.
UM234 FLIGHT PLAN NOT    UM169 ‗FLIGHT PLAN NOT     IR-108  The ATN ground
HELD                     HELD‘                      system shall convert the ATN
                                                    UM234 message element into
                                                    FANS 1/A UM169 message
                                                    element.
                                                    IR-109 The ATN ground
                                                    system shall ignore the
                                                    ROGER response for ATN
                                                    message UM234.
                                                    Response attribute for UM169 is
                                                    different than UM234: N in ATN,
                                                    R in FANS 1/A.
UM235 ROGER 7500         UM169 ‗ROGER 7500‘         IR-110  The ATN ground
                                                    system shall convert the ATN
                                                    UM235 message element into
                                                    FANS 1/A UM169 message
                                                    element.
                                                    IR-111 The ATN ground
                                                    system shall ignore the
                                                    ROGER response for ATN
                                                    message UM235.
                                                    Response attribute for UM169 is
                                                    different than UM235: N in ATN,
                                                    R in FANS 1/A.
UM236 LEAVE CONTROLLED   None.                      Not viable.
AIRSPACE                                            The use of FANS 1/A message
                                                    element UM169 to use the ATN
                                                    message UM236 is not considered
                                                    a valid option in this document
                                                    (no free text UM with W/U
                                                    response attribute).
4-82


       ATN Message Element     FANS 1/A Message Element    Interoperability Requirement
       UM237 REQUEST AGAIN     UM169 ‗REQUEST AGAIN        IR-112  The ATN ground
       WITH NEXT UNIT          WITH NEXT UNIT‘             system shall convert the ATN
                                                           message element UM237 into
                                                           the FANS 1/A message
                                                           element UM169.
                                                           IR-113 The ATN ground
                                                           system shall ignore the
                                                           ROGER response received as a
                                                           response to the ATN message
                                                           element UM237.
                                                           Response attribute for UM169 is
                                                           different than UM237: N in ATN,
                                                           R in FANS 1/A.
       UM238 SECONDARY         UM169 ‗SECONDARY            IR-114   The ATN ground
       FREQUENCY [frequency]   FREQUENCY [xxx]‘            system shall convert the ATN
                               Where [xxx] = [frequency]   UM238 message element into
                                                           FANS 1/A UM169 message
                                                           element.
                                                           IR-115 When sending UM238,
                                                           the ATN ground system shall
                                                           include the [frequency]
                                                           parameter in the free text
                                                           parameter of UM169 as an
                                                           integer converted to a max of
                                                           12 character string.
       UM239 STOP ADS-B        UM169 ‗STOP ADS-B           IR-116  The ATN ground
       TRANSMISSION            TRANSMISSION‘               system shall convert the ATN
                                                           UM239 message element into
                                                           FANS 1/A UM169 message
                                                           element.
                                                           Response attribute different: W/U
                                                           in the ATS INTEROP Standard, R
                                                           in the FANS 1/A INTEROP
                                                           Standard.
                                                           IR-117  See paragraph 1.1.1 for
                                                           handling of the W/U and R
                                                           responses.
                                                                                4-83


ATN Message Element     FANS 1/A Message Element   Interoperability Requirement
UM240 TRANSMIT ADS-B    UM169 ‗TRANSMIT ADS-B      IR-118  The ATN ground
ALTITUDE                ALTITUDE‘                  system shall convert the ATN
                                                   UM240 message element into
                                                   FANS 1/A UM169 message
                                                   element.
                                                   Response attribute different: W/U
                                                   in the ATS INTEROP Standard,
                                                   R in the FANS 1/A INTEROP
                                                   Standard.
                                                   IR-119  See paragraph 1.1.1
                                                   for handling of the W/U and R
                                                   responses.
UM241 STOP ADS-B        UM169 ‗STOP ADS-B          IR-120  The ATN ground
ALTITUDE TRANSMISSION   ALTITUDE TRANSMISSION‘     system shall convert the ATN
                                                   UM241 message element into
                                                   FANS 1/A UM169 message
                                                   element.
                                                   Response attribute different: W/U
                                                   in the ATS INTEROP Standard,
                                                   R in the FANS 1/A INTEROP
                                                   Standard.
                                                   See paragraph 1.1.1 for handling
                                                   of the W/U and R responses.
UM242 TRANSMIT ADS-B    UM169 ‗TRANSMIT ADS-B      IR-121  The ATN ground
IDENT                   IDENT‘                     system shall convert the ATN
                                                   UM242 message element into
                                                   FANS 1/A UM169 message
                                                   element.
                                                   Response attribute different: W/U
                                                   in the ATS INTEROP Standard,
                                                   R in the FANS 1/A INTEROP
                                                   Standard.
                                                   See paragraph 1.1.1 for handling
                                                   of the W/U and R responses.
UM243 REPORT CLEAR OF   None.                      Not viable.
WEATHER                                            The use of FANS 1/A message
                                                   element UM169 to use the ATN
                                                   message UM243 is not
                                                   considered a valid option in this
                                                   document (no free text UM with
                                                   W/U response attribute).
                                                   In addition, the response message
                                                   DM114 CLEAR OF WEATHER
                                                   is not supported in FANS 1/A.
4-84


       ATN Message Element           FANS 1/A Message Element    Interoperability Requirement
       UM244 IDENTIFICATION          UM169 ‗IDENTIFICATION       IR-122  The ATN ground
       TERMINATED                    TERMINATED‘                 system shall convert the ATN
                                                                 UM244 message element into
                                                                 FANS 1/A UM169 message
                                                                 element.
       UM245 EXPECT CLIMB AT         UM7 EXPECT CLIMB AT         IR-123  The ATN ground
       [timesec]                     [time]                      system shall convert the ATN
                                                                 message UM245 to the FANS
                                                                 1/A message UM7.
                                                                 See paragraph 4.2.12.6 for use of
                                                                 the time/timesec parameter.
       UM246 EXPECT DESCENT AT       UM9 EXPECT DESCENT AT       IR-124  The ATN ground
       [timesec]                     [time]                      system shall convert the ATN
                                                                 message UM246 to the FANS
                                                                 1/A message UM9.
                                                                 See paragraph 4.2.12.6 for use of
                                                                 the time/timesec parameter.
       UM247 EXPECT CRUISE           UM11 EXPECT CRUISE          IR-125  The ATN ground
       CLIMB AT [timesec]            CLIMB AT [time]             system shall convert the ATN
                                                                 message UM247 to the FANS
                                                                 1/A message UM11.
                                                                 See paragraph 4.2.12.6 for use of
                                                                 the time/timesec parameter.
       UM248 AT [timesec] CLIMB TO   UM21 AT [time] CLIMB TO     IR-126  The ATN ground
       [level]                       AND MAINTAIN [altitude]     system shall convert the ATN
                                                                 message UM248 to the FANS
                                                                 1/A message UM21.
                                                                 See paragraph 4.2.12.6 for use of
                                                                 the time/timesec parameter.
                                                                 See paragraph 4.2.12.1 for use of
                                                                 level/altitude parameter.
       UM249 AT [timesec] DESCEND    UM24 AT [time] DESCEND TO   IR-127  The ATN ground
       TO [level]                    [altitude]                  system shall convert the ATN
                                                                 message UM249 to the FANS
                                                                 1/A message UM24.
                                                                 See paragraph 4.2.12.6 for use of
                                                                 the time/timesec parameter.
                                                                 See paragraph 4.2.12.1 for use of
                                                                 level/altitude parameter.
                                                                                        4-85


ATN Message Element          FANS 1/A Message Element      Interoperability Requirement
UM250 CLIMB TO REACH         UM26 CLIMB TO REACH           IR-128  The ATN ground
[level] BY [timesec]         [altitude] BY [time]          system shall convert the ATN
                                                           message UM250 to the FANS
                                                           1/A message UM26.
                                                           See paragraph 4.2.12.6 for use of
                                                           the time/timesec parameter.
                                                           See paragraph 4.2.12.1 for use of
                                                           level/altitude parameter.
UM251 DESCEND TO REACH       UM28 DESCEND TO REACH         IR-129  The ATN ground
[level] BY [timesec]         [altitude] BY [time]          system shall convert the ATN
                                                           message UM251 to the FANS
                                                           1/A message UM28.
                                                           See paragraph 4.2.12.6 for use of
                                                           the time/timesec parameter.
                                                           See paragraph 4.2.12.1 for use of
                                                           level/altitude parameter.
UM252 CROSS [position] AT    UM51 CROSS [position] AT      IR-130  The ATN ground
[timesec]                    [time]                        system shall convert the ATN
                                                           message UM252 to the FANS
                                                           1/A message UM51.
                                                           See paragraph 4.2.12.6 for use of
                                                           the time/timesec parameter.
                                                           See paragraph 4.2.12.2 for use of
                                                           position parameter.
UM253 CROSS [position] AT OR UM52 CROSS [position] AT OR   IR-131  The ATN ground
BEFORE [timesec]             BEFORE [time]                 system shall convert the ATN
                                                           message UM253 to the FANS
                                                           1/A message UM52.
                                                           See paragraph 4.2.12.6 for use of
                                                           the time/timesec parameter.
                                                           See paragraph 4.2.12.2 for use of
                                                           position parameter.
UM254 CROSS [position] AT OR UM53 CROSS [position] AT OR   IR-132  The ATN ground
AFTER [timesec]              AFTER [time]                  system shall convert the ATN
                                                           message UM254 to the FANS
                                                           1/A message UM53.
                                                           See paragraph 4.2.12.6 for use of
                                                           the time/timesec parameter.
                                                           See paragraph 4.2.12.2 for use of
                                                           position parameter.
4-86


       ATN Message Element          FANS 1/A Message Element      Interoperability Requirement
       UM255 CROSS [position]       UM54 CROSS [position]         IR-133  The ATN ground
       BETWEEN [timesec] AND        BETWEEN [time] AND [time]     system shall convert the ATN
       [timesec]                                                  message UM255 to the FANS
                                                                  1/A message UM54.
                                                                  See paragraph 4.2.12.6 for use of
                                                                  the time/timesec parameter.
                                                                  See paragraph 4.2.12.2 for use of
                                                                  position parameter.
       UM256 CROSS [position] AT    UM58 CROSS [position] AT      IR-134  The ATN ground
       [timesec] AT [level]         [time] AT [altitude]          system shall convert the ATN
                                                                  message UM256 to the FANS
                                                                  1/A message UM58.
                                                                  See paragraph 4.2.12.6 for use of
                                                                  the time/timesec parameter.
                                                                  See paragraph 4.2.12.2 for use of
                                                                  position parameter.
                                                                  See paragraph 4.2.12.1 for use of
                                                                  level/altitude parameter.
       UM257 CROSS [position] AT OR UM59 CROSS [position] AT OR   IR-135  The ATN ground
       BEFORE [timesec] AT [level]  BEFORE [time] AT [altitude]   system shall convert the ATN
                                                                  message UM257 to the FANS
                                                                  1/A message UM59.
                                                                  See paragraph 4.2.12.6 for use of
                                                                  the time/timesec parameter.
                                                                  See paragraph 4.2.12.2 for use of
                                                                  position parameter.
                                                                  See paragraph 4.2.12.1 for use of
                                                                  level/altitude parameter.
       UM258 CROSS [position] AT OR UM60 CROSS [position] AT OR   IR-136  The ATN ground
       AFTER [timesec] AT [level]   AFTER [time] AT [altitude]    system shall convert the ATN
                                                                  message UM258 to the FANS
                                                                  1/A message UM60.
                                                                  See paragraph 4.2.12.6 for use of
                                                                  the time/timesec parameter.
                                                                  See paragraph 4.2.12.2 for use of
                                                                  position parameter.
                                                                  See paragraph 4.2.12.1 for use of
                                                                  level/altitude parameter.
                                                                                                  4-87


ATN Message Element                 FANS 1/A Message Element         Interoperability Requirement
UM259 AT [timesec] CROSS            UM62 AT [time] CROSS             IR-137  The ATN ground
[position] AT AND MAINTAIN          [position] AT AND MAINTAIN       system shall convert the ATN
[level]                             [altitude]                       message UM259 to the FANS
                                                                     1/A message UM62.
                                                                     See paragraph 4.2.12.6 for use of
                                                                     the time/timesec parameter.
                                                                     See paragraph 4.2.12.2 for use of
                                                                     position parameter.
                                                                     See paragraph 4.2.12.1 for use of
                                                                     level/altitude parameter.
UM260 CROSS [position] AT           UM63 AT [time] CROSS             IR-138  The ATN ground
[timesec] AT AND MAINTAIN           [position] AT AND MAINTAIN       system shall convert the ATN
[level] AT [speed]                  [altitude] AT [speed]            message UM260 to the FANS
                                                                     1/A message UM63.
                                                                     See paragraph 4.2.12.6 for use of
                                                                     the time/timesec parameter.
                                                                     See paragraph 4.2.12.2 for use of
                                                                     position parameter.
                                                                     See paragraph 4.2.12.1 for use of
                                                                     level/altitude parameter
                                                                     requirements.
                                                                     See paragraph 4.2.12.3 for use of
                                                                     speed parameter.
UM261 AT [timesec] OFFSET          UM66 AT [time] OFFSET             IR-139  The ATN ground
[specifiedDistance] [direction] OF [distanceoffset] [direction] OF   system shall convert the ATN
ROUTE                              ROUTE                             message UM261 to the FANS
                                                                     1/A message UM66.
                                                                     See paragraph 4.2.12.6 for use of
                                                                     the time/timesec parameter.
                                                                     See paragraph 4.2.12.4 for use of
                                                                     specified distance parameter.

UM262 REJOIN ROUTE BY               UM69 REJOIN ROUTE BY             IR-140  The ATN ground
[timesec]                           [time]                           system shall convert the ATN
                                                                     message UM262 to the FANS
                                                                     1/A message UM69.
                                                                     See paragraph 4.2.12.6 for use of
                                                                     the time/timesec parameter.
4-88


       ATN Message Element            FANS 1/A Message Element      Interoperability Requirement
       UM263 EXPECT BACK ON           UM71 EXPECT BACK ON           IR-141  The ATN ground
       ROUTE BY [timesec]             ROUTE BY [time]               system shall convert the ATN
                                                                    message UM263 to the FANS
                                                                    1/A message UM71.
                                                                    See paragraph 4.2.12.6 for use of
                                                                    the time/timesec parameter.
       UM264                          UM73 [predepartureclearance] + IR-142 The ATN ground
       [DepartureClearanceRouting]    UM169 [freetext] + UM158 ATIS system shall convert the ATN
                                      [atis code]                    message UM264 to the FANS
                                                                    1/A message UM73 + UM169
                                                                    + UM158.
                                                                    See paragraph 0 for use of the
                                                                    predeparture clearance parameter.
       UM265 AT [timesec] PROCEED     UM76 AT [time] PROCEED        IR-143  The ATN ground
       DIRECT TO [position]           DIRECT TO [position]          system shall convert the ATN
                                                                    message UM265 to the FANS
                                                                    1/A message UM76.
                                                                    See paragraph 4.2.12.6 for use of
                                                                    the time/timesec parameter.
                                                                    See paragraph 4.2.12.2 for use of
                                                                    position parameter.
       UM266 CLEARED TO [position]    UM79 CLEARED TO [position]    IR-144  The ATN ground
       VIA [routeClearanceEnhanced]   VIA [routeclearance]          system shall convert the ATN
                                                                    message UM266 to the FANS
                                                                    1/A message UM79.
                                                                    See paragraph 4.2.12.2 for use of
                                                                    position parameter.
                                                                    See paragraph 4.2.12.11 for use
                                                                    of route clearance parameter.


       UM267 CLEARED                  UM80 CLEARED                  IR-145  The ATN ground
       [routeClearanceEnhanced]       [routeclearance]              system shall convert the ATN
                                                                    message UM267 to the FANS
                                                                    1/A message UM80.
                                                                    See paragraph 4.2.12.11 for use
                                                                    of route clearance parameter.
                                                                                          4-89


ATN Message Element           FANS 1/A Message Element       Interoperability Requirement
UM268 AT [position] CLEARED   UM83 AT [position] CLEARED     IR-146  The ATN ground
[routeClearanceEnhanced]      [routeclearance]               system shall convert the ATN
                                                             message UM268 to the FANS
                                                             1/A message UM83.
                                                             See paragraph 4.2.12.2 for use of
                                                             position parameter.
                                                             See paragraph 4.2.12.11 for use
                                                             of route clearance parameter.
UM269 EXPECT                  UM85 EXPECT [routeclearance]   IR-147  The ATN ground
[routeClearanceEnhanced]                                     system shall convert the ATN
                                                             message UM269 to the FANS
                                                             1/A message UM85.
                                                             See paragraph 4.2.12.11 for use
                                                             of route clearance parameter.
UM270 AT [position] EXPECT    UM86 AT [position] EXPECT      IR-148  The ATN ground
[routeClearanceEnhanced]      [routeclearance]               system shall convert the ATN
                                                             message UM270 to the FANS
                                                             1/A message UM86.
                                                             See paragraph 4.2.12.2 for use of
                                                             position parameter.
                                                             See paragraph 4.2.12.11 for use
                                                             of route clearance parameter.
UM271 AT [timesec] EXPECT     UM89 AT [time] EXPECT          IR-149  The ATN ground
DIRECT TO [position]          DIRECT TO [position]           system shall convert the ATN
                                                             message UM271 to the FANS
                                                             1/A message UM89.
                                                             See paragraph 4.2.12.6 for use of
                                                             the time/timesec parameter.
                                                             See paragraph 4.2.12.2 for use of
                                                             position parameter.
UM272 EXPECT FURTHER          UM93 EXPECT FURTHER            IR-150  The ATN ground
CLEARANCE AT [timesec]        CLEARANCE AT [time]            system shall convert the ATN
                                                             message UM272 to the FANS
                                                             1/A message UM93.
                                                             See paragraph 4.2.12.6 for use of
                                                             the time/timesec parameter.
4-90


       ATN Message Element          FANS 1/A Message Element     Interoperability Requirement
       UM273 AT [timesec] EXPECT    UM100 AT [time] EXPECT       IR-151  The ATN ground
       [speed]                      [speed]                      system shall convert the ATN
                                                                 message UM273 to the FANS
                                                                 1/A message UM100.
                                                                 See paragraph 4.2.12.6 for use of
                                                                 the time/timesec parameter.
                                                                 See paragraph 4.2.12.3 for use of
                                                                 speed parameter.
       UM274 AT [timesec] EXPECT    UM103 AT [time] EXPECT       IR-152  The ATN ground
       [speed] TO [speed]           [speed] TO [speed]           system shall convert the ATN
                                                                 message UM274 to the FANS
                                                                 1/A message UM103.
                                                                 See paragraph 4.2.12.6 for use of
                                                                 the time/timesec parameter.
                                                                 See paragraph 4.2.12.3 for use of
                                                                 speed parameter.
       UM275 AT [timesec] CONTACT   UM119 AT [time] CONTACT      IR-153  The ATN ground
       [unitname] [frequency]       [icaounitname] [frequency]   system shall convert the ATN
                                                                 message UM275 to the FANS
                                                                 1/A message UM119.
                                                                 See paragraph 4.2.12.9 for use of
                                                                 unit name parameter.
                                                                 See paragraph 4.2.12.6 for use of
                                                                 the time/timesec parameter.
       UM276 AT [timesec] MONITOR   UM122 AT [time] MONITOR      IR-154  The ATN ground
       [unitname] [frequency]       [icaounitname] [frequency]   system shall convert the ATN
                                                                 message UM276 to the FANS
                                                                 1/A message UM122.
                                                                 See paragraph 4.2.12.9 for use of
                                                                 unit name parameter.
                                                                 See paragraph 4.2.12.6 for use of
                                                                 the time/timesec parameter.
       UM277 CAN YOU ACCEPT         UM150 CAN YOU ACCEPT         IR-155  The ATN ground
       [level] AT [timesec]         [altitude] AT [time]         system shall convert the ATN
                                                                 message UM277 to the FANS
                                                                 1/A message UM150.
                                                                 See paragraph 4.2.12.1 for use of
                                                                 level/altitude parameter.
                                                                 See paragraph 4.2.12.6 for use of
                                                                 the time/timesec parameter.
                                                                                         4-91


ATN Message Element        FANS 1/A Message Element     Interoperability Requirement
UM278 ALTIMETER        UM169 ‗ALTIMETER [yyyy][time]‘   IR-156   The ATN ground
[altimeter][timesec]   Where                            system shall convert the
                       [altimeter] = yyyy               UM278 message into UM169.
                       And [time] is optional           IR-157 When sending
                                                        UM278, the ATN ground
                                                        system shall include the
                                                        [altimeter] parameter in the
                                                        free text parameter of UM169
                                                        as a ten-characters string
                                                        according to the following
                                                        rules:
                                                        • case of AltimeterEnglish
                                                        data:
                                                        ―nn.nn INHG― where nn.nn is
                                                        the character string
                                                        representation of the altimeter
                                                        setting value (from 22.00 to
                                                        32.00)
                                                        • case of AltimeterMetric data:
                                                        None.
                                                        IR-158 When sending UM278
                                                        the ATN ground system shall
                                                        include the [time] parameter in
                                                        the free text parameter of
                                                        UM169 as a 4 character string
                                                        of converted integers in the
                                                        time parameter.
                                                        Despite the use of free text, it is
                                                        recommended to only use four
                                                        letters because the FANS 1/A
                                                        aircraft only displays four letters
                                                        for facility indication to the flight
                                                        crew.
                                                        The R response attribute is not
                                                        the same in the ATS INTEROP
                                                        Standard and the FANS 1/A
                                                        INTEROP Standard.
                                                        Processing the pilot‘s UNABLE
                                                        response is a local matter.
                                                        See paragraph 4.2.4, for
                                                        processing message attributes.
                                                        If a timesec parameter is
                                                        provided, see paragraph 4.2.12.6
                                                        for use of the time/timesec
                                                        parameter.
4-92


       ATN Message Element         FANS 1/A Message Element   Interoperability Requirement
       UM279 CHECK STUCK           UM157 CHECK STUCK          IR-159  When a frequency is
       MICROPHONE [frequencyValue] MICROPHONE [frequency]     provided, the ATN ground
                                   or                         system shall convert the ATN
                                   UM169 ‗CHECK STUCK         UM279 message element into
                                   MICROPHONE‘                FANS 1/A UM157 message
                                                              element.
                                                              IR-160 The ATN ground
                                                              system shall ignore the
                                                              ROGER response when
                                                              received as answer to UM157.
                                                              Response attribute is different: N
                                                              in the ATS INTEROP Standard,
                                                              R in the FANS 1/A INTEROP
                                                              Standard.
                                                              See paragraph 4.2.12.16 for use
                                                              of frequency parameter.
                                                              IR-161  When no frequency is
                                                              provided, the ATN ground
                                                              system shall convert the ATN
                                                              UM279 message element into
                                                              FANS 1/A UM169 message
                                                              element.
                                                              IR-162 The ATN ground
                                                              system shall ignore the
                                                              ROGER response when
                                                              received as a response to
                                                              UM169.
                                                                                         4-93


ATN Message Element             FANS 1/A Message Element   Interoperability Requirement
UM280 AT [timesec] REPORT       UM169 ―AT TIME [xxx]‖ +    IR-163   The ATN ground
DISTANCE [to/from] [position]   UM181 REPORT DISTANCE      system shall convert the ATN
                                [to/from] [position]       UM280 message into FANS
                                                           1/A UM169 and UM181.
                                Where [xxx] = [time].      IR-164 The ATN ground
                                                           system shall ignore the
                                                           ROGER response when
                                                           received as a response to
                                                           UM280.
                                                           IR-165 When sending UM280
                                                           the ATN ground system shall
                                                           include the [time] parameter in
                                                           the free text parameter of
                                                           UM169 as a 4 character string
                                                           of converted integers in the
                                                           time parameter.
                                                           IR-166
                                                           See paragraph 4.2.12.2 for use of
                                                           position parameter.
                                                           See paragraph 4.2.12.6 for use of
                                                           the time/timesec parameter.
UM281 REACH [level] BY          None.                      Not viable.
[timesec]                                                  The use of FANS 1/A message
                                                           element UM169 to use the ATN
                                                           message UM281 is not
                                                           considered a valid option in this
                                                           document (no free text UM with
                                                           W/U response attribute).
4-94


       ATN Message Element             FANS 1/A Message Element       Interoperability Requirement
       UM282 [facilitydesignation]    UM169 ‗[xxxx] ALTIMETER         IR-167   The ATN ground
       ALTIMETER [altimeter][timesec] [yyyy][time]‘                   system shall convert the
                                      Where                           UM282 message into UM169.
                                      [facility designation] = xxxx   IR-168 When sending
                                      [altimeter] = yyyy              UM282, the ATN ground
                                      And [time] optional             system shall include the
                                                                      [facilitydesignation] parameter
                                                                      in the free text parameter of
                                                                      UM169 as a character string of
                                                                      four letters, representing the
                                                                      location indicator of the
                                                                      facility designation
                                                                      IR-169 When sending
                                                                      UM282, the ATN ground
                                                                      system shall include the
                                                                      [altimeter] parameter in the
                                                                      free text parameter of UM169
                                                                      as a ten-characters string
                                                                      according to the following
                                                                      rules:
                                                                      • case of AltimeterEnglish
                                                                      data:
                                                                      ―nn.nn INHG― where nn.nn is
                                                                      the character string
                                                                      representation of the altimeter
                                                                      setting value (from 22.00 to
                                                                      32.00)
                                                                      • case of AltimeterMetric data:
                                                                      None.
                                                                      IR-170 When sending UM282
                                                                      the ATN ground system shall
                                                                      include the [time] parameter in
                                                                      the free text parameter of
                                                                      UM169 as a 4 character string
                                                                      of converted integers in the
                                                                      time parameter.
                                                                      Despite the use of free text, it is
                                                                      recommended to only use four
                                                                      letters because the FANS 1/A
                                                                      aircraft only displays four letters
                                                                      for facility indication to the flight
                                                                      crew.
                                                                      The R response attribute is not
                                                                      the same in the ATS INTEROP
                                                                      Standard and the FANS 1/A
                                                                      INTEROP Standard.
                                                                      Processing the pilot‘s UNABLE
                                                                      response is a local matter.
                                                                      See paragraph 4.2.4, for
                                                                      processing message attributes.
                                                                      See paragraph 4.2.12.6 for use of
                                                                      the time/timesec parameter.
                                                                                    4-95


ATN Message Element       FANS 1/A Message Element     Interoperability Requirement
UM283 RVR RUNWAY          UM169 ‗RVR RUNWAY            IR-171   The ATN ground
[runwayRVREnhanced]       [xxx][yyy]‘                  system shall convert the
                          Where [xxx] = [runway] and   UM283 message into UM169.
                          [yyy]=[rvr]                  IR-172 When sending
                                                       UM283, the ATN ground
                                                       system shall include the
                                                       [runway] parameter in the free
                                                       text parameter of UM169 as a
                                                       9 character string comprised
                                                       of the runway direction
                                                       converted from integer to a 2
                                                       character string concatenated
                                                       with a space, concatenated to
                                                       the runway configuration with
                                                       exception to the configuration
                                                       of none.
                                                       IR-173 When sending
                                                       UM283, the ATN ground
                                                       system shall include the [rvr]
                                                       parameter in the free text
                                                       parameter of UM169 as an
                                                       integer converted to a 4
                                                       character string.
UM284 EXPECTED            UM169 ‗EXPECTED              IR-174   The ATN ground
APPROACH TIME [timesec]   APPROACH TIME [xxx]‘         system shall convert the ATN
                          Where [xxx] = [time].        UM284 message into FANS
                                                       1/A UM169.
                                                       IR-175 When sending UM284
                                                       the ATN ground system shall
                                                       include the [time] parameter in
                                                       the free text parameter of
                                                       UM169 as a 4 character string
                                                       of converted integers in the
                                                       time parameter.
                                                       See paragraph 4.2.12.6 for use of
                                                       the time/timesec parameter.
4-96


       ATN Message Element      FANS 1/A Message Element   Interoperability Requirement
       UM285 CURRENT ATC UNIT   UM169 ‗CURRENT ATC UNIT    IR-176   The ATN ground
       [unitName]               [xxx]‘                     system shall convert the ATN
                                Where [xxx] = [unitName]   UM285 message element into
                                                           FANS 1/A UM169 message
                                                           element
                                                           IR-177 When sending UM285
                                                           the ATN ground system shall
                                                           include the [unitName]
                                                           parameter in the free text
                                                           parameter of UM169 as a
                                                           string of characters.
                                                           IR-178 The ATN ground
                                                           system shall ignore the
                                                           ROGER response when
                                                           received as a response to
                                                           UM285 .
                                                           Response attribute for UM169 is
                                                           different than UM285 : N in
                                                           ATN, R in FANS 1/A.
                                                           See paragraph 4.2.12.9 for use of
                                                           unit name parameter.
       UM286 CPDLC NOW IN USE   UM169 ‗CPDLC NOW IN USE‘   IR-179  The ATN ground
                                                           system shall convert the ATN
                                                           UM286 message element into
                                                           FANS 1/A UM169 message
                                                           element
                                                           IR-180 The ATN ground
                                                           system shall ignore the
                                                           ROGER response when
                                                           received as a response to
                                                           UM286.
                                                           Response attribute for UM169 is
                                                           different: N in ATN, R in
                                                           FANS 1/A.
                                                                                   4-97


ATN Message Element      FANS 1/A Message Element    Interoperability Requirement
UM287 CPDLC NOT IN USE   UM169 ‗CPDLC NOT IN USE‘    IR-181  The ATN ground
                                                     system shall convert the ATN
                                                     UM287 message element into
                                                     FANS 1/A UM169 message
                                                     element.
                                                     IR-182 The ATN ground
                                                     system shall ignore the
                                                     ROGER response when
                                                     received as a response to
                                                     UM287.
                                                     Response attribute for UM169 is
                                                     different than UM287: N in ATN,
                                                     R in FANS 1/A.
UM288 VERIFY MONITORED   UM169 ‗VERIFY MONITORED IR-183 The ATN ground
FREQUENCY [frequency]    FREQUENCY [xxx]‘          system shall convert the ATN
                         Where [xxx] = [frequency] UM288 message element into
                                                     FANS 1/A UM169 message
                                                     element.
                                                     IR-184 When sending
                                                     UM288, the ATN ground
                                                     system shall include the
                                                     parameters in the free text
                                                     parameter of UM169 as a
                                                     string of characters.
                                                     Response attribute different: W/U
                                                     in the ATS INTEROP Standard,
                                                     R in the FANS 1/A INTEROP
                                                     Standard.
                                                     IR-185  See paragraph 1.1.1
                                                     for handling of the W/U and R
                                                     responses.
UM289 REST OF ROUTE      UM169 ‗REST OF ROUTE        IR-186  The ATN ground
UNCHANGED                UNCHANGED‘                  system shall convert the ATN
                                                     UM289 message element into
                                                     FANS 1/A UM169 message
                                                     element.
UM290 DESCEND VIA        None.                       Not viable.
[procedure name]                                     The use of FANS 1/A message
                                                     element UM169 to use the ATN
                                                     message UM290 is not
                                                     considered a valid option in this
                                                     document (no free text UM with
                                                     W/U response attribute).
4-98


       ATN Message Element           FANS 1/A Message Element   Interoperability Requirement
       UM291 AT [timesec] DESCEND    None.                      Not viable.
       VIA [procedure name]                                     The use of FANS 1/A message
                                                                element UM169 to use the ATN
                                                                message UM291 is not
                                                                considered a valid option in this
                                                                document (no free text UM with
                                                                W/U response attribute).
       UM292 AT [position] DESCEND   None.                      Not viable.
       VIA [procedure name]                                     The use of FANS 1/A message
                                                                element UM169 to use the ATN
                                                                message UM292 is not
                                                                considered a valid option in this
                                                                document (no free text UM with
                                                                W/U response attribute).
       UM293 CLIMB VIA [procedure    None.                      Not viable.
       name]                                                    The use of FANS 1/A message
                                                                element UM169 to use the ATN
                                                                message UM293 is not
                                                                considered a valid option in this
                                                                document (no free text UM with
                                                                W/U response attribute).
       UM294 AT [timesec] CLIMB      None.                      Not viable.
       VIA [procedure name]                                     The use of FANS 1/A message
                                                                element UM169 to use the ATN
                                                                message UM294 is not
                                                                considered a valid option in this
                                                                document (no free text UM with
                                                                W/U response attribute).
       UM295 AT [position] CLIMB     None.                      Not viable.
       VIA [procedure name]                                     The use of FANS 1/A message
                                                                element UM169 to use the ATN
                                                                message UM295 is not
                                                                considered a valid option in this
                                                                document (no free text UM with
                                                                W/U response attribute).
                                                                                 4-99


ATN Message Element      FANS 1/A Message Element   Interoperability Requirement
UM296 EXPECT HIGHER AT   UM169 ‗EXPECT HIGHER AT    IR-187   The ATN ground
[timesec]                [time]‘                    system shall convert the ATN
                                                    UM296 message into FANS
                                                    1/A UM169.
                                                    IR-188 When sending UM296
                                                    the ATN ground system shall
                                                    include the [time] parameter in
                                                    the free text parameter of
                                                    UM169 as a 4 character string
                                                    of converted integers in the
                                                    time parameter.
                                                    UM296See paragraph 4.2.12.6
                                                    for use of the time/timesec
                                                    parameter.
UM297 EXPECT HIGHER AT   UM169 ‗EXPECT HIGHER AT    IR-189   The ATN ground
[position]               [position]‘                system shall convert the ATN
                                                    UM297 message into FANS
                                                    1/A UM169.
                                                    IR-190 When sending
                                                    UM297, the ATN ground
                                                    system shall include the
                                                    [position] parameter in the
                                                    free text parameter of UM169
                                                    as a string of characters.
                                                    IR-191 When sending
                                                    UM297, the ATN ground
                                                    system shall prohibit the use
                                                    of place bearing distance and
                                                    latitude/longitude parameters
                                                    included in the [position].
                                                    See paragraph 4.2.12.2 for use of
                                                    position parameter.
4-100


        ATN Message Element     FANS 1/A Message Element   Interoperability Requirement
        UM298 EXPECT LOWER AT   UM169 ‗EXPECT LOWER AT     IR-192   The ATN ground
        [timesec]               [time]‘                    system shall convert the ATN
                                                           UM298 message into FANS
                                                           1/A UM169.
                                                           IR-193 When sending UM298
                                                           the ATN ground system shall
                                                           include the [time] parameter in
                                                           the free text parameter of
                                                           UM169 as a 4 character string
                                                           of converted integers in the
                                                           time parameter.
                                                           UM298See paragraph 4.2.12.6
                                                           for use of the time/timesec
                                                           parameter.
        UM299 EXPECT LOWER AT   UM169 ‗EXPECT LOWER AT     IR-194   The ATN ground
        [position]              [position]‘                system shall convert the ATN
                                                           UM299 message into FANS
                                                           1/A UM169.
                                                           IR-195 When sending
                                                           UM299, the ATN ground
                                                           system shall include the
                                                           [position] parameter in the
                                                           free text parameter of UM169
                                                           as a string of characters.
                                                           IR-196 When sending
                                                           UM299, the ATN ground
                                                           system shall prohibit the use
                                                           of place bearing distance and
                                                           latitude/longitude parameters
                                                           included in the [position].
                                                           See paragraph 4.2.12.2 for use of
                                                           position parameter.
                                                                                   4-101


ATN Message Element         FANS 1/A Message Element   Interoperability Requirement
UM300 AT [timesec] EXPECT   UM169 ‗AT [time] EXPECT    IR-197   The ATN ground
[level]                     [altitude]‘                system shall convert the ATN
                                                       UM300 message into FANS
                                                       1/A UM169.
                                                       IR-198 When sending UM300
                                                       the ATN ground system shall
                                                       include the [time] parameter in
                                                       the free text parameter of
                                                       UM169 as a 4 character string
                                                       of converted integers in the
                                                       time parameter.
                                                       IR-199 The ATN ground
                                                       system shall convert the
                                                       level/altitude parameter in
                                                       UM300 to a string of
                                                       characters of converted
                                                       integers in the level/altitude
                                                       parameter.
                                                       UM300See paragraph 4.2.12.1
                                                       for use of level/altitude
                                                       parameter.
                                                       See paragraph 4.2.12.6 for use of
                                                       the time/timesec parameter.
4-102


        ATN Message Element           FANS 1/A Message Element         Interoperability Requirement
        UM301 AT [position] EXPECT    UM169 ‗AT [position] EXPECT      IR-200   The ATN ground
        [level]                       [altitude]‘                      system shall convert the ATN
                                                                       UM301 message into FANS
                                                                       1/A UM169.
                                                                       IR-201 The ATN ground
                                                                       system shall convert the
                                                                       level/altitude parameter in
                                                                       UM301 to a string of
                                                                       characters of converted
                                                                       integers in the level/altitude
                                                                       parameter.
                                                                       IR-202 When sending
                                                                       UM301, the ATN ground
                                                                       system shall include the
                                                                       [position] parameter in the
                                                                       free text parameter of UM169
                                                                       as a string of characters.
                                                                       IR-203 When sending
                                                                       UM301, the ATN ground
                                                                       system shall prohibit the use
                                                                       of place bearing distance and
                                                                       latitude/longitude parameters
                                                                       included in the [position].
                                                                       See paragraph 4.2.12.2 for use of
                                                                       position parameter.
                                                                       See paragraph 4.2.12.1 for use of
                                                                       level/altitude parameter.
        UM302 EXPECT                  UM169 ‗EXPECT                    IR-204   The ATN ground
        [level][timeduration] AFTER   [levelsec][timeduration] AFTER   system shall convert the ATN
        DEPARTURE                     DEPARTURE‘                       UM302 message into FANS
                                                                       1/A UM169.
                                                                       IR-205 When sending
                                                                       UM302, the ATN ground
                                                                       system shall include the
                                                                       parameters in the free text
                                                                       parameter of UM169 as a
                                                                       string of characters.
                                                                       See paragraph 4.2.12.1 for use of
                                                                       level/altitude parameter.
                                                                       See paragraph 4.2.12.6 for use of
                                                                       the time/timesec parameter.
                                                                                    4-103


ATN Message Element         FANS 1/A Message Element   Interoperability Requirement
UM303 CLEARED TO            None.                      Not viable.
DEVIATE UP TO [degrees]                                The use of FANS 1/A message
DEGREES [direction] OF                                 element UM169 to use the ATN
ROUTE                                                  message UM303 is not
                                                       considered a valid option in this
                                                       document (no free text UM with
                                                       W/U response attribute).
UM304 CLEAR TO [position]   None.                      Not viable.
                                                       The use of FANS 1/A message
                                                       element UM169 to use the ATN
                                                       message UM304 is not
                                                       considered a valid option in this
                                                       document (no free text UM with
                                                       W/U response attribute).
UM305 HOLD [direction] AS   None.                      Not viable.
PUBLISHED                                              The use of FANS 1/A message
                                                       element UM169 to use the ATN
                                                       message UM305 is not
                                                       considered a valid option in this
                                                       document (no free text UM with
                                                       W/U response attribute).
UM306 HOLD [direction] ON   None.                      Not viable.
[inboundradial] RADIAL                                 The use of FANS 1/A message
[airway][direction] TURNS                              element UM169 to use the ATN
[legtype] LEGS                                         message UM306 is not
                                                       considered a valid option in this
                                                       document (no free text UM with
                                                       W/U response attribute).
UM307 REPORT REQUIRED       None.                      Not viable.
RVR [runway][rvr]                                      The use of FANS 1/A message
                                                       element UM169 to use the ATN
                                                       message UM307 is not
                                                       considered a valid option in this
                                                       document (no free text DM
                                                       pairing with Y response
                                                       attribute).
UM308 MAINTAIN MAXIMUM None.                           Not viable.
FORWARD SPEED                                          The use of FANS 1/A message
                                                       element UM169 to use the ATN
                                                       message UM308 is not
                                                       considered a valid option in this
                                                       document (no free text UM with
                                                       W/U response attribute).
4-104


        ATN Message Element         FANS 1/A Message Element   Interoperability Requirement
        UM309 MAINTAIN SLOWEST      None.                      Not viable.
        PRACTICAL SPEED                                        The use of FANS 1/A message
                                                               element UM169 to use the ATN
                                                               message UM309 is not
                                                               considered a valid option in this
                                                               document (no free text UM with
                                                               W/U response attribute).
        UM310 AT [level] MAINTAIN   None.                      Not viable.
        SPEED                                                  The use of FANS 1/A message
                                                               element UM169 to use the ATN
                                                               message UM310 is not
                                                               considered a valid option in this
                                                               document (no free text UM with
                                                               W/U response attribute).
        UM311 STARTUP APPROVED      None.                      Not viable.
        [assigned time]                                        IR-206   The use of FANS 1/A
                                                               message element UM169 to
                                                               use the ATN message UM311
                                                               is not considered a valid
                                                               option in this document.
        UM312 CANCEL START UP       None.                      Not viable.
                                                               The use of FANS 1/A message
                                                               element UM169 to use the ATN
                                                               message UM312 is not
                                                               considered a valid option in this
                                                               document.
        UM313 PUSH BACK             None.                      Not viable.
        APPROVED                                               The use of FANS 1/A message
        [pushbackInformation]                                  element UM169 to use the ATN
        [assignedTime]                                         message UM313 is not
                                                               considered a valid option in this
                                                               document.
                                                                                          4-105


ATN Message Element              FANS 1/A Message Element        Interoperability Requirement
UM314 EXPECT [clearance          UM73 [preDepartureClearance]:   IR-207   When the ATN
type][assigned time]             [timeDepartureEDCT]             message UM314 is
                                                                 concatenated with the ATN
                                                                 message UM264 and the
                                                                 parameter ―clearance type‖
                                                                 equals ―departure‖ the ATN
                                                                 ground system shall convert
                                                                 the parameter ―assigned time‖
                                                                 to the FANS 1/A
                                                                 timeDepartureEDCT within
                                                                 the FANS 1/A message
                                                                 element UM73.
                                                                 IR-208 See paragraph 0 for
                                                                 use of the predeparture
                                                                 clearance parameter.
UM315 EXPECT TAXI                None.                           Not viable.
[taxiRoute]                                                      IR-209   The use of FANS 1/A
                                                                 message element UM169 to
                                                                 use the ATN message UM315
                                                                 is not considered a valid
                                                                 option in this document.
UM316 WHEN CAN YOU               None.                           IR-210   The use of FANS 1/A
ACCEPT [clearanceType]                                           message element UM169 to
                                                                 use the ATN message UM316
                                                                 is not considered a valid
                                                                 option in this document.
UM317 REMAIN                     None.                           Not viable.
[prepositionDirectionLocation]                                   IR-211   The use of FANS 1/A
                                                                 message element UM169 to
                                                                 use the ATN message UM317
                                                                 is not considered a valid
                                                                 option in this document.
UM318 CROSS                      None.                           Not viable.
[positionInformation]                                            IR-212   The use of FANS 1/A
                                                                 message element UM169 to
                                                                 use the ATN message UM318
                                                                 is not considered a valid
                                                                 option in this document.
4-106


        ATN Message Element         FANS 1/A Message Element   Interoperability Requirement
        UM319 TAXI [taxiRoute]      None.                      Not viable.
                                                               IR-213   The use of FANS 1/A
                                                               message element UM169 to
                                                               use the ATN message UM319
                                                               is not considered a valid
                                                               option in this document.
        UM320 RUNWAY [runway]       None.                      Not viable.
        TAXI [taxiRoute]                                       IR-214   The use of FANS 1/A
                                                               message element UM169 to
                                                               use the ATN message UM320
                                                               is not considered a valid
                                                               option in this document.
        UM321 WHEN REACHING         None.                      Not viable.
        [positionInformation]                                  IR-215   The use of FANS 1/A
                                                               message element UM169 to
                                                               use the ATN message UM321
                                                               is not considered a valid
                                                               option in this document.
        UM322 HOLD POSITION         None.                      Not viable.
                                                               IR-216   The use of FANS 1/A
                                                               message element UM169 to
                                                               use the ATN message UM322
                                                               is not considered a valid
                                                               option in this document.
        UM323 FOR REMOTE DE         None.                      Not viable.
        ICING                                                  IR-217   The use of FANS 1/A
                                                               message element UM169 to
                                                               use the ATN message UM323
                                                               is not considered a valid
                                                               option in this document.
        UM324 YOU ACCEPT            None.                      Not viable.
        INTERSECTION                                           IR-218   The use of FANS 1/A
        [positionInformation] FOR
                                                               message element UM169 to
        RUNWAY [runway]
                                                               use the ATN message UM324
                                                               is not considered a valid
                                                               option in this document.
        UM325 REVISED               UM169 ‗REVISED‘            IR-219  The ATN ground
                                                               system shall convert the ATN
                                                               UM325 message into FANS
                                                               1/A UM169.
                                                                                       4-107


ATN Message Element            FANS 1/A Message Element   Interoperability Requirement
UM326 DEPARTURES               None.                      Not viable.
STOPPED                                                   The use of FANS 1/A message
                                                          element UM169 to use the ATN
                                                          message UM326 is not
                                                          considered a valid option in this
                                                          document.
UM327 ENGINE SHUTDOWN          None.                      Not viable.
PERMITTED                                                 The use of FANS 1/A message
                                                          element UM169 to use the ATN
                                                          message UM327 is not
                                                          considered a valid option in this
                                                          document.
UM328 [distanceGround]         None.                      Not viable.
AVAILABLE                                                 The use of FANS 1/A message
                                                          element UM169 to use the ATN
                                                          message UM328 is not
                                                          considered a valid option in this
                                                          document.
UM329 INTERSECTION             None.                      Not viable.
DEPARTURE [intersection]                                  The use of FANS 1/A message
                                                          element UM169 to use the ATN
                                                          message UM329 is not
                                                          considered a valid option in this
                                                          document.
UM330 [graphicTaxiRoute]       None.                      Not viable.
                                                          The use of FANS 1/A message
                                                          element UM169 to use the ATN
                                                          message UM330 is not
                                                          considered a valid option in this
                                                          document.
UM331 [position information]   None.                      Not viable.
[assigned time] CONTACT                                   IR-220   The use of FANS 1/A
[facility function ground]
                                                          message element UM169 to
[frequency]
                                                          use the ATN message UM331
                                                          is not considered a valid
                                                          option in this document.
UM332 STANDARD                 None.                      Not viable.

                                                          The use of FANS 1/A message
                                                          element UM169 to use the ATN
                                                          message UM332 is not
                                                          considered a valid option in this
                                                          document.
4-108


        ATN Message Element       FANS 1/A Message Element   Interoperability Requirement
        UM333 HOLD SHORT          None.                      Not viable.
        [positionInformation]
                                                             The use of FANS 1/A message
                                                             element UM169 to use the ATN
                                                             message UM333 is not
                                                             considered a valid option in this
                                                             document.
        UM334 IN THE CLIMB        UM169 ―IN THE CLIMB‖ +     IR-221  The ATN ground
        [speedschedule]           UM106 MAINTAIN [speed] +   system shall convert the ATN
                                  UM106 MAINTAIN [speed]     message UM334 to the FANS
                                                             1/A free text message UM 169
                                                             concatenated with a sequence
                                                             of two FANS 1/A UM106
                                                             messages.
                                                             See paragraph 4.2.12.29 for the
                                                             use of the speed schedule
                                                             parameter.
        UM335 IN THE DESCENT      UM169 ―IN THE DESCENT‖ +   IR-222  The ATN ground
        [speedschedule]           UM106 MAINTAIN [speed] +   system shall convert the ATN
                                  UM106 MAINTAIN [speed]     message UM335 to the FANS
                                                             1/A free text message UM 169
                                                             concatenated with a sequence
                                                             of two FANS 1/A UM106
                                                             messages.
                                                             See paragraph 4.2.12.29 for the
                                                             use of the speed schedule
                                                             parameter.
        UM336 CANCEL [position]   None.                      Not viable.
        TIME CONSTRAINT                                      The use of FANS 1/A message
                                                             element UM169 to use the ATN
                                                             message UM336 is not
                                                             considered a valid option in this
                                                             document (no free text UM with
                                                             W/U response attribute).
        UM337 CLEARANCE LIMIT     None.                      Not viable.
        [position]                                           The use of FANS 1/A message
                                                             element UM169 to use the ATN
                                                             message UM337 is not
                                                             considered a valid option in this
                                                             document (no free text UM with
                                                             W/U response attribute).
                                                                                                 4-109


ATN Message Element               FANS 1/A Message Element          Interoperability Requirement
UM338 MAINTAIN TIME               None.                             Not viable.
CONSTRAINT                                                          The use of FANS 1/A message
                                                                    element UM169 to use the ATN
                                                                    message UM338 is not
                                                                    considered a valid option in this
                                                                    document (no free text UM with
                                                                    W/U response attribute).
UM339 AT [position] CLEARED       None.                             Not viable.
TO [position] VIA [route                                            The use of FANS 1/A message
clearance enhanced]                                                 element UM169 to use the ATN
                                                                    message UM339 is not
                                                                    considered a valid option in this
                                                                    document (no free text UM with
                                                                    W/U response attribute).
UM340 LATENCY TIME                None.                             Not viable.
VALUE [ValueLatency]                                                The use of FANS 1/A message
                                                                    element UM169 to use the ATN
                                                                    message UM340 is not
                                                                    considered a valid option in this
                                                                    document .
UM341 ITP                         None.                             Not viable.
[aircraftReferenceListDistance]                                     The use of FANS 1/A message
                                                                    element UM169 to use the ATN
                                                                    message UM341 is not
                                                                    considered a valid option in this
                                                                    document .
UM342 REPORT SIGHTING             UM169 ‗REPORT SIGHTING            IR-223   The ATN ground
AND PASSING OPPOSITE              AND PASSING OPPOSITE              system shall convert the ATN
DIRECTION [traffic description]   DIRECTION [traffic description]   UM342 message into FANS
ETP [timesec]                     ETP [time]‘                       1/A UM169.
                                                                    IR-224 When sending
                                                                    UM342, the ATN ground
                                                                    system shall include the
                                                                    parameters in the free text
                                                                    parameter of UM169 as a
                                                                    string of characters.
                                                                    See paragraph 4.2.12.6 for use of
                                                                    the time/timesec parameter.
4-110


        ATN Message Element                   FANS 1/A Message Element             Interoperability Requirement
        UM343 WHEN WILL YOU                   UM169 ‗WHEN WILL YOU                 IR-225   The ATN ground
        MAINTAIN [level]                      MAINTAIN [level]‘                    system shall convert the ATN
                                                                                   UM343 message into FANS
                                                                                   1/A UM169.
                                                                                   IR-226 When sending
                                                                                   UM343, the ATN ground
                                                                                   system shall include the
                                                                                   parameters in the free text
                                                                                   parameter of UM169 as a
                                                                                   string of characters.
                                                                                   See paragraph 4.2.12.1 for use of
                                                                                   level/altitude parameter.
        UM344 AT WHAT DISTANCE                UM169 ‗AT WHAT DISTANCE              IR-227   The ATN ground
        [specifiedDistance][direction][posi   [specifiedDistance][direction][pos   system shall convert the ATN
        tion] WILL YOU MAINTAIN               ition] WILL YOU MAINTAIN             UM344 message into FANS
        [level]                               [level]‘                             1/A UM169.
                                                                                   IR-228 When sending
                                                                                   UM344, the ATN ground
                                                                                   system shall include the
                                                                                   parameters in the free text
                                                                                   parameter of UM169 as a
                                                                                   string of characters.
                                                                                   See paragraph 4.2.12.1 for use of
                                                                                   level/altitude parameter.
                                                                                   See paragraph 4.2.12.2 for use of
                                                                                   position parameter.


        UM345 REPORT RADIAL AND               UM343 REPORT RADIAL AND IR-229 The ATN ground
        DISTANCE [to/from][position]          DISTANCE [to/from][position]‘ system shall convert the ATN
                                                                                   UM345 message into FANS
                                                                                   1/A UM169.
                                                                                   IR-230 When sending
                                                                                   UM345, the ATN ground
                                                                                   system shall include the
                                                                                   parameters in the free text
                                                                                   parameter of UM169 as a
                                                                                   string of characters.
                                                                                   See paragraph 4.2.12.2 for use of
                                                                                   position parameter.
                                                                                            4-111


ATN Message Element             FANS 1/A Message Element        Interoperability Requirement
UM346 CHECK AND RESPOND UM169 ‗CHECK AND                        IR-231  The ATN ground
TO OPEN CPDLC MESSAGES  RESPOND TO OPEN CPDLC                   system shall convert the ATN
                        MESSAGES‘                               UM346 message into FANS
                                                                1/A UM169.

UM347 EXPECT SELCAL             UM169 ‗EXPECT SELCAL            IR-232   The ATN ground
CHECK HF [frequency]            CHECK HF [frequency]‘           system shall convert the ATN
                                                                UM347 message into FANS
                                                                1/A UM169.
                                                                IR-233 When sending
                                                                UM347, the ATN ground
                                                                system shall include the
                                                                parameters in the free text
                                                                parameter of UM169 as a
                                                                string of characters.
UM348 EXPECT CPDLC              UM169 ‗EXPECT CPDLC             IR-234   The ATN ground
TRANSFER AT [timesec]           TRANSFER AT [time]‘             system shall convert the ATN
                                                                UM348 message into FANS
                                                                1/A UM169.
                                                                IR-235 When sending
                                                                UM348, the ATN ground
                                                                system shall include the
                                                                parameters in the free text
                                                                parameter of UM169 as a
                                                                string of characters.
                                                                See paragraph 4.2.12.6 for use of
                                                                the time/timesec parameter.
UM349 EXPECT NEXT               UM169 ‗EXPECT NEXT              IR-236   The ATN ground
CENTER [facility designation]   CENTER [facility designation]   system shall convert the ATN
CONTACT WITH [facility          CONTACT WITH [facility          UM349 message into FANS
designation] NOT REQUIRED       designation] NOT REQUIRED‘      1/A UM169.
                                                                IR-237 When sending
                                                                UM349, the ATN ground
                                                                system shall include the
                                                                parameters in the free text
                                                                parameter of UM169 as a
                                                                string of characters.
4-112


        ATN Message Element           FANS 1/A Message Element     Interoperability Requirement
        UM350 TRAFFIC IS [traffic     UM169 ‗TRAFFIC IS [traffic   IR-238   The ATN ground
        description]                  description]‘                system shall convert the ATN
                                                                   UM350 message into FANS
                                                                   1/A UM169.
                                                                   IR-239 When sending
                                                                   UM350, the ATN ground
                                                                   system shall include the
                                                                   parameters in the free text
                                                                   parameter of UM169 as a
                                                                   string of characters.
        UM351 EXPECT TO MAINTAIN UM169 ‗EXPECT TO                  IR-240   The ATN ground
        [speed] UNTIL [timesec/position] MAINTAIN [speed] UNTIL    system shall convert the ATN
                                         [time/position]‘          UM351 message into FANS
                                                                   1/A UM169.
                                                                   IR-241 When sending
                                                                   UM351, the ATN ground
                                                                   system shall include the
                                                                   parameters in the free text
                                                                   parameter of UM169 as a
                                                                   string of characters.
                                                                   See paragraph 4.2.12.6 for use of
                                                                   the time/timesec parameter.
                                                                   See paragraph 4.2.12.3 for use of
                                                                   speed parameter.
4.2.9              Downlink Message Elements
                   The interoperability requirements for processing FANS 1/A downlink message elements
                   supporting AMC, ACL, DCL, and ACM are provided in paragraph 4.2.9.1. Guidance for
                   processing FANS 1/A downlink emergency message elements is provided in paragraph
                   4.2.9.2.
                   The ATN ground system may receive downlink message elements from FANS 1/A
                   aircraft that are not supported.
                   IR-242   When the ATN ground system receives any message element or any message
                   element parameter/data type that it does not support, the ATN ground system shall
                   reject the message and respond per paragraph 0.
        4.2.9.1         Downlink Message Elements supporting ACM, ACL, DCL, and AMC
                   Table 4-16 lists the ATN downlink message elements supporting ACM, ACL, DCL and
                   AMC, the corresponding FANS 1/A downlink message elements, and related
                   interoperability requirements.


                            Table 4-16 ATN and FANS 1/A CPDLC downlink message elements

           FANS 1/A Message           ATN Message Element     Interoperability Requirement
           Element
           DM0 WILCO                  DM0 WILCO               None.
           DM1 UNABLE                 DM1 UNABLE              None.
           DM2 STANDBY                DM2 STANDBY             None.
           DM3 ROGER                  DM3 ROGER               None.
           DM4 AFFIRM                 DM4 AFFIRM              None.
           DM5 NEGATIVE               DM5 NEGATIVE            None.
           DM6 REQUEST [altitude]     DM6 REQUEST [level]     See paragraph 4.2.12.1 for use of altitude/level
                                                              parameter.
           DM7 REQUEST BLOCK          DM6 REQUEST [level]     IR-243  The ATN ground system shall
           [altitude] TO [altitude]                           convert the FANS 1/A message element
                                                              DM7 to ATN message element DM6 using
                                                              a BLOCK level parameter.
                                                              See paragraph 4.2.12.1 for use of altitude/level
                                                              parameter.
                                                              Note: ATN message DM7 is replaced by ATN
                                                              message DM6.
           DM8 REQUEST CRUISE         DM8 REQUEST CRUISE      See paragraph 4.2.12.1 for use of altitude/level
           CLIMB TO [altitude]        CLIMB TO [level]        parameter
           DM9 REQUEST CLIMB          DM9 REQUEST CLIMB       See paragraph 4.2.12.1 for use of altitude/level
           TO [altitude]              TO [level]              parameter.
                                                              See paragraph 4.2.13.1 for processing message
                                                              elements with a ―Y‖ response attribute.
FANS 1/A Message               ATN Message Element        Interoperability Requirement
Element
DM10 REQUEST                   DM10 REQUEST               See paragraph 4.2.12.1 for use of altitude/level
DESCENT TO [altitude]          DESCENT TO [level]         parameter.
                                                          See paragraph 4.2.13.1 for processing message
                                                          elements with a ―Y‖ response attribute.
DM11 AT [position]             DM11 AT [position]         See paragraph 4.2.12.2 for use of position
REQUEST CLIMB TO               REQUEST CLIMB TO           parameter.
[altitude]                     [level]                    See paragraph 4.2.12.1 for use of altitude/level
                                                          parameter.


DM12 AT [position]             DM12 AT [position]         See paragraph 4.2.12.1 for use of altitude/level
REQUEST DESCENT TO             REQUEST DESCENT TO         parameter.
[altitude]                     [level]                    See paragraph 4.2.12.2 for use of position
                                                          parameter.


DM13 AT [time]                 DM119 AT [timesec]         IR-244  The ATN ground system shall
REQUEST CLIMB TO               REQUEST CLIMB TO           convert the FANS 1/A message DM13 to
[altitude]                     [level]                    ATN message DM119.
                                                          See paragraph 4.2.12.1 for use of altitude/level
                                                          parameter.
                                                          See paragraph 4.2.12.6 for use of the
                                                          time/timesec parameter.


DM14 AT [time]                 DM120 AT [timesec]         IR-245  The ATN ground system shall
REQUEST DESCENT TO             REQUEST DESCENT TO         convert the FANS 1/A message DM14 to
[altitude]                     [level]                    ATN message DM120.
                                                          See paragraph 4.2.12.1 for use of altitude/level
                                                          parameter.
                                                          See paragraph 4.2.12.6 for use of the
                                                          time/timesec parameter.
DM15 REQUEST                   DM15 REQUEST               See paragraph 4.2.12.4 for use of distance offset
OFFSET [distanceoffset]        OFFSET [specified          parameter.
[direction] OF ROUTE           distance] [direction] OF
                               ROUTE
DM16 AT [position]             DM16 AT [position]         See paragraph 4.2.12.4 for use of distance offset
REQUEST OFFSET                 REQUEST OFFSET             parameter.
[distanceoffset] [direction]   [specified distance]       See paragraph 4.2.12.2 for use of position
OF ROUTE                       [direction] OF ROUTE       parameter.
DM17 AT [time]                 DM121 AT [timesec]         IR-246  The ATN ground system shall
REQUEST OFFSET                 REQUEST OFFSET             convert the FANS 1/A message DM17 to
[distanceoffset] [direction]   [specified distance]       ATN message DM121.
OF ROUTE                       [direction] OF ROUTE
                                                          See paragraph 4.2.12.4 for use of distance offset
                                                                                                   4-115


FANS 1/A Message           ATN Message Element        Interoperability Requirement
Element
                                                      parameter.
                                                      See paragraph 4.2.12.6 for use of the
                                                      time/timesec parameter.
DM18 REQUEST [speed]       DM18 REQUEST [speed]       See paragraph 4.2.12.3 for use of speed
                                                      parameter.
                                                      See paragraph 4.2.13.1 for processing message
                                                      elements with a ―Y‖ response attribute.
DM19 REQUEST [speed]       DM19 REQUEST [speed]       See paragraph 4.2.12.3 for use of speed
TO [speed]                 TO [speed]                 parameter.
DM20 REQUEST VOICE         DM20 REQUEST VOICE         None.
CONTACT                    CONTACT

DM21 REQUEST VOICE         DM21 REQUEST VOICE         See paragraph 4.2.12.16 for use of frequency
CONTACT [frequency]        CONTACT [frequency]        parameter.


DM22 REQUEST               DM22 REQUEST               See paragraph 4.2.12.2 for use of position
DIRECT TO [position]       DIRECT TO [position]       parameter.
                                                      See paragraph 4.2.13.1 for processing message
                                                      elements with a ―Y‖ response attribute.
DM23 REQUEST               DM23 REQUEST               See paragraph 4.2.12.19 for use of the
[procedure name]           [procedure name]           procedure name parameter.
DM24 REQUEST [route        DM122 REQUEST              IR-247  The ATN ground system shall
clearance]                 CLEARANCE [route           convert the FANS 1/A message DM24 to
                           clearance]                 ATN message DM122.
                                                      See paragraph 4.2.12.11 for use of route
                                                      clearance parameter.
DM25 REQUEST               DM25 REQUEST               IR-248  The ATN ground system shall set
CLEARANCE                  [clearance type]           the ATN [clearance type] parameter in
                           CLEARANCE                  DM25 to noneSpecified when
                                                      accommodating a FANS 1/A aircraft
                                                      sending DM25.
                                                      Note: No [clearance type] parameter in FANS
                                                      1/A.
DM26 REQUEST               DM123 REQUEST              IR-249  The ATN ground system shall
WEATHER DEVIATION          WEATHER DEVIATION          convert the FANS 1/A message DM26 to
TO [position] VIA [route   TO [position] VIA [route   ATN message DM123.
clearance]                 clearance]
                                                      See paragraph 4.2.12.2 for use of position
                                                      parameter.
                                                      See paragraph 4.2.12.11 for use of route
                                                      clearance parameter.
FANS 1/A Message          ATN Message Element         Interoperability Requirement
Element
DM27 REQUEST              DM27 REQUEST                See paragraph 4.2.12.4 for use of distance offset
WEATHER DEVIATION         WEATHER DEVIATION           parameter.
UP TO [distanceoffset]    UP TO [specifiedDistance]   See paragraph 4.2.13.1 for processing message
[direction] OF ROUTE      [direction] OF ROUTE        elements with a ―Y‖ response attribute.
DM28 LEAVING              DM28 LEAVING [level]        See paragraph 4.2.12.1 for use of altitude/level
[altitude]                                            parameter.


DM29 CLIMBING TO          DM29 CLIMBING TO            See paragraph 4.2.12.1 for use of altitude/level
[altitude]                [level]                     parameter.


DM30 DESCENDING TO        DM30 DESCENDING TO          See paragraph 4.2.12.1 for use of altitude/level
[altitude]                [level]                     parameter.


DM31 PASSING              DM31 PASSING                See paragraph 4.2.12.2 for use of position
[position]                [position]                  parameter.
DM32 PRESENT              DM32 PRESENT LEVEL          See paragraph 4.2.12.1 for use of altitude/level
ALTITUDE [altitude]       [level]                     parameter.
                                                      See paragraph 4.2.13.2 for use of this message
                                                      element as a response to a message element
                                                      with a ―Y‖ response attribute.
DM33 PRESENT              DM33 PRESENT                See paragraph 4.2.12.2 for use of position
POSITION [position]       POSITION [position]         parameter.
DM34 PRESENT SPEED        DM34 PRESENT SPEED          See paragraph 4.2.12.3 for use of speed
[speed]                   [speed]                     parameter.
DM35 PRESENT              DM35 PRESENT                None.
HEADING [degrees]         HEADING [degrees]
DM36 PRESENT              DM36 PRESENT                None.
GROUND TRACK              GROUND TRACK
[degrees]                 [degrees]
DM37 LEVEL [altitude]     DM37 MAINTAINING            See paragraph 4.2.12.1 for use of altitude/level
                          [level]                     parameter.
DM38 ASSIGNED             DM38 ASSIGNED               See paragraph 4.2.12.1 for use of altitude/level
ALTITUDE [altitude]       LEVEL [level]               parameter.
                                                      See paragraph 4.2.13.2 for use of this message
                                                      element as a response to a message element
                                                      with a ―Y‖ response attribute.
DM39 ASSIGNED SPEED DM39 ASSIGNED SPEED See paragraph 4.2.12.3 for use of speed
[speed]             [speed]             parameter.
DM40 ASSIGNED             DM124 ASSIGNED              IR-250  The ATN ground system shall
ROUTE [route clearance]   ROUTE [route clearance]     convert the FANS 1/A message DM40 to
                                                                                                  4-117


FANS 1/A Message          ATN Message Element        Interoperability Requirement
Element
                                                     ATN message DM124.
                                                     See paragraph 4.2.12.11 for use of route
                                                     clearance parameter.
DM41 BACK ON ROUTE DM41 BACK ON ROUTE None.
DM42 NEXT WAYPOINT DM42 NEXT WAYPOINT See paragraph 4.2.12.2 for use of position
[position]         [position]         parameter.
DM43 NEXT WAYPOINT DM125 NEXT                        IR-251  The ATN ground system shall
ETA [time]         WAYPOINT ETA                      convert the FANS 1/A message DM43 to
                   [timesec]                         ATN message DM125.
                                                     See paragraph 4.2.12.6 for use of the
                                                     time/timesec parameter.
DM44 ENSUING              DM44 ENSUING               See paragraph 4.2.12.2 for use of position
WAYPOINT [position]       WAYPOINT [position]        parameter.
DM45 REPORTED             DM45 REPORTED              See paragraph 4.2.12.2 for use of position
WAYPOINT [position]       WAYPOINT [position]        parameter.
DM46 REPORTED             DM126 REPORTED             IR-252  The ATN ground system shall
WAYPOINT [time]           WAYPOINT [timesec]         convert the FANS 1/A message DM46 to
                                                     ATN message DM126.
                                                     See paragraph 4.2.12.6 for use of the
                                                     time/timesec parameter.
DM47 SQUAWKING            DM47 SQUAWKING             None.
[beaconcode]              [code]
DM48 POSITION             DM127 POSITION             IR-253  The ATN ground system shall
REPORT [positionreport]   REPORT [position report]   convert the FANS 1/A message DM48 to
                                                     ATN message DM127.
                                                     See paragraph 4.2.12.23 for use of position
                                                     report parameter.
DM49 WHEN CAN WE          DM49 WHEN CAN WE           See paragraph 4.2.12.3 for use of speed
EXPECT [speed]            EXPECT [speed]             parameter.
DM50 WHEN CAN WE          DM50 WHEN CAN WE           See paragraph 4.2.12.3 for use of speed
EXPECT [speed] TO         EXPECT [speed] TO          parameter.
[speed]                   [speed]
DM51 WHEN CAN WE          DM51 WHEN CAN WE           None.
EXPECT BACK ON            EXPECT BACK ON
ROUTE                     ROUTE
DM52 WHEN CAN WE   DM52 WHEN CAN WE   None.
EXPECT LOWER LEVEL EXPECT LOWER LEVEL
DM53 WHEN CAN WE          DM53 WHEN CAN WE           None.
EXPECT HIGHER             EXPECT HIGHER
LEVEL                     LEVEL
FANS 1/A Message               ATN Message Element        Interoperability Requirement
Element
DM54 WHEN CAN WE    DM54 WHEN CAN WE    See paragraph 4.2.12.1 for use of altitude/level
EXPECT CRUISE CLIMB EXPECT CRUISE CLIMB parameter.
TO [altitude]       TO [level]
DM55 PAN PAN PAN               DM55 PAN PAN PAN           Response attribute different: Y in the ATS
                                                          INTEROP Standard, N in the FANS 1/A
                                                          INTEROP Standard.
DM56 MAYDAY                    DM56 MAYDAY                Response attribute different: Y in the ATS
MAYDAY MAYDAY                  MAYDAY MAYDAY              INTEROP Standard
DM57[remainingfuel] OF         DM128[remaining fuel]      IR-254  The ATN ground system shall
FUEL REMAINING AND             OF FUEL REMAINING          convert the FANS 1/A message DM57 to
[remainingsouls] SOULS         AND [personnes on board]   ATN message DM128.
ON BOARD                       PERSONS ON BOARD
                                                          Response attribute different: Y in the ATS
                                                          INTEROP Standard
                                                          See paragraph 4.2.12.24 for use of remaining
                                                          fuel parameter.
                                                          See paragraph 4.2.12.25 for use of remaining
                                                          persons parameter.
DM58 CANCEL                    DM58 CANCEL                Response attribute different: Y in the ATS
EMERGENCY                      EMERGENCY                  INTEROP Standard
DM59 DIVERTING TO              DM129 DIVERTING TO         IR-255  The ATN ground system shall
[position] VIA                 [position] VIA [route      convert the FANS 1/A message DM59 to
[routeclearance]               clearance]                 ATN message DM129.
                                                          Response attribute different: Y in the ATS
                                                          INTEROP Standard
                                                          See paragraph 4.2.12.2 for use of position
                                                          parameter.
                                                          See paragraph 4.2.12.11 for use of route
                                                          clearance parameter.
DM60 OFFSETTING                DM60 OFFSETTING            Response attribute different: Y in the ATS
[distanceoffset] [direction]   [specified distance]       INTEROP Standard
OF ROUTE                       [direction] OF ROUTE       See paragraph 4.2.12.4 for use of distance offset
                                                          parameter.
DM61 DESCENDING TO             DM61 DESCENDING TO         Response attribute different: Y in the ATS
[altitude]                     [level]                    INTEROP Standard.
                                                          See paragraph 4.2.12.1 for use of altitude/level
                                                          parameter.
DM62 ERROR                     DM62 ERROR [error          See paragraph 4.2.11.3 for use of error
[errorinformation]             information]               information parameter.
DM63 NOT CURRENT               DM63 NOT CURRENT           None.
DATA AUTHORITY                 DATA AUTHORITY
DM64 [facility                 DM64 [facility             See paragraph 4.2.12.8.2 for use of facility
                                                                                          4-119


FANS 1/A Message       ATN Message Element     Interoperability Requirement
Element
designation]           designation]            designation parameter.
DM65 DUE TO            DM65 DUE TO             None.
WEATHER                WEATHER
DM66 DUE TO            DM66 DUE TO             None.
AIRCRAFT               AIRCRAFT
PERFORMANCE            PERFORMANCE
DM67 [free text]       DM67 [free text]        None.
DM68 [free text]       DM68 [free text]        None.
DM69 REQUEST VMC       DM69 REQUEST VMC        None.
DESCENT                DESCENT

DM70 REQUEST           DM70 REQUEST            None.
HEADING [degrees]      HEADING [degrees]
DM71 REQUEST           DM71 REQUEST            None.
GROUND TRACK           GROUND TRACK
[degrees]              [degrees]
DM72 REACHING          DM72 Reserved           IR-256   The ATN Ground system shall
ALTITUDE [altitude]                            reject the FANS 1/A message DM72.
DM73 [versionnumber]   DM73 [version number]   None.
DM74 MAINTAIN OWN      DM74 REQUEST TO         Response attribute different: Y in the ATS
SEPARATION AND         MAINTAIN OWN            INTEROP Standard, N in the FANS 1/A
VMC                    SEPARATION AND          INTEROP Standard.
                       VMC
DM75 AT PILOTS         DM75 AT PILOTS          None.
DISCRETION             DISCRETION
DM76 REACHING          DM6 REACHING [level]    IR-257  The ATN ground system shall
BLOCK [altitude]TO                             convert the FANS 1/A message DM76 to
[altitude]                                     the ATN message DM6 using the BLOCK
                                               parameter for level.
                                               See paragraph 4.2.12.1 for use of altitude/level
                                               parameter.
                                               Note: ATN message DM76 is replaced by ATN
                                               message DM6.


DM77 ASSIGNED          DM38 ASSIGNED [level]   IR-258  The ATN ground system shall
BLOCK [altitude]TO                             convert the FANS 1/A message DM77 to
[altitude]                                     the ATN message DM38 using the BLOCK
                                               parameter for level.
                                               See paragraph 4.2.12.1 for use of altitude/level
                                               parameter.
                                               Note: ATN message DM77 is replaced by ATN
FANS 1/A Message              ATN Message Element       Interoperability Requirement
Element
                                                        message DM38.
DM78 AT [time] [distance] DM130 AT [timesec]            IR-259  The ATN ground system shall
[tofrom][position]        [distance]                    convert the FANS 1/A message DM78 to
                          [to/from][position]           ATN message DM130.
                                                        See paragraph 4.2.12.6 for use of the
                                                        time/timesec parameter.
                                                        See paragraph 4.2.12.2 for use of position
                                                        parameter.
                                                        See paragraph 4.2.12.4 for use of distance
                                                        parameter.
DM79 ATIS [atis code]         DM79 ATIS [atis code]     None.
DM80 DEVIATING                DM80 DEVIATING UP         Response attribute different: Y in the ATS
[distanceoffset][direction]   TO [specified             INTEROP Standard, N in the FANS 1/A
OF ROUTE                      distance][direction] OF   INTEROP Standard.
                              ROUTE                     See paragraph 4.2.12.4 for use of distance offset
                                                        parameter.
DM67 ‘WE CAN                  DM81 WE CAN ACCEPT        IR-260  The ATN ground system shall
ACCEPT [altitude] AT          [level] AT [time]         process DM67 message element as follows:
[time or waypoint]‘
                                                        • when [freetext] parameter containing at least
                              Or                        ―WE CANNOT ACCEPT,‖ convert it to DM82
Or                                                      message element containing the previously
                                                        uplinked level in UM148 message;
                              DM82 WE CANNOT
DM67 ‗WE CANNOT               ACCEPT [level]            • when [freetext] parameter containing ―WE
ACCEPT [altitude]‘                                      CAN ACCEPT<altitude>‖ and the last four or
                                                        five characters represent a time value (four
                                                        digits or four digits plus ´Z´ character), convert
Note: These are                                         it to DM81 message element containing the time
preformatted free text                                  corresponding to the downlinked freetext;
messages, per the FANS                                  • when [freetext] parameter equal to ―WE CAN
1/A INTEROP Standard.                                   ACCEPT <altitude> BY NOW,‖ convert it to
                                                        DM81 message element, inserting the current
                                                        time in [time] field;
                                                        The processing of this free text message for use
                                                        by the ATN ground system and the controller is
                                                        a local matter. Any safety assessment
                                                        associated with the implementation of this free
                                                        text functionality should take into account the
                                                        unreferenced nature of the downlink free text
                                                        reply, the potential for non-standard message
                                                        contents, the effects of intended and unintended
                                                        manipulation of the free text message by the
                                                        automation prior to use by the controller or
                                                        other functionality of the ATN ground system.
                                                        See paragraph 4.2.9 and IR-262 for further
                                                                                                     4-121


FANS 1/A Message                 ATN Message Element      Interoperability Requirement
Element
                                                          processing and rejection response.
                                                          See paragraph 4.2.12.1 for use of level/altitude.
                                                          See paragraph 4.2.13.2 for use of this message
                                                          element as a response to a message element
                                                          with a ―Y‖ response attribute.
DM67 ‗MONITORING                 DM89 MONITORING          IR-261  When supported, the ATN ground
[unitname] [frequency]‘          [unitname] [frequency]   system shall convert the equivalent
                                                          FANS 1/A message element DM67 into
Where                                                     ATN message element DM89.
[unitname] = [facility                                    The content of DM67 is aligned with DM89 in
identification] [facility                                 the ICAO Doc-4444 message set to maintain
function]                                                 operational seamlessness.
[facility identification] = 4-                            The processing of this free text message for use
character ICAO code                                       by the ATN ground system and the controller is
[facility function] = any of                              a local matter. Any safety assessment
the ICAOfacilityfunction                                  associated with the implementation of this free
values of CENTER,                                         text functionality should take into account the
APPROACH, etc. per the                                    unreferenced nature of the downlink free text
ATS INTEROP Standard                                      reply, the potential for non-standard message
                                                          contents, the effects of intended and unintended
[frequency] = a VHF                                       manipulation of the free text message by the
frequency as nnn.nnn or an                                automation prior to use by the controller or
HF frequency as nnnnn                                     other functionality of the ATN ground system.
                                                          See paragraph 4.2.9 and IR-262 for further
Note: It is anticipated that                              processing and rejection response.
airborne automation (i.e.,                                See paragraph 4.2.12.16 for use of frequency
preformatted message                                      parameter.
rather than the pilot typing
the text) may be necessary                                See paragraph for use of DM89 in the ACM
for message composition                                   service.
and to ensure accuracy of
the message content.
Consequently, it is likely
that not all aircraft will be
equipped with such
automation.
DM67 [free text]                 DM98 [freetext]          IR-262  When the [freetext] parameter of
                                                          the FANS 1/A message element is equal to
                                                          any value other than as specified in
                                                          paragraph or the expected value cannot be
                                                          converted in ASN.1, the ATN ground
                                                          system shall convert the FANS 1/A
                                                          message element DM67 into the ATN
                                                          message element DM98 and display the
                                                          message to the controller.
                                                          The processing of this free text message for use
FANS 1/A Message                ATN Message Element   Interoperability Requirement
Element
                                                      by the ATN ground system and the controller is
                                                      a local matter. Any safety assessment
                                                      associated with the implementation of this free
                                                      text functionality should take into account the
                                                      unreferenced nature of the downlink free text
                                                      reply, the potential for non-standard message
                                                      contents, the effects of intended and unintended
                                                      manipulation of the free text message by the
                                                      automation prior to use by the controller or
                                                      other functionality of the ATN ground system.
                                                      DM67 used as equivalent means to provide
                                                      responses to UM148, UM231, UM232
                                                      See this table for use of DM67 as equivalent of
                                                      DM106, DM135, DM81, DM82, DM89
                                                      See paragraph 4.2.9 for rejection response.
                                                      See paragraph 0 for use of DM67 with DM62.
DM67 ‗FL[level]‘                DM106 PREFERRED       IR-263  The ATN ground system shall
                                LEVEL [level]         convert the equivalent FANS 1/A message
Where                                                 element DM67 into the ATN message
[level] = character string (2                         element DM106 and display it in the form
or 3 characters) that                                 used for an ATN message element DM106.
represents an integer from                            The content of DM67 as sent by the flight crew
30 to 600.                                            is aligned with established use in oceanic
                                                      operations to obtain operational seamlessness.
                                                      The processing of this free text message for use
                                                      by the ATN ground system and the controller is
                                                      a local matter. Any safety assessment
                                                      associated with the implementation of this free
                                                      text functionality should take into account the
                                                      unreferenced nature of the downlink free text
                                                      reply, the potential for non-standard message
                                                      contents, the effects of intended and unintended
                                                      manipulation of the free text message by the
                                                      automation prior to use by the controller or
                                                      other functionality of the ATN ground system.
                                                      The displayed reply in this case (i.e. aligned
                                                      with DM106) is different from what the flight
                                                      crew actually sent, but the intent/use of the
                                                      message is the same.
                                                      See paragraph 4.2.9 and IR-262 for further
                                                      processing and rejection response.
                                                      See paragraph 4.2.13.2 for use of this message
                                                      element as a response to a message element
                                                      with a ―Y‖ response attribute.
DM64 [facility                  DM107 NOT             See paragraph 4.2.2 for use of FANS 1/A
                                                                                               4-123


FANS 1/A Message               ATN Message Element   Interoperability Requirement
Element
designation]                   AUTHORIZED NEXT       message element DM64 with ATN message
                               DATA AUTHORITY        element DM107.
DM67 ‗TOD [time]‘              DM135 TOP OF          IR-264  The ATN ground system shall
                               DESCENT [time]        convert the equivalent FANS 1/A message
Where                                                element DM67 into ATN message element
[time] = [hh][mm][z]                                 DM135 and display it in the form used for
                                                     an ATN message element DM135.
[hh] = 2-character string
that represents an integer                           TOP OF DESCENT is abbreviated in the DM67
between 00 and 23;                                   free text message to ease the burden of message
                                                     composition for the flight crew.
[mm] = 2-characters string
that represents an integer                           The processing of this free text message for use
between 00 and 59; and                               by the ATN ground system and the controller is
                                                     a local matter. Any safety assessment
[z] = an optional character,
                                                     associated with the implementation of this free
Z.
                                                     text functionality should take into account the
                                                     unreferenced nature of the downlink free text
                                                     reply, the potential for non-standard message
                                                     contents, the effects of intended and unintended
                                                     manipulation of the free text message by the
                                                     automation prior to use by the controller or
                                                     other functionality of the ATN ground system.
                                                     The displayed reply in this case (i.e. aligned
                                                     with DM135) is different from what the flight
                                                     crew actually sent, but the intent/use of the
                                                     message is the same.
                                                     See paragraph 4.2.9 and IR-262 for further
                                                     processing and rejection response.
                                                     See paragraph 4.2.13.2 for use of this message
                                                     element as a response to a message element
                                                     with a ―Y‖ response attribute.
4.2.9.2        Aircraft emergency data communication capability
          The Standard for Advanced ATS Data Communications includes provisions for the
          processing CPDLC emergency messages that the ground system may receive from the
          aircraft. While the CPDLC message set for continental data link services does not
          include emergency messages, the FANS 1/A aircraft includes an emergency data
          communication capability using the CPDLC application.
          Table 4-17 lists the FANS 1/A emergency message elements. When the ATN ground
          system receives a message that contains any of the message elements listed in this table,
          the message should be displayed to the controller. The controller should acknowledge
          receipt of the message by sending UM3 ROGER to the FANS 1/A aircraft.
          Note 1: The response attribute is “N” for FANS 1/A CPDLC emergency message
                  elements. The response attribute is “Y” for ICAO Doc 4444 emergency
                  message elements.
          Note 2: DM112 is not included in the FANS 1/A CPDLC message set.
          Note 3: While DM80 is included in the FANS 1/A CPDLC message set, it is not
                  processed as an emergency message element.
          Note 4: The following variables are used in the FANS 1/A emergency message elements


                  FANS 1/A variable               ICAO Doc 4444 variable        Guidance
                                                  (equivalent)
                  [remaining fuel]                [remaining fuel]              SEQUENCE
                                                                                 timehours Timehours,
                                                                                 timeminutes Timeminutes
                                                                                See paragraph 4.2.12.6.
                  [souls on board]                [persons on board]            INTEGER (1:1024)
                  [position]                      [position]                    See paragraph 4.2.12.2.
                  [route clearance]               [route clearance]             See paragraph 4.2.12.11.
                  [direction][distance offset]    [specified                    See paragraph 4.2.12.4.
                                                  distance][direction]
                  [altitude]                      [level] (Single level only)   See paragraph 4.2.12.1.
                                                                                                      4-125


                             Table 4-17 FANS 1/A CPDLC emergency message elements

               Ref #      FANS 1/A Message Element
               DM55       PAN PAN PAN
               DM56       MAYDAY MAYDAY MAYDAY
               DM128      [remaining fuel] OF FUEL REMAINING AND [souls on board] SOULS ON BOARD
               DM58       CANCEL EMERGENCY
               DM129      DIVERTING TO [position] VIA [route clearance]
               DM60       OFFSETTING [distance offset] [direction] OF ROUTE
               DM61       DESCENDING TO [altitude]



4.2.10          Concatenating Messages Elements
    4.2.10.1           High-Level Requirements
                Table 4-18 presents the ATN and comparable FANS 1/A CPDLC high-level
                requirements for concatenation of message elements.


                                 Table 4-18 High Level Concatenation Requirements

         Table ATN Concatenation rule     FANS 1/A             Interoperability Requirement
                                          Concatenation rule
         CPC-OR-60 Ground systems shall No equivalent.         Any message element concatenated
         not send uplink message element                       with UM72 will be accepted by the
         UM72 (RESUME OWN                                      FANS 1/A aircraft.
         NAVIGATION) without                                   See paragraph 4.2.8 for use of UM72,
         concatenating it after one of the                     UM74, UM266, and UM267.
         following message elements:
         UM74, UM266, or UM267,
         denoting the position to which to
         be navigated.
4-126
               Table ATN Concatenation rule   FANS 1/A             Interoperability Requirement
                                              Concatenation rule
        CPC-IR 28 When the Aircraft     No equivalent.       Any message element concatenated
        System rejects a CPDLC message                       with UM72 will be accepted by the
        containing message element                           FANS 1/A aircraft.
        UM72 RESUME OWN                                      See paragraph 4.2.9 for use of DM62.
        NAVIGATION because it does
        not also contain one of the
        following message elements:
        UM74, UM266 (NEW UM79), or
        UM267 (NEW UM80) it shall
        send a CPDLC downlink message
        containing the concatenation of
        message element DM62 (ERROR
        (error information)) with the
        choice (2) followed by message
        element DM98 (MESSAGE
        DOES NOT CONTAIN THE
        POSITION TO BE NAVIGATED
        TO).



    4.2.10.2         Responding to Concatenated Messages
                 Table 4-19 presents the ATN and comparable FANS 1/A CPDLC requirements for
                 responses to concatenated messages.
                                                                                             4-127


            Table 4-19 ATN and FANS 1/A CPDLC responses to concatenated messages

ATN concatenation rule         FANS 1/A             Interoperability Requirement
                               Concatenation rule
CPC-IR 105 When                No equivalent.       IR-265  When receiving a single element DM0
responding positively to a                          or DM1 as a response to the concatenated
received concatenated uplink                        uplink message containing message elements
message containing message                          VCI and other UM, the ATN ground system
elements VCI and other
                                                    shall:
messages requiring a
response, the aircraft shall                         accept the DM0 or DM1 single element
respond with a concatenated                         message as closure response, and
downlink message containing                          cancel the ‗tts‘ timer (when used) on the basis
DM0 WILCO and the                                   of DM0 or DM1.
response messages(s).                               Some FANS 1/A aircraft will respond with single
                                                    element DM0 message and the DM38 is sent later as
                                                    an unreferenced message.
                                                    When the FANS 1/A aircraft sends the DM38 as an
                                                    unreferenced message:
                                                    • If the active connection is closed (DM0 sending),
                                                    to the next Centre (R-ATSU) if any, when it
                                                    becomes the CDA;
                                                    • If the active connection remains active (DM1
                                                    sending), to the current Centre
                                                    Any message element concatenated with UM120
                                                    will be accepted by the FANS 1/A aircraft.
                                                    See paragraph 4.2.2 for use of CPDLC-End Service.
                                                    See paragraph 4.2.8 for use of UM117, UM120 and
                                                    UM135.
4-128

         ATN concatenation rule      FANS 1/A             Interoperability Requirement
                                     Concatenation rule
         CPC-IR 17 When a CPDLC- No equivalent.           Any message element concatenated with UM120
         end-request is received,                         will be accepted by the FANS 1/A aircraft.
         containing a CPDLC message                       See paragraph 4.2.2 for use of CPDLC-End Service.
         element that is not UM117,
                                                          See paragraph 4.2.8 for use of UM117, UM120 and
         UM120 or UM135
                                                          UM135.
         concatenated with either VCI,
         and if the airborne system
         does not allow the message
         element within the CPDLC-
         end, then the airborne system
         shall reject the end request
         and respond by generating a
         CPDLC downlink message
         containing the concatenation
         of message element DM62
         (ERROR (error information))
         with the choice (0) followed
         by message element DM98
         (THIS MESSAGE
         ELEMENT NOT
         PERMITTED IN END)
         within the CPDLC-end
         response.



4.2.11          Error Information
    4.2.11.1         General Rules
                Table 4-20 presents the general ATN and the comparable FANS 1/A ERROR
                information requirements.
                                                                                                    4-129


                   Table 4-20 ATN and FANS 1/A ERROR information requirements

ATN ERROR information general rule                FANS 1/A         Interoperability Requirement
                                                  ERROR
                                                  information
                                                  general rule
3.3.2 CPDLC Message Errors                        No equivalent.   See paragraph 4.2.11.2 for processing
Note: In the ATS INTEROP Standard, two                             Uplink errors using the
types of errors are distinguished:                                 [errorinformation] parameter.
a) A "technical error" occurs when the local                       See paragraph 4.2.11.3 for processing
system detects that the peer system has not                        Downlink errors using the
been designed according to the ATN                                 [errorinformation] parameter.
requirements. The error text is intended to be
used for debugging purposes rather than
displayed to the controller or pilot.
b) An "operational error" occurs when the
local system detects that the peer user does
not behave according to the ATN
requirements or local constraints prevent an
operational response. The error text is
intended for display to the controller or pilot
to provide an explanation of the error
situation.
3.3.2.1 Composition of CPDLC Error            No equivalent.       See paragraph 4.2.11.2 for processing
Messages                                                           Uplink errors using the
CPC-IR 12 When the error case is specified                         [errorinformation] parameter.
in ICAO Documents 9880 or [PM-FIS], the                            See paragraph 4.2.11.3 for processing
system shall send a CPDLC Message                                  Downlink errors using the
containing an ERROR message element alone                          [errorinformation] parameter.
(UM159 or DM62) with the
[errorinformation] value as specified in ICAO
Document 9880 (0 for "unrecognized
message reference number", 1 for "logical
acknowledgement not supported", 2 for
"insufficient resources", 3 for "invalid
message element combination" and 4 for
"invalid message element").
CPC-IR 13 When the error case is specific to No equivalent.        None.
the ATS INTEROP Standard, and                                      See paragraph 4.2.11.2 for processing
a) the error is a technical error, the system                      Uplink errors using the
will send a CPDLC message containing an                            [errorinformation] parameter.
ERROR message element with                                         See paragraph 4.2.11.3 for processing
[errorinformation] value (0) concatenated                          Downlink errors using the
with a FREE TEXT message element                                   [errorinformation] parameter.
describing the error;
                                                                   See paragraph 4.2.12.28.2 for the use of
b) the error is an operational error and is an                     FREETEXT.
extension of an error specified in Doc 9880
(―3‖ for invalid message element combination
and ―4‖ for invalid message element), the
4-130

        ATN ERROR information general rule                FANS 1/A         Interoperability Requirement
                                                          ERROR
                                                          information
                                                          general rule
        system will send a CPDLC message
        containing an ERROR message element with
        [errorinformation] value (3) or (4)
        concatenated with a FREE TEXT message
        element describing the error; or
        c) the error is an operational error but is not
        an extension of an error specified in Doc
        9880, the system will send a CPDLC message
        containing an ERROR message element with
        [errorinformation] value (2) concatenated
        with a FREE TEXT message element
        describing the error.
        CPC-IR 16 When a CPDLC Message                   No equivalent.    See paragraph 4.2.11.2 for processing
        containing an ERROR message element                                Uplink errors using the
        concatenated with a FREE TEXT message                              [errorinformation] parameter.
        element is received, the display of the                            See paragraph 4.2.11.3 for processing
        message shall be performed based on the                            Downlink errors using the
        following rules:                                                   [errorinformation] parameter.
        a) When an ERROR message element with                              See paragraph 4.2.12.28.2 for the use of
        [errorinformation] value (0) concatenated                          FREETEXT.
        with a FREE TEXT message element is
        received (e.g. it is a technical error), it is a
        local decision whether to make or not to make
        the included free text available to the
        controller/pilot.
        b) When an ERROR message element with
        [errorinformation] value (2), (3) or (4)
        concatenated with a FREE TEXT message
        element is received (e.g. it is an operational
        error), then the received free text is made
        available for display to the pilot/controller.
        CPC-IRec 1The ERROR [errorinformation]            No equivalent.   None.
        associated text (e.g. insufficient resources)                      The FANS 1/A aircraft does not display
        should not be displayed when the FREE                              the [errorinformation] value.
        TEXT message element is appended to the
        error.
        CPC-IRec 2 When DM62 ERROR (4) (invalid
        message element) is received, the ATSU
        System should display the message to the
        Controller as “PROHIBITED MESSAGE
        ELEMENT”.
        CPC-IRec 3 When UM159 ERROR (4)
        (invalid message element) is received, the
        Aircraft System should display the message to
        the Aircrew as “PROHIBITED MESSAGE
        ELEMENT”.
                                                                                                    4-131


  ATN ERROR information general rule         FANS 1/A            Interoperability Requirement
                                             ERROR
                                             information
                                             general rule
  CPC-IR 14 ATN systems shall not append the No equivalent.      See paragraph 4.2.11.2 for processing
  FREE TEXT message element to the ERROR                         Uplink errors using the
  with [errorinformation] value (1).                             [errorinformation] parameter.
                                                                 See paragraph 4.2.11.3 for processing
                                                                 Downlink errors using the
                                                                 [errorinformation] parameter.
  CPC-IR 15 An ERROR message shall not be    No equivalent.      None.
  sent in response to a LACK or ERROR
  message



4.2.11.2       Uplink Error Information – UM159 [errorinformation] Parameter
           Note:    The information provided in this paragraph together with the information in
                    paragraph 4.2.8 (Uplink message elements) for the use of FREE TEXT message
                    element UM183 provides the means to exchange UPLINK ERROR Information.
           Table 4-21 presents the ATN and the comparable FANS 1/A UM159 error information
           parameter.


                   Table 4-21 ATN and FANS 1/A uplink [errorinformation] parameter

  ATN UM159 Error             FANS 1/A UM 159 Error         Interoperability Requirement
  Information Parameter       Information Parameter
  (0) Unrecognized message    (2) Unrecognized message      IR-266  The ATN ground system
  reference number            reference number              shall convert the ATN message
                                                            element UM159 containing (0)
                                                            Unrecognized message reference
                                                            number to the FANS 1/A message
                                                            element UM159 containing (2)
                                                            Unrecognized message reference
                                                            number.
                                                            IR-267 If a technical error occurs, the
                                                            ATN ground system shall send
                                                            UM159 as a single element message
                                                            to the FANS 1/A aircraft.
                                                            This is done to avoid the FREE TEXT
                                                            message being presented to the flight
                                                            crew in case of a technical error.
  (1) Logical                 None                          None.
  acknowledgement not
  accepted
4-132

        ATN UM159 Error              FANS 1/A UM 159 Error      Interoperability Requirement
        Information Parameter        Information Parameter
        (2) Insufficient resources   (5) Insufficient message   IR-268   The ATN ground system
                                     storage capacity           shall convert the ATN message
                                                                element UM159 containing (2)
                                                                Insufficient resources to the
                                                                FANS 1/A message element UM159
                                                                containing (5) Insufficient message
                                                                storage capacity.
        (3) Invalid Message Element (0) Application error       IR-269  The ATN ground system
        Combination                                             shall convert the ATN message
                                                                element UM159 containing (3)
                                                                Invalid Message Element
                                                                Combination to the FANS 1/A
                                                                message element UM159 containing
                                                                (0) Application error.
        (4) Invalid Message Element (10) Invalid data           IR-270  The ATN ground system
                                                                shall convert the ATN message
                                                                element UM159 containing (4)
                                                                Invalid Message Element to the
                                                                FANS 1/A message element UM159
                                                                containing (10) Invalid data.


     4.2.11.3          Downlink Error Information when DM62 is received as Single Element in IMI
                       AT1/DR1
                 Note:      The FANS 1/A aircraft concatenates DM62 with DM67 (Free Text) in one case,
                            which is presented in paragraph 4.2.1.3 - Message Latency.
4.2.11.3.1       Downlink [errorinformation] Parameter
                 Table 4-22 presents the ATN and comparable FANS 1/A DM62 error information
                 parameter.
                                                                                                4-133


              Table 4-22 ATN and FANS 1/A downlink [errorinformation] parameter

ATN DM62 Error             FANS 1/A DM62 Error            Interoperability Requirement
Information Parameter      Information Parameter
(3) Invalid message        (0) Application error          IR-271   The ATN ground system
element combination                                       shall process an AT1 IMI containing
                                                          a DM62 (application error) as a
                                                          CPDLC message containing DM62
                                                          (invalid message element
                                                          combination).
                                                          The FANS 1/A aircrafts send a DM62
                                                          ERROR ‗applicationError‘ when an
                                                          unsupported combination of uplink
                                                          elements is received.
None                       (1) Duplicate message          None.
                           identification number          As per ―Air CPDLC-user-abort service
                                                          (CPDLCUserAbort),― ‘Duplicate
                                                          message identification number‘ error
                                                          information is sent in AT1 IMI by the
                                                          FANS 1/A aircraft, but is considered as a
                                                          connection abort by the ATN ground
                                                          system.
                                                          See Table 4-8, ―Air CPDLC-user-abort
                                                          service (CPDLCUserAbort)‖ for use of
                                                          ‗Duplicate message identification
                                                          number‘ error information.
(0) Unrecognized message   (2) Unrecognized message       IR-272   The ATN ground system
reference number           reference number               shall process an AT1 IMI containing
                                                          a DM62 (Unrecognized message
                                                          reference number) as a CPDLC
                                                          message containing DM62
                                                          (Unrecognized message reference
                                                          number).
None                       (3) End service with pending   As per the FANS 1/A INTEROP
                           messages                       Standard, End service with pending
                                                          messages, error information is only sent
                                                          in an IMI -DR1.
                                                          See Table 4-8, ―Air CPDLC-user-abort
                                                          service (unsolicited DR1),‖ for use of
                                                          ‗End service with pending messages‘
                                                          error information.
4-134

        ATN DM62 Error               FANS 1/A DM62 Error             Interoperability Requirement
        Information Parameter        Information Parameter
        None                         (4) End service with no valid   As per the FANS 1/A INTEROP
                                     response                        Standard, ‗End service with no valid
                                                                     response‘ error information is sent by the
                                                                     FANS 1/A aircraft in response to a
                                                                     ground CPDLC user abort.
                                                                     See Table 4-8, ―Ground CPDLC-user-
                                                                     abort service,‖ for use of ‗End service
                                                                     with no valid response‘ error
                                                                     information.
        (2) Insufficient resources   (5) Insufficient message        IR-273   The ATN ground system
                                     storage capacity                shall process an AT1 IMI containing
                                                                     a DM62 (Insufficient message
                                                                     storage capacity) as a CPDLC
                                                                     message containing DM62
                                                                     (Insufficient resources).
        None                         (6) No available message         ‗No available message identification
                                     identification number           number‘ error information is only sent in
                                                                     an IMI DR1.
                                                                     See Table 4-8, ―Air CPDLC-user-abort
                                                                     service (unsolicited DR1),‖ for use of
                                                                     ‗No available message identification
                                                                     number‘ error information.
        None                         (7) Commanded termination        ‗Commanded termination‘ error
                                                                     information is only sent in an IMI DR1.
                                                                     See Table 4-8, ―Air CPDLC-user-abort
                                                                     service (unsolicited DR1),‖ for use of
                                                                     ‘Commanded termination‘ error
                                                                     information.
        None                         (8) Insufficient Data           See Table 4-8, ―Air CPDLC-user-abort
                                                                     service,‖ for use of ‗Insufficient Data‘
                                                                     error information.
        (3) Invalid message          (9) Unexpected data             IR-274   The ATN ground system
        element combination                                          shall process an AT1 IMI containing
                                                                     a DM62 (Unexpected data) as a
                                                                     CPDLC message containing DM62
                                                                     (Invalid message element
                                                                     combination).
        (3) Invalid message          (10) Invalid data               IR-275   The ATN ground system
        element combination                                          shall process an AT1 IMI containing
                                                                     a DM62 (Invalid data) as a CPDLC
                                                                     message containing DM62 (Invalid
                                                                     message element combination).
                                                                                                   4-135


4.2.11.3.2      Further Downlink Error Information Case
                Table 4-23 gives an indication of the FANS 1/A Downlink Error Information Cases not
                mentioned elsewhere and the related interoperability requirements.


                            Table 4-23 ATN and FANS 1/A DOWNLINK error information

        ATN DOWNLINK Error cases                        FANS 1/A DOWNLINK   Interoperability
                                                        Error cases         Requirement
        CPC-IR 9          When the aircraft is in the   No equivalent.      None.
        CPDLC inhibited state and the Aircraft System
        receives a CPDLC-start indication, the Aircraft
        System shall reject the CPDLC-start request,
        the CPDLC-start response shall include a
        CPDLC message containing the concatenation
        of message element DM62 (ERROR (error
        information)) with the choice (2) followed by
        message element DM98 (FLIGHT CREW
        HAS INHIBITED CPDLC).
        CPC-IR 10 When the aircraft reverts to the                          The FANS 1/A aircraft
        CPDLC inhibited state, it shall abort all the                       will reject the connection
        active CPDLC connections.                                           initiation if no or another
                                                                            message element than
                                                                            UM163 is contained; see
                                                                            paragraph 4.3.2.1.
                                                                            See paragraph 4.2.11.3.1
                                                                            for use of Downlink
                                                                            [errorinformation]
                                                                            Parameter.




        CPC-IR 86 When the air system rejects a         No equivalent.      The FANS 1/A aircraft
        CPDLC message containing the concatenation                          accepts the ―no or another
        of message element DM62 (ERROR (error                               message element than
        information)) with the choice (0) followed by                       UM163 is contained; see
        message element DM98 (MESSAGE NOT                                   paragraph 4.3.2.1.
        PERMITTED IN A START REQUEST).                                      See paragraph 4.2.11.3.1
                                                                            for use of Downlink
                                                                            [errorinformation]
                                                                            Parameter.
4-136

        ATN DOWNLINK Error cases                       FANS 1/A DOWNLINK   Interoperability
                                                       Error cases         Requirement
        CPC-IR 28 When the Aircraft System rejects a   No equivalent.      See paragraph 4.2.11.3.1
        CPDLC message containing message element                           for use of Downlink
        UM72 RESUME OWN NAVIGATION                                         [errorinformation]
        because it does not also contain one of the                        Parameter.
        following message elements: UM74, UM266
        (NEW UM79), or UM267 (NEW UM80) it
        shall send a CPDLC downlink message
        containing the concatenation of message
        element DM62 (ERROR (error information))
        with the choice (2) followed by message
        element DM98 (MESSAGE DOES NOT
        CONTAIN THE POSITION TO BE
        NAVIGATED TO).
        CPC-IR 29 When the Aircraft System rejects a                       The FANS 1/A aircraft
        CPDLC message containing message element                           accepts all message
        UM337 CLERANCE LIMIT [position]                                    elements which can be
        because it does not also contain one of the                        encoded following the
        following message elements: UM266,                                 FANS 1/A ASN1
        UM267, UM268, it shall send a CPDLC                                definitions in the
        downlink message containing the                                    FANS 1/A INTEROP
        concatenation of message element DM62                              Standard.
        (ERROR (error information)) with the choice                        UM163, UM166, UM167
        (2) followed by message element DM98                               are not within the scope
        (MESSAGE DOES NOT CONTAIN THE                                      of this document provided
        CLEARANCE TO WHICH THE LIMIT                                       in paragraph 1.2.
        APPLIES).
                                                                           See paragraph 4.2.11.3.1
                                                                           for use of Downlink
                                                                           [errorinformation]
                                                                           Parameter.
                                                                                            4-137


ATN DOWNLINK Error cases                           FANS 1/A DOWNLINK   Interoperability
                                                   Error cases         Requirement
CPC-IR 30 When the Aircraft System receives No equivalent.             See paragraph 4.2.11.3.1
a concatenated uplink CPDLC message that it                            for use of Downlink
does not support (invalid element                                      [errorinformation]
combination), it shall discard the received                            Parameter.
CPDLC message and send a CPDLC downlink
message containing the concatenation of
message element DM62 (ERROR (error
information)) with the choice (3) followed by
message element DM98 (ELEMENT
COMBINATION NOT SUPPORTED BY
THIS AIRCRAFT)..
CPC-IR 37 When the airborne system shall           No equivalent.      The FANS 1/A aircraft
discard the received message and send a                                accepts all message
CPDLC message containing the concatenation                             elements which can be
of message element DM62 (ERROR (error                                  encoded following the
information)) with the choice (4) followed by                          FANS 1/A ASN1
message element DM98 (free text).                                      definitions in the
                                                                       FANS 1/A INTEROP
                                                                       Standard.
                                                                       UM163, UM166, UM167
                                                                       are not within the scope
                                                                       of this document provided
                                                                       in paragraph 1.2.
                                                                       See paragraph 4.2.11.3.1
                                                                       for use of Downlink
                                                                       [errorinformation]
                                                                       Parameter.
CPC-IR 50 When the Aircraft System receives        No equivalent.      None.
a CPDLC message with a free text message
element containing more than the supported
number of free text characters, it shall discard
the received message and send a CPDLC
downlink message containing the
concatenation of message element DM62
(ERROR (error information)) with the choice
(2) followed by message element DM98
(FREE TEXT MESSAGE TOO LARGE).
4-138

        ATN DOWNLINK Error cases                        FANS 1/A DOWNLINK   Interoperability
                                                        Error cases         Requirement
        CPC-IR 17 When a CPDLC message is                No equivalent.     None.
        received that results in an error not defined in
        the ICAO Document 9880 and not defined
        explicitly elsewhere in this document, the
        Aircraft System shall discard the received
        message and send a CPDLC downlink message
        containing the concatenation of message
        element DM62 (ERROR (error information))
        with the choice (0) or choice (2) followed by
        message element DM98 composed of the fixed
        text ―Undefined ERROR‖ plus optionally a
        user-defined free text.
        CPC-IR 18 When a CPDLC message is              No equivalent.       None.
        received that results in an error, that is not
        already covered in ICAO Document 9880, and
        not defined explicitly elsewhere in this
        document, the ATSU System shall discard the
        message and send a CPDLC uplink message
        containing the message element UM159
        (ERROR (error information)) with the choice
        (0) or choice (2) followed by message element
        UM183 composed of the fixed text ―Undefined
        ERROR‖ plus optionally a user-defined free
        text
        CPC-IR 58 When the Aircraft System receives No equivalent.          See paragraph 4.2.11.3.1
        a CPDLC message containing data that it does                        for use of Downlink
        not support, it shall discard the received                          [errorinformation]
        CPDLC message and send a CPDLC downlink                             Parameter.
        message containing the message element
        DM62 (ERROR (error information)) with the
        choice (0) followed by message element DM98
        (TYPE OF DATA NOT SUPPORTED BY
        THIS AIRCRAFT).
        CPC-IR 65 When the Aircraft system receives     No equivalent.      See paragraph 4.2.11.3.1
        a CPDLC message containing data that it does                        for use of Downlink
        not support, it shall discard the received                          [errorinformation]
        message and send a CPDLC message                                    Parameter.
        containing the concatenation of message
        element DM62 (ERROR (error information))
        with the choice (0) followed by message
        element DM98 (MESSAGE DOES NOT
        CONTAIN FACILITY NAME).
                                                                                     4-139


ATN DOWNLINK Error cases                    FANS 1/A DOWNLINK   Interoperability
                                            Error cases         Requirement
CPC-IR 68 When the airborne system receives No equivalent.      None.
a CPDLC message with a CPDLC message
element that contains the unitname data type,
but rejects the message because it does not
specify valid VHF channel designators, it shall
discard the received CPDLC message and send
a CPDLC downlink message containing the
concatenation of message element DM62
(ERROR (error information)) with the choice
(0) followed by message element DM98
(INVALID VALUE FOR VHF CHANNEL).
CPC-IR 70When the Aircraft System receives No equivalent.       None.
a CPDLC message containing message element                      The FANS 1/A aircraft
UM266 (NEW UM79), if it rejects the message                     does not execute a check
because it contains any of the following:                       on the validity of the VHF
departure airport, departure runway or                          frequency communicated.
departure procedure, in the [routeClearance]
field, then it shall discard the received message
and send a CPDLC downlink message
containing the message element DM62
(ERROR (error information)) with the choice
(0) followed by message element DM98
(UNACCEPTABLE DATA COMBINATION
IN MESSAGE ).
CPC-IR 71When the Aircraft System receives No equivalent.       None.
a CPDLC message containing the message                          The FANS 1/A aircraft
element UM266 (NEW UM79) or message                             does not reject the
element UM267 (NEW UM80) that is                                message in this case;
concatenated with message element UM74,                         airborne automation
and if it rejects the message because UM74                      (upload into FMS) may
does not follow UM266 (NEW UM79) or                             fail.
UM267 (NEW UM80), then it shall discard the
received message and send a CPDLC downlink
message containing the concatenation of
message element DM62 (ERROR (error
information)) with the choice (0)) followed by
message element DM98 (ELEMENT ORDER
NOT SUPPORTED BY THIS AIRCRAFT).
4-140

        ATN DOWNLINK Error cases                    FANS 1/A DOWNLINK   Interoperability
                                                    Error cases         Requirement
        CPC-IR 72When the Aircraft System receives No equivalent.       None.
        a CPDLC message with a message element                          The FANS 1/A aircraft
        containing the ATSroutedesignator parameter                     does not reject the
        in the routeinformation variable, if it rejects the             message in this case;
        message because the first occurrence of this                    airborne automation
        parameter is not preceded by a                                  (upload into FMS) may
        publishedidentifer parameter, then it shall                     fail.
        discard the received message and send a
        CPDLC downlink message containing the
        concatenation of message element DM62
        (ERROR (error information)) with the choice
        (0)) followed by message element DM98
        (UNACCEPTABLE DATA COMBINATION
        IN MESSAGE)
        CPC-IR 73When the ATSU System receives a No equivalent.         None.
        CPDLC message with a message element                            The FANS 1/A aircraft
        containing the ATSroutedesignator parameter                     does not reject the
        in the routeinformation variable, if it rejects the             message in this case;
        message because the first occurrence of this                    airborne automation
        parameter is not preceeded by a                                 (upload into FMS) may
        publishedidentifer parameter, then it shall                     fail.
        discard the received message and send a
        CPDLC uplink message containing the
        concatenation of message element UM159
        (ERROR (error information)) with the choice
        (0) followed by message element UM183
        (UNACCEPTABLE DATA COMBINATION
        IN MESSAGE).
        CPC-IR 76 When the Aircraft System receives No equivalent.      See paragraph 4.2.11.3.1
        a CPDLC message with a message element that                     for use of Downlink
        contains an IRA5String, but specifies IRA5                      [errorinformation]
        characters the Aircraft System does not                         Parameter.
        support, it shall discard the received message
        and send a CPDLC downlink message
        containing the concatenation of message
        element DM62 (ERROR (error information))
        with the choice (0) followed by message
        element DM98 (UNABLE TO DISPLAY
        CHARACTER).
                                                                                                     4-141


ATN DOWNLINK Error cases                          FANS 1/A DOWNLINK             Interoperability
                                                  Error cases                   Requirement
3.3.7.6.4.16.1.1 When the airborne system       No equivalent.                  None.
receives a CPDLC message with a message                                         The FANS 1/A aircraft
element, containing the ATSroutedesignator                                      does not reject the
parameter in the routeinformation parameter, if                                 message in this case;
it rejects the message because the first                                        airborne automation
occurrence of this parameter is not preceded by                                 (upload into FMS) may
a publishedidentifer parameter, then it shall                                   fail.
discard the received message and send a
CPDLC downlink message containing the
concatenation of message element DM62
(ERROR (error information)) with the choice
(0)) followed by message element DM98
(UNACCEPTABLE DATA COMBINATION
IN ROUTE CLEARANCE).
3.3.7.6.4.16.2.1 When the airborne system         No equivalent.                None.
receives a CPDLC message with a message                                         The FANS 1/A aircraft
element, containing the ATSroutedesignator                                      does not reject the
parameter, if it rejects the message because this                               message in this case;
parameter is not followed by a                                                  airborne automation
Publishedidentifer parameter or a                                               (upload into FMS) may
ATSroutedesignator parameter, then it shall                                     fail.
discard the received message and send a
CPDLC downlink message containing the
concatenation of message element DM62
(ERROR (error information)) with the choice
(3) followed by message element DM98
(UNACCEPTABLE DATA COMBINATION
IN ROUTE CLEARANCE).
3.3.7.6.4.21.1 When the airborne system           4.6.6.1 d.                    See paragraph 4.2.11.3.1
receives an CPDLC message with a message          If a message is received      for use of Downlink
element that contains an IA5 string, but          and there are message         [errorinformation]
specifies IA5 characters the airborne system      elements containing an        Parameter.
does not support, it shall discard the received   IA5 string character not
message and send a CPDLC downlink message         supported, CPDLC shall
containing the concatenation of message           send a message with the
element DM62 (ERROR (error information))          DM62 ERROR message
with the choice (0) followed by message           element
element DM98 (UNABLE TO DISPLAY
                                                  together with Appendix
CHARACTER).
                                                  A.4.6 - 10 ..... [with
                                                  errorinformation] value set
                                                  to [invalidData]
4-142

         ATN DOWNLINK Error cases                      FANS 1/A DOWNLINK         Interoperability
                                                       Error cases               Requirement
         4.2.1.3.7 Upon expiry of ttr, the airborne    No equivalent.            None.
         system shall automatically send a CPDLC                                 The FANS 1/A aircraft
         downlink message containing the                                         does not use the ‗ttr‘
         concatenation of message element DM62                                   timer.
         (ERROR (error information)) with the choice
         (2) followed by message element DM98 (AIR
         SYSTEM TIMEOUT) closing the dialogue.



4.2.12          Message Element Parameters and Data Type
     4.2.12.1        Level/Altitude Parameter
                The level parameter in ATN CPDLC messages is comparable to the altitude parameter in
                FANS 1/A CPDLC messages. In ATN systems, any message that contains the level
                parameter can contain a single level (LevelType) or a vertical range (Sequence of 2
                LevelType). In FANS 1/A systems the altitude parameter is always a single altitude.
IR-276   The ATN ground system shall reject the use of a vertical range to a FANS 1/A aircraft except for
the messages that have interoperability requirements associated with using a vertical range.
IR-277    See paragraph 4.2.8 and paragraph 4.2.9 for interoperability requirements associated with using a
vertical range.
                There are differences in the ATN choices of LevelType and the FANS 1/A choices of
                Altitude. Where the ATN Level Type choices have comparable FANS 1/A Altitude
                choices, there are differences in the parameter ranges and resolutions.
                Table 4-24 presents the LevelType/Altitude differences between ATN and FANS 1/A
                and the impact on the ATN ground system.
                Note:     See paragraph 4.2.9 for processing downlink message elements containing the
                          following parameter/data types, which are not supported by the ATN ground
                          system:
                              FANS 1/A „Altitude qfe‟ and „Altitude qfe meters,‟ which are only used as a
                               response to an uplink message.
                              FANS 1/A „Altitude gnss‟ and „Altitude gnss meters,‟ which are only used
                               as a response to an uplink message.
                                                                                        4-143


                   Table 4-24 ATN LevelType and FANS 1/A altitude

ATN LevelType                FANS 1/A Altitude         Interoperability Requirement
Level feet:                  Altitude qnh:             IR-278   The ATN ground system
 Range: -600 to 70000         Range: 0 to 25000        shall use the Level Flight Level
 Units: feet                  Units: feet              only with values from 0 feet to
 Resolution: 10               Resolution: 10           25000 feet inclusive.
                                                       No additional interoperability
                                                       requirement for downlink message
                                                       elements.
                                                       The ATN ground system can process
                                                       the altitude qnh choice from the
                                                       FANS 1/A aircraft.
Level flight level:          Altitude flight level:    IR-279   The ATN ground system
 Range: 030 to 700            Range: 030 to 600        shall use the Level Flight Level
 Units: hundreds of feet      Unit: hundreds of feet   only with values from FL30 to
 Resolution: 1                Resolution: 1            FL600 inclusive.
                                                       No additional interoperability
                                                       requirement for downlink message
                                                       elements.
                                                       The ATN ground system can process
                                                       the altitude flight level choice from
                                                       the FANS 1/A aircraft.
Level meters:                Altitude qnh meters:      IR-280   The ATN ground system
 Range: -30 to 25000          Range: 0 to 16000        shall prohibit the use of Level
 Units: meters                Units: meters            meters parameter not respecting
Resolution: 1                Resolution: 1             the FANS 1/A parameter range.
                                                       No additional interoperability
                                                       requirement for downlink message
                                                       elements.
                                                       The ATN ground system can process
                                                       the altitude flight level choice from
                                                       the FANS 1/A aircraft.
Level flight level metric:   Altitude flight level     IR-281   The ATN ground system
 Range: 100 to 2500          metric:                   shall use the Level Flight Level
 Units: tens of meters        Range: 1000 to 20000     Metric only with values from
 Resolution: 10               Unit: tens of meters     FL100 to FL2000 inclusive.
                             Resolution: 10            No additional interoperability
                                                       requirement for downlink message
                                                       elements.
                                                       The ATN ground system can process
                                                       the altitude flight level choice from
                                                       the FANS 1/A aircraft.
4-144
        4.2.12.2         Position Parameter
             The position parameter in CPDLC message elements is comparable in ATN and
             FANS 1/A. The position parameter has same choice types, in the same order in both ATN
             and FANS 1/A. However, the Data Types in the position choices are not the same. There
             are also differences in the ATN and the FANS 1/A position parameter ranges and
             resolutions.
             Table 4-25 presents the position Data Type differences between ATN and FANS 1/A and
             the impact on the ATN ground system.


                                Table 4-25 ATN and FANS 1/A position data type

              ATN Position                  FANS 1/A Position    Interoperability Requirement
              Fix name:                     Fix name             IR-282  The ATN ground
                Fix                                              system shall prohibit the use of
                Latitude and/or longitude                        Latitude and/or longitude in the
                (optional)                                       FANS 1/A Fix name parameter.
                                                                 No additional interoperability
                                                                 requirement for downlink message
                                                                 elements.
                                                                 The ATN Fix part of the Fix Name
                                                                 parameter is equivalent to the Fix
                                                                 name parameter in FANS 1/A.
                                                                 The use of Lat/Lon is required by
                                                                 the ATS INTEROP Standard,
                                                                 Annex B for uplink messages.
                                                                 The ATN ground system can
                                                                 process the fix name choice from
                                                                 the FANS 1/A aircraft.
              Navaid:                       Navaid               IR-283  The ATN ground
               Navaid name                                       system shall prohibit the use of
               Latitude and/or longitude                         Latitude and/or longitude in the
               (optional)                                        FANS 1/A Navaid parameter.
                                                                 No additional interoperability
                                                                 requirement for downlink message
                                                                 elements.
                                                                 The ATN navaid name part of the
                                                                 navaid parameter is equivalent to
                                                                 the navaid parameter in FANS 1/A.
                                                                 The use of Lat/Lon is required by
                                                                 the ATS INTEROP Standard,
                                                                 Annex B for uplink messages.
                                                                 The ATN ground system can
                                                                 process the Navaid choice from the
                                                                 FANS 1/A aircraft.
                                                                                                  4-145


           ATN Position                FANS 1/A Position           Interoperability Requirement
           Airport                     Airport                     None.
                                                                   The ATN ground system can
                                                                   process the Airport choice from the
                                                                   FANS 1/A aircraft.
           Latitude and/or Longitude   Latitude and Longitude      See paragraph 4.2.12.15 for use of
                                                                   latitude/longitude parameter.
           Place Bearing Distance:     Place Bearing Distance      See paragraph 4.2.12.13 for use of
                                                                   Place Bearing Distance.



4.2.12.3       Speed Parameter
           The speed parameter in CPDLC message elements is comparable in ATN and FANS 1/A.
           There are differences in the ATN and the FANS 1/A choices of speed. Where the ATN
           and FANS 1/A speed choices are comparable there are differences in the parameter
           ranges and resolutions.
           Table 4-26 presents the speed Data Type differences between ATN and FANS 1/A and
           the impact on the ATN ground system.
                              Table 4-26 ATN and FANS 1/A speed data type

   ATN Speed                FANS 1/A Speed             Interoperability Requirement
   Speed ground:            Speed ground:              IR-284   The ATN ground system shall use
    Range: -50 to 2000       Range: 70 to 700          the Speed Ground only with the resolution
    Resolution: 1            Resolution 10             equal to 10 Knots and values of 70 to 700
    Unit: knots              Unit: knots               Knots inclusive.
                                                       IR-285 The ATN ground system shall
                                                       prohibit the use of the Speed Ground data not
                                                       respecting the FANS 1/A parameter
                                                       resolution and range.
                                                       No additional interoperability requirement for
                                                       downlink message elements.
                                                       Whether only input with the permitted resolution
                                                       is enabled or a rounding mechanism is used is a
                                                       local matter.
                                                       The ATN ground system can process the Speed
                                                       Ground choice from the FANS 1/A aircraft.
4-146

        ATN Speed                FANS 1/A Speed           Interoperability Requirement
        Speed Ground Metric:     Speed ground metric:     IR-286   The ATN ground system shall use
         Range: -100 to 4000      Range: 100 to 2650      the Speed Ground Metric only with the
         Resolution: 1            Resolution: 10          resolution equal to 10 Kilometers/hour and
         Unit: Kilometers/Hour    Unit: Kilometers/Hour   values of 100 to 2650 Kilometers/hour
                                                          inclusive.
                                                          IR-287 The ATN ground system shall
                                                          prohibit the use of the Speed Ground Metric
                                                          data not respecting the FANS 1/A parameter
                                                          resolution and range.
                                                          No additional interoperability requirement for
                                                          downlink message elements.
                                                          Whether only input with the permitted resolution
                                                          is enabled or a rounding mechanism is used is a
                                                          local matter.
                                                          The ATN ground system can process the Speed
                                                          Ground Metric choice from the FANS 1/A
                                                          aircraft.
        Speed indicated:         Speed indicated:         IR-288   The ATN ground system shall use
         Range: 0 to 400          Range: 70 to 380        the Speed Indicated only with the resolution
         Resolution: 1            Resolution: 10          equal to 10 Knots and values of 70 to 380
         Unit: knots              Unit: knots             Knots inclusive.
                                                          IR-289 The ATN ground system shall
                                                          prohibit the use of Speed Indicated data not
                                                          respecting the FANS 1/A parameter
                                                          resolution and range.
                                                          No additional interoperability requirement for
                                                          downlink message elements.
                                                          Whether only input with the permitted resolution
                                                          is enabled or a rounding mechanism is used is a
                                                          local matter.
                                                          The ATN ground system can process the Speed
                                                          Indicated choice from the FANS 1/A aircraft.
                                                                                               4-147


ATN Speed                 FANS 1/A Speed            Interoperability Requirement
Speed indicated metric:   Speed indicated metric:   IR-290   The ATN ground system shall use
 Range: 0 to 800           Range: 100 to 1370       the Speed Indicated Metric only with the
 Resolution: 1             Resolution: 10           resolution equal to 10 Kilometers/Hour and
 Unit: kilometers/hour     Unit: kilometers/hour    values of 100 to 1370 Kilometers/Hour
                                                    inclusive.
                                                    IR-291 The ATN ground system shall
                                                    prohibit the use of Speed Indicated Metric
                                                    data not respecting the FANS 1/A parameter
                                                    resolution and range.
                                                    No additional interoperability requirement for
                                                    downlink message elements.
                                                    Whether only input with the permitted resolution
                                                    is enabled or a rounding mechanism is used is a
                                                    local matter.
                                                    The ATN ground system can process the Speed
                                                    Indicated Metric choice from the FANS 1/A
                                                    aircraft.
Speed True:               Speed True:               IR-292   The ATN ground system shall use
 Range: 0 to 2000          Range: 70 to 700         the Speed True only with the resolution equal
 Resolution: 1             Resolution: 10           to 10 Knots and values of 70 to 700 Knots
 Unit: Knots               Unit: Knots              inclusive.
                                                    IR-293 The ATN ground system shall
                                                    prohibit the use of Speed True data not
                                                    respecting the FANS 1/A parameter
                                                    resolution and range.
                                                    No additional interoperability requirement for
                                                    downlink message elements.
                                                    Whether only input with the permitted resolution
                                                    is enabled or a rounding mechanism is used is a
                                                    local matter.
                                                    The ATN ground system can process the Speed
                                                    True choice from the FANS 1/A aircraft.
4-148

        ATN Speed               FANS 1/A Speed          Interoperability Requirement
        Speed True Metric:      Speed True Metric:      IR-294   The ATN ground system shall use
         Range: 0 to 4000        Range: 100 to 1370     the Speed True Metric only with the
         Resolution: 1           Resolution: 10         resolution equal to 10 Kilometers/Hour and
        Unit: Kilometers/Hour   Unit: Kilometers/Hour   values of 100 to 1370 Kilometers/Hour
                                                        inclusive.
                                                        IR-295 The ATN ground system shall
                                                        prohibit the use of Speed True Metric data
                                                        not respecting the FANS 1/A parameter
                                                        resolution and range.
                                                        No additional interoperability requirement for
                                                        downlink message elements.
                                                        Whether only input with the permitted resolution
                                                        is enabled or a rounding mechanism is used is a
                                                        local matter.
                                                        The ATN ground system can process the Speed
                                                        True Metric choice from the FANS 1/A aircraft.
        Speed mach:             Speed mach:             IR-296   The ATN ground system shall uplink
         Range .5 to 4.0         Range: .61 to .92      the SpeedMach only with the resolution equal
         Resolution: 0.001       Resolution: 0.01       to 0.01 and values of .61 to 4.0 Mach
         Unit: mach              Unit: mach             inclusive.
                                                        IR-297 When requiring Mach speeds in the

                                Or
                                                        range 0.61 to 0.92, the ATN ground system
                                                        shall use the Speed mach data type to uplink
                                                        the Speed mach parameter.
                                Speed mach large
                                                        IR-298 When requiring Mach speeds in the
                                 Range: .93 to 6.04     range 0.93 to 4.0, the ATN ground system
                                 Resolution: 0.01       shall use the Speed mach large data type to
                                 Unit: mach             uplink the Speed mach parameter.
                                                        IR-299 The ATN ground system shall
                                                        prohibit the use of Speed Mach data not
                                                        respecting the FANS 1/A parameter
                                                        resolution and range.
                                                        IR-300 When receiving a message element
                                                        with the DataType choice Speed Mach Large
                                                        containing a value higher than 4.0, the ATN
                                                        ground system shall reject the message and
                                                        respond per the ATS INTEROP Standard,
                                                        paragraph 3.3.7.6.4.1.2, and this document,
                                                        paragraph 0.
                                                        Whether only input with the permitted resolution
                                                        is enabled or a rounding mechanism is used is a
                                                        local matter.
                                                                                               4-149


4.2.12.4        Specified Distance/Distance Offset Parameter Message
           The specified distance parameter in ATN CPDLC messages is comparable to the distance
           offset parameter in FANS 1/A CPDLC messages. There are differences in the ATN and
           the FANS 1/A choices of distance offset. Where the ATN and FANS 1/A specified
           distance/distance offset choices are comparable there are differences in the parameter
           ranges and resolutions.
           Table 4-27 presents the specified distance/distance offset Data Type differences between
           ATN and FANS 1/A and the impact on the ATN ground system.


               Table 4-27 ATN specified distance and FANS 1/A distance offset data type

   ATN Specified Distance    FANS 1/A Distance         Interoperability Requirement
                             Offset
   Distance specified nm:    Distance offset nm:       IR-301  The ATN ground system shall use
    Range: 1 to 250           Range: 1 to 128          the Distance Specified Nm only with values
    Resolution: 1             Resolution: 1            from 1 to 128 Nm inclusive.
    Unit: nautical miles      Unit: nautical miles     IR-302 The ATN ground system shall
                                                       prohibit the use of Distance Specified Nm
                                                       not respecting the FANS 1/A parameter
                                                       range.
                                                       No additional interoperability requirement for
                                                       downlink message elements.
                                                       The ATN ground system can process the
                                                       Distance offset Nm from the FANS 1/A aircraft.
   Distance specified km:    Distance offset nm:       IR-303  The ATN ground system shall use
    Range: 1 to 500           Range: 1 to 256          the Distance Specified Km only with values
    Resolution: 1             Resolution: 1            from 1 to 256 Km inclusive.
    Unit: kilometers          Unit: kilometers         IR-304 The ATN ground system shall
                                                       prohibit the use of Distance Specified Km
                                                       not respecting the FANS 1/A parameter
                                                       range.
                                                       No additional interoperability requirement for
                                                       downlink message elements.
                                                       The ATN ground system can process the
                                                       Distance offset Nm from the FANS 1/A aircraft.



4.2.12.5        Direction Parameter Message
           The direction parameter in CPDLC message elements is identical in ATN and FANS 1/A.
           The enumerated values and definitions in ATN and FANS 1/A are identical.
4-150
         4.2.12.6        Time/Timesec Parameter
               The timesec parameter in ATN CPDLC messages is comparable to the time parameter in
               FANS 1/A CPDLC messages. There are differences in the ATN and the FANS 1/A
               choices of timesec.
               Table 4-28 presents the time/timesec Data Type differences between ATN and FANS 1/A
               and the impact on the ATN ground system.


                             Table 4-28 ATN Timesec and FANS 1/A Time data type

               ATN Timesec               FANS 1/A Time             Interoperability Requirement
               TimeHours:                TimeHours:                None.
                Range: 0 to 23            Range: 0 to 23
                Resolution: 1             Resolution: 1
                Unit: Hour                Unit: Hour
               TimeMinutes:              TimeMinutes:              None.
                Range: 0 to 59            Range: 0 to 59
                Resolution: 1             Resolution: 1
                Unit: Hour                Unit: Hour
               TimeSeconds: (Optional)   None.                     IR-305   The ATN ground system
                Range: 0 to 59                                     shall prohibit the use of
                Resolution: 1                                      TimeSeconds to a FANS 1/A
                Unit: Second                                       aircraft when timeSeconds are
                                                                   specified.




    4.2.12.7        Vertical Rate Parameter Message
               The vertical rate parameter in CPDLC message elements is comparable in ATN and
               FANS 1/A CPDLC messages. There are differences in the ATN and FANS 1/A choices
               of vertical rate. Where the ATN and FANS 1/A vertical rate choices are comparable there
               are differences in the parameter ranges and resolutions.
               Table 4-29 the vertical rate parameter differences between ATN and FANS 1/A and the
               impact on the ATN ground system.
                                                                                                    4-151


                           Table 4-29 ATN and FANS 1/A vertical rate parameter

  ATN Vertical Rate            FANS 1/A Vertical Rate       Interoperability Requirement
  Parameter                    Parameter
  Vertical rate English:       Vertical rate English:       IR-306  The ATN ground system shall
   Range: 0 to 30000            Range: 0 to 6000            use the Vertical Rate English only with
   Resolution: 10               Resolution: 100             the resolution equal to 100 Feet/Minute
   Unit: feet/minute            Unit: feet/minute           and values of 0 to 6000 Feet/Minute
                                                            inclusive.
                                                            IR-307 The ATN ground system shall
                                                            prohibit the use of Vertical Rate English
                                                            data not respecting the FANS 1/A
                                                            parameter resolution and range.
                                                            No additional interoperability requirement for
                                                            downlink message elements.
                                                            Whether only input with the permitted
                                                            resolution is enabled or a rounding
                                                            mechanism is used is a local matter.
                                                            The ATN ground system can process the
                                                            Vertical Rate English parameter from a FANS
                                                            1/A aircraft.
  Vertical rate Metric:        Vertical rate Metric:        IR-308   The ATN ground system shall
   Range: 0 to 10000            Range: 0 to 2000            use the Vertical Rate Metric only with the
   Resolution: 10               Resolution: 10              resolution equal to 10 Meters/Minute and
   Unit: meters/minute          Unit: meters/minute         values of 0 to 2000 Meters/Minute
                                                            inclusive.
                                                            IR-309 The ATN ground system shall
                                                            prohibit the use of Vertical Rate Meters
                                                            data not respecting the FANS 1/A
                                                            parameter resolution and range.
                                                            No additional interoperability requirement for
                                                            downlink message elements.
                                                            Whether only input with the permitted
                                                            resolution is enabled or a rounding
                                                            mechanism is used is a local matter.
                                                            The ATN ground system can process the
                                                            Vertical Rate Metric parameter from a FANS
                                                            1/A aircraft.



4.2.12.8         Facility and Facility Designation/ ICAO Facility Designation Parameter
           The facility parameter in ATN allows message elements to be sent either without
           specifying a facility designation or with specifying a facility designation; this option does
           not exist in FANS 1/A.
4-152
        The facility designation parameter or Data Type in ATN CPDLC messages is comparable to the
                   ICAO facility designation parameter in FANS 1/A.
                 The ATN facility designation parameter or Data Type and the FANS 1/A ICAO facility
                 designation parameter differ only in the number of characters that can be used to specify
                 a facility.
4.2.12.8.1       Facility Parameter
                 Table 4-30 the facility parameter differences between ATN and FANS 1/A and the
                 impact on the ATN ground system.


                                               Table 4-30 ATN facility parameter

                  ATN Facility                  FANS 1/A               Interoperability Requirement
                  Facility                      No equivalent.         IR-310   The ATN ground system
                   (null) or                                           shall prohibit the use of null Data
                   Facility Designation                                Type.
                     size: 4 to 8 characters                           The ATN ground system has no
                                                                       possibility to cancel a previously sent
                                                                       Next Data Authority identification.
                                                                       See paragraph 4.2.12.8.2 for use of
                                                                       facility designation parameter.



4.2.12.8.2       Facility Designation / ICAO Facility Designation Data Type
                 Table 4-31 present the facility designation and ICAO facility designation Data Type
                 differences between ATN and FANS 1/A and the impact on the ATN ground system.
                                                                                                  4-153


           Table 4-31 ATN facility designation and FANS 1/A ICAO facility designation data
                                                     type

           ATN Facility Designation    FANS 1/A ICAO Facility       Interoperability Requirement
                                       Designation
           Facility designation:       ICAO facility designation:   IR-311  The ATN ground
            Size: 4 to 8 characters      Size: 4 characters         system shall use the Facility
                                                                    Designation only with size 4,
                                                                    using the first 4 letters.
                                                                    No additional interoperability
                                                                    requirement for downlink message
                                                                    elements.
                                                                    The ATN ground system can
                                                                    process the ICAO Facility
                                                                    Designation from the FANS 1/A
                                                                    aircraft.
                                                                    Facility Designation is also a Data
                                                                    Type within the Unit Name
                                                                    Parameter.
                                                                    The truncation should be assessed
                                                                    for an ATN ground system that
                                                                    shares the same location indicator,
                                                                    but has a different function
                                                                    indicator.



4.2.12.9        Full Unit Name/ICAO Unit Name Parameter
           The full unit name parameter in ATN CPDLC message elements is comparable to the
           ICAO unit name parameter in FANS 1/A CPDLC message elements. There are
           differences in the ATN and the FANS 1/A parameter composition of full unit name /
           ICAO unit name. Where the ATN full unit name and FANS 1/A ICAO unit name
           parameter composition is comparable there are differences in the parameter designations.
           Table 4-32 presents the full unit name/ICAO unit name Data Type differences between
           ATN and FANS 1/A and the impact on the ATN ground system.
4-154
                Table 4-32       ATN unit name and FANS 1/A ICAO unit name data type

                ATN Full Unit Name           FANS 1/A ICAO Unit             Interoperability Requirement
                                             Name
                Facility designation:        ICAO facility identification   IR-312  When using the Unit
                 Size: 4 to 8 characters     ICAO facility designation      Name data type, the ATN
                Facility name                  Size: 4 characters           ground system shall convert
                 Size: 3 to 18 characters,                                  the ATN parameter ―Facility
                                                                            Name‖ to the FANS 1/A
                                             Or
                                                                            parameter ―ICAO Facility
                Facility function:                                          Name.
                 centre                      ICAO facility name:
                                                                            IR-313 The ATN ground
                 approach                      Size: 3 to 18 characters     system shall prohibit the use of
                 tower                                                      radio Data Type.
                 final                       ICAO facility function:        No additional interoperability
                 ground control                centre                       requirement for downlink message
                 clearance delivery            approach                     elements.
                 departure                     tower                        There are no FANS 1/A downlink
                                                                            messages containing the ICAO
                 control                       final                        unit name parameter.
                 radio                         ground control
                                               clearance delivery
                                               departure
                                               control



    4.2.12.10       Degrees Parameter
                The degrees parameter in CPDLC message elements are identical in ATN and
                FANS 1/A.
                The degrees parameter is also part of the position and route clearance parameters. See
                paragraph 4.2.12.2 when using the degrees parameter as part of the position parameter.
                See paragraph 4.2.12.11 when using the degrees parameter as part of the route clearance
                parameter.
    4.2.12.11       Route Clearance /Route Clearance Enhanced Parameter
                The route clearance parameter in CPDLC message elements is comparable in ATN and
                FANS 1/A. There are differences in the ATN and the FANS 1/A choices of route
                clearance. Where the ATN and FANS 1/A route clearance choices are comparable there
                are differences in the parameter ranges and resolutions.
                Table 4-33 presents the route clearance Data Type differences between ATN and
                FANS 1/A and the impact on the ATN ground system.
                                                                                       4-155


              Table 4-33 ATN and FANS 1/A route clearance data type

ATN Route Clearance          FANS 1/A Route               Interoperability Requirement
                             Clearance
AirportDeparture             AirportDeparture             None.
AirportDestination:          Airportdestination           None.
 A5string (size(4))
RunwayArrival                Runwayarrival                None.
RunwayDeparture              RunwayDeparture              None.
Procedure name (departure,   Procedure name (departure,   IR-314  The ATN ground
approach and arrival):       approach and arrival):       system shall prohibit the use of
  Procedure type,              Procedure type,            procedure Data Type with
  Procedure:                   Procedure:                 more than 6 characters length.
   1 to 20 characters           1 to 6 characters
  Procedure transition:        Procedure transition:
   1 to 5 characters            1 to 5 characters
   OPTIONAL                     OPTIONAL
Route information:         Route information:             None.
 Published identifier, or   Published identifier, or      See each route information choice
 Latitude Longitude, or     Latitude Longitude, or        in the following rows of this table
                                                          for their use.
 PlaceBearingPlaceBearing,  PlaceBearingPlaceBearing,
 or                         or
 PlaceBearing Distance, or  PlaceBearing Distance, or
 ATS route designator       Airway Identifier, or
                            Track detail
Published Identifier         Published identifier         See paragraph 4.2.12.12 for use of
                                                          published identifier Data Type.
Latitude Longitude           Latitude Longitude           See paragraph 4.2.12.15 for use of
                                                          latitude/longitude Data Type.
PlaceBearing Distance        PlaceBearing Distance        See paragraph 4.2.12.13 for use of
                                                          place bearing distance Data Type.
ATS route designator:        Airway identifier:           IR-315  The ATN ground
 Size: 2 to 7 characters      Size: 1 to 5 characters     system shall prohibit the use of
                                                          ATS Route Designator Data
                                                          Type with more than 5
                                                          characters length.
4-156

        ATN Route Clearance         FANS 1/A Route             Interoperability Requirement
                                    Clearance
        Route information           Route information          None.
        additional:                 additional:                See each route information
          Holdatwaypoint (1-8)        Holdatwaypoint (1-8)     additional choice in the following
          WaypointSpeedLevel          WaypointSpeedLevel       rows of this table for their use.
          (1-32)                      (1-32)
          RTARequiredTimeArrival      RTARequiredTimeArrival
          (1-32) optional             (1-32) optional
        Holdatwaypoint (1-8):       Hold at waypoint (1-8):    IR-316  The ATN ground
         Position                    Position                  system shall prohibit the use of
         Speed (low)                 Speed (low)               blockLevel in the ATW Level
         ATW level                   ATW altitude              Data Type.
         Speed (high)                Speed (high)              See paragraph 4.2.12.2 for use of
                                                               position parameter.
         Direction                   Direction
                                                               See paragraph 4.2.12.3 for use of
         Degrees                     Degrees                   speed parameter.
         Timesec (EFC time)          Time (EFC time)           No additional interoperability
         Leg type                    Leg type                  requirement for
                                                               ATWLevel/Altitude tolerance.
                                                               See paragraph 4.2.12.5 for use of
                                                               direction parameter.
                                                               See paragraph 4.2.12.10 for use of
                                                               degrees parameter.
                                                               See paragraph 4.2.12.6 for use of
                                                               time/timeSec parameter.
                                                               See paragraph 4.2.12.14 for use of
                                                               leg type parameter.
        Waypoint speed level (1-32): Waypoint speed altitude   See IR-316.
         Position                    (1-32):                   See paragraph 4.2.12.2 for use of
         Speed                         Position                position parameter.
         ATW level sequence            Speed                   See paragraph 4.2.12.3 for use of
                                       ATW altitude sequence   speed parameter.
                                                               No additional interoperability
                                                               requirement for
                                                               ATWLevel/Altitude tolerance.
                                                               See paragraph 4.2.12.1 for use of
                                                               level/altitude parameter.
                                                                                                 4-157


            ATN Route Clearance         FANS 1/A Route               Interoperability Requirement
                                        Clearance
            RTA Required TimeSec        RTA Required Time Arrival    See paragraph 4.2.12.2 for use of
            Arrival                     (1-32):                      position parameter.
            (1-32):                       Position                   See paragraph 4.2.12.6 for use of
              Position                    RTA time                   time/timesec parameter.
              RTA timeSec                 RTA tolerance              No additional interoperability
              RTA tolerance                                          requirement for time tolerance.
                                                                     Note: RTA Required TimeSec is
                                                                     only included in the ATN Route
                                                                     Clearance Enhanced Parameter.



4.2.12.12          Published Identifier Parameter
            Table 4-34 presents the published identifier Data Type differences between ATN and
            FANS 1/A and the impact on the ATN ground system.


                        Table 4-34 ATN and FANS 1/A published identifier data type

            ATN Published Identifier    FANS 1/A Published          Interoperability Requirement
                                        Identifier
            Published Identifier:       Published identifier:       IR-317  The ATN ground
             Fix Name:                   Fix Name:                  system shall prohibit the use of
             Fix                           Latitude Longitude       Navaid Data Type.
               Latitude Longitude                                   No additional interoperability
                                                                    requirement for downlink message
                                                                    elements.
              Or
                                                                    The ATN Fix part of the Fix
                                                                    Name parameter is equivalent to
              Navaid:                                               the FANS 1/A Fix Name
               Navaid name                                          parameter.
               Latitude Longitude                                   The use of Lat/Lon is required by
                                                                    the ATS INTEROP Standard,
                                                                    Annex B for uplink messages.
                                                                    The ATN ground system can
                                                                    process the fix name choice from
                                                                    the FANS 1/A aircraft.
                                                                    See paragraph 4.2.12.15 for use of
                                                                    latitude/longitude Data Type.
4-158
         4.2.12.13         Place Bearing Distance Data Type
                Table 4-35 presents the place bearing distance uplink Data Type differences between
                ATN and FANS 1/A and the impact on the ATN ground system.
                          Table 4-35 ATN and FANS 1/A place bearing distance data type

                ATN Place Bearing           FANS 1/A Place Bearing   Interoperability Requirement
                Distance                    Distance
                Published identifier        Published identifier     Distance specified in miles is the
                Degrees                     Degrees                  same in ATN and FANS 1/A.
                Distance                    Distance                 See paragraph 4.2.12.12 for use of
                                                                     Published Identifier Data Type.
                                                                     See paragraph 4.2.12.10 for use of
                                                                     degrees parameter.



    4.2.12.14        Leg Type Parameter
                Table 4-36 presents the leg type parameter differences between ATN and FANS 1/A and
                the impact on the ATN ground system.
                                   Table 4-36 ATN and FANS 1/A leg type data type

                ATN Leg Type                FANS 1/A Leg Type        Interoperability Requirement
                Leg distance English:       Leg distance English:    IR-318   The ATN ground
                 Range: 0 to 50              Range: 1 to 99.9        system shall prohibit the use of
                 Resolution: 1               Resolution: 0.1         Leg Distance English with
                 Unit: nautical mile         Unit: nautical mile     value 0.
                                                                     IR-319 The ATN ground
                                                                     system shall reject a FANS 1/A
                                                                     downlink message that
                                                                     contains the Leg distance
                                                                     English parameter that does not
                                                                     respect the ATN range.
                                                                     Note: Rounding is a local matter.
                Leg distance Metric:        Leg distance Metric:     None.
                 Range: 1 to 128             Range: 1 to 128
                 Resolution: 1               Resolution: 1
                 Unit: kilometer             Unit: kilometer


                Leg time:                   Leg time:                IR-320  The ATN ground
                 Range: 1 to 10              Range: 1 to 9.9         system shall prohibit the use of
                 Resolution: 1               Resolution: 0.1         Leg Time with value 10.
                 Unit: minutes               Unit: minutes           Note: Rounding is a local matter.
4.2.12.15       Latitude/Longitude Parameter
            Table 4-37 presents the Latitude/Longitude data type differences between ATN and
            FANS 1/A and the impact on the ATN ground system.


                        Table 4-37 ATN and FANS 1/A latitude/longitude data type

   ATN Latitude Longitude           FANS 1/A Latitude            Interoperability Requirement
                                    Longitude
   Latitude:                        Latitude:                    IR-321    The ATN ground system shall
    Latitude type:                   Latitude degrees            provide both the Latitude and the
      Latitude degrees, or           minutes latlon (optional)   Longitude data variable.
      Latitude degrees minutes,      Latitude direction          IR-322 When receiving a message

      or                            Longitude:                   with message element containing the
      Latitude degrees minutes       Longitude degrees
                                                                 data type minutes latlon and the value
                                                                 for latitude degrees is 90 or the value
      seconds                        minutes latlon (optional)
                                                                 for longitude degrees is 180 and one
    Latitude direction               Longitude direction         of the minutes lat lon value is not 0,
   Longitude:                                                    the ATN ground system shall reject
    Longitude type:                                              the message and respond per the ATS
      Longitude degrees, or                                      INTEROP Standard, paragraph
      Longitude degrees minutes, or                              3.3.7.6.4.1.2, and this document,
                                                                 paragraph 0.
      Longitude degrees minutes
      seconds                                                    IR-323 When receiving a message
    Longitude direction                                          with a message element containing
                                                                 the data type minutes latlon and the
                                                                 value for latitude degrees is 90 or the
                                                                 value for longitude degrees is 180, the
                                                                 ATN ground system shall ignore the
                                                                 minutes latlon value and use the
                                                                 latitude degrees type and/or the
                                                                 longitude degree type for further
                                                                 processing.
                                                                 See Latitude degrees, Latitude degrees
                                                                 minutes, Longitude degrees, and
                                                                 Longitude degrees minutes, in the
                                                                 following rows of this table for their use.
                                                                 No additional interoperability
                                                                 requirement for Latitude direction and
                                                                 Longitude direction.
                                                                 The Latitude and the Longitude are
                                                                 optional in the LatitudeLongitude Data
                                                                 Type in the ATS INTEROP Standard;
                                                                 both are required in the FANS 1/A
                                                                 INTEROP Standard.
                                                                 When ‗minutes latlon‘ are omitted by the
                                                                 FANS 1/A aircraft, the ATN ground
                                                                 system can use the latitude/longitude
4-160


        ATN Latitude Longitude      FANS 1/A Latitude     Interoperability Requirement
                                    Longitude
                                                          degrees part of the latitude/longitude
                                                          parameter in the latitude/longitude
                                                          degrees choice of latitude/longitude type.
                                                          When ‗minutes latlon‘ are included by the
                                                          FANS 1/A aircraft and the value of
                                                          latitude degrees is not 90 and/or,
                                                          longitude degrees is not 180, the ATN
                                                          ground system can use the
                                                          latitude/longitude parameter in the
                                                          latitude/longitude degrees minutes choice
                                                          of latitude/longitude type.
        Latitude degrees:           Latitude degrees:     IR-324  The ATN ground system shall
         Range: 0 to 90              Range: 0 to 90       prohibit the use of resolutions finer
         Resolution: .001            Resolution: 1        than 1.
         Unit: degrees               Unit: degrees        See top row in this table for use of
                                                          downlink message elements.
        Latitude degrees minutes:   Latitude:             IR-325  The ATN ground system shall
         Latitude whole degrees:     Latitude degrees     prohibit the use of resolutions finer
           Range: 0 to 89              Range: 0 to 90     than 0.1 in the Minutelatlon variable.
           Resolution: 1               Resolution: 1      See top row in this table for use of
                                                          downlink message elements.
           Unit: degrees               Unit: degrees
         Minutes latlon:             Minutes latlon
           Range: 0 to 59.99         (optional):
           Resolution: .01             Range: 0 to 59.9
           Unit: minutes               Resolution: .1
                                       Unit: minutes
        Latitude degrees minutes    Latitude:             IR-326  The ATN ground system shall
        seconds:                     Latitude degrees:    prohibit the use of the LatitudeDMS
          Latitude whole degrees:      Range: 0 to 90     Latitude Type choice.
           Range: 0 to 90              Resolution: 1      No additional interoperability
           Resolution: 1                                  requirement for downlink message
                                       Unit: degrees
                                                          elements.
           Unit: degrees             Minutes latlon
                                                          This choice is not available in the
          Latlon whole minutes:      (optional):
                                                          FANS 1/A aircraft.
           Range: 0 to 59              Range: 0 to 59.9
           Resolution: 1               Resolution: .1
           Unit: minutes               Unit: minutes
          Seconds latlon:
           Range: 0 to 59
           Resolution: 1
           Unit: seconds
                                                                                          4-161

ATN Latitude Longitude       FANS 1/A Latitude     Interoperability Requirement
                             Longitude
Longitude degrees:           Longitude degrees:    IR-327  The ATN ground system shall
 Range: 0 to 180              Range: 0 to 180      prohibit the use of resolutions finer
 Resolution: .001             Resolution: 1        than 1.
 Unit: degrees                Unit: degrees        See top row in this table for use of
                                                   downlink message elements.
Longitude degrees minutes:   Longitude:            IR-328  The ATN ground system shall
 Longitude whole degrees:     Longitude degrees:   prohibit the use of resolutions finer
   Range: 0 to 179              Range: 0 to 180    than 0.1 in the Minutelatlon variable.
   Resolution: 1                Resolution: 1      See top row in this table for use of
                                                   downlink message elements.
   Unit: degrees                Unit: degrees
 Minutes latlon:              Minutes latlon:
   Range: 0 to 59.99            Range: 0 to 59.9
   Resolution: .01              Resolution: .1
   Unit: minutes                Unit: minutes
Longitude degrees minutes    Longitude:            IR-329  The ATN ground system shall
seconds:                      Longitude degrees:   prohibit the use of the LongitudeDMS
  Longitude whole degrees:      Range: 0 to 180    Longitude Type choice.
   Range: 0 to 179              Resolution: 1      No additional interoperability
   Resolution: 1                                   requirement for downlink message
                                Unit: degrees
                                                   elements.
   Unit: degrees              Minutes latlon:
                                                   This choice is not available in the
  Latlon whole minutes:         Range: 0 to 59.9   FANS 1/A aircraft.
   Range: 0 to 59               Resolution: .1
   Resolution: 1                Unit: minutes
   Unit: minutes
  Seconds Latlon:
   Range: 0 to 59
   Resolution: 1
   Unit: seconds
4.2.12.16       Frequency Parameter
            The frequency parameter in CPDLC message elements is identical in ATN and
            FANS 1/A.
            Table 4-38 presents the ATN and FANS 1/A Frequency data type comparison and
            impact.


                           Table 4-38 ATN and FANS 1/A frequency data type

   ATN Frequency                             FANS 1/A Frequency   Interoperability Requirement
   FrequencyVHF                              FrequencyVHF         IR-330   The ATN ground
   Encoded Range: 23600-27398                  Encoded Range:     system shall only accept the
   Resolution: 1                               117000-138000      FrequencyVHF parameter only
   Unit: 0.005 MHz                             Resolution: 1      with the resolution equal to
                                               Unit: 0.001 MHz    0.005 MHz and decoded values
   Decoded Range: 118.000 MHz –
   136.990 MHz                                 Decoded Range:
                                                                  118.000MHz to 136.990 MHz
                                               117.000 MHz –      inclusive.
                                               138.000 MHz        IR-331 The ATN ground
   Additional ATN ground system
   requirement:                                                   system shall reject the use of
                                                                  FrequencyVHF data not
   3.3.7.6.4.3 The values contained in the
                                                                  respecting the ATN parameter
   data type frequencyVHF shall
   correspond to the voice channel                                resolution and range.
   designators for VHF channels separated                         No additional interoperability
   by 8.33khz and 25khz spacing, as                               requirement for uplink message
   specified by the relevant provisions in                        elements.
   ICAO Annex 10, Volume V, Chapter 4.1                           Whether only input with the
   (bis).                                                         permitted resolution is enabled or a
                                                                  rounding mechanism is used is a
                                                                  local matter.


   FrequencyHF:                              FrequencyHF:          None.
   Encoded Range: 2850 – 28000               Encoded Range: 2850 –
   Resolution: 1                             28000
   Unit: Kilohertz                           Resolution: 1
   Decoded Range: 2850 kHz – 28000 kHz       Unit: Kilohertz
                                             Decoded Range: 2850
                                             kHz – 28000 kHz
   FrequencyUHF:                             FrequencyUHF:        IR-332  The ATN ground
   Encoded Range: 9000-15999                 Encoded Range:       system shall only accept the
   Resolution: 0.025                         225000-399975        FrequencyUHF parameter only
   Unit: Megahertz                           Resolution: 0.001    with the resolution equal to
                                             Unit: Megahertz      0.001 MHz and decoded values
   Decoded Range: 225.000 MHz -
   399.975 MHz                               Decoded Range:
                                                                  225.000MHz to 399.975 MHz
                                             225.000 MHz -        inclusive.
                                             399.975 MHz
4-163


        ATN Frequency                          FANS 1/A Frequency     Interoperability Requirement
        FrequencySatChannel:                   FrequencySatChannel:   None.
        NumericString( SIZE(12) )              NumericString(
                                               SIZE(12) )



    4.2.12.17       Code Parameter
                The code parameter in CPDLC message elements is identical in ATN and FANS 1/A.
                Table 4-39 presents ATN and FANS 1/A Code data type comparison and impact.
                Note:    See paragraph 4.2.9 for processing downlink message elements containing the
                         following parameter/data type, which is not supported by the ATN ground
                         system:
                            ATN „code‟ and corresponding FANS 1/A „beaconcode‟ in downlink
                             message elements.


                                    Table 4-39 ATN and FANS 1/A code data type

                ATN Code               FANS 1/A Code           Interoperability Requirement
                Parameter              Parameter
                Code                   Beaconcode              None.
                 CodeOctaldigit         Beaconcodeoctaldigit   The naming is different. Range and
                                                               resolution are identical.
4.2.12.18       Departure Clearance Parameter
            Table 4-40 presents the Departure Clearace Parameter data type differences between
            ATN and FANS 1/A and the impact on the ATN ground system.


                     Table 4-40 ATN and FANS 1/A Departure Clearance Parameter

            ATN Departure Clearance FANS 1/A PreDeparture Interoperability
            Parameter               Clearance Parameter   Requirement
            aircraftFlightIdentification -- UM73                          IR-333   The ATN ground
            > String (2..8)                 [PreDepartureClearance]:      system shall convert the
                                            aircraftFlightIdentificaion   ATN
                                            --> String(2..7)              aircraftFlightIdentification
                                                                          parameter to the FANS 1/A
                                                                          aircraftFlightIdentification
                                                                          parameter within the
                                                                          predeparture clearance
                                                                          paramenter.
                                                                          IR-334 When the string
                                                                          length of the ATN
                                                                          parameter is greater than 7,
                                                                          the ATN ground system
                                                                          shall reject the use of the
                                                                          message element.
            clearedFrom --> Airport        UM73                           IR-335  The ATN ground
                                           [PreDepartureClearance]:       system shall convert the
                                           routeClearance --              ATN aiport parameter to
                                           >airportDeprature              the FANS 1/A
                                                                          departureAirport parameter
                                                                          within the predeparture
                                                                          clearance paramenter.
            clearedFrom --> Location       None.                          IR-336  The ATN ground
                                                                          system shall ignore the
                                                                          clearedFrom location
                                                                          parameter when sending to
                                                                          a FANS 1/A aircraft.
            clearedTo -->                  UM73                           IR-337   The ATN ground
            clearanceLimit                 [PreDepartureClearance]:       system shall convert the
                                           routeClearance --              ATN clearanceLimit
                                           >airportDestination            parameter to the FANS 1/A
                                                                          destinationAirport
                                                                          parameter within the
                                                                          predeparture clearance
                                                                          paramenter.
4-165


        ATN Departure Clearance FANS 1/A PreDeparture Interoperability
        Parameter               Clearance Parameter   Requirement
        departureRoute -->          UM73                        IR-338  The ATN ground
        Departure --> SIDTransition [PreDepartureClearance]:    system shall convert the
                                    routeClearance -->          ATN SIDTransition
                                    procedureDeparture          parameter to the FANS 1/A
                                                                procedureDeparture
                                                                parameter within the
                                                                predeparture clearance
                                                                paramenter.
        departureRoute -->           UM73                       IR-339  The ATN ground
        Departure -->                [PreDepartureClearance]:   system shall convert the
        routeInformation             routeClearance -->         ATN RouteInformation
                                     routeInformation           parameter to the FANS 1/A
                                                                routeInformation parameter
                                                                within the predeparture
                                                                clearance paramenter.
                                                                IR-340

        departureRoute -->           UM73                       IR-341  The ATN ground
        Departure -->                [PreDepartureClearance]:   system shall convert the
        routeInformationAdditional   routeClearance -->         ATN RouteInformation
                                     routeInformationAddition   parameter to the FANS 1/A
                                     al                         routeInformationAdditional
                                                                parameter within the
                                                                predeparture clearance
                                                                paramenter.
                                                                IR-342

        departureRoute -->            UM169 [free text]:        IR-343  The ATN ground
        Departure --> ThenAsFiled    ―THEN AS FILED‖            system shall convert the
                                                                ATN ThenAsFiled
                                                                parameter to free text in the
                                                                concatenated message
                                                                UM169.


        departureRoute -->           UM169 [free text]: ―AS     IR-344  The ATN ground
        Departure --> AsFiled        FILED‖                     system shall convert the
                                                                ATN ThenAsFiled
                                                                parameter to free text in the
                                                                concatenated message
                                                                UM169.
ATN Departure Clearance FANS 1/A PreDeparture Interoperability
Parameter               Clearance Parameter   Requirement
departureLevel          IR-345   UM169 [free       IR-346   The ATN ground
                        text]: ―MAINTAIN [level]   system shall convert the
                        + UNTIL [constraint] +     ATN departureLevel
                        EXPECT [level] + UNTIL     parameter to free text in the
                        [constraint]‖              concatenated message
                                                   UM169.
                                                   IR-347 The ATN ground
                                                   system shall convert the
                                                   [level] parameter to a string
                                                   of characters in the free text
                                                   message UM169.
departureSpeed          UM169 [free text]:         IR-348   The ATN ground
                        ―MAINTAIN [speed] +        system shall convert the
                        UNTIL [constraint]‖        ATN departureSpeed
                                                   parameter to free text in the
                                                   concatenated message
                                                   UM169.
                                                   IR-349 The ATN ground
                                                   system shall convert the
                                                   [speed] parameter to a
                                                   string of characters in the
                                                   free text message UM169.
4-167


        ATN Departure Clearance FANS 1/A PreDeparture Interoperability
        Parameter               Clearance Parameter   Requirement
        [constraint]:                UM169 [free text]:         IR-350   When sending
        minutesAfterDeparture        ―MAINTAIN [speed] +        [constraint], the ATN
        (time)                       UNTIL [constraint]‖        ground system shall include
                                                                the [time] parameter in the
         OR
                                                                free text parameter of
         Position                                               UM169 as a 6 character
        OR                                                      string of converted integers.
        Level                                                   IR-351 When sending
                                                                [constraint], the ATN
                                                                ground system shall include
                                                                the [position] parameter in
                                                                the free text parameter of
                                                                UM169 as one of the
                                                                choices:
                                                                IR-352 a character string of
                                                                four letters, representing the
                                                                location indicator of the
                                                                facility designation for
                                                                navid, airport, and fix name
                                                                IR-353 place bearing
                                                                distance and
                                                                latitude/longitude are not
                                                                viable options.
                                                                IR-354 When sending
                                                                [constraint], the ATN
                                                                ground system shall include
                                                                the [level] parameter in the
                                                                free text parameter of
                                                                UM169 as a string of
                                                                characters.
        additionalInstructions -->   UM73                       IR-355  The ATN ground
        ExpectedArrivalProcedure     [PreDepartureClearance]:   system shall convert the
                                     routeClearance -->         ATN
                                     procedureArrival           ExpectedArrivalProcedure
                                                                parameter to the FANS 1/A
                                                                procedureArrival parameter
                                                                within the predeparture
                                                                clearance paramenter.
                 ATN Departure Clearance FANS 1/A PreDeparture Interoperability
                 Parameter               Clearance Parameter   Requirement
                 additionalInstructions -->   UM169 [free text]:           IR-356  The ATN ground
                 FreeText                     Additional Instructions --   system shall convert the
                                              > FreeText                   ATN Free Text parameter
                                                                           of AdditionalInstructions
                                                                           parameter to free text in the
                                                                           concatenated message
                                                                           UM169.
                 Code                         UM73                         IR-357  The ATN ground
                                              [PreDepartureClearance]:     system shall convert the
                                              beaconCode                   ATN Code parameter to the
                                                                           FANS 1/A beaconCode
                                                                           parameter within the
                                                                           predeparture clearance
                                                                           paramenter.
                 atisCode                     UM158 ATIS CODE [atis IR-358 The ATN ground
                                              code]                 system shall convert the
                                                                    ATN atisCode parameter to
                                                                    free text in the concatenated
                                                                    message UM158.
                 departureFrequency           UM73                         IR-359  The ATN ground
                                              [PreDepartureClearance]:     system shall convert the
                                              frequencyDeparture           ATN departureFrequency
                                                                           parameter to the FANS 1/A
                                                                           departureFrequency
                                                                           parameter within the
                                                                           predeparture clearance
                                                                           paramenter.
IR-360

     4.2.12.19       Procedure Name Parameter
                 The procedure name parameter in CPDLC message elements is comparable in ATN and
                 FANS 1/A.
                 Table 4-41 presents the ATN and FANS 1/A procedure name data type comparison and
                 impact.


                            Table 4-41 ATN and FANS 1/A Procedure Name Parameter

                 ATN Procedure          FANS 1/A Procedure      Interoperability Requirement
                 Name Parameter         Name Parameter
                   ProcedureType         ProcedureType          None.
4-169


                ATN Procedure           FANS 1/A Procedure      Interoperability Requirement
                Name Parameter          Name Parameter
                  Procedure:             Procedure:             IR-361  The ATN ground system shall
                  String(1..20)          String(1..6)           prohibit sending the Procedure data
                                                                type with a string length greater than
                                                                6.
                  ProcedureTransition    ProcedureTransition    None.



    4.2.12.20       Altimeter Parameter
                The altimeter parameter in CPDLC message elements is equivalent in ATN and FANS
                1/A.
                Table 4-42 presents the ATN and FANS 1/A altimeter data type comparison and impact.


                                  Table 4-42 ATN and FANS 1/A Altimeter Parameter

                ATN                     FANS 1/A                Interoperability Requirement
                Altimeter Parameter     Altimeter Parameter
                  altimeterEnglish:      altimeterEnglish:      None.
                    Range: 2200-3200       Range: 2200-3200
                    Resolution: 0.01       Resolution: 0.01
                    Unit: Inches         Unit: Inches Mercury
                    Mercury
                  altimeterMetric:       altimeterMetric:       None.
                    Range: 7500-           Range: 7500-12500
                    12500                  Resolution: 0.1
                    Resolution: 0.1      Unit: Hectopascal
                    Unit: Hectopascal



    4.2.12.21       Atis Code Parameter
                The atis code parameter in CPDLC message elements is equivalent in ATN and FANS
                1/A.
                Table 4-43 presents the ATN and FANS 1/A atis code data type comparison and impact.
                              Table 4-43 ATN and FANS 1/A Atis Code Parameter

            ATN                        FANS 1/A                  Interoperability Requirement
            Atis Code Parameter        Atis Code Parameter
              ATISCode:                 ATISCode:                None.
              String(1)                 String(1)



4.2.12.22          To/From Parameter
            The to/from parameter in CPDLC message elements is equivalent in ATN and FANS
            1/A.
            Table 4-44 presents the ATN and FANS 1/A To/From data type comparison and impact.


                                  Table 4-44 ATN and FANS 1/A To/From Parameter

            ATN                        FANS 1/A                  Interoperability Requirement
            To/From Parameter          To/From Parameter
              To                        To                       None.
              From                      From                     None.



4.2.12.23          Position Report Parameter
            The position report parameter in CPDLC message elements is comparable in ATN and
            FANS 1/A.
            Table 4-45 presents the ATN and FANS 1/A position report data type comparison and
            impact.


                           Table 4-45 ATN and FANS 1/A position report parameter

            ATN Position Report           FANS 1/A Position        Interoperability Requirement
            Parameter                     Parameter
              Position Current               Position Current      See paragraph 4.2.12.2 for use of
                     Position                       Position       position parameter.

            Time at Position Current      Time at Position Current None.
                    Time                   Time
            Level                            Altitude              See paragraph 4.2.12.1 for use of
                                                                   level/altitude parameter.
            Fix Next                      Fix Next                 See paragraph 4.2.12.2 for use of
                       Position             Position               position parameter.

            Time ETA at Fix Next          Time ETA at Fix Next     None.
                   Time                    Time
4-171


        ATN Position Report        FANS 1/A Position   Interoperability Requirement
        Parameter                  Parameter
        Fix Next Plus One          Fix Next Plus One   See paragraph 4.2.12.2 for use of
                Position             Position          position parameter.

        Time ETA at Destination    Time ETA at         None.
               Time                Destination
                                    Time
        Remaining Fuel              Remaining Fuel     See paragraph 4.2.12.24 for use of the
                                                       remaining fuel parameter.
        Temperature                 Temperature        See paragraph 4.2.12.27for use of the
                                                       temperature parameter.
        Winds                       Winds              None.
        Turbulence                  Turbulence         None.
        Icing                       Icing              In FANS 1/A Icing selection [0] is
                                                       trace and selection [0] is reserved in
                                                       ATN.
                                                       IR-362   The ATN ground system
                                                       shall ignore any icing parameter of
                                                       trace.
                                                       IR-363 The ATN ground system
                                                       shall send an error message to the
                                                       aircraft indicating that trace is an
                                                       unacceptable section for icing in an
                                                       ATN system.
        Speed                       Speed              See paragraph 4.2.12.3 for use of speed
                                                       parameter.
        Speed Ground               Speed Ground        See paragraph 4.2.12.3 for use of speed
                Speed Ground        Speed Ground       parameter.

        Vertical Change            Vertical Change     See paragraph 4.2.12.28 for use of the
                 Vertical Change    Vertical Change    vertical change parameter.

        Track Angle                Track Angle         See paragraph 4.2.12.10 for use of
                Degrees             Degrees            degrees parameter.

        Heading                    True Heading        The naming is different.
                   Degrees          Degrees            See paragraph 4.2.12.10 for use of
                                                       degrees parameter.
        Distance                    Distance           See paragraph 4.2.12.4 for use of
                                                       distance parameter.
            ATN Position Report        FANS 1/A Position       Interoperability Requirement
            Parameter                  Parameter
            Humidity                     Supplementary         FANS 1/A uses free text for the
                                         Information           supplementary information and ATN
                                                               uses the Humidity parameter.
                                                               IR-364   The ATN ground system
                                                               shall disregard any information
                                                               entered in the supplementary
                                                               information parameter.
                                                               Note: Humidity will not be reported for
                                                               FANS 1/A Aircraft.
            Reported Waypoint          Reported Waypoint       See paragraph 4.2.12.2 for use of
            Position                   Position                position parameter.
                     Position           Position
            Reported Waypoint Time     Reported Waypoint       None.
                    Time               Time
                                        Time
            Reported Waypoint Level      Reported Waypoint     See paragraph 4.2.12.1 for use of
                    Level                Altitude              level/altitude parameter.
                                                Altitude



4.2.12.24       Remaining Fuel Parameter
            The remaining fuel parameter in CPDLC message elements is equivalent in ATN and
            FANS 1/A.
            Table 4-46 presents the ATN and FANS 1/A remaining fuel data type comparison and
            impact.
                        Table 4-46 ATN and FANS 1/A Remaining Fuel Parameter

            ATN Remaining Fuel FANS 1/A Remaining            Interoperability Requirement
            Parameter          Fuel Parameter
              Time                    Time                   See paragraph 4.2.12.6 for use of the
                                                             time/timesec parameter.



4.2.12.25       Persons On Board / Remaining Souls Parameter
            The persons on board parameter in ATN CPDLC messages is equivalent to the remaining
            souls parameter in FANS 1/A CPDLC messages. Both parameter versions have the same
            data type and resolution.
            Table 4-47 presents the ATN and FANS 1/A persons on board data type comparison and
            impact.
4-173


                       Table 4-47     ATN and FANS 1/A Persons on Board Parameter

                ATN Persons on        FANS 1/A Remaining      Interoperability Requirement
                Board Parameter       Souls Parameter
                  PersonsOnBoard       RemainingSouls         None.



    4.2.12.26       Version Number Parameter
                The version number parameter in CPDLC message elements is equivalent in ATN and
                FANS 1/A.
                Table 4-48 presents the ATN and FANS 1/A version number data type comparison and
                impact.
                       Table 4-48     ATN and FANS 1/A Version Number Parameter

                ATN Version           FANS 1/A Version        Interoperability Requirement
                Number Parameter      Number Parameter
                  VersionNumber        VersionNumber          None.



    4.2.12.27       Temperature Parameter
                The temperature parameter in CPDLC message elements in ATN requires a different
                unit, range, and resolution than the temperature parameter in CPDLC message elements
                in FANS 1/A.
                Table 4-49 presents the ATN and FANS 1/A temperature data type comparison and
                impact.
                              Table 4-49 ATN and FANS 1/A temperature data type

        ATN Temperature Parameter     FANS 1/A temperature             Interoperability Requirement
                                      Parameter
         Temperature                   Temperaturec                    None.
              -Unit: Degree Celsius         -Unit: Degree Centigrade   The temperaturec parameter is
              -Range: (-100…100)            -Range: (-80…47)           never sent as an uplink.
              -Resolution: 1                -Resolution: 1
       ATN Temperature Parameter       FANS 1/A temperature               Interoperability Requirement
                                       Parameter
                                        Temperaturef                      IR-365  The temperaturef
                                               -Unit: Degree Fahrenheit   parameter is never sent as an
                                               -Range: (-105…150)         uplink.
                                        -Resolution: 1                    IR-366 The ATN ground
                                                                          system shall convert the FANS
                                                                          1/A parameter temperaturef
                                                                          Fahrenheit temperature to the
                                                                          ATN temperature in Celsius
                                                                          when receiving a downlink from
                                                                          a FANS 1/A aircraft.
                                                                          Note: The FANS 1/A range in
                                                                          Fahrenheit is within the ATN range
                                                                          in Celsius.
                                                                          No additional interopability
                                                                          requirements for uplink.



    4.2.12.28        Vertical Change Parameter
                The vertical change sequenced parameter in ATN CPDLC messages is identical to the
                vertical change parameter in the FANS 1/A CPDLC messages.
                Table 4-50 presents the ATN and FANS 1/A vertical change data type comparison and
                impact.
                Note: Differences in the vertical rate parameter must be accounted for when the vertical
                change parameter is used. See paragraph 4.2.12.28.2 for use of the vertical rate
                parameter.
                        Table 4-50      ATN and FANS 1/A Vertical Change Parameter

                ATN Vertical           FANS 1/A Vertical         Interoperability Requirement
                Change Parameter       Change Parameter
                  VerticalDirection     VerticalDirection        None.
                  VerticalRate          VerticalRate             See paragraph 4.2.12.28.2 for use of the
                                                                 vertical rate parameter.



4.2.12.28.1     Vertical Direction Parameter
                The vertical direction parameter in ATN CPDLC messages is identical to the vertical
                direction parameter in the FANS 1/A CPDLC messages.
                Table 4-51 presents the ATN and FANS 1/A Vertical Direction data type comparison and
                impact.
4-175


                          Table 4-51          ATN and FANS 1/A Vertical Direction Parameter

                  ATN Vertical              FANS 1/A Vertical            Interoperability Requirement
                  Direction Parameter       Direction Parameter
                   Up                         Up                         None.
                   Down                       Down                       None.

4.2.12.28.2      Vertical Rate Parameter
                 The vertical rate parameter in ATN CPDLC messages is comparable to the vertical rate
                 parameter in the FANS 1/A CPDLC messages.
                 Table 4-52 presents the ATN and FANS 1/A Vertical Direction data type comparison and
                 impact.
                                 Table 4-52 ATN and FANS 1/A vertical rate data type

              ATN Vertical Rate Parameter          FANS 1/A Vertical Rate        Interoperability Requirement
                                                   Parameter
              Vertical Rate English                Vertical Rate English         IR-367   The ATN ground
                       Integer: 0 to 3000                   Integer: 0 to 60     system shall only accept the
                       Units: Feet/Minute                   Units: Feet/Minute   Vertical Rate English
                       Range: 0 to 30000                    Range: 0 to 6000     parameter only with the
                                                                                 resolution equal to 100 feet per
                       Resolution: 10                       Resolution: 100
                                                                                 minute and decoded values 0 to
                                                                                 6000 feet per minute inclusive.
                                                                                 IR-368 The ATN ground
                                                                                 system shall reject the use of
                                                                                 Vertical Rate English data not
                                                                                 respecting the FANS 1/A
                                                                                 parameter resolution and range.
              Vertical Rate Metric                 Vertical Rate Metric          IR-369  The ATN ground
                       Integer: 0 to 1000                   Integer: 0 to 200    system shall only accept the
                       Units: Meters/Minute                 Units:               Vertical Rate Metric parameter
                       Range: 0 to 10000                    Meters/Minute        only with the resolution equal
                                                            Range: 0 to 2000     to 10 meters per minute and
                       Resolution: 10
                                                            Resolution: 10
                                                                                 decoded values 0 to 2000
                                                                                 meters per minute inclusive.
                                                                                 IR-370 The ATN ground
                                                                                 system shall reject the use of
                                                                                 Vertical Rate English data not
                                                                                 respecting the FANS 1/A
                                                                                 parameter resolution and range.
     4.2.12.29        Speed Schedule Parameter
                 The Speed Schedule parameter is a sequence of two speed paratmeters.
IR-371  The ATN ground system shall convert the Speed Schedule parameter into two speed parameters
to accommodate a FANS 1/A aircraft.
                 See paragraph 4.2.12.3 for use of speed parameter.

4.2.13           ATN and FANS 1/A Message Element Pairing
     4.2.13.1         Downlink Message Elements
                 Table 4-53 presents the Downlink message elements with Y Response attribute together
                 with the expected responses and the impact on the ATN ground system to support the
                 FANS 1/A message elements.
                 Note:    Only message elements that are in scope of this document per paragraph 1.2
                          are listed. See paragraph 4.2.9 for processing downlink message elements that
                          are not supported by the ATN ground system.
                                 Table 4-53 ATN downlink message elements with Y response attribute

ATN Message   ATN Response Message                FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                           Message Element                                         Requirement
DM6 REQUEST   UM0 UNABLE                            DM6 REQUEST     UM0 UNABLE                            See paragraph 4.2.8 for
[level]       UM1 STANDBY                           [altitude]      UM1 STANDBY                           use of uplink message
              UM2 REQUEST DEFERRED                                  UM2 REQUEST DEFERRED                  elements.
              UM162 MESSAGE NOT SUPPORTED BY                        UM162 MESSAGE NOT SUPPORTED
              THIS UNIT                                             BY THIS UNIT
              UM211 REQUEST FORWARDED                               UM169 ‗REQUEST FORWARDED‘
              UM218 REQUEST ALREADY RECEIVED                        UM169 ‗REQUEST ALREADY
              UM234 FLIGHT PLAN NOT HELD                            RECEIVED‘
              UM19 MAINTAIN [level]                                 UM169 ‗FLIGHT PLAN NOT HELD‘
              UM20 CLIMB TO [level]                                 UM19 MAINTAIN [level]
              UM251 AT [timesec] CLIMB TO [level]                   UM20 CLIMB TO [level]
              UM22 AT [position] CLIMB TO [level]                   UM21 AT [time] CLIMB TO [level]
              UM23 DESCEND TO [level]                               UM22 AT [position] CLIMB TO [level]
              UM252 AT [timesec] DESCEND TO [level]                 UM23 DESCEND TO [level]
              UM25 AT [position] DESCEND TO [level]                 UM24 AT [time] DESCEND TO [level]
              UM253 CLIMB TO REACH [level] BY                       UM25 AT [position] DESCEND TO
              [timesec]                                             [level]
              UM27 CLIMB TO REACH [level] BY                        UM26 CLIMB TO REACH [level] BY
              [position]                                            [time]
              UM254 DESCEND TO REACH [level] BY                     UM27 CLIMB TO REACH [level] BY
              [timesec]                                             [position]
              UM29 DESCEND TO REACH [level] BY                      UM28 DESCEND TO REACH [level] BY
              [position]                                            [time]
              UM46 CROSS [position] AT [level]                      UM29 DESCEND TO REACH [level] BY
              UM47 CROSS [position] AT OR ABOVE                     [position]
              [level]                                               UM46 CROSS [position] AT [level]
              UM48 CROSS [position] AT OR BELOW                     UM47 CROSS [position] AT OR ABOVE
              [level]                                               [level]
              UM185 AFTER PASSING [position]                        UM48 CROSS [position] AT OR BELOW
              CLIMB TO [level]                                      [level]
ATN Message      ATN Response Message                  FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                                Message Element                                         Requirement
                 UM186 AFTER PASSING [position]                          UM159 ERROR [errorInformation] + UM
                 DESCEND TO [level]                                      169 [freetext]
                 UM292 REACH [level] BY [timesec]                        UM169 ‗REQUEST AGAIN WITH NEXT
                 UM209 REACH [level] BY [position]                       UNIT‘
                 UM159 ERROR [errorInformation] + UM
                 183 [freetext]
                 UM237 REQUEST AGAIN WITH NEXT
                 UNIT
DM8 REQUEST     UM0 UNABLE                          DM8 REQUEST          UM0 UNABLE                            See paragraph 4.2.8 for
CRUISE CLIMB TO UM1 STANDBY                         CRUISE CLIMB         UM1 STANDBY                           use of uplink message
[level]         UM2 REQUEST DEFERRED                TO [altitude]        UM2 REQUEST DEFERRED                  elements.
                UM162 MESSAGE NOT SUPPORTED BY                           UM162 MESSAGE NOT SUPPORTED
                THIS UNIT                                                BY THIS UNIT
                UM211 REQUEST FORWARDED                                  UM169 ‗REQUEST FORWARDED‘
                UM218 REQUEST ALREADY RECEIVED                           UM169 ‗REQUEST ALREADY
                UM234 FLIGHT PLAN NOT HELD                               RECEIVED‘
                UM19 MAINTAIN [level]                                    UM169 ‗FLIGHT PLAN NOT HELD‘
                UM20 CLIMB TO [level]                                    UM19 MAINTAIN [level]
                UM251 AT [timesec] CLIMB TO [level]                      UM20 CLIMB TO [level]
                UM22 AT [position] CLIMB TO [level]                      UM21 AT [time] CLIMB TO [level]
                UM23 DESCEND TO [level]                                  UM22 AT [position] CLIMB TO [level]
                UM253 CLIMB TO REACH [level] BY                          UM23 DESCEND TO [level]
                [timesec]                                                UM26 CLIMB TO REACH [level] BY
                UM27 CLIMB TO REACH [level] BY                           [time]
                [position]                                               UM27 CLIMB TO REACH [level] BY
                UM28 DESCEND TO REACH [level] BY                         [position]
                [time]                                                   UM28 DESCEND TO REACH [level] BY
                UM29 DESCEND TO REACH [level] BY                         [time]
                [position]                                               UM29 DESCEND TO REACH [level] BY
                UM36 EXPEDITE CLIMB TO [level]                           [position]
                UM38 IMMEDIATELY CLIMB TO [level]                        UM36 EXPEDITE CLIMB TO [level]
                UM46 CROSS [position] AT [level]                         UM38 IMMEDIATELY CLIMB TO
                UM47 CROSS [position] AT OR ABOVE                        [level]
4-179


ATN Message        ATN Response Message                  FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                                  Message Element                                         Requirement
                   [level]                                                 UM46 CROSS [position] AT [level]
                   UM48 CROSS [position] AT OR BELOW                       UM47 CROSS [position] AT OR ABOVE
                   [level]                                                 [level]
                   UM185 AFTER PASSING [position]                          UM48 CROSS [position] AT OR BELOW
                   CLIMB TO [level]                                        [level]
                   UM292 REACH [level] BY [timesec]                        UM159 ERROR [errorInformation] + UM
                   UM209 REACH [level] BY [position]                       169 [freetext]
                   UM159 ERROR [errorInformation] + UM                     UM169 ‗REQUEST AGAIN WITH NEXT
                   169 [freetext]                                          UNIT‘
                   UM169 ‗REQUEST AGAIN WITH NEXT
                   UNIT‘
DM9 REQUEST        UM0 UNABLE                          DM9 REQUEST         UM0 UNABLE                            See paragraph 4.2.8 for
CLIMB TO [level]   UM1 STANDBY                         CLIMB TO            UM1 STANDBY                           use of uplink message
                   UM2 REQUEST DEFERRED                [altitude]          UM2 REQUEST DEFERRED                  elements.
                   UM162 MESSAGE NOT SUPPORTED BY                          UM162 MESSAGE NOT SUPPORTED
                   THIS UNIT                                               BY THIS UNIT
                   UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
                   UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
                   RECEIVED‘                                               RECEIVED‘
                   UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                   UM19 MAINTAIN [level]                                   UM19 MAINTAIN [level]
                   UM20 CLIMB TO [level]                                   UM20 CLIMB TO [level]
                   UM21 AT [time] CLIMB TO [level]                         UM21 AT [time] CLIMB TO [level]
                   UM22 AT [position] CLIMB TO [level]                     UM22 AT [position] CLIMB TO [level]
                   UM23 DESCEND TO [level]                                 UM23 DESCEND TO [level]
                   UM26 CLIMB TO REACH [level] BY                          UM26 CLIMB TO REACH [level] BY
                   [time]                                                  [time]
                   UM27 CLIMB TO REACH [level] BY                          UM27 CLIMB TO REACH [level] BY
                   [position]                                              [position]
                   UM28 DESCEND TO REACH [level] BY                        UM28 DESCEND TO REACH [level] BY
                   [time]                                                  [time]
                   UM29 DESCEND TO REACH [level] BY                        UM29 DESCEND TO REACH [level] BY
ATN Message    ATN Response Message                  FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                              Message Element                                         Requirement
               [position]                                              [position]
               UM36 EXPEDITE CLIMB TO [level]                          UM36 EXPEDITE CLIMB TO [level]
               UM38 IMMEDIATELY CLIMB TO [level]                       UM38 IMMEDIATELY CLIMB TO
               UM46 CROSS [position] AT [level]                        [level]
               UM47 CROSS [position] AT OR ABOVE                       UM46 CROSS [position] AT [level]
               [level]                                                 UM47 CROSS [position] AT OR ABOVE
               UM48 CROSS [position] AT OR BELOW                       [level]
               [level]                                                 UM48 CROSS [position] AT OR BELOW
               UM185 AFTER PASSING [position]                          [level]
               CLIMB TO [level]                                        UM159 ERROR [errorInformation] + UM
               UM292 REACH [level] BY [timesec]                        169 [freetext]
               UM209 REACH [level] BY [position]                       UM169 ‗REQUEST AGAIN WITH NEXT
               UM159 ERROR [errorInformation] + UM                     UNIT‘
               169 [freetext]
               UM169 ‗REQUEST AGAIN WITH NEXT
               UNIT‘
DM10 REQUEST   UM0 UNABLE                            DM10 REQUEST      UM0 UNABLE                            See paragraph 4.2.8 for
DESCEND TO     UM1 STANDBY                           DESCEND TO        UM1 STANDBY                           use of uplink message
[level]        UM2 REQUEST DEFERRED                  [altitude]        UM2 REQUEST DEFERRED                  elements.
               UM162 MESSAGE NOT SUPPORTED BY                          UM162 MESSAGE NOT SUPPORTED
               THIS UNIT                                               BY THIS UNIT
               UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
               UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
               RECEIVED‘                                               RECEIVED‘
               UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
               UM19 MAINTAIN [level]                                   UM19 MAINTAIN [level]
               UM20 CLIMB TO [level]                                   UM20 CLIMB TO [level]
               UM23 DESCEND TO [level]                                 UM23 DESCEND TO [level]
               UM252 AT [timesec] DESCEND TO [level]                   UM24 AT [time] DESCEND TO [level]
               UM25 AT [position] DESCEND TO [level]                   UM25 AT [position] DESCEND TO
               UM253[timesec]                                          [level]
               UM27 CLIMB TO REACH [level] BY                          UM26 CLIMB TO REACH [level] BY
               [position]                                              [time]
4-181


ATN Message          ATN Response Message                  FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                                    Message Element                                         Requirement
                     UM28 DESCEND TO REACH [level] BY                        UM27 CLIMB TO REACH [level] BY
                     [time]                                                  [position]
                     UM29 DESCEND TO REACH [level] BY                        UM28 DESCEND TO REACH [level] BY
                     [position]                                              [time]
                     UM46 CROSS [position] AT [level]                        UM29 DESCEND TO REACH [level] BY
                     UM47 CROSS [position] AT OR ABOVE                       [position]
                     [level]                                                 UM46 CROSS [position] AT [level]
                     UM48 CROSS [position] AT OR BELOW                       UM47 CROSS [position] AT OR ABOVE
                     [level]                                                 [level]
                     UM186 AFTER PASSING [position]                          UM48 CROSS [position] AT OR BELOW
                     DESCEND TO [level]                                      [level]
                     UM292 REACH [level] BY [timesec]                        UM159 ERROR [errorInformation] + UM
                     UM209 REACH [level] BY [position]                       169 [freetext]
                     UM159 ERROR [errorInformation] + UM                     UM169 ‗REQUEST AGAIN WITH NEXT
                     169 [freetext]                                          UNIT‘
                     UM169 ‗REQUEST AGAIN WITH NEXT
                     UNIT‘
DM11 AT [position]   UM0 UNABLE                            DM11 AT           UM0 UNABLE                            See paragraph 4.2.8
REQUEST CLIMB        UM1 STANDBY                           [position]        UM1 STANDBY                           for use of uplink
TO [level]           UM2 REQUEST DEFERRED                  REQUEST           UM2 REQUEST DEFERRED                  message elements.
                     UM162 MESSAGE NOT SUPPORTED BY        CLIMB TO          UM162 MESSAGE NOT SUPPORTED
                     THIS UNIT                             [altitude]        BY THIS UNIT
                     UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
                     UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
                     RECEIVED‘                                               RECEIVED‘
                     UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                     UM19 MAINTAIN [level]                                   UM19 MAINTAIN [level]
                     UM20 CLIMB TO [level]                                   UM20 CLIMB TO [level]
                     UM22 AT [position] CLIMB TO [level]                     UM22 AT [position] CLIMB TO [level]
                     UM23 DESCEND TO [level]                                 UM23 DESCEND TO [level]
                     UM26 CLIMB TO REACH [level] BY                          UM26 CLIMB TO REACH [level] BY
                     [time]                                                  [time]
ATN Message   ATN Response Message                    FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                               Message Element                                         Requirement
              UM27 CLIMB TO REACH [level] BY                            UM27 CLIMB TO REACH [level] BY
              [position]                                                [position]
              UM28 DESCEND TO REACH [level] BY                          UM28 DESCEND TO REACH [level] BY
              [time]                                                    [time]
              UM29 DESCEND TO REACH [level] BY                          UM29 DESCEND TO REACH [level] BY
              [position]                                                [position]
              UM159 ERROR [errorInformation] + UM                       UM159 ERROR [errorInformation] + UM
              169 [freetext]                                            169 [freetext]
              UM169 ‗REQUEST AGAIN WITH NEXT                            UM169 ‗REQUEST AGAIN WITH NEXT
              UNIT‘                                                     UNIT‘
DM12 AT       UM0 UNABLE                              DM12 AT           UM0 UNABLE                            See paragraph 4.2.8
[position]    UM1 STANDBY                             [position]        UM1 STANDBY                           for use of uplink
REQUEST       UM2 REQUEST DEFERRED                    REQUEST           UM2 REQUEST DEFERRED                  message elements.
DESCENT TO    UM162 MESSAGE NOT SUPPORTED BY          DESCENT TO        UM162 MESSAGE NOT SUPPORTED
[level]       THIS UNIT                               [altitude]        BY THIS UNIT
              UM169 ‗REQUEST FORWARDED‘                                 UM169 ‗REQUEST FORWARDED‘
              UM169 ‗REQUEST ALREADY                                    UM169 ‗REQUEST ALREADY
              RECEIVED‘                                                 RECEIVED‘
              UM169 ‗FLIGHT PLAN NOT HELD‘                              UM169 ‗FLIGHT PLAN NOT HELD‘
              UM19 MAINTAIN [level]                                     UM19 MAINTAIN [level]
              UM20 CLIMB TO [level]                                     UM20 CLIMB TO [level]
              UM23 DESCEND TO [level]                                   UM23 DESCEND TO [level]
              UM25 AT [position] DESCEND TO [level]                     UM25 AT [position] DESCEND TO
              UM26 CLIMB TO REACH [level] BY                            [level]
              [time]                                                    UM26 CLIMB TO REACH [level] BY
              UM27 CLIMB TO REACH [level] BY                            [time]
              [position]                                                UM27 CLIMB TO REACH [level] BY
              UM28 DESCEND TO REACH [level] BY                          [position]
              [time]                                                    UM28 DESCEND TO REACH [level] BY
              UM29 DESCEND TO REACH [level] BY                          [time]
              [position]                                                UM29 DESCEND TO REACH [level] BY
              UM159 ERROR [errorInformation] + UM                       [position]
              169 [freetext]                                            UM159 ERROR [errorInformation] + UM
4-183


ATN Message        ATN Response Message                  FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                                  Message Element                                         Requirement
                   UM169 ‗REQUEST AGAIN WITH NEXT                          169 [freetext]
                   UNIT‘                                                   UM169 ‗REQUEST AGAIN WITH NEXT
                                                                           UNIT‘
DM119 AT           UM0 UNABLE                            DM13 AT [time]    UM0 UNABLE                            See paragraph 4.2.8
[timesec]          UM1 STANDBY                           REQUEST           UM1 STANDBY                           for use of uplink
REQUEST            UM2 REQUEST DEFERRED                  CLIMB TO          UM2 REQUEST DEFERRED                  message elements.
CLIMB TO [level]   UM162 MESSAGE NOT SUPPORTED BY        [altitude]        UM162 MESSAGE NOT SUPPORTED
                   THIS UNIT                                               BY THIS UNIT
                   UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
                   UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
                   RECEIVED‘                                               RECEIVED‘
                   UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                   UM21 AT [time] CLIMB TO [level]                         UM21 AT [time] CLIMB TO [level]
                   UM159 ERROR [errorInformation] + UM                     UM159 ERROR [errorInformation] + UM
                   169 [freetext]                                          169 [freetext]
                   UM169 ‗REQUEST AGAIN WITH NEXT                          UM169 ‗REQUEST AGAIN WITH NEXT
                   UNIT‘                                                   UNIT‘
DM120 AT           UM0 UNABLE                            DM14 AT [time]    UM0 UNABLE                            See paragraph 4.2.8
[timesec]          UM1 STANDBY                           REQUEST           UM1 STANDBY                           for use of uplink
REQUEST            UM2 REQUEST DEFERRED                  DESCENT TO        UM2 REQUEST DEFERRED                  message elements.
DESCENT TO         UM162 MESSAGE NOT SUPPORTED BY        [altitude]        UM162 MESSAGE NOT SUPPORTED
[level]            THIS UNIT                                               BY THIS UNIT
                   UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
                   UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
                   RECEIVED‘                                               RECEIVED‘
                   UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                   UM24 AT [time] DESCEND TO [level]                       UM24 AT [time] DESCEND TO [level]
                   UM159 ERROR [errorInformation] + UM                     UM159 ERROR [errorInformation] + UM
                   169 [freetext]                                          169 [freetext]
                   UM169 ‗REQUEST AGAIN WITH NEXT                          UM169 ‗REQUEST AGAIN WITH NEXT
                   UNIT‘                                                   UNIT‘
DM15 REQUEST       UM0 UNABLE                            DM15              UM0 UNABLE                            See paragraph 4.2.8
ATN Message         ATN Response Message                     FANS 1/A           FANS 1/A Response Message                  Interoperability
Element                                                      Message Element                                               Requirement
OFFSET [specified UM1 STANDBY                                REQUEST            UM1 STANDBY                                for use of uplink
distance]         UM2 REQUEST DEFERRED                       OFFSET             UM2 REQUEST DEFERRED                       message elements.
[direction] OF    UM162 MESSAGE NOT SUPPORTED BY             [distanceoffset]   UM162 MESSAGE NOT SUPPORTED
ROUTE             THIS UNIT                                  [direction] OF     BY THIS UNIT
                  UM169 ‗REQUEST FORWARDED‘                  ROUTE              UM169 ‗REQUEST FORWARDED‘
                  UM169 ‗REQUEST ALREADY                                        UM169 ‗REQUEST ALREADY
                  RECEIVED‘                                                     RECEIVED‘
                  UM169 ‗FLIGHT PLAN NOT HELD‘                                  UM169 ‗FLIGHT PLAN NOT HELD‘
                  UM64 OFFSET [specifiedDistance]                               UM64 OFFSET [specifiedDistance]
                  [direction] OF ROUTE                                          [direction] OF ROUTE
                  UM65 AT [position] OFFSET                                     UM65 AT [position] OFFSET
                  [specifiedDistance] [direction] OF ROUTE                      [specifiedDistance] [direction] OF ROUTE
                  UM265 AT [timesec] OFFSET                                     UM66 AT [time] OFFSET
                  [specifiedDistance] [direction] OF ROUTE                      [specifiedDistance] [direction] OF ROUTE
                   UM82 CLEARED TO DEVIATE UP TO                                 UM82 CLEARED TO DEVIATE UP TO
                  [specifiedDistance] [direction] OF ROUTE                      [specifiedDistance] [direction] OF ROUTE
                  UM159 ERROR [errorInformation] + UM                           UM159 ERROR [errorInformation] + UM
                  169 [freetext]                                                169 [freetext]
                  UM169 ‗REQUEST AGAIN WITH NEXT                                UM169 ‗REQUEST AGAIN WITH NEXT
                  UNIT‘                                                         UNIT‘
DM16 AT           UM0 UNABLE                                 DM16 AT            UM0 UNABLE                                 See paragraph 4.2.8 for
[position]        UM1 STANDBY                                [position]         UM1 STANDBY                                use of uplink message
REQUEST           UM2 REQUEST DEFERRED                       REQUEST            UM2 REQUEST DEFERRED                       elements.
OFFSET [specified UM162 MESSAGE NOT SUPPORTED BY             OFFSET             UM162 MESSAGE NOT SUPPORTED
distance]         THIS UNIT                                  [distanceoffset]   BY THIS UNIT
[direction] OF    UM169 ‗REQUEST FORWARDED‘                  [direction] OF     UM169 ‗REQUEST FORWARDED‘
ROUTE             UM169 ‗REQUEST ALREADY                     ROUTE              UM169 ‗REQUEST ALREADY
                  RECEIVED‘                                                     RECEIVED‘
                  UM169 ‗FLIGHT PLAN NOT HELD‘                                  UM169 ‗FLIGHT PLAN NOT HELD‘
                  UM65 AT [position] OFFSET                                     UM65 AT [position] OFFSET
                  [specifiedDistance] [direction] OF ROUTE                      [specifiedDistance] [direction] OF ROUTE
                   UM82 CLEARED TO DEVIATE UP TO                                 UM82 CLEARED TO DEVIATE UP TO
                  [specifiedDistance] [direction] OF ROUTE                      [specifiedDistance] [direction] OF ROUTE
4-185


ATN Message             ATN Response Message                       FANS 1/A           FANS 1/A Response Message                  Interoperability
Element                                                            Message Element                                               Requirement
                        UM159 ERROR [errorInformation] + UM                           UM159 ERROR [errorInformation] + UM
                        169 [freetext]                                                169 [freetext]
                        UM169 ‗REQUEST AGAIN WITH NEXT                                UM169 ‗REQUEST AGAIN WITH NEXT
                        UNIT‘                                                         UNIT‘
DM121 AT                UM0 UNABLE                                 DM17 AT [time]     UM0 UNABLE                                 See paragraph 4.2.8 for
[timesec] REQUEST       UM1 STANDBY                                REQUEST            UM1 STANDBY                                use of uplink message
OFFSET [specified       UM2 REQUEST DEFERRED                       OFFSET             UM2 REQUEST DEFERRED                       elements.
distance] [direction]   UM162 MESSAGE NOT SUPPORTED BY             [distanceoffset]   UM162 MESSAGE NOT SUPPORTED
OF ROUTE                THIS UNIT                                  [direction] OF     BY THIS UNIT
                        UM169 ‗REQUEST FORWARDED‘                  ROUTE              UM169 ‗REQUEST FORWARDED‘
                        UM169 ‗REQUEST ALREADY                                        UM169 ‗REQUEST ALREADY
                        RECEIVED‘                                                     RECEIVED‘
                        UM169 ‗FLIGHT PLAN NOT HELD‘                                  UM169 ‗FLIGHT PLAN NOT HELD‘
                        UM265 AT [timesec] OFFSET                                     UM66 AT [time] OFFSET
                        [specifiedDistance] [direction] OF ROUTE                      [specifiedDistance] [direction] OF ROUTE
                        UM159 ERROR [errorInformation] + UM                           UM159 ERROR [errorInformation] + UM
                        169 [freetext]                                                169 [freetext]
                        UM169 ‗REQUEST AGAIN WITH NEXT                                UM169 ‗REQUEST AGAIN WITH NEXT
                        UNIT‘                                                         UNIT‘
DM18 REQUEST            UM0 UNABLE                       DM18 REQUEST                 UM0 UNABLE                                 See paragraph 4.2.8 for
SPEED [speed]           UM1 STANDBY                      SPEED [speed]                UM1 STANDBY                                use of uplink message
                        UM2 REQUEST DEFERRED                                          UM2 REQUEST DEFERRED                       elements.
                        UM162 MESSAGE NOT SUPPORTED BY                                UM162 MESSAGE NOT SUPPORTED
                        THIS UNIT                                                     BY THIS UNIT
                        UM169 ‗REQUEST FORWARDED‘                                     UM169 ‗REQUEST FORWARDED‘
                        UM169 ‗REQUEST ALREADY                                        UM169 ‗REQUEST ALREADY
                        RECEIVED‘                                                     RECEIVED‘
                        UM169 ‗FLIGHT PLAN NOT HELD‘                                  UM169 ‗FLIGHT PLAN NOT HELD‘
                        UM55 CROSS [position] AT [speed]                              UM55 CROSS [position] AT [speed]
                        UM61 CROSS [position] AT AND                                  UM61 CROSS [position] AT AND
                        MAINTAIN [level] AT [speed]                                   MAINTAIN [level] AT [speed]
ATN Message          ATN Response Message                  FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                                    Message Element                                         Requirement
                     UM106 MAINTAIN [speed]                                  UM106 MAINTAIN [speed]
                     UM107 MAINTAIN PRESENT SPEED                            UM107 MAINTAIN PRESENT SPEED
                     UM108 MAINTAIN [speed] OR                               UM108 MAINTAIN [speed] OR
                     GREATER                                                 GREATER
                     UM109 MAINTAIN [speed] OR LESS                          UM109 MAINTAIN [speed] OR LESS
                     UM111 INCREASE SPEED TO [speed]                         UM111 INCREASE SPEED TO [speed]
                     UM112 INCREASE SPEED TO [speed]                         UM112 INCREASE SPEED TO [speed]
                     OR GREATER                                              OR GREATER
                     UM113 REDUCE SPEED TO [speed]                           UM113 REDUCE SPEED TO [speed]
                     UM114 REDUCE SPEED TO [speed] OR                        UM114 REDUCE SPEED TO [speed] OR
                     LESS                                                    LESS
                     UM115 DO NOT EXCEED [speed]                             UM115 DO NOT EXCEED [speed]
                     UM116 RESUME NORMAL SPEED                               UM116 RESUME NORMAL SPEED
                     UM189 ADJUST SPEED TO [speed]                           UM189 ADJUST SPEED TO [speed]
                     UM222 NO SPEED RESTRICTION                              UM169 ‗NO SPEED RESTRICTION‘
                     UM159 ERROR [errorInformation] + UM                     UM159 ERROR [errorInformation] + UM
                     169 [freetext]                                          169 [freetext]
                     UM169 ‗REQUEST AGAIN WITH NEXT                          UM169 ‗REQUEST AGAIN WITH NEXT
                     UNIT‘                                                   UNIT‘
DM19 REQUEST         UM0 UNABLE                            DM19              UM0 UNABLE                            See paragraph 4.2.8
[speed] TO [speed]   UM1 STANDBY                           REQUEST           UM1 STANDBY                           for use of uplink
                     UM2 REQUEST DEFERRED                  [speed] TO        UM2 REQUEST DEFERRED                  message elements.
                     UM162 MESSAGE NOT SUPPORTED BY        [speed]           UM162 MESSAGE NOT SUPPORTED
                     THIS UNIT                                               BY THIS UNIT
                     UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
                     UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
                     RECEIVED‘                                               RECEIVED‘
                     UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                     UM110 MAINTAIN [speed] TO [speed]                       UM110 MAINTAIN [speed] TO [speed]
                     UM159 ERROR [errorInformation] + UM                     UM159 ERROR [errorInformation] + UM
                     169 [freetext]                                          169 [freetext]
                     UM169 ‗REQUEST AGAIN WITH NEXT                          UM169 ‗REQUEST AGAIN WITH NEXT
                     UNIT‘                                                   UNIT‘
4-187


ATN Message    ATN Response Message                   FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                               Message Element                                         Requirement
DM20 REQUEST   UM0 UNABLE                             DM20              UM0 UNABLE                            See paragraph 4.2.8
VOICE          UM1 STANDBY                            REQUEST           UM1 STANDBY                           for use of uplink
CONTACT        UM2 REQUEST DEFERRED                   VOICE             UM2 REQUEST DEFERRED                  message elements.
               UM162 MESSAGE NOT SUPPORTED BY         CONTACT           UM162 MESSAGE NOT SUPPORTED
               THIS UNIT                                                BY THIS UNIT
               UM169 ‗REQUEST FORWARDED‘                                UM169 ‗REQUEST FORWARDED‘
               UM169 ‗REQUEST ALREADY                                   UM169 ‗REQUEST ALREADY
               RECEIVED‘                                                RECEIVED‘
               UM169 ‗FLIGHT PLAN NOT HELD‘                             UM169 ‗FLIGHT PLAN NOT HELD‘
               UM117 CONTACT [unitname] [frequency]                     UM117 CONTACT [unitname]
               UM118 AT [position] CONTACT                              [frequency]
               [unitname] [frequency]                                   UM118 AT [position] CONTACT
               UM282 AT [timesec] CONTACT                               [unitname] [frequency]
               [unitname] [frequency]                                   UM119 AT [time] CONTACT [unitname]
               UM159 ERROR [errorInformation] + UM                      [frequency]
               169 [freetext]                                           UM159 ERROR [errorInformation] + UM
               UM169 ‗REQUEST AGAIN WITH NEXT                           169 [freetext]
               UNIT‘                                                    UM169 ‗REQUEST AGAIN WITH NEXT
                                                                        UNIT‘
DM21 REQUEST   UM0 UNABLE                             DM21 REQUEST      UM0 UNABLE                            See paragraph 4.2.8 for
VOICE          UM1 STANDBY                            VOICE             UM1 STANDBY                           use of uplink message
CONTACT        UM2 REQUEST DEFERRED                   CONTACT           UM2 REQUEST DEFERRED                  elements.
[frequency]    UM162 MESSAGE NOT SUPPORTED BY         [frequency]       UM162 MESSAGE NOT SUPPORTED
               THIS UNIT                                                BY THIS UNIT
               UM169 ‗REQUEST FORWARDED‘                                UM169 ‗REQUEST FORWARDED‘
               UM169 ‗REQUEST ALREADY                                   UM169 ‗REQUEST ALREADY
               RECEIVED‘                                                RECEIVED‘
               UM169 ‗FLIGHT PLAN NOT HELD‘                             UM169 ‗FLIGHT PLAN NOT HELD‘
               UM117 CONTACT [unitname] [frequency]                     UM117 CONTACT [unitname]
               UM118 AT [position] CONTACT                              [frequency]
               [unitname] [frequency]                                   UM118 AT [position] CONTACT
               UM282 AT [timesec] CONTACT                               [unitname] [frequency]
ATN Message    ATN Response Message                  FANS 1/A          FANS 1/A Response Message              Interoperability
Element                                              Message Element                                          Requirement
               [unitname] [frequency]                                  UM119 AT [time] CONTACT [unitname]
               UM159 ERROR [errorInformation] + UM                     [frequency]
               169 [freetext]                                          UM159 ERROR [errorInformation] + UM
               UM169 ‗REQUEST AGAIN WITH NEXT                          169 [freetext]
               UNIT‘                                                   UM169 ‗REQUEST AGAIN WITH NEXT
                                                                       UNIT‘
DM22 REQUEST   UM0 UNABLE                          DM22 REQUEST        UM0 UNABLE                          See paragraph 4.2.8 for
DIRECT TO      UM1 STANDBY                         DIRECT TO           UM1 STANDBY                         use of uplink message
[position]     UM2 REQUEST DEFERRED                [position]          UM2 REQUEST DEFERRED                elements.
               UM162 MESSAGE NOT SUPPORTED BY                          UM162 MESSAGE NOT SUPPORTED
               THIS UNIT                                               BY THIS UNIT
               UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
               UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
               RECEIVED‘                                               RECEIVED‘
               UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
               UM74 PROCEED DIRECT TO [position]                       UM74 PROCEED DIRECT TO [position]
               UM75 WHEN ABLE PROCEED DIRECT                           UM75 WHEN ABLE PROCEED DIRECT
               TO [position]                                           TO [position]
               UM268 AT [timesec] PROCEED DIRECT                       UM71 AT [time] PROCEED DIRECT TO
               TO [position]                                           [position]
               UM77 AT [position] PROCEED DIRECT                       UM77 AT [position] PROCEED DIRECT
               TO [position]                                           TO [position]
               UM78 AT [level] PROCEED DIRECT TO                       UM78 AT [level] PROCEED DIRECT TO
               [position]                                              [position]
                UM96 CONTINUE PRESENT HEADING                           UM96 CONTINUE PRESENT
                UM190 FLY HEADING [degrees]                            HEADING
               UM159 ERROR [errorInformation] + UM                      UM190 FLY HEADING [degrees]
               169 [freetext]                                          UM159 ERROR [errorInformation] + UM
               UM169 ‗REQUEST AGAIN WITH NEXT                          169 [freetext]
               UNIT‘                                                   UM169 ‗REQUEST AGAIN WITH NEXT
                                                                       UNIT‘
DM23 REQUEST   UM0 UNABLE                            DM23              UM0 UNABLE                             See paragraph 4.2.8
               UM1 STANDBY                           REQUEST           UM1 STANDBY                            for use of uplink
4-189


ATN Message         ATN Response Message                 FANS 1/A           FANS 1/A Response Message             Interoperability
Element                                                  Message Element                                          Requirement
[procedure name]    UM2 REQUEST DEFERRED                [procedure name]    UM2 REQUEST DEFERRED                  message elements.
                    UM162 MESSAGE NOT SUPPORTED BY                          UM162 MESSAGE NOT SUPPORTED
                    THIS UNIT                                               BY THIS UNIT
                    UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
                    UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
                    RECEIVED‘                                               RECEIVED‘
                    UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                    UM81 CLEARED [procedure name]                           UM81 CLEARED [procedure name]
                    UM84 AT [position] CLEARED                              UM84 AT [position] CLEARED
                    [procedureName]                                         [procedureName]
                    UM99 EXPECT [procedureName]                             UM99 EXPECT [procedureName]
                    UM159 ERROR [errorInformation] + UM                     UM159 ERROR [errorInformation] + UM
                    169 [freetext]                                          169 [freetext]
                    UM169 ‗REQUEST AGAIN WITH NEXT                          UM169 ‗REQUEST AGAIN WITH NEXT
                    UNIT‘                                                   UNIT‘
DM122               UM0 UNABLE                          DM24 REQUEST        UM0 UNABLE                            See paragraph 4.2.8 for
REQUEST             UM1 STANDBY                         [route clearance]   UM1 STANDBY                           use of uplink message
CLEARANCE           UM2 REQUEST DEFERRED                                    UM2 REQUEST DEFERRED                  elements.
[route clearance]   UM162 MESSAGE NOT SUPPORTED BY                          UM162 MESSAGE NOT SUPPORTED
                    THIS UNIT                                               BY THIS UNIT
                    UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
                    UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
                    RECEIVED‘                                               RECEIVED‘
                    UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                    UM266 CLEARED TO [position] VIA                         UM79 CLEARED TO [position] VIA
                    [routeClearanceenhanced]                                [routeClearance]
                    UM267 CLEARED [route clearance                          UM80CLEARED [route clearance]
                    enhanced]                                               UM83 AT [position] CLEARED
                    UM268 AT [position] CLEARED                             [routeClearance]
                    [routeClearance enhanced]                               UM85 EXPECT [route Clearance]
                    UM269 EXPECT [route Clearance                           UM86 AT [position] EXPECT
                    enhanced]                                               [routeClearance]
ATN Message             ATN Response Message                  FANS 1/A            FANS 1/A Response Message             Interoperability
Element                                                       Message Element                                           Requirement
                        UM270 AT [position] EXPECT                                UM159 ERROR [errorInformation] + UM
                        [routeClearance enhanced]                                 169 [freetext]
                        UM159 ERROR [errorInformation] + UM                       UM169 ‗REQUEST AGAIN WITH NEXT
                        169 [freetext]                                            UNIT‘
                        UM169 ‗REQUEST AGAIN WITH NEXT
                        UNIT‘
DM25 REQUEST            UM0 UNABLE                          DM25 REQUEST          UM0 UNABLE                            See paragraph 4.2.8 for
[clearance type]        UM1 STANDBY                         CLEARANCE             UM1 STANDBY                           use of uplink message
CLEARANCE               UM6 EXPECT [level]                                        UM6 EXPECT [level]                    elements.
                        UM264 [Departure Clearance routing]                       UM73 [predepartureclearance] + UM79
                        UM79 CLEARED TO [position] VIA                            CLEARED TO [position] VIA
                        [routeClearance]                                          [routeclearance] + UM6 EXPECT
                        UM162 MESSAGE NOT SUPPORTED BY                            [altitude] + UM169 [freetext]
                        THIS UNIT                                                 UM162 MESSAGE NOT SUPPORTED
                        UM196 [freeText]                                          BY THIS UNIT
                        UM159 ERROR [errorInformation] + UM                       UM169 [freeText]
                        169 [freetext]                                            UM159 ERROR [errorInformation] + UM
                        UM169 ‗REQUEST AGAIN WITH NEXT                            169 [freetext]
                        UNIT‘
                                                                                  UM169 ‗REQUEST AGAIN WITH NEXT
                                                                                  UNIT‘
DM123 REQUEST           UM0 UNABLE                            DM26 REQUEST        UM0 UNABLE                            See paragraph 4.2.8 for
WEATHER                 UM1 STANDBY                           WEATHER             UM1 STANDBY                           use of uplink message
DEVIATION TO            UM2 REQUEST DEFERRED                  DEVIATION TO        UM2 REQUEST DEFERRED                  elements.
[position] VIA [route   UM162 MESSAGE NOT SUPPORTED BY        [position] VIA      UM162 MESSAGE NOT SUPPORTED
clearance]              THIS UNIT                             [route clearance]   BY THIS UNIT
                        UM169 ‗REQUEST FORWARDED‘                                 UM169 ‗REQUEST FORWARDED‘
                        UM169 ‗REQUEST ALREADY                                    UM169 ‗REQUEST ALREADY
                        RECEIVED‘                                                 RECEIVED‘
                        UM169 ‗FLIGHT PLAN NOT HELD‘                              UM169 ‗FLIGHT PLAN NOT HELD‘
                        UM79 CLEARED TO [position] VIA                            UM79 CLEARED TO [position] VIA
                        [routeClearance]                                          [routeClearance]
                        UM159 ERROR [errorInformation] + UM                       UM159 ERROR [errorInformation] + UM
4-191


ATN Message           ATN Response Message                       FANS 1/A              FANS 1/A Response Message                 Interoperability
Element                                                          Message Element                                                 Requirement
                      169 [freetext]                                                   169 [freetext]
                      UM169 ‗REQUEST AGAIN WITH NEXT                                   UM169 ‗REQUEST AGAIN WITH NEXT
                      UNIT‘                                                            UNIT‘
 DM27 REQUEST         UM0 UNABLE                                 DM27 REQUEST          UM0 UNABLE                               See paragraph 4.2.8 for
WEATHER               UM1 STANDBY                                WEATHER               UM1 STANDBY                              use of uplink message
DEVIATION UP TO       UM2 REQUEST DEFERRED                       DEVIATION UP          UM2 REQUEST DEFERRED                     elements.
[specifieddistance]   UM162 MESSAGE NOT SUPPORTED BY             TO [distanceoffset]   UM162 MESSAGE NOT SUPPORTED
[direction] OF        THIS UNIT                                  [direction] OF        BY THIS UNIT
ROUTE                 UM169 ‗REQUEST FORWARDED‘                  ROUTE                 UM169 ‗REQUEST FORWARDED‘
                      UM169 ‗REQUEST ALREADY                                           UM169 ‗REQUEST ALREADY
                      RECEIVED‘                                                        RECEIVED‘
                      UM169 ‗FLIGHT PLAN NOT HELD‘                                     UM169 ‗FLIGHT PLAN NOT HELD‘
                      UM64 OFFSET [specifiedDistance]                                  UM64 OFFSET [specifiedDistance]
                      [direction] OF ROUTE                                             [direction] OF ROUTE
                      UM74 PROCEED DIRECT TO [position]                                UM74 PROCEED DIRECT TO [position]
                      UM75 WHEN ABLE PROCEED DIRECT                                    UM75 WHEN ABLE PROCEED DIRECT
                      TO [position]                                                    TO [position]
                      UM77 AT [position] PROCEED DIRECT                                UM77 AT [position] PROCEED DIRECT
                      TO [position]                                                    TO [position]
                      UM78 AT [level] PROCEED DIRECT TO                                UM78 AT [level] PROCEED DIRECT TO
                      [position]                                                       [position]
                      UM82 CLEARED TO DEVIATE UP TO                                    UM82 CLEARED TO DEVIATE UP TO
                      [specifiedDistance] [direction] OF ROUTE                         [specifiedDistance] [direction] OF ROUTE
                      UM96 CONTINUE PRESENT HEADING                                    UM96 CONTINUE PRESENT HEADING
                      UM190 FLY HEADING [degrees]                                      UM190 FLY HEADING [degrees]
                      UM159 ERROR [errorInformation] + UM                              UM159 ERROR [errorInformation] + UM
                      169 [freetext]                                                   169 [freetext]
                      UM169 ‗REQUEST AGAIN WITH NEXT                                   UM169 ‗REQUEST AGAIN WITH NEXT
                      UNIT‘                                                            UNIT‘
DM49 WHEN CAN         UM0 UNABLE                                 DM49 WHEN             UM0 UNABLE                                See paragraph 4.2.8
WE EXPECT             UM1 STANDBY                                CAN WE                UM1 STANDBY                               for use of uplink
ATN Message      ATN Response Message                    FANS 1/A          FANS 1/A Response Message          Interoperability
Element                                                  Message Element                                      Requirement
[speed]          UM2 REQUEST DEFERRED                    EXPECT [speed] UM2 REQUEST DEFERRED                  message elements.
                 UM162 MESSAGE NOT SUPPORTED BY                         UM162 MESSAGE NOT SUPPORTED
                 THIS UNIT                                              BY THIS UNIT
                 UM169 ‗REQUEST FORWARDED‘                              UM169 ‗REQUEST FORWARDED‘
                 UM169 ‗REQUEST ALREADY                                 UM169 ‗REQUEST ALREADY
                 RECEIVED‘                                              RECEIVED‘
                 UM169 ‗FLIGHT PLAN NOT HELD‘                           UM169 ‗FLIGHT PLAN NOT HELD‘
                 UM276 AT [timesec] EXPECT [speed]                      UM100 AT [time] EXPECT [speed]
                 UM101 AT [position] EXPECT [speed]                     UM101 AT [position] EXPECT [speed]
                 UM102 AT [level] EXPECT [speed]                        UM102 AT [level] EXPECT [speed]
                 UM159 ERROR [errorInformation] + UM                    UM159 ERROR [errorInformation] + UM
                 169 [freetext]                                         169 [freetext]
                 UM169 ‗REQUEST AGAIN WITH NEXT                         UM169 ‗REQUEST AGAIN WITH NEXT
                 UNIT‘                                                  UNIT‘
DM50 WHEN        UM0 UNABLE                              DM50 WHEN      UM0 UNABLE                            See paragraph 4.2.8
CAN WE           UM1 STANDBY                             CAN WE         UM1 STANDBY                           for use of uplink
EXPECT [speed]   UM2 REQUEST DEFERRED                    EXPECT [speed] UM2 REQUEST DEFERRED                  message elements.
TO [speed]       UM162 MESSAGE NOT SUPPORTED BY          TO [speed]     UM162 MESSAGE NOT SUPPORTED
                 THIS UNIT                                              BY THIS UNIT
                 UM169 ‗REQUEST FORWARDED‘                              UM169 ‗REQUEST FORWARDED‘
                 UM169 ‗REQUEST ALREADY                                 UM169 ‗REQUEST ALREADY
                 RECEIVED‘                                              RECEIVED‘
                 UM169 ‗FLIGHT PLAN NOT HELD‘                           UM169 ‗FLIGHT PLAN NOT HELD‘
                 UM100 Replaced by UM276*                               UM100 AT [time] EXPECT [speed]
                 UM101 AT [position] EXPECT [speed]                     UM101 AT [position] EXPECT [speed]
                 UM102 AT [level] EXPECT [speed]                        UM102 AT [level] EXPECT [speed]
                 UM103 Replaced by UM277*                               UM103 Replaced by UM277*
                 UM104 AT [position] EXPECT [speed] TO                  UM104 AT [position] EXPECT [speed]
                 [speed]                                                TO [speed]
                 UM105 AT [level] EXPECT [speed] TO                     UM105 AT [level] EXPECT [speed] TO
                 [speed]                                                [speed]
                 UM159 ERROR [errorInformation] + UM                    UM159 ERROR [errorInformation] + UM
                 169 [freetext]                                         169 [freetext]
4-193


ATN Message    ATN Response Message                   FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                               Message Element                                         Requirement
               UM169 ‗REQUEST AGAIN WITH NEXT                           UM169 ‗REQUEST AGAIN WITH NEXT
               UNIT‘                                                    UNIT‘
               UM276 AT [timesec] EXPECT [speed]                        UM103 AT [time] EXPECT [speed] TO
               UM277 AT [timesec] EXPECT [speed] TO                     [speed]
               [speed]
DM51 WHEN      UM0 UNABLE                             DM51 WHEN         UM0 UNABLE                            See paragraph 4.2.8
CAN WE         UM1 STANDBY                            CAN WE            UM1 STANDBY                           for use of uplink
EXPECT BACK    UM2 REQUEST DEFERRED                   EXPECT BACK       UM2 REQUEST DEFERRED                  message elements.
ON ROUTE       UM162 MESSAGE NOT SUPPORTED BY         ON ROUTE          UM162 MESSAGE NOT SUPPORTED
               THIS UNIT                                                BY THIS UNIT
               UM169 ‗REQUEST FORWARDED‘                                UM169 ‗REQUEST FORWARDED‘
               UM169 ‗REQUEST ALREADY                                   UM169 ‗REQUEST ALREADY
               RECEIVED‘                                                RECEIVED‘
               UM169 ‗FLIGHT PLAN NOT HELD‘                             UM169 ‗FLIGHT PLAN NOT HELD‘
               UM67 PROCEED BACK ON ROUTE                               UM67 PROCEED BACK ON ROUTE
               UM68 REJOIN ROUTE BY [position]                          UM68 REJOIN ROUTE BY [position]
               UM266 REJOIN ROUTE BY [timesec]                          UM69 REJOIN ROUTE BY [time]
               UM70 EXPECT BACK ON ROUTE BY                             UM70 EXPECT BACK ON ROUTE BY
               [position]                                               [position]
               UM267 EXPECT BACK ON ROUTE BY                            UM71 EXPECT BACK ON ROUTE BY
               [timesec]                                                [time]
               UM159 ERROR [errorInformation] + UM                      UM159 ERROR [errorInformation] + UM
               169 [freetext]                                           169 [freetext]
               UM169 ‗REQUEST AGAIN WITH NEXT                           UM169 ‗REQUEST AGAIN WITH NEXT
               UNIT‘                                                    UNIT‘
DM52 WHEN      UM0 UNABLE                             DM52 WHEN         UM0 UNABLE                            See paragraph 4.2.8 for
CAN WE         UM1 STANDBY                            CAN WE            UM1 STANDBY                           use of uplink message
EXPECT LOWER   UM2 REQUEST DEFERRED                   EXPECT LOWER      UM2 REQUEST DEFERRED                  elements.
LEVEL          UM162 MESSAGE NOT SUPPORTED BY         LEVEL             UM162 MESSAGE NOT SUPPORTED
               THIS UNIT                                                BY THIS UNIT
               UM169 ‗REQUEST FORWARDED‘                                UM169 ‗REQUEST FORWARDED‘
               UM169 ‗REQUEST ALREADY                                   UM169 ‗REQUEST ALREADY
ATN Message     ATN Response Message                  FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                               Message Element                                         Requirement
                RECEIVED‘                                               RECEIVED‘
                UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                UM249 EXPECT DESCENT AT [timesec]                       UM9 EXPECT DESCENT AT [time]
                UM10 EXPECT DESCENT AT [position]                       UM10 EXPECT DESCENT AT [position]
                UM15 AT [timesec] EXPECT DESCENT                        UM15 AT [timesec] EXPECT DESCENT
                TO [level]                                              TO [level]
                UM16 AT [position] EXPECT DESCENT                       UM16 AT [position] EXPECT DESCENT
                TO [level]                                              TO [level]
                UM159 ERROR [errorInformation] + UM                     UM159 ERROR [errorInformation] + UM
                169 [freetext]                                          169 [freetext]
                UM169 ‗REQUEST AGAIN WITH NEXT                          UM169 ‗REQUEST AGAIN WITH NEXT
                UNIT‘                                                   UNIT‘
DM53 WHEN CAN   UM0 UNABLE                            DM53 WHEN         UM0 UNABLE                            See paragraph 4.2.8
WE EXPECT       UM1 STANDBY                           CAN WE            UM1 STANDBY                           for use of uplink
HIGHER LEVEL    UM2 REQUEST DEFERRED                  EXPECT            UM2 REQUEST DEFERRED                  message elements.
                UM162 MESSAGE NOT SUPPORTED BY        HIGHER            UM162 MESSAGE NOT SUPPORTED
                THIS UNIT                             LEVEL             BY THIS UNIT
                UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
                UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
                RECEIVED‘                                               RECEIVED‘
                UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                UM248 EXPECT CLIMB AT [timesec]                         UM7 EXPECT CLIMB AT [time]
                UM8 EXPECT CLIMB AT [position]                          UM8 EXPECT CLIMB AT [position]
                UM13 AT [timesec] EXPECT CLIMB TO                       UM13 AT [timesec] EXPECT CLIMB TO
                [level]                                                 [level]
                UM14 AT [position] EXPECT CLIMB TO                      UM14 AT [position] EXPECT CLIMB
                [level]                                                 TO [level]
                UM159 ERROR [errorInformation] + UM                     UM159 ERROR [errorInformation] + UM
                169 [freetext]                                          169 [freetext]
                UM169 ‗REQUEST AGAIN WITH NEXT                          UM169 ‗REQUEST AGAIN WITH NEXT
                UNIT‘                                                   UNIT‘
DM54 WHEN       UM1 STANDBY                           DM54 WHEN         UM1 STANDBY                           See paragraph 4.2.8
CAN WE          UM2 REQUEST DEFERRED                  CAN WE            UM2 REQUEST DEFERRED                  for use of uplink
4-195


ATN Message        ATN Response Message                    FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                                    Message Element                                         Requirement
EXPECT CRUISE UM162 MESSAGE NOT SUPPORTED BY EXPECT        UM162 MESSAGE NOT SUPPORTED                             message elements.
CLIMB TO [level] THIS UNIT                   CRUISE CLIMB BY THIS UNIT
                 UM169 ‗REQUEST FORWARDED‘   TO [altitude] UM169 ‗REQUEST FORWARDED‘
                   UM169 ‗REQUEST ALREADY                                    UM169 ‗REQUEST ALREADY
                   RECEIVED‘                                                 RECEIVED‘
                   UM169 ‗FLIGHT PLAN NOT HELD‘                              UM169 ‗FLIGHT PLAN NOT HELD‘
                   UM250 EXPECT CRUISE CLIMB AT                              UM11 EXPECT CRUISE CLIMB AT
                   [timesec]                                                 [time]
                   UM12 EXPECT CRUISE CLIMB AT                               UM12 EXPECT CRUISE CLIMB AT
                   [position]                                                [position]
                   UM17 AT [timesec] EXPECT CRUISE                           UM17 AT [timesec] EXPECT CRUISE
                   CLIMB TO [level]                                          CLIMB TO [level]
                   UM18 AT [position] EXPECT CRUISE                          UM18 AT [position] EXPECT CRUISE
                   CLIMB TO [level]                                          CLIMB TO [level]
                   UM159 ERROR [errorInformation] + UM                       UM159 ERROR [errorInformation] + UM
                   169 [freetext]                                            169 [freetext]
                   UM169 ‗REQUEST AGAIN WITH NEXT                            UM169 ‗REQUEST AGAIN WITH NEXT
                   UNIT‘                                                     UNIT‘
DM55 PAN PAN       UM3 ROGER                               DM55 PAN PAN      UM3 ROGER                             See paragraph 4.2.8 for
PAN                UM159 ERROR [errorInformation] + UM     PAN               UM159 ERROR [errorInformation] + UM   use of uplink message
                   169 [freetext]                                            169 [freetext]                        elements.
DM56 MAYDAY        UM3 ROGER                               DM56 MAYDAY       UM3 ROGER                             See paragraph 4.2.8 for
MAYDAY             UM159 ERROR [errorInformation] + UM     MAYDAY            UM159 ERROR [errorInformation] + UM   use of uplink message
MAYDAY             169 [freetext]                          MAYDAY            169 [freetext]                        elements.
DM128[remaining      UM3 ROGER                             DM57[remainingfu UM3 ROGER                              See paragraph 4.2.8 for
fuel] OF FUEL        UM159 ERROR [errorInformation] + UM   el] OF FUEL      UM159 ERROR [errorInformation] + UM    use of uplink message
REMAINING AND 169 [freetext]                               REMAINING        169 [freetext]                         elements.
[personnes on board]                                       AND
PERSONS ON                                                 [remainingsouls]
BOARD                                                      SOULS ON
                                                           BOARD
ATN Message         ATN Response Message                    FANS 1/A           FANS 1/A Response Message             Interoperability
Element                                                     Message Element                                          Requirement
DM58 CANCEL         UM3 ROGER                               DM58 CANCEL        UM3 ROGER                             See paragraph 4.2.8 for
EMERGENCY           UM159 ERROR [errorInformation] + UM     EMERGENCY          UM159 ERROR [errorInformation] + UM   use of uplink message
                    169 [freetext]                                             169 [freetext]                        elements.
DM129                 UM3 ROGER                             DM59             UM3 ROGER                               See paragraph 4.2.8
DIVERTING TO          UM159 ERROR [errorInformation] + UM   DIVERTING TO UM159 ERROR [errorInformation] + UM         for use of uplink
[position] VIA [route 169 [freetext]                        [position] VIA   169 [freetext]                          message elements.
clearance]                                                  [routeclearance]
DM60                 UM3 ROGER                              DM60               UM3 ROGER                             See paragraph 4.2.8 for
OFFSETTING           UM159 ERROR [errorInformation] + UM    OFFSETTING         UM159 ERROR [errorInformation] + UM   use of uplink message
[specified distance] 169 [freetext]                         [distanceoffset]   169 [freetext]                        elements.
[direction] OF                                              [direction] OF
ROUTE                                                       ROUTE
DM61                UM3 ROGER                               DM61               UM3 ROGER                             See paragraph 4.2.8 for
DESCENDING TO       UM159 ERROR [errorInformation] + UM     DESCENDING         UM159 ERROR [errorInformation] + UM   use of uplink message
[level]             169 [freetext]                          TO [altitude]      169 [freetext]                        elements.
DM68 [free text]    UM3 ROGER                               DM68 [free text]   UM3 ROGER                             See paragraph 4.2.8 for
                    UM159 ERROR [errorInformation] + UM                        UM159 ERROR [errorInformation] + UM   use of uplink message
                    183 [freetext]                                             183 [freetext]                        elements.
DM69 REQUEST        UM0 UNABLE                          DM69                   UM0 UNABLE                            See paragraph 4.2.8
VMC DESCENT         UM1 STANDBY                         REQUEST VMC            UM1 STANDBY                           for use of uplink
                    UM2 REQUEST DEFERRED                DESCENT                UM2 REQUEST DEFERRED                  message elements.
                    UM162 MESSAGE NOT SUPPORTED BY                             UM162 MESSAGE NOT SUPPORTED
                    THIS UNIT                                                  BY THIS UNIT
                    UM169 ‗REQUEST FORWARDED‘                                  UM169 ‗REQUEST FORWARDED‘
                    UM169 ‗REQUEST ALREADY                                     UM169 ‗REQUEST ALREADY
                    RECEIVED‘                                                  RECEIVED‘
                    UM169 ‗FLIGHT PLAN NOT HELD‘                               UM169 ‗FLIGHT PLAN NOT HELD‘
                    UM3 ROGER                                                  UM3 ROGER
                    UM176 MAINTAIN OWN SEPARATION                              UM176 MAINTAIN OWN
                    AND VMC                                                    SEPARATION AND VMC
                    UM159 ERROR [errorInformation] + UM                        UM159 ERROR [errorInformation] + UM
4-197


ATN Message       ATN Response Message                  FANS 1/A          FANS 1/A Response Message             Interoperability
Element                                                 Message Element                                         Requirement
                  169 [freetext]                                          169 [freetext]
                  UM169 ‗REQUEST AGAIN WITH NEXT                          UM169 ‗REQUEST AGAIN WITH NEXT
                  UNIT‘                                                   UNIT‘
DM70 REQUEST      UM0 UNABLE                            DM70              UM0 UNABLE                            See paragraph 4.2.8
HEADING           UM1 STANDBY                           REQUEST           UM1 STANDBY                           for use of uplink
[degrees]         UM2 REQUEST DEFERRED                  HEADING           UM2 REQUEST DEFERRED                  message elements.
                  UM162 MESSAGE NOT SUPPORTED BY        [degrees]         UM162 MESSAGE NOT SUPPORTED
                  THIS UNIT                                               BY THIS UNIT
                  UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
                  UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
                  RECEIVED‘                                               RECEIVED‘
                  UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                  UM94 TURN [direction] HEADING                           UM94 TURN [direction] HEADING
                  [degrees]                                               [degrees]
                  UM97 AT [position] FLY HEADING                          UM97 AT [position] FLY HEADING
                  [degrees]                                               [degrees]
                  UM190 FLY HEADING [degrees]                             UM190 FLY HEADING [degrees]
                  UM159 ERROR [errorInformation] + UM                     UM159 ERROR [errorInformation] + UM
                  169 [freetext]                                          169 [freetext]
                  UM169 ‗REQUEST AGAIN WITH NEXT                          UM169 ‗REQUEST AGAIN WITH NEXT
                  UNIT‘                                                   UNIT‘
DM71 REQUEST      UM0 UNABLE                            DM71 REQUEST      UM0 UNABLE                            See paragraph 4.2.8 for
GROUND            UM1 STANDBY                           GROUND            UM1 STANDBY                           use of uplink message
TRACK [degrees]   UM2 REQUEST DEFERRED                  TRACK [degrees]   UM2 REQUEST DEFERRED                  elements.
                  UM162 MESSAGE NOT SUPPORTED BY                          UM162 MESSAGE NOT SUPPORTED
                  THIS UNIT                                               BY THIS UNIT
                  UM169 ‗REQUEST FORWARDED‘                               UM169 ‗REQUEST FORWARDED‘
                  UM169 ‗REQUEST ALREADY                                  UM169 ‗REQUEST ALREADY
                  RECEIVED‘                                               RECEIVED‘
                  UM169 ‗FLIGHT PLAN NOT HELD‘                            UM169 ‗FLIGHT PLAN NOT HELD‘
                  UM95 TURN [direction] GROUND                            UM95 TURN [direction] GROUND
                  TRACK [degrees]                                         TRACK [degrees]
ATN Message         ATN Response Message                        FANS 1/A            FANS 1/A Response Message                   Interoperability
Element                                                         Message Element                                                 Requirement
                    UM159 ERROR [errorInformation] + UM                             UM159 ERROR [errorInformation] + UM
                    169 [freetext]                                                  169 [freetext]
                    UM169 ‗REQUEST AGAIN WITH NEXT                                  UM169 ‗REQUEST AGAIN WITH NEXT
                    UNIT‘                                                           UNIT‘
DM74 REQUEST         UM0 UNABLE                                 DM74                 UM0 UNABLE                                 See paragraph 4.2.8
TO MAINTAIN          UM1 STANDBY                                MAINTAIN             UM1 STANDBY                                for use of uplink
OWN                  UM2 REQUEST DEFERRED                       OWN                  UM2 REQUEST DEFERRED                       message elements.
SEPARATION AND       UM162 MESSAGE NOT SUPPORTED BY             SEPARATION           UM162 MESSAGE NOT SUPPORTED
VMC                  THIS UNIT                                  AND VMC              BY THIS UNIT
                     UM169 ‗REQUEST FORWARDED‘                                       UM169 ‗REQUEST FORWARDED‘
                     UM169 ‗REQUEST ALREADY                                          UM169 ‗REQUEST ALREADY
                     RECEIVED‘                                                       RECEIVED‘
                     UM169 ‗FLIGHT PLAN NOT HELD‘                                    UM169 ‗FLIGHT PLAN NOT HELD‘
                     UM176 MAINTAIN OWN SEPARATION                                   UM176 MAINTAIN OWN
                     AND VMC                                                         SEPARATION AND VMC
                     UM159 ERROR [errorInformation] + UM                             UM159 ERROR [errorInformation] + UM
                     169 [freetext]                                                  169 [freetext]
                     UM169 ‗REQUEST AGAIN WITH NEXT                                  UM169 ‗REQUEST AGAIN WITH NEXT
                     UNIT‘                                                           UNIT‘
DM80                 UM0 UNABLE                                 DM80                 UM0 UNABLE                                 See paragraph 4.2.8 for
DEVIATING UP UM1 STANDBY                                        DEVIATING            UM1 STANDBY                                use of uplink message
TO [specified        UM3 ROGER                                  [distanceoffset][dir UM3 ROGER                                  elements.
distance][direction] UM82 CLEARED TO DEVIATE UP TO              ection] OF           UM82 CLEARED TO DEVIATE UP TO
OF ROUTE             [specifiedDistance] [direction] OF ROUTE   ROUTE                [specifiedDistance] [direction] OF ROUTE
                     UM159 ERROR [errorInformation] + UM                             UM159 ERROR [errorInformation] + UM
                     169 [freetext]                                                  169 [freetext]
    4.2.13.2       Uplink Message Elements with Y Response Attribute
               Table 4-54 presents the Uplink message elements with Y Response attribute together with the expected responses, and the impact
               on the ATN ground system to support the FANS 1/A message elements.
               Note:     Only message elements with a Y response attribute that are in scope of this document per paragraph 1.2 are listed.


                                           Table 4-54 ATN uplink message elements with Y response attribute

ATN Message            ATN Response           FANS 1/A Message       FANS 1/A Response       Interoperability Requirement
Element                Message                Element                Message
UM131 REPORT           DM128 [remaining       UM131 REPORT           DM57 [remainingfuel]    IR-372  The ATN ground system shall accept a
REMAINING FUEL         fuel enhanced] OF      REMAINING FUEL         OF FUEL                 DM57 downlink message received from the
AND PERSONS ON         FUEL REMAINING         AND PERSONS ON         REMAINING AND           FANS 1/A aircraft after the sending of UM131 as the
BOARD                  AND [persons on        BOARD                  [remainingsouls]        response to the UM131 message element.
                       board] PERSONS ON                             SOULS ON BOARD
                       BOARD
                                                                                             Response Attribute is different:
                                                                                             Y in ATN, UM131
                                                                                             NE in FANS 1/A, UM131.
                                                                                             The downlink message is not received as a response
                                                                                             message (no message reference number) since
                                                                                             UM131 has a NE response attribute in the FANS 1/A
                                                                                             aircraft.
                                                                                             See paragraph 4.2.9 for use of downlink message
                                                                                             elements.
4-200

ATN Message     ATN Response          FANS 1/A Message   FANS 1/A Response     Interoperability Requirement
Element         Message               Element            Message
UM132 REPORT    DM33 PRESENT          UM132 CONFIRM      DM32 PRESENT          IR-373    The ATN ground system shall accept a
POSITION        POSITION [position]   POSITION           POSITION [position]   DM32 downlink message received from the
                                                                               FANS 1/A aircraft after the sending of UM132 as the
                                                                               response to the UM132 message element.
                                                                               Response Attribute is different:
                                                                               Y in ATN, UM132
                                                                               NE in FANS 1/A, UM132.
                                                                               The downlink message is not received as a response
                                                                               message (no message reference number) since
                                                                               UM132 has a NE response attribute in the FANS 1/A
                                                                               aircraft.
                                                                               See paragraph 4.2.9 for use of downlink message
                                                                               elements.
UM133 REPORT    DM32 PRESENT          UM133 CONFIRM      DM32 PRESENT          IR-374    The ATN ground system shall accept a
PRESENT LEVEL   LEVEL [level]         ALTITUDE           ALTITUDE [altitude]   DM32 downlink message received from the
                                                                               FANS 1/A aircraft after the sending of UM133 as the
                                                                               response to the UM133 message element although it
                                                                               does not refer (no MRN) to the uplink (MIN).
                                                                               Response Attribute is different:
                                                                               Y in ATN, UM133
                                                                               NE in FANS 1/A, UM133.
                                                                               The downlink message is not received as a response
                                                                               message (no message reference number) since
                                                                               UM133 has a NE response attribute in the FANS 1/A
                                                                               aircraft.
                                                                               See paragraph 4.2.9 for use of downlink message
                                                                               elements.
                                                                                                                                  4-201

ATN Message           ATN Response       FANS 1/A Message   FANS 1/A Response     Interoperability Requirement
Element               Message            Element            Message
UM134 REPORT          DM113     [speedType] UM134 CONFIRM   DM34 PRESENT          IR-375    The ATN ground system shall accept a
[speed type] [speed   [speedType]           SPEED           SPEED [speed]         DM34 downlink message received from the
type] [speed type]    [speedType]    SPEED                                        FANS 1/A aircraft after the sending of UM134 as the
SPEED                 [speed]                                                     response to the UM134 message element.
                      DM34 PRESENT                                                Response Attribute is different:
                      SPEED [speed]                                               Y in ATN, UM134
                                                                                  NE in FANS 1/A, UM134.
                                                                                  The downlink message is not received as a response
                                                                                  message (no message reference number) since
                                                                                  UM134 has a NE response attribute in the FANS 1/A
                                                                                  aircraft.
                                                                                  See paragraph 4.2.9 for use of downlink message
                                                                                  elements.
UM135 CONFIRM         DM38 ASSIGNED      UM135 CONFIRM      DM38 ASSIGNED         IR-376   The ATN ground system shall accept a
ASSIGNED LEVEL        LEVEL[level]       ASSIGNED           ALTITUDE[altitude]    DM38 downlink message received from the
                                         ALTITUDE                                 FANS 1/A aircraft after the sending of UM133 as the
                                                                                  response to the UM133 message element although it
                                                            Or
                                                                                  does not refer (no MRN) to the uplink (MIN).
                                                                                  Response Attribute is different:
                                                            DM77 ASSIGNED         Y in ATN, UM135
                                                            BLOCK [altitude] TO   NE in FANS 1/A, UM135.
                                                            [altitude]
                                                                                  See paragraph 4.2.9 for use of downlink message
                                                                                  elements.
4-202

ATN Message      ATN Response         FANS 1/A Message   FANS 1/A Response   Interoperability Requirement
Element          Message              Element            Message
UM136 CONFIRM    DM39 ASSIGNED         UM136 CONFIRM      DM39 ASSIGNED      IR-377    The ATN ground system shall accept a
ASSIGNED SPEED   SPEED [speed]         ASSIGNED SPEED      SPEED [speed]     DM39 downlink message received from the
                                                                             FANS 1/A aircraft after the sending of UM139 as the
                                                                             response to the UM139 message element.
                                                                             Response Attribute is different:
                                                                             Y in ATN, UM139
                                                                             NE in FANS 1/A, UM139.
                                                                             The downlink message is not received as a response
                                                                             message (no message reference number) since
                                                                             UM139 has a NE response attribute in the FANS 1/A
                                                                             aircraft.
                                                                             See paragraph 4.2.9 for use of downlink message
                                                                             elements.
UM137 CONFIRM    DM126 REPORTED        UM137 CONFIRM     DM40 ASSIGNED       IR-378    The ATN ground system shall accept a
ASSIGNED ROUTE   WAYPOINT [timesec]    ASSIGNED ROUTE    ROUTE               DM40 downlink message received from the
                                                         [routeclearance]    FANS 1/A aircraft after the sending of UM137 as the
                                                                             response to the UM137 message element.
                                                                             Response Attribute is different:
                                                                             Y in ATN, UM137
                                                                             NE in FANS 1/A, UM137.
                                                                             The downlink message is not received as a response
                                                                             message (no message reference number) since
                                                                             UM137 has a NE response attribute in the FANS 1/A
                                                                             aircraft.
                                                                             See paragraph 4.2.9 for use of downlink message
                                                                             elements.
                                                                                                                           4-203

ATN Message     ATN Response      FANS 1/A Message   FANS 1/A Response     Interoperability Requirement
Element         Message           Element            Message
UM138 CONFIRM   DM45 REPORTED       UM138 CONFIRM    DM46 REPORTED         IR-379    The ATN ground system shall accept a
TIME OVER       WAYPOINT [position] TIME OVER        WAYPOINT [time]       DM46 downlink message received from the
REPORTED                            REPORTED                               FANS 1/A aircraft after the sending of UM138 as the
WAYPOINT                            WAYPOINT                               response to the UM138 message element.
                                                                           Response Attribute is different:
                                                                           Y in ATN, UM138
                                                                           NE in FANS 1/A, UM138.
                                                                           The downlink message is not received as a response
                                                                           message (no message reference number) since
                                                                           UM138 has a NE response attribute in the FANS 1/A
                                                                           aircraft.
                                                                           See paragraph 4.2.9 for use of downlink message
                                                                           elements.
UM139 CONFIRM   DM42 NEXT           UM139 CONFIRM    DM45 REPORTED         IR-380    The ATN ground system shall accept a
REPORTED        WAYPOINT [position] REPORTED         WAYPOINT [position]   DM45 downlink message received from the
WAYPOINT                            WAYPOINT                               FANS 1/A aircraft after the sending of UM139 as the
                                                                           response to the UM139 message element.
                                                                           Response Attribute is different:
                                                                           Y in ATN, UM139
                                                                           NE in FANS 1/A, UM139.
                                                                           The downlink message is not received as a response
                                                                           message (no message reference number) since
                                                                           UM139 has a NE response attribute in the FANS 1/A
                                                                           aircraft.
                                                                           See paragraph 4.2.9 for use of downlink message
                                                                           elements.
4-204

ATN Message     ATN Response      FANS 1/A Message   FANS 1/A Response   Interoperability Requirement
Element         Message           Element            Message
UM140 CONFIRM   DM125 NEXT        UM140 CONFIRM      DM42 ASSIGNED       IR-381    The ATN ground system shall accept a
NEXT WAYPOINT   WAYPOINT ETA      NEXT WAYPOINT      ROUTE               DM42 downlink message received from the
                [timesec]                            [routeclearance]    FANS 1/A aircraft after the sending of UM140 as the
                                                                         response to the UM140 message element.
                                                                         Response Attribute is different:
                                                                         Y in ATN, UM140
                                                                         NE in FANS 1/A, UM140.
                                                                         The downlink message is not received as a response
                                                                         message (no message reference number) since
                                                                         UM140 has a NE response attribute in the FANS 1/A
                                                                         aircraft.
                                                                         See paragraph 4.2.9 for use of downlink message
                                                                         elements.
UM141 CONFIRM   DM44 ENSUING        UM141 CONFIRM    DM43 NEXT           IR-382    The ATN ground system shall accept a
NEXT WAYPOINT   WAYPOINT [position] NEXT WAYPOINT    WAYPOINT ETA        DM43 downlink message received from the
ETA                                 ETA              [time]              FANS 1/A aircraft after the sending of UM141 as the
                                                                         response to the UM141 message element.
                                                                         Response Attribute is different:
                                                                         Y in ATN, UM141
                                                                         NE in FANS 1/A, UM141.
                                                                         The downlink message is not received as a response
                                                                         message (no message reference number) since
                                                                         UM141 has a NE response attribute in the FANS 1/A
                                                                         aircraft.
                                                                         See paragraph 4.2.9 for use of downlink message
                                                                         elements.
                                                                                                                                4-205

ATN Message      ATN Response            FANS 1/A Message   FANS 1/A Response      Interoperability Requirement
Element          Message                 Element            Message
UM142 CONFIRM    DM44 ENSUING             UM142 CONFIRM      DM44 ENSUING       IR-383 The ATN ground system shall accept a
ENSUING          WAYPOINT [position]         ENSUING        WAYPOINT [position] DM44 downlink message received from the
WAYPOINT                                    WAYPOINT                            FANS 1/A aircraft after the sending of UM142 as the
                                                                                response to the UM142 message element.
                                                                                Response Attribute is different:
                                                                                Y in ATN, UM142
                                                                                NE in FANS 1/A, UM142.
                                                                                The downlink message is not received as a response
                                                                                message (no message reference number) since
                                                                                UM142 has a NE response attribute in the FANS 1/A
                                                                                aircraft.
                                                                                See paragraph 4.2.9 for use of downlink message
                                                                                elements.
 UM143 CONFIRM   Last downlink request    UM143 CONFIRM      Multiple responses None.
   REQUEST       sent                       REQUEST              expected       Response Attribute is different:
                                                                                Y in ATN, UM142
                                                                                NE in FANS 1/A, UM142.
                                                                                The downlink message is not received as a response
                                                                                message (no message reference number) since
                                                                                UM142 has a NE response attribute in the FANS 1/A
                                                                                aircraft.
4-206

ATN Message     ATN Response        FANS 1/A Message   FANS 1/A Response   Interoperability Requirement
Element         Message             Element            Message
UM144 CONFIRM   DM47 SQUAWKING      UM144 CONFIRM      DM47 SQUAWKING      IR-384    The ATN ground system shall accept a
SQUAWK          [code]              SQUAWK             [beaconcode]        DM47 downlink message received from the
                                                                           FANS 1/A aircraft after the sending of UM144 as the
                                                                           response to the UM144 message element.
                                                                           Response Attribute is different:
                                                                           Y in ATN, UM144
                                                                           NE in FANS 1/A, UM144.
                                                                           The downlink message is not received as a response
                                                                           message (no message reference number) since
                                                                           UM144 has a NE response attribute in the FANS 1/A
                                                                           aircraft.
                                                                           See paragraph 4.2.9 for use of downlink message
                                                                           elements.
UM145 CONFIRM   DM35 PRESENT        UM145 CONFIRM      DM48 POSITION       IR-385    The ATN ground system shall accept a
HEADING         HEADING [degrees]   HEADING            REPORT              DM48 downlink message received from the
                                                       [positionreport]    FANS 1/A aircraft after the sending of UM145 as the
                                                                           response to the UM145 message element.
                                                                           Response Attribute is different:
                                                                           Y in ATN, UM145
                                                                           NE in FANS 1/A, UM145.
                                                                           The downlink message is not received as a response
                                                                           message (no message reference number) since
                                                                           UM145 has a NE response attribute in the FANS 1/A
                                                                           aircraft.
                                                                           See paragraph 4.2.9 for use of downlink message
                                                                           elements.
                                                                                                                            4-207

ATN Message       ATN Response       FANS 1/A Message   FANS 1/A Response   Interoperability Requirement
Element           Message            Element            Message
UM146 REPORT      DM36 PRESENT       UM146 CONFIRM      DM36 PRESENT        IR-386    The ATN ground system shall accept a
GROUND TRACK      GROUND TRACK       GROUND TRACK       GROUND TRACK        DM36 downlink message received from the
                  [degrees]                             [degrees]           FANS 1/A aircraft after the sending of UM146 as the
                                                                            response to the UM146 message element.
                                                                            Response Attribute is different:
                                                                            Y in ATN, UM146
                                                                            NE in FANS 1/A, UM146.
                                                                            The downlink message is not received as a response
                                                                            message (no message reference number) since
                                                                            UM146 has a NE response attribute in the FANS 1/A
                                                                            aircraft.
                                                                            See paragraph 4.2.9 for use of downlink message
                                                                            elements.
UM147 REQUEST     DM127 POSITION     UM147 REQUEST      DM48 POSITION       IR-387    The ATN ground system shall accept a
POSITION REPORT   REPORT [position   POSITION REPORT    REPORT              DM48 downlink message received from the
                  report enhanced]                      [positionreport]    FANS 1/A aircraft after the sending of UM147 as the
                                                                            response to the UM147 message element.
                                                                            Response Attribute is different:
                                                                            Y in ATN, UM147
                                                                            NE in FANS 1/A, UM147.
                                                                            The downlink message is not received as a response
                                                                            message (no message reference number) since
                                                                            UM147 has a NE response attribute in the FANS 1/A
                                                                            aircraft.
                                                                            See paragraph 4.2.9 for use of downlink message
                                                                            elements.
4-208

ATN Message          ATN Response          FANS 1/A Message     FANS 1/A Response       Interoperability Requirement
Element              Message               Element              Message
UM148 WHEN CAN       DM131 WE CAN          UM148 WHEN CAN       DM67 ‘WE CAN            IR-388    The ATN ground system shall accept a
YOU ACCEPT [level]   ACCEPT [level] AT     YOU ACCEPT           ACCEPT [altitude] AT    DM67 downlink message received from the
                     [timesec]             [altitude]           [time or waypoint]      FANS 1/A aircraft after the sending of UM148 and
                                                                                        containing the given free text as the response to the
                     DM82 WE CANNOT                                                     UM148 message element.
                     ACCEPT [level]                             Or
                                                                                        DM81 and DM82 are not available in the FANS 1/A
                     DM115 WE CAN                                                       aircraft.
                     ACCEPT [level] AT                          DM67 ‗WE CANNOT
                     [position]                                                         The FANS 1/A message element DM67 does not
                                                                ACCEPT [altitude]
                                                                                        refer (no MRN) to the uplink (MIN).
                                                                                        Response Attribute is different:
                                                                                        Y in ATN, UM148
                                                                                        NE in FANS 1/A., UM148
                                                                                        See paragraph 4.2.9 for use of downlink message
                                                                                        elements.
UM181 REPORT         DM130 AT [timesec]    UM181 REPORT         DM78 AT                 IR-389 The ATN ground system shall accept a
DISTANCE [to/from]   [distance] [tofrom]   DISTANCE [to/from]   [time][distance][toFrom DM78 downlink message received from the
[position]           [position]            [position]           ][position]             FANS 1/A aircraft after the sending of UM181 as the
                                                                                        response to the UM181 message element.
                                                                                        Response Attribute is different:
                                                                                        Y in ATN, UM181
                                                                                        NE in FANS 1/A, UM181.
                                                                                        The downlink message is not received as a response
                                                                                        message (no message reference number) since
                                                                                        UM181 has a NE response attribute in the FANS 1/A
                                                                                        aircraft.
                                                                                        See paragraph 4.2.9 for use of downlink message
                                                                                        elements.
                                                                                                                                     4-209

ATN Message         ATN Response          FANS 1/A Message    FANS 1/A Response      Interoperability Requirement
Element             Message               Element             Message
UM182 CONFIRM       DM79 ATIS [atiscode] UM182 CONFIRM        DM79 ATIS [atiscode]   IR-390    The ATN ground system shall accept a
ATIS CODE                                ATIS CODE                                   DM79 downlink message received from the
                                                                                     FANS 1/A aircraft after the sending of UM182 as the
                                                                                     response to the UM182 message element.
                                                                                     Response Attribute is different:
                                                                                     Y in ATN, UM182
                                                                                     NE in FANS 1/A, UM182.
                                                                                     The downlink message is not received as a response
                                                                                     message (no message reference number) since
                                                                                     UM182 has a NE response attribute in the FANS 1/A
                                                                                     aircraft.
                                                                                     See paragraph 4.2.9 for use of downlink message
                                                                                     elements.
UM194 [free text]   No defined response   UM169 [free text]   No defined response    None.
UM204 [free text]   No defined response   UM169 [free text]   No defined response    None.

UM206 [free text]   No defined response   UM169 [free text]   No defined response    None.

UM207 [free text]   No defined response   UM169 [free text]   No defined response    None.
4-210

ATN Message       ATN Response      FANS 1/A Message   FANS 1/A Response   Interoperability Requirement
Element           Message           Element            Message
UM231 STATE       DM106 PREFERRED   UM169 ‗STATE       DM3 ROGER           IR-391   The ATN ground system shall process the
PREFERRED LEVEL   LEVEL [level]     PREFERRED LEVEL‘   DM67 ‗FL[level]‘    FANS 1/A message element DM3 as a positive
                                                                           response to the ATN message element UM231.
                                                                           IR-392 After sending the converted ATN message
                                                                           element UM231, the ATN ground system shall
                                                                           technically close the dialogue upon receipt of a
                                                                           FANS 1/A message element DM3.
                                                                           IR-393 After sending the converted ATN message
                                                                           element UM231, the ATN ground system shall
                                                                           process a FANS 1/A message element DM67
                                                                           containing, FL [level], as the response to the ATN
                                                                           message element UM231.
                                                                           Response Attribute is different:
                                                                           Y in ATN, UM231
                                                                           R in FANS 1/A, UM169
                                                                           The operational response, using data link, is an
                                                                           unreferenced FREE TEXT message. The indication
                                                                           of the operational closure of the dialogue is a local
                                                                           matter.
                                                                           See paragraph 4.2.9 for use and display of downlink
                                                                           message elements.
                                                                                                                               4-211

ATN Message        ATN Response     FANS 1/A Message   FANS 1/A Response   Interoperability Requirement
Element            Message          Element            Message
UM232 STATE-TOP-   DM135 TOP OF     UM169 ‗STATE TOP   DM3 ROGER           IR-394   The ATN ground system shall process the
OF- DESCENT        DESCENT [time]   OF DESCENT‘        DM67 ‗TOD [time]‘   FANS 1/A message element DM3 as a positive
                                                                           response to the ATN message element UM232.
                                                                           IR-395 After sending the converted ATN message
                                                                           element UM232, the ATN ground system shall
                                                                           technically close the dialogue upon receipt of a
                                                                           FANS 1/A message element DM3.
                                                                           IR-396 After sending the converted ATN message
                                                                           element UM232, the ATN ground system shall
                                                                           process a FANS 1/A message element DM67
                                                                           containing, TOD [time], as the response to the ATN
                                                                           message element UM232.
                                                                           Response Attribute is different
                                                                           Y in ATN, UM232
                                                                           R in FANS 1/A, UM169.
                                                                           The operational response, using data link, is an
                                                                           unreferenced FREE TEXT message. The indication
                                                                           of the operational closure of the dialogue is a local
                                                                           matter.
                                                                           See paragraph 4.2.9 for use and display of downlink
                                                                           message elements.
4.2.14         ATN UM with W/U resp and Corresponding FANS 1/A Messages with R resp
               The ATN Uplink message elements in Table 4-55 have the WILCO/UNABLE response
               messages, while the FANS 1/A message elements have the ROGER response. ROGER
               may be substituted for WILCO/UNABLE only for the messages in Table 4-55.
               IR-397  When an ATN message element requires a WILCO/UNABLE response and the
               matching FANS 1/A message element requires a ROGER response, the ATN ground
               system shall convert the FANS 1/A response of ROGER to WILCO.
IR-398 When an ATN message element requires a WILCO/UNABLE response and the matching FANS
1/A message element requires a ROGER response, the airborne crew shall use voice communications to
transmit an UNABLE response.


                Table 4-55 ATN UM with W/U Resp and Corresponding FANS Messages with R
                                                     Resp

                ATN Message Element with W/U          FANS Message Element with R
                Response                              Response
                UM127 REPORT BACK ON ROUTE            UM127 REPORT BACK ON ROUTE
                UM128 REPORT LEAVING [level]          UM128 REPORT LEAVING [altitude]
                UM129 REPORT MAINTAINING [level] UM129 REPORT LEVEL [altitude]
                UM130 REPORT PASSING [position]       UM130 REPORT PASSING [position]
                UM239 STOP ADS-B TRANSMISSION         UM169 ‗STOP ADS-B
                                                      TRANSMISSION‘
                UM240 TRANSMIT ADS-B ALTITUDE         UM169 ‗TRANSMIT ADS-B
                                                      ALTITUDE‘
                UM241 STOP ADS-B ALTITUDE             UM169 ‗STOP ADS-B ALTITUDE
                TRANSMISSION                          TRANSMISSION‘
                UM242 TRANSMIT ADS-B IDENT            UM169 ‗TRANSMIT ADS-B IDENT‘
                UM288 VERIFY MONITORED                UM169 ‗VERIFY MONITORED
                FREQUENCY [frequency]                 FREQUENCY [frequency]‘
4.2.15   Timers
         Table 4-56 presents the ATN and comparable FANS 1/A CPDLC timers and the impact on the ATN ground system.
                                                       Table 4-56 ATN and FANS 1/A CPDLC timers

         ATN CPDLC Timers                               FANS 1/A CPDLC Timers           Interoperability Requirement
         ‗t-start‘ timer is an ASE timer in the DOC     No equivalent.                  IR-399 The ATN ground system shall set a
         9880 and is used for CPDLC connection                                          6-minute timer to detect the absence of a
         establishment to detect the absence of a                                       response after a CPDLC connection request.
         connection confirmation from the aircraft
                                                                                        This is required because the ‗connection
         system in an acceptable period of time.
                                                                                        inactivity‘ timer is set to 16 minutes per the
                                                                                        FANS 1/A INTEROP Standard, paragraph 5.3.1.2.
         ‗tts‘ Termination timer (sender) is used by    No equivalent.                  IR-400   The ATN ground system shall set the
         the ATN ground system to detect the                                            ‗tts‘ timer value per the ATS INTEROP
         absence of an CPDLC response from the                                          Standard, paragraph 4.2.1.5.3.
         aircraft system in an acceptable period of
         time.
         ‗ttr‘ Termination timer (receiver) is used     No equivalent.                  IR-401   The ATN ground system shall set the
         by the ATN ground system to detect the                                         ‗ttr‘ timer value per the ATS INTEROP
         absence of an CPDLC response from the                                          Standard, paragraph 4.2.1.3.3.
         aircraft system in an acceptable period of
         time.
         ‗tr‘ LACK timer is used by the ATN             No equivalent.                  IR-402   When using the ‗tr‘timer, the ATN
         ground system to detect the absence of a                                       ground system shall set ‗tr‘ timer value per
         Logical Acknowledgement (LACK)                                                 the ATS INTEROP Standard, paragraph
                                                                                        4.2.1.2.2.
                                                                                        See paragraph 4.2.5 for use of LACK.
         ‗t-CPDLC-end‘ timer is used by the ATN         No equivalent.                  IR-403   When using the ‗t-CPDLC-end‘
         ground system after generation of an                                           timer, the ATN ground system shall set
         CPDLC-end request to detect the absence                                        ‗t-CPDLC-end‘ timer value per the ATS
         of a CPDLC End Confirmation from the                                           INTEROP Standard, paragraph 4.2.1.6.1.
         aircraft in an acceptable period of time.
5       DYNAMIC FUNCTIONS/OPERATIONS OF DATA LINK SERVICES
        This section provides the interoperability requirements as they relate to the dynamic
        behavior of the following data link services, as defined by the Continental SPR Standard:
        DLIC, ACM, ACL and AMC.
        Note: DCL, D-TAXI and D-OTIS data link services are not provided to FANS 1/A
        aircraft.
        The interoperability requirements are provided in tables, which also describe for each
        element of procedures supporting theof the data link services, the sequence of operations
        from a purely ATN interoperability perspective and a purely FANS 1/A interoperability
        perspective.
        The first column provides the sequence number for the operationassociated
        Interoperability Requirement or Recommendation (DO-305 IR or IRec). The second
        column describes the sequence and includes the interoperability requirements for the
        ATN ground system and ATN aircraft systems, while the third column provides the same
        information for the FANS 1/A ground system and the FANS 1/A aircraft system. The
        fourth column specifies the interoperability requirements and guidance material for the
        ATN ground system providing data link services to the FANS 1/A aircraft.

5.1     DLIC
        This section provides the interoperability requirements for the ATN B1 ground system
        providing the DLIC data link service to the FANS 1/A aircraft. The DLIC service
        encompasses the following functions:
           Logon: data link application initiation and, when required, flight plan association;
           Contact: instructions to perform data link initiation with another specified ground
            system.

5.1.1   Scope and Objective
        DLIC is the name of an air traffic service which uses the CM application to provide the
        necessary information to enable data link communications between ground and air
        systems, for applications such as CPDLC. To achieve unambiguous identification of the
        aircraft executing DLIC, in accordance with this standard, the aircraft provides its
        airframe identification (i.e. the aircraft 24 bit address), aircraft flight identification,
        departure airport, destination airport, and optionally estimated off block time (EOBT), as
        well as information about available air applications.
        Positive response to a CM-logon request does not indicate that the ATSU System will
        request or accept the establishment of a connection.
        The Advanced Services DLIC service encompasses the following functions:
           DLIC LogonDLIC Initiation Function: data link application initiation and, when
            required, flight plan association,
           DLIC Contact Function: instructions to perform data link initiation with another
            specified ATSU System.
           DLIC Update Function: update the aircraft with data link application information.
                                                                                                                     5-215

                  Note: The Update, Dissemination, and Ground forwarding functions are out of scope.

5.1.1.1           DLIC Initiation Function
                  The DLIC initiation function will be provided by all ATSUs that offer data link
                  application services.
                  Table 5-1 presents the sequence of operations for DLIC logon using the ATN CM and
                  FANS 1/A AFN, and specifies the related interoperability requirements for the ATN
                  ground system providing data link services to the FANS 1/A aircraft.


                               Table 5-1      DLIC initiation using ATN CM and FANS 1/A AFN

          Step   ATN CM logon                                  FANS 1/A AFN                 Interoperability
                                                                                            Requirement
          1      Prior to entry into data link airspace, the   The aircrew manually         The FANS 1/A aircraft cannot
                 aircrew must ensure that the CM-logon         triggers the AFN contact,    request information from a
                 is triggered. The CM-logon provides the       providing the ground         facility other than that with
                 ground system with flight identification      system with flight           which AFN is being
                 data, which can be either pre-stored in       identification data, the     performed. This does not
                 the aircraft systems or entered by the        aircraft position, and for   create an issue unless a CM
                 aircrew, i.e.:                                each application             server architecture is in place.
                 facility designation (about which             available, its name and      See paragraph 4.1.4 for use of
                 information is being requested),              version.                     ‗tts‘ timer.
                 CMLongTSAP (including 24-bit aircraft         ATC centre address
                 address),                                     Flight number
                 aircraft flight identification (2-8           Aircraft registration
                 characters), departure airport (4             24-bit aircraft address
                 characters), destination airport (4           (optional)
                 characters), date/time departure ETD /
                                                               Note: Some aircraft may
                 estimated off block time (optional)
                                                               provide the 24-bit
                 Note: These are synonymous, “EOBT”            aircraft address.
                 is used from here on.                         Timestamp
                 Plus the applications data (names)            Aircraft position
                 available, the application addresses, and     Active flag
                 the application versions, and optionally      Application name (for all
                 Class of Communications Service using         supported applications)
                 a CM-logon request.                           Version number (for all
                 When the aircraft has implemented tts         supported applications)
                 for DLIC, tts is set.                         The FANS 1/A aircraft
                                                               set ATST1 (10mn) for
                                                               the AFN Contact
5-216

        Step   ATN CM logon                                  FANS 1/A AFN                Interoperability
                                                                                         Requirement
        2      The ground system shall retain the            Functionally equivalent.    None.
               applications data for use at the
               appropriate time. The ground system
               shall delete and replace all previously
               held applications data relating to this
               aircraft.
               Note: Within a domain of continuous
               data link airspace, the application data
               may be forwarded by ground co-
               ordination to subsequent ATSUs for use
               at a later stage of flight. The
               management of, and means to achieve
               this, are outside the scope of this
               standard.
        3      The ground system shall notify the            The ground system           The conditions of the success
               aircraft of the success or failure of the     notifies the airborne       or failure of the logon process
               Logon process, using a CM-logon               system of the success or    is a local matter. The ATN
               response. The ground system may               failure of the contact      ground system has to
               optionally provide applications data for      process, using an AFN       determine if data provided in
               the applications it is able/willing to        acknowledgement             FANS 1/A AFN contact are
               support:                                      (FN_AK).                    sufficient to perform the
               Application name(s)                           When the AFN                logon process.
               Application Address(es)                       acknowledgement is          See paragraph 4.1.4 for use of
                                                             received prior to the       ‗tts‘ timer.
               Application version number(s)
                                                             expiry of ATST1,
               When the aircraft has implemented tts         ATST1 is cancelled
               for DLIC and the CM-logon response is
                                                             Note: Only the result of
               received prior to the expiry of tts, tts is
                                                             the AFN Contact (reason
               cancelled.
                                                             code) is relevant for the
               When CM-logon is successful, the              FANS 1/A aircraft.
               aircraft shall retain applications data for
               use at the appropriate time.
                                                                                                               5-217

5.1.2           DLIC Contact Function
                Table 5-2 presents the DLIC CM Contact sequence of operations using ATN CM and
                FANS 1/A AFN, and specifies the related interoperability requirements for the ATN
                ground system providing data link services to the FANS 1/A aircraft.


                             Table 5-2     DLIC contact using ATN CM and FANS 1/A AFN

        Step   ATN CM                             FANS 1/A AFN                 Interoperability Requirement
        4      When required, prior to step 1a    The ground system            The FANS 1/A INTEROP Standard does
               of the transfer of                 requests the airborne        not require an order.
               communications (transmission       system to contact the        When a CM Contact request is issued
               of the NDA) the ground system      specified ground system      and a timer is used, the ATN ground
               shall request the aircraft to      (B) FANS- address, using     system sets the timer to detect the
               contact the R-ATSU, using a        an AFN Contact Advisory      absence of an expected response.
               CM-contact request.                (FN_CAD).
                                                                               When CM-contact request is not
               Note: Depending on bi-lateral      FANS 1/A ground system       used,the ATN ground system exchanges
               agreements, and the                sets ATST2 (5mn) to          aircraft application and address
               availability of ground-ground      detect the absence of the    information (ATN or FANS logon info)
               communications, the CM-            AFN Response and             via ground-ground messages.
               contact and transmission of the    ATST3 (15mn) to detect
                                                                               See paragraph 4.1.4 for use of ‗tts‘ timer.
               NDA may have to be done at a       the absence of the AFN
               particular time and in a           Complete in response to an
               particular order, to allow         AFN Contact Advisory.
               efficient handovers. (Reversing
               the order presented above.)
               When the ground system has
               implemented tts for DLIC, tts is
               set.
        5      On receipt of the CM-contact       Functionally equivalent.     None.
               indication information, the
               aircraft will automatically
               begin the CM logon process at
               step 1 above with the R-ATSU
               (as per Doc 9705).
5-218

        Step   ATN CM                             FANS 1/A AFN                   Interoperability Requirement
        6      The aircraft will advise the       The aircraft will advise the   IR-404    When using the ‗tts‘ timer,
               initiating ATSU of the success     initiating ATSU of the         the ATN ground system shall cancel
               or failure of the requested        success or failure of the      the ‗tts‘ timer upon the reception of
               contact, using a CM-contact        requested contact, in two      negative AFN Response or AFN
               response (as per Doc 9705).        steps:
                                                                                 Complete.
               When the ground system has         Step 1: Upon receipt of the
                                                                                 The ATN ground system may ignore the
               implemented tts for DLIC and       AFN-Contact-Advisory
                                                                                 reception of positive AFN Response
               the CM-contact response is         (FN_ CAD), the aircraft
                                                                                 regardless of the reception prior or after
               received priory to the expiry of   automatically responds
                                                                                 the AFN Complete.
               tts, tts is cancelled.             with a downlink AFN
               Note 1: The use of this            Response (FN_RESP)
               information is a matter of local   indicating intent to
               procedures.                        perform the AFN Logon
                                                  and automatically goes
               Note 2: The aircraft will send a
                                                  through the same process
               positive CM-contact response
                                                  as an initial DLIC Logon
               only if the protocol of the CM
                                                  with the R-ATSU.
               Logon with the R-ATSU is
               completed, regardless of the       Step 2: Once the AFN
               contents of the R-ATSU CM-         Logon is performed with
               logon response. If there is no     the R_ATSU the aircraft
               CM-logon response from the R-      advise the initiating ATSU
               ATSU then the aircraft             of the result by sending the
               indicates that the requested       downlink AFN Complete
               contact was unsuccessful.          (FN_COMP) message. The
                                                  FN_COMP contains the
                                                  next Centre address data
                                                  which is not use by the
                                                  FANS 1/A system.
                                                  FANS 1/A ground system
                                                  cancels ATST2 upon
                                                  reception of the AFN
                                                  Response in due time and
                                                  ATST3 upon reception of
                                                  the AFN Complete in due
                                                  time.
                                                                                             5-219

Step   ATN CM                          FANS 1/A AFN               Interoperability Requirement
7      Period of validity:             Functionally equivalent.   None.
       There are no protocol
       exchanges to note the ending of
       the validity of logon
       information; however, it is
       important that neither aircraft
       nor ATSUs retain obsolete
       application information about
       communications partners after
       the completion of
       communications.
       For the aircraft, information
       should be deleted no later than
       the end of a flight.
       Note 1: The aircraft may need
       to retain logon information for
       a number of Centres.
       Note 2: The means of deleting
       obsolete information for the
       ATN ground system, and the
       timing of such deletion, is
       outside the scope of this
       standard.
5-220

5.2                 CPDLC
                    This section provides the interoperability requirements for the ATN ground system to
                    provide the ACM, ACL, and AMC data link services to the FANS 1/A aircraft.


5.2.1               Timers in CPDLC-based services


        5.2.1.1           tr Timers
                                                           Table 5-3   tr Timers

           ATN CPDLC                                       FANS 1/A CPDLC            Interoperability Requirement
           CPDLC-IRec 7 When tr is implemented,            No equivalent.            None.
           the value for the airborne timer tr should be   Note: tr is not
           for the ACM, ACL, AMC, D-TAXI and               implemented in FANS 1/A
           DCL services 40 seconds.                        aircraft, CPDLC-IRec 7
                                                           does not apply.
           CPDLC-IRec 8 When tr is implemented,            Same.                     None.
           the value for the ground timer tr should be
           for the ACM, ACL, AMC, D-TAXI and
           DCL services 40 seconds.
           CPC-IR 159 If the air timer tr is       No equivalent.                    None.
           implemented, when a downlink message is Note: tr is not
           sent and requires a LACK, the aircraft  implemented in FANS 1/A
           system shall set tr.                    aircraft, CPDLC-IR 103
           Note: This is not applicable when the does not apply.
           downlink message is sent on an accepted
           CPDLC-end response (e.g. WILCO
           response sent on an accepted CPDLC-end
           response in ACM).

           CPC-IR 160 If the air timer tr is               No equivalent.            None.
           implemented, when a LACK for the                Note: tr is not
           downlink message is received before the         implemented in FANS 1/A
           expiration of tr, the aircraft system shall     aircraft, CPDLC-IR 104
           cancel tr.                                      does not apply.
           CPC-IR 161 If the ground timer tr is            Same.                     None.
           implemented, and the uplink message
           requires a LACK, the ATSU system shall
           set tr.
           CPC-IR 162 If the ground timer tr is            Not equivalent.           None.
           implemented, when a LACK for the uplink         Note: LACK is not
           message is received before the expiration of    implemented in FANS 1/A
           tr, the ATSU system shall cancel tr.            aircraft.
                                                                                                              5-221

   ATN CPDLC                                        FANS 1/A CPDLC                 Interoperability Requirement
   CPC-IR 163 When tr is implemented,               Not equivalent.                None.
   expiry of tr shall result in a notification to   Note 1: LACK is not
   the sender of the message requiring a            implemented in FANS 1/A
   LACK.                                            aircraft.
   Note: When tr is implemented, and when a         Note 2: When tr is
   LACK is received after expiry of tr, the         implemented, and when a
   LACK may be discarded.                           MA is received after
                                                    expiry of tr, the indication
                                                    may be ignored.



5.2.1.2           ttr Timers
                                                    Table 5-4     ttr Timers
   ATN CPDLC                                                    FANS 1/A CPDLC             Interoperability
                                                                                           Requirement

   CPC-IR 164 The ground termination CPDLC timer ttr Same.                                 None.
   shall be implemented.
   Note: Operational values to be used for the ground
   CPDLC timer ttr are provided for each CPDLC data
   link service in the SPR.

   CPC-IR 165 When a downlink message that does not             Same.                      None.
   have an N response attribute is received, the ATSU
   system shall set the ground CPDLC timer ttr..

   CPC-IR 166 When an uplink STANDBY message is                 Same.                      None.
   sent in response to a downlink message before the
   expiration of the ground CPDLC timer ttr, the ATSU
   system shall cancel the ground CPDLC timer ttr.

   CPC-IR 167 When an uplink message is sent as a               Same.                      None.
   closure response to a downlink message before the
   expiration of the ground CPDLC timer ttr, the ATSU
   system shall cancel the ground CPDLC timer ttr.

   Upon expiry of the ground CPDLC timer ttr,                   Same.                      See Table 4-15 ATN
                                                                                           and FANS 1/A CPDLC
                                                                                           uplink message
                                                                                           elements for use of
                                                                                           UM0, UM159 and
                                                                                           UM183.

   CPC-IR 113 When a received uplink message                  No equivalent.               None.
   requires a response, the aircraft system shall set the air Note: ttr is not
   CPDLC timer ttr.                                           implemented in FANS
                                                              1/A aircraft, CPDLC-IR
                                                              113 does not apply.
5-222

        ATN CPDLC                                                  FANS 1/A CPDLC           Interoperability
                                                                                            Requirement

        CPC-IR 114 When a downlink STANDBY message                 No equivalent.           None.
        is sent in response to an uplink message before the        Note: ttr is not
        expiration of the air CPDLC timer ttr, the aircraft        implemented in FANS
        shall reset the air CPDLC timer ttr.                       1/A aircraft, CPDLC-IR
                                                                   114 does not apply.

        CPC-IR 115 When the downlink message is a closure          No equivalent.           None.
        response sent in response to an uplink message before      Note: ttr is not
        the expiration of the air CPDLC timer ttr, the aircraft    implemented in FANS
        shall cancel the air CPDLC timer ttr.                      1/A aircraft, CPDLC-IR
                                                                   115 does not apply.

        CPC-IR 116 Upon expiry of the air CPDLC timer ttr,         No equivalent.           None.
        the aircraft system shall automatically send a CPDLC       Note: ttr is not
        downlink error message containing the concatenation        implemented in FANS
        of message element DM62 (ERROR (error                      1/A aircraft, CPDLC-IR
        information)) with the choice (2) followed by              116 does not apply.
        message element DM98 (AIRCRAFT SYSTEM
        TIMEOUT) closing the dialogue.
        Note. The flight crew is notified of the timer
        expiration (as per OSD).

        CPC-IR 117 Upon expiry of the ground CPDLC timer Functionally equivalent.           See Table 4-15 ATN
        ttr, the ATSU System shall either automatically send:                               and FANS 1/A CPDLC
                                                                                            uplink message
             a CPDLC uplink message containing the                                         elements for use of
        concatenation of message elementUM159 (ERROR                                        UM0, UM159 and
        (error information)) with the choice (2) followed by                                UM183.
        message element UM183 (ATC TIMEOUT -
        REPEAT REQUEST) closing the dialogue, or
             a CPDLC uplink message containing the
        concatenation of message element UM0 UNABLE
        followed by message element UM183 (ATC
        TIMEOUT - REPEAT REQUEST) closing the
        dialogue.
        Note. The controller is notified of the timer expiration
        (as per OSD).
                                                                                                            5-223

5.2.1.3             tts Timers
                                                     Table 5-5      tts Timers

          ATN CPDLC                                              FANS 1/A CPDLC                 Interoperability
                                                                                                Requirement

          CPC-IR 168 The ground CPDLC timer tts shall            Same.                          None.
          be implemented.
          Note: Operational values to be used for the
          ground CPDLC timer tts are provided for each
          CPDLC data link service in the ISPR [ref. n].

          CPC-IR 169 The value for the ground CPDLC
          timer tts shall be one of the four values assigned
          to TRN in in the Performance Requirements
          section of the ISPR [ref. n].

          CPC-IR 170 When a downlink message is sent             No equivalent.                 None.
          and does not have a N response attribute, and the      Note: tts is not implemented
          aircraft has implemented tts, the aircraft shall set   in FANS 1/A aircraft,
          the air CPDLC timer tts..                              CPDLC-IR 119 does not
                                                                 apply.

          CPC-IR-171 When an uplink STANDBY                      No equivalent.                 None.
          message is received in response to a downlink          Note: tts is not implemented
          message before the expiration of the air CPDLC         in FANS 1/A aircraft,
          timer tts, and the aircraft has implemented tts, the   CPDLC-IR 120 does not
          aircraft shall cancel the air CPDLC timer tts.         apply.

          CPC-IR-172 When an uplink message is a                 Same.                          None.
          closure response received in response to a
          downlink message before the expiration of
          the air CPDLC timer tts, and the aircraft has
          implemented tts, the aircraft shall cancel the
          air CPDLC timer tts

          CPC-IR 173 When an uplink message is sent and          Same.                          None.
          requires an operational response, the ATSU
          system shall set the ground CPDLC timer tts.

          CPC-IR 174 When a downlink message is             Same.                               None.
          received in response to an uplink message before
          the expiration of the ground CPDLC timer tts, the
          ATSU system shall reset the ground CPDLC
          timer tts.
5-224

                  ATN CPDLC                                              FANS 1/A CPDLC          Interoperability
                                                                                                 Requirement

                  CPC-IR 175 When a downlink message is a       Same.                            None.
                  closure response received in response to an
                  uplink message before the expiration of the
                  ground CPDLC timer tts, the ATSU System shall
                  cancel the ground CPDLC timer tts.
                  Note 1. The controller or the flight crew is
                  notified of the timer expiration (as per OSD).
                  Note 2. Upon the expiry of tts, the sending
                  system operator (flight crew or Controller) will
                  revert to alternate procedures (e.g., voice) to
                  complete the dialogue. Although operationally
                  the dialogue is closed at this point, technically
                  the dialogue remains open, until a response is
                  received, or the connection is terminated. (i.e. the
                  message identification number remains in use.)



        5.2.1.4             t-CPDLC-end Timer


                                                     Table 5-6       t-CPDLC-end Timer

           ATN CPDLC                                               FANS 1/A          Interoperability Requirement
                                                                   CPDLC

           CPDLC-IRec 8 When t-CPDLC-end is                        No equivalent.    None.
           implemented, the value for t-CPDLC-end should                             See Table 4-56 ATN and
           be 6 minutes.                                                             FANS 1/A CPDLC timers.

           CPC-IR 176 When t-CPDLC-end is                          No equivalent.    None.
           implemented, and when the ATSU System does
           not receive a CPDLC-end confirmation prior to
           expiration of the CPDLC-end timer (t-CPDLC-
           end), the ATSU System shall abort the CPDLC
           connection with a CPDLC-user abort
           (undefined).



5.2.2                 ATC Communication Management (ACM) Service
                      The ACM Service provides automated assistance to the aircrew and current and next
                      controllers for conducting this transfer of ATC communications. The ACM Service
                      encompasses the transfer of all controller/aircrew communications, both the voice
                      channel and the new data communications channel used to accomplish the ACM Service.
                      The ACM service supports the following operating conditions:
                      Inter-ATSU (with simultaneous transfer of data and frequency)
                                                                                                  5-225

               transfer from T-ATSU to R-ATSU both CPDLC-equipped with simultaneous
                transfer of data and frequency communications (by data link or voice)
               transfer from a CPDLC-equipped T-ATSU to a not CPDLC-equipped R-ATSU with
                simultaneous transfer of data and frequency communications (by data link or voice)
           Inter-ATSU (with independent transfer of data and frequency)
               transfer from a not CPDLC-equipped T-ATSU to a CPDLC-equipped R-ATSU
               transfer from T-ATSU to R-ATSU both CPDLC-equipped with independent transfer
                of data and frequency communications (by data link or voice)
               transfer from a CPDLC-equipped T-ATSU to a not CPDLC-equipped R-ATSU with
                independent transfer of data and frequency communications (by data link or voice)
           Intra-ATSU(only transfer of frequency)
               Transfer with no change                  of   CPDLC     connection    (T-sector      and
                R-sector both using CPDLC)
           Termination
               C-ATSU ends CPDLC connection
           ACM supporting CPDLC exchanges
               flight crew requests change of frequency
               Deferred instruction to change frequency




5.2.2.1          ACM Service General Requirements


                                     Table 5-7 ACM General Requirements

   ATN CPDLC                                    FANS 1/A CPDLC        Interoperability Requirement
   ACM-IR 1 An aircraft supporting ACM           Same.                None.
   shall be able to interact correctly with ATSU
   Systems concatenating (or not) operational
   instructions with the transfer instruction.

   ACM-IRec 1 ATSU Systems should only           Same.                None.
   request CPDLC connections when an
   aircraft is within the agreed amount of time
   (subject to bilateral or regional agreements)
   of boundary crossing
5-226

    5.2.2.2          Requirements on UM160 NEXT DATA AUTHORITY


                           Table 5-8 Requirements on UM160 NEXT DATA AUTHORITY

        ATN CPDLC                                    FANS 1/A CPDLC          Interoperability Requirement
        ACM-IR 2 For operating conditions where      The choice              IR-405 When the NDA has been sent, the
                                                                             next centre changes and the T-ATSU is
        the T-ATSU System has already sent an        (noFacility) is not
                                                                             aware that the R-ATSU is not providing data
        NDA and the next center changes, the T-      available in FANS 1/A   link services to FANS 1/A aircraft, the
        ATSU System shall automatically:             INTEROP Standard.       ATN B1 ground system shall resend UM160
                                                                             (NDA) with the facility designator of the
        unless the T-ATSU is aware that the new R-                           new R-ATSU.
        ATSU is not data link equipped or is not
        using data link, resend UM160 NEXT
        DATA AUTHORITY to the aircraft
        containing the facility designation of the
        new R-ATSU or
        when T-ATSU is aware that the new R-
        ATSU is not data link equipped or is not
        using data link, resend UM160 NEXT
        DATA AUTHORITY to the aircraft with the
        choice (noFacility) to cancel the NDA
        indication.
        ACM-IR 3 For transfers for which an NDA Same.                        None.
        has been sent, before sending the VCI, the
        ATSU System shall:
        ensure that the facility designation for NDA
        and VCI are consistent and
        in case of inconsistency, send a new NDA,
        containing the facility designation consistent
        with that of the VCI, following the
        requirements given in 4.3.6.1.
        Note: The determination of the relationship
        of the VCI and NDA facility designator is a
        local decision
        ACM-IR 4 For transfers for which a NDA is Same.                      None.
        required but has not yet been sent, the
        ATSU System shall send UM160 NEXT
        DATA AUTHORITY, containing the
        facility designation consistent with that of
        the VCI, before sending the VCI.
                                                                                                         5-227

        ATN CPDLC                                       FANS 1/A CPDLC         Interoperability Requirement
        ACM-IR 5 The T-ATSU system shall be             No equivalent.          None.
        prohibited from sending UM160 NEXT              Note: ACM-IR 5 does
        DATA AUTHORITY until after receipt of           not apply to FANS 1/A
        DM99 CDA.                                       aircraft since there is
        Note 1: In some cases the trigger to send the   no DM99.
        NDA message is initiated prior receipt of
        DM99.
        Note 2: The precise timing of this
        transmission and the means by which the
        message is triggered is outside the scope of
        this document.



     5.2.2.3          Open dialogues Management
5.2.2.3.1        Transfer of Data Communications with Open Dialogues (with change of the CPLDC
                 connection)


                 Table 5-9     Transfer of Data Communications with Open Dialogues (with change of
                                                    the CPLDC connection)

        ATN CPDLC                                       FANS 1/A CPDLC         Interoperability Requirement
        ACM-IR 9 When a CPDLC-end request               Functionally           None.
        (including or not a VCI) is generated but not   equivalent.
        yet sent, and there are open ground initiated
        dialogues the Controller shall :
        be informed of the open ground initiated
        dialogues, and
        before continuing with the transfer
        instructions:
        waits for the responses to the open ground
        initiated dialogues, or
        resolves the open ground initiated dialogues
        (via voice instructions).
        Note. Local procedures govern the display
        characteristics of canceled open ground
        initiated dialogues for the pilot and
        Controller.
5-228

        ATN CPDLC                                        FANS 1/A CPDLC       Interoperability Requirement
        ACM-IR 10 When a CPDLC-end request               Functionally         IR-406       When UM161 END SERVICE
                                                                              is generated there are open air initiated
        (including or not a VCI) is generated there      equivalent.
                                                                              dialogues, the ATSU System shall close
        are open air initiated dialogues, the ATSU                            each of these dialogues with a closure
        System shall close each of these dialogues                            response before sending the transfer
        with a closure response before sending the                            instruction (VCI) sending UM161.
        CPDLC-end request.                                                    Note.: Closure uplink responses
        Note. Closure uplink responses are any                                are any response (except message
        response (except message elements                                     elements STANDBY and LACK),
        STANDBY and LACK), and are expected to                                and are expected to be CPDLC
        be CPDLC messages containing one of the                               messages containing one of the
        following:                                                            following:
        the message element UNABLE (UM0), or                                  the message element UNABLE
                                                                              (UM0), or the message element
        the message element REQUEST AGAIN
                                                                              REQUEST AGAIN WITH NEXT
        WITH NEXT UNIT (UM237).
                                                                              UNIT (UM237).



        ACM-IR 11 When there are open ground             No equivalent.       None.
        initiated dialogues, and the pilot responds to   Note: Requirements
        the transfer instruction with a WILCO, the       not placed on FANS
        aircraft system shall cancel all open ground     1/A aircraft.
        initiated dialogues.
        ACM-IR 12 When there are open ground             No equivalent.       None.
        initiated dialogues, and the pilot responds to   Note: Requirements
        the transfer instruction with an UNABLE or       not placed on FANS
        STANDBY, the aircraft system shall leave         1/A aircraft.
        the open dialogues unchanged.
        ACM-IR 13 When there are open air initiated      No equivalent.       None.
        dialogues, and the pilot responds to the         Note: Requirements
        transfer instruction with a WILCO, the           not placed on FANS
        aircraft system shall cancel all open air        1/A aircraft.
        initiated dialogues.
        ACM-IR 14 When there are open air initiated      No equivalent.       None.
        dialogues, and the pilot responds to the         Note: Requirements
        transfer instruction with an UNABLE or           not placed on FANS
        STANDBY, the aircraft system shall leave         1/A aircraft.
        the open dialogues unchanged.
                                                                                                           5-229

5.2.2.3.2        Transfer of Data Communications with Open Dialogues (with change of the CPLDC
                 connection)


                  Table 5-10 Transfer of Data Communications with Open Dialogues (with change of
                                                  the CPLDC connection)

        ATN CPDLC                                        FANS 1/A CPDLC      Interoperability Requirement
        ACM-IR 15 When the T-sector and the R- Same.                         None.
        sector are the same, the transmission of the
        transfer instruction shall maintain open
        ground initiated dialogues.
        ACM-IR 16 When the T-sector and the R- Same.                         None.
        sector are the same, the transmission of the
        transfer instruction shall maintain open air
        initiated dialogues.



     5.2.2.4           Management of the Data link Voice Contact Instruction (VCI)
5.2.2.4.1        Sending the VCI
                                                       Table 5-11 Sending the VCI

        ATN CPDLC                                        FANS 1/A CPDLC     Interoperability Requirement
        ACM-IR 17 When the T-ATSU/T-sector               Functionally       See Table 4-15 ATN and FANS 1/A
        Controller triggers the transfer instruction     equivalent.        CPDLC uplink message elements for
        to contact or monitor the R-ATSU/R-                                 use of VCI.
        sector on the R-ATSU/R-sector voice
        channel without requesting to close the
        CPDLC connection, the T-ATSU ground
        system shall send the VCI message
        optionally concatenated with other
        message elements using the CPDLC-
        message request.
        Note: The VCI can be concatenated with
        other message elements
5-230

        ATN CPDLC                                   FANS 1/A CPDLC           Interoperability Requirement
        ACM-IR18 When the T-ATSU/T-sector                                    IR-407 When the T-ATSU controller initiates
                                                     Functionally            the transfer instruction (UM117 to UM122), the
        Controller triggers the transfer instruction equivalent.
                                                                             T-ATSU‘s ground system shall concatenate
        to contact or monitor the R-ATSU/R-                                  UM161 END SERVICE with contact or monitor
        sector on the R-ATSU/R-sector voice                                  (UM117 to UM120).
        channel requesting to close the CPDLC                                IR-408 When the T-ATSU controller
        connection, the T-ATSU ground system                                 concatenates an uplink message (e.g. instruction
        shall send the VCI message optionally                                UM135 CONFIRM ASSIGNED LEVEL) with
                                                                             the transfer instruction, the T-ATSU‘s ground
        concatenated with other message elements                             system shall concatenate UM161 END SERVICE
        using the CPDLC-end request.                                         with Contact or Monitor and (UM117 to UM120)
                                                                             and the uplink message."
        Note 1: The VCI can be concatenated with
        other message elements.                                              See Table 4-8 for additional
        Note 2: Sending the transfer instruction in                          requirement on CPDLC-end service.
        a CPDLC-end request will prevent a
        LACK to the WILCO of the transfer
        instruction as per ICAO Document 9880 –
        Chapter 5 Protocol Description
        ACM-IR 19 Once the T-ATSU initiates         Same.                    None.
        the transfer instruction (VCI), it shall
        prohibit transmission of any other CPDLC
        messages unless and until:
        receipt of an ERROR response, or
        receipt of an UNABLE response.

5.2.2.4.2       Acknowledging the VCI
                                             Table 5-12 Acknowledging the VCI

        ATN CPDLC                                   FANS 1/A CPDLC                 Interoperability Requirement

        ACM-IR 20 When the flight crew              No equivalent.                 None.
        acknowledges the VCI with a STANDBY,        Note: Requirements not
        the aircraft system shall send a DM2        placed on FANS 1/A
        STANDBY not requiring a LACK using a        aircraft.
        CPDLC-message request.
        Note: As per ICAO Document 9880, it is
        not possible for ATSU Systems to send a
        LACK in response to STANDBY after
        CPDLC-end request.
                                                                                             5-231

ATN CPDLC                                    FANS 1/A CPDLC           Interoperability Requirement

ACM-IR 21 When the flight crew         No equivalent.                 None.
acknowledges the VCI with a WILCO, the Note: Requirements not
aircraft system shall:                 placed on FANS 1/A
     send a DM0 WILCO response,       aircraft.

    confirm the CPDLC termination, if
requested
Note . The WILCO can be concatenated
with another message element (e.g
DM38).

ACM-IR 22 When the flight crew               No equivalent.           None.
acknowledges via VCI with a                  Note: Requirements not
UNABLE/ERROR, the aircraft system            placed on FANS 1/A
shall:                                       aircraft.
    send an UNABLE/ERROR
response,
    reject the CPDLC termination, if
requested.
Note: This results in continued capability
to exchange operational messages with
the T-ATSU.

ACM-IR 23 When the VCI message is            No equivalent.           None.
received and a flight crew                   Note: Requirements not
acknowledgement to the VCI is sent, it       placed on FANS 1/A
shall be sent using:                         aircraft.
    A CPDLC-message request when
the VCI has been received in a CPDLC-
message indication and the
acknowledgement to the VCI is a DM0
WILCO or UNABLE/ERROR,
    An accepted CPDLC-end response
when the VCI has been received in a
CPDLC-end indication and the
acknowledgement to the VCI is a DM0
WILCO,
Note: in the case of an accepted CPDLC-
end response, the link is terminated.
A rejected CPDLC-end response when the
VCI has been received in a CPDLC-end
indication and the acknowledgement to
the VCI is a UNABLE/ERROR,
5-232



     5.2.2.5          Management of the Current Data Authority (CDA)
5.2.2.5.1       Sending the CDA
                                                Table 5-13 Sending the CDA

        ATN CPDLC                                    FANS 1/A CPDLC         Interoperability Requirement
        ACM-IR 24 To notify the R-ATSU that it       No equivalent.         None.
        becomes the CDA, the aircraft system         Note1: DM99 is not
        shall send a DM99 CURRENT DATA               available in FANS
        AUTHORITY requesting a LACK for this         1/A aircraft.
        downlink.
                                                     Note 2: The airborne
        Note 1: The aircraft system considers the    system automatically
        R-ATSU as the CDA after sending the          enables CPDLC with
        WILCO to the T-ATSU, i.e., before            the R-ATSU.
        sending DM99.
                                                     Note 3: Requirements
        Note 2: When DM99 is not available in        not placed on FANS
        the message set, another message (e.g.       1/A aircraft.
        DM48 POSITION REPORT) can be used
        instead.
        ACM-IR 25 The aircrew shall be             No equivalent.           None.
        prohibited from sending message to the R-
        ATSU until the CDA is sent.
        Note: The aircraft system can be more
        restrictive and waits for the reception of
        the CURRENT ATC UNIT message
        before allowing any downlink..


5.2.2.5.2       Notifying CPDLC is NOT USED
                                           Table 5-14 Notifying CPDLC is OFF
        ATN CPDLC                                     FANS 1/A CPDLC        Interoperability Requirement
        ACM-IR 26 Upon receipt of DM99                No equivalent.        IR-409      When CPDLC is OFF, the R-ATSU
                                                                            System shall send using CPDLC-message
        CURRENT DATA AUTHORITY and
                                                                            request the UM287 CPDLC NOT IN USE.
        CPDLC is not used by the receiving sector,
        the R-ATSU System shall send using                                  See Table 4-15 ATN and
        CPDLC-message request the UM287                                     FANS 1/A CPDLC uplink message
        CPDLC NOT IN USE requiring a LACK                                   elements for use of UM287
        for this message.
        ACM-IR 27 Whenever the status of the use      No Equivalent.        None.
        of CPDLC changes, the R-ATSU System
        shall send using CPDLC-message request
        either UM287 CPDLC NOT IN USE or
        UM286 CPDLC NOW IN USE
                                                                                                            5-233

5.2.2.5.3        Notifying LACK is prohibited
Note. LACKs are not available in FANS 1/A aircraft.
                                           Table 5-15 Notifying LACK is prohibited
        ATN CPDLC                                      FANS 1/A CPDLC        Interoperability Requirement

        ACM-IR 28 Upon receipt of DM99                 No equivalent.        See Table 4-15 ATN and
        CURRENT DATA AUTHORITY and                      Note: UM233 is not   FANS 1/A CPDLC uplink message
        LACKs are not supported, the R-ATSU            available in FANS     elements for use of UM233.
        System shall send UM233 USE OF LACK            1/A aircraft.         None.
        PROHIBITED to the aircraft requiring a         Note: Requirements
        LACK for this message.                         not placed on FANS
        Note: Some R-ATSUs consider CPDLC              1/A aircraft.
        available at this step and may indicate this
        to the Controller.

        ACM-IR 29 Until the R-ATSU System              No equivalent.        None.
        receives a LACK to UM233, it shall not         Note: Requirements
        reject any downlink message because it         not placed on FANS
        requires a LACK.                               1/A aircraft.



        ACM-IR 30 After the R-ATSU System         No equivalent.             None.
        receives a LACK to UM233, it shall reject Note: Requirements
        any downlink messages requiring a LACK. not placed on FANS
                                                  1/A aircraft.
5-234

    5.2.2.6          Enabling CPDLC


                                               Table 5-16 Enabling CPDLC

        ATN CPDLC                                   FANS 1/A CPDLC           Interoperability
                                                                             Requirement

        ACM-IR 31 Until transmission of DM99,       No equivalent.           None.
        the aircraft system shall prohibit the      Note: Requirements
        exchange of other operational messages      not placed on FANS
        with the R-ATSU.                            1/A aircraft.

        ACM-IR 32 When there is a CPDLC                                      IR-410      In addition to other local
                                                    Functionally             conditions, the R-ATSU/initial ATSU
        connection change, the R-ATSU shall         equivalent.              shall enable CPDLC using ―Connect
        enable CPDLC only upon receipt of DM99                               Confirm‖ IMI CC1.
        CURRENT DATA AUTHORITY and
                                                    Other local conditions
        satisfaction of required local conditions
                                                    for enabling CPDLC
        (e.g., ASSUME input, boundary proximity,
                                                    include, for example,
        etc.)
                                                    ASSUME input,
                                                    boundary proximity,
                                                    etc.

                                                    DM89, DM99 cannot
                                                    be used as a condition
                                                    for CPDLC enabled.

        ACM-IR 33 When there is no CPDLC            Same.                    None.
        connection change, the R-sector shall
        enable CPDLC enabled only upon
        satisfaction of required local conditions
        (e.g., ASSUME input, boundary proximity,
        etc.).

        ACM-IR 34 Until CPDLC is enabled, the       Same.                    None.
        R-ATSU System shall prohibit the
        Controller from sending any CPDLC
        messages
                                                                                                   5-235

ATN CPDLC                                     FANS 1/A CPDLC   Interoperability
                                                               Requirement
                                                               IR-411 Until CPDLC is enabled,
                                            Functionally       the R-ATSU System shallreject any
ACM-IR 35 Until CPDLC is enabled, when
                                            equivalent.        downlink message; except DM62.
a message is received with the exception of
emergency messages and messages                                IR-412       When rejecting a
                                                               downlink message, the ATN ground
containing message elements DM99,                              system shall send (ERROR UM159)
DM62, or messages containing the                               with error information choice 5
concatenation of message elements DM62                         concatenated free text (UM169).
and DM98, the R-ATSU System shall                              Note. For free text content, see
either:                                                        the ATN B1 INTEROP
                                                               Standard.
accept the message and do one of the                            After CPDLC is enabled, the
following:                                                     ATN ground system shall send
                                                               UM169 [SET MAX UPLINK
        when the message permits a                             DELAY VALUE TO 40 SEC]
        response, send UM2 REQUEST
        DEFERRED followed by message
        element       UM183     (CPDLC
        TRANSFER IN PROGRESS) and
        process the message when CPDLC
        is enabled, or

        when the message permits a
        response, send UM1 STANDBY
        followed by message element
        UM183 (CPDLC TRANSFER IN
        PROGRESS) and process the
        message when CPDLC is enabled.
        Or

        just process it when CPDLC is
        enabled, or

Reject the request or reject the message as
follows:
        when the message permits a
        response, send UM0 UNABLE
        followed by message element
        UM183 (CPDLC TRANSFER IN
        PROGRESS - REPEAT
        MESSAGE AFTER
        COMPLETION), or
        send an error message containing
        message element UM183 (CPDLC
        TRANSFER IN PROGRESS -
        REPEAT REQUEST AFTER
        COMPLETION)
5-236

        ATN CPDLC                                    FANS 1/A CPDLC       Interoperability
                                                                          Requirement

        ACM-IR 36 The R-ATSU System shall            Same.                None.
        indicate to the Controller when CPDLC is
        enabled.



     5.2.2.7          LACK Management
5.2.2.7.1       Disabling LACK
                                                   Table 5-17 Disabling LACK

        ATN CPDLC                                   FANS 1/A CPDLC       Interoperability Requirement

        ACM-OR When the aircraft system             No equivalent.       None.
        receives UM233 USE OF LACK                  Note: Requirements
        PROHIBITED, it shall set all future         not placed on FANS
        downlinks for this CPDLC connection to      1/A aircraft.
        ‗LACK not required‘.

        ACM-IR 37 When the ATSU system              No equivalent.       See Table for UM233
        indicates the aircraft that no logical                           accommodation.
        LACK is required on the CPDLC
        connection, it shall send a UM233 USE
        OF LACK PROHIBITED using CPDLC-
        message

        ACM-IR-38 When UM233 has been               No equivalent.       None.
        validated and requires a LACK, the          Note: Requirements
        aircraft system shall respond with a        not placed on FANS
        LACK to UM233.                              1/A aircraft.
                                                                                                         5-237

5.2.2.7.2        Sending LACKs
                                                     Table 5-18 Sending LACK
        ATN CPDLC                                     FANS 1/A CPDLC           Interoperability Requirement

        CPC-IR 177 When the ATSU system               No equivalent.           None.
        receives a downlink message, the ATSU         Note. LACKs are not
        system shall send a LACK to the aircraft      available in FANS 1/A
        when:                                         aircraft.
        The message has been received before
        expiration of the ground CPDLC timer tts
        when tts was set,
           LACK is required in the downlink
            message,
           for all downlink messages except
            DM99 CURRENT DATA
            AUTHORITY, if in a LACK region,
        Note: A LACK to DM99 CURRENT
        DATA AUTHORITY is always sent even in
        a non-LACK region.
           the received downlink message has
            been validated and is available for
            display to the Controller, and
           the downlink message is received
            with the acceptation of the CPDLC
            connection termination.
        Note: As per ICAO Document 9880, it is
        not possible for ATSU Systems to send a
        LACK in response to STANDBY or a
        WILCO after CPDLC-end request.

        CPC-IR 178 When an uplink message is          No equivalent.           None.
        received, the aircraft system shall send a    Note: Requirements not
        LACK to the T-ATSU system when:               placed on FANS 1/A
                                                      aircraft.
           The message has been received
            before expiration of the air timer tts
            when tts was set,
           LACK is required in the uplink
            message, and
           the received uplink message has been
            validated and is available for display
            to the flight crew.

        CPC-IR 179 When a LACK is sent, the           No equivalent.           None.
        LACK shall be sent using the CPDLC-           Note. LACKs are not
        message request.                              available in FANS 1/A
                                                      aircraft.
5-238

5.2.3               Handling CPDLC connections
5.2.3.1.1           Connection Establishment


                                                Table 5-19 Connection Establishment

            ATN CPDLC                                     FANS 1/A CPDLC      Interoperability Requirement
            CPC-IR 180 When the T-ATSU/T-sector           None.               See paragraph 4.2.2 for CPDLC
            Controller triggers the establishment of a                        start request requirements.
            CPDLC connection, the T-ATSU ground
            system shall use the CPDLC-start request.


5.2.3.1.2           Connection Termination


                                                 Table 5-20 Connection Termination

            ATN CPDLC                                     FANS 1/A CPDLC      Interoperability Requirement
            CPC-IR 181 When the T-ATSU/T-sector           None.               See paragraph 4.2.2 for CPDLC
            Controller triggers the termination of a                          end request requirements.
            CPDLC connection, the T-ATSU ground
            system shall use the CPDLC-end request.
                                                                                                          5-239


5.2.4             Transfer from T-ATSU to R-ATSU with simultaneous transfer of data and
                  frequency
        5.2.4.1          Operating Method
IR-413   (ED110B None)Ground and aircraft systems shall conduct the ACM service when both T-ATSU
and R-ATSU are CPDLC equipped and the Voice Contact Intruction is simultaneously sent with the
transfer of communication in accordance with Table 5-21.
                  Table 5-21 Transfer from T-ATSU to R-ATSU with simultaneous transfer of data
                                                      and frequency

                  Step        Requirements

                  1           The T-ATSU system automatically sends UM160 NDA, authorizing the aircraft to
                              accept a CPDLC connection request from the R-ATSU as per 5.2.2.2.

                  2           The CPDLC connection is established at the initiation of the R-ATSU.
                              Note 1: The precise timing of the connection request and the means by which the
                              request is triggered is outside the scope of this document.
                              Note 2: When the NDA or the aircraft system does not request the establishment of
                              the CPDLC connection prior to termination of the CDA connection, this will result
                              in no CPDLC connection. At this point any ATSU System can establish a CPDLC
                              connection.
                              Note 3: Some ATSU Systems consider CPDLC available at this step and may
                              indicate this to the Controller.


                  3 DL        Communication transfer with VCI by data link

                         a    Case A (VCI only)                       Case B (Concatenated VCI)

                              Open dialogues are closed by the        As Case A, but the T-ATSU Controller
                              ATSU System as per 5.2.2.3.1.           concatenates      an   instruction UM135
                                                                      CONFIRM ASSIGNED LEVEL with the
                              The T-ATSU Controller instructs
                                                                      transfer instruction (VCI).
                              by data link (VCI) the flight crew to
                              contact or monitor the R-ATSU on
                              the R-ATSU voice channel and
                              requests the CPDLC termination as
                              per 5.2.2.4.
5-240

        Step       Requirements

               b   Case A (VCI only)                       Case B (Concatenated VCI)

                   The flight crew acknowledges the        As case A, except the flight crew enters its
                   instruction to transfer voice and       currently assigned level and the aircraft
                   CPDLC       communications    and       system downlinks this concatenated with the
                   acknowledges        the   CPDLC         WILCO (DM0+DM38).
                   termination as per 0.
                   Open dialogues are closed by the
                   Aircraft System as per 5.2.2.3.1.

        3 VOICE    Communication transfer with VCI by voice

               a   Case A (VCI only)                            Case B (Concatenated VCI)

                   The T-ATSU Controller instructs the          The transfer instruction may also require
                   aircraft to contact or monitor the R-        the flight crew to provide the assigned
                   ATSU on its voice channel, using voice.      level.
                   Once the Controller issues the transfer
                   instruction via voice, the Controller
                   does not initiate/respond to any CPDLC
                   message.

               b   Case A (VCI only)                            Case B (Concatenated VCI)

                   The flight crew must acknowledge the
                   instruction to transfer voice via voice to
                   the
                   T-ATSU.
                   Upon flight crew WILCO via voice to          When the transfer instruction includes
                   the transfer instruction, the flight crew    the request of the assigned level, the
                   must not respond/initiate transmission       flight crew includes the assigned level
                   of any other operational messages with       with the WILCO response.
                   the T-ATSU.
                   Upon flight crew UNABLE via voice to
                   the transfer instruction, the flight crew
                   and aircraft system continues the
                   capability to exchange operational
                   messages with the T-ATSU.
                   The CPDLC connection is terminated at
                   the initiation of the T-ATSU based on
                   local conditions, (e.g., automatically
                   detected condition, T-ATSU Controller
                   input) using CPDLC-end request using
                   CPDLC-end request as per 5.2.10.
                                                                                    5-241


Step      Requirements

4 VOICE   The flight crew must contact the R-ATSU Controller on the voice channel after
          receipt of UM117/UM118/UM275, or monitor the voice channel after receipt of
          UM120/UM121/UM276, as and when appropriate.

5         No equivalent.
          Note: DM99 not supported by FANS 1/A aircraft.

6 (OPT)   No equivalent.
          Note: Not supported by FANS 1/A aircraft.

7         The R-ATSU notifies the aircraft of the Control Authority identity by sending a
          UM282 CURRENT ATC UNIT.
          See Table 4-15   ATN and FANS 1/A CPDLC uplink message elements for use of
          UM282.

8 (OPT)   If the R-ATSU receiving sector does not use CPDLC, the R-ATSU notifies the
          aircraft that CPDLC is not in use as per 5.2.2.5.1.

9 (OPT)   The T-ATSU notifies the R-ATSU that a given frequency has been selected by the
          pilot. The R-ATSU can use voice or data link (UM117 CONTACT) to request
          confirmation of the monitored frequency.

10        The R-ATSU enables CPDLC as per 5.2.2.6 (with change of CPDLC connection).
5-242

5.2.5         Transfer from a not CPDLC-equipped T-ATSU to a CPDLC-equipped R-ATSU

5.2.5.1          Operating Method
     (ED110B None)Ground and aircraft systems shall conduct the ACM service when T-ATSU is not
IR-414
CPDLC-equipped and R-ATSU is CPDLC-equipped in accordance with Table 5-22.
                 Table 5-22 Transfer from a not CPDLC-equipped T-ATSU to a CPDLC-equipped
                                                       R-ATSU

             Step        Requirements

             2           The CPDLC connection is established at the initiation of the R-ATSU/initial ATSU
                         as per section 4.2.2.
                          Note 1: The precise timing of this the connection request and the means by which
                         the request is triggered is outside the scope of this document.
                         Note 2: When the NDA or the aircraft system does not request the establishment of
                         the CPDLC connection prior to termination of the CDA connection, this will result in
                         no CPDLC connection. At this point any ATSU System can establish a CPDLC
                         connection.
                         Note 3: Some ATSU Systems consider CPDLC available at this step and may
                         indicate this to the Controller.

             5           No equivalent.
                         Note: DM99 not supported by FANS 1/A aircraft.

             6 (OPT)     No equivalent.
                         Note: LACK not supported by FANS 1/A aircraft.

             7           The R-ATSU notifies the aircraft of the Control Authority identity by sending a
                         UM282 CURRENT ATC UNIT message.
                         See Table 4-15   ATN and FANS 1/A CPDLC uplink message elements for use of
                         UM282.

             8 (OPT)     If the receiving R-ATSU sector does not use CPDLC, the R-ATSU notifies the
                         aircraft that CPDLC is not in use as per 5.2.2.5.1.

             VOICE       When the CPDLC connection is not with an initial ATSU, the T-ATSU Controller
                         instructs the aircraft via voice to contact or monitor the R-ATSU on the R-ATSU
                         voice channel.

             VOICE       When the CPDLC connection is not with an initial ATSU, the flight crew must
                         acknowledge the verbal instruction to transfer voice communications. The
                         acknowledgment is via voice to the T-ATSU.

             VOICE       When the CPDLC connection is not with an initial ATSU, the flight crew must
                         contact the R-ATSU Controller on the voice channel or monitor the voice channel
                         after receipt of the verbal transfer instruction from the T-ATSU.
                                                                                                              5-243


                    Step        Requirements

                    9 (OPT)     The R-ATSU can use voice or data link (UM117 CONTACT) to request
                                confirmation of the monitored frequency.

                    10a         The R-ATSU/initial ATSU enables CPDLC as per IR-410and IR-411



5.2.6                Transfer from a CPDLC-equipped T-ATSU to a not CPDLC-equipped R-ATSU
                     with simultaneous transfer of data and frequency communications
        5.2.6.1             Operating Method
IR-415  (ED110B None)Ground and aircraft systems shall conduct the ACM service for Transfer from a
CPDLC-equipped T-ATSU to a CPDLC-equipped R-ATSU and the Voice Contact Intruction is
simultaneously sent with the transfer of communication in accordance with Table 5-23.

                  Table 5-23 Transfer from a CPDLC-equipped T-ATSU to a not CPDLC-equipped R-
                  ATSU with simultaneous transfer of data and frequency communications

                     Step       Requirements

                     1          Unless the T-ATSU is aware that the R-ATSU is not data link equipped or is not
                                using data link, the T-ATSU automatically sends UM160 NDA authorizing the
                                aircraft to accept a CPDLC connection request from the R-ATSU as per ACM-IR 2,
                                ACM-IR 3, and ACM-IR 5.

                     3 DL       Communication transfer with VCI by data link (CPDLC ON)

                            a   Case A (VCI only)                       Case B (Concatenated VCI)

                                Open dialogues are closed by the ATSU   As Case A, but the T-ATSU Controller
                                System.                                 concatenates an instruction UM135
                                                                        CONFIRM ASSIGNED LEVEL with the
                                The T-ATSU Controller instructs by
                                                                        transfer instruction (VCI).
                                data link (VCI) the flight crew to
                                contact or monitor the R-ATSU on the
                                R-ATSU voice channel and requests the
                                CPDLC using UM161 END SERVICE.

                            b   Case A (VCI only)                       Case B (Concatenated VCI)

                                The flight crew acknowledges the        As case A, except the flight crew enters its
                                instruction to transfer voice and       currently assigned level.
                                CPDLC communications.
5-244

        Step       Requirements

        3          Communication transfer with VCI by voice (CPDLC OFF)
        VOICE

               a   Case A (VCI only)                            Case B (Concatenated VCI)

                   The T-ATSU Controller instructs the          The transfer instruction may also require
                   aircraft via voice to contact or monitor     the flight crew to provide the assigned
                   the R-ATSU on the R-ATSU voice               level.
                   channel.
                   Once the Controller issues the transfer
                   instruction via voice, the Controller
                   does not initiate/respond to any CPDLC
                   message.

               b   Case A (VCI only)                            Case B (Concatenated VCI)

                   The flight crew must acknowledge the         When the transfer instruction includes the
                   instruction to transfer voice via voice to   request of the assigned level, the flight
                   the T-ATSU.                                  crew includes the assigned level with the
                                                                WILCO response.
                   Upon flight crew WILCO via voice to
                   the transfer instruction, the flight crew
                   must not respond/initiate transmission
                   of any other operational messages with
                   the T-ATSU.
                   Upon flight crew UNABLE via voice to
                   the transfer instruction, the flight crew
                   and aircraft system continues the
                   capability to exchange operational
                   messages with the T-ATSU.
                   The ATSU System and the aircraft
                   terminate the CPDLC connection.

        4          The flight crew must contact the R-ATSU Controller on the voice channel after
        VOICE      receipt of UM117/UM118/UM119, or monitor the voice channel after receipt of
                   UM120/UM121/UM122.
                                                                                                           5-245



5.2.7          Transfer from T-sector to R-sector both using CPDLC

5.2.7.1        Operating Method
IR-416 (ED110B None)Ground and aircraft systems shall conduct the ACM service transfer with no
change of CPDLC connection (T-sector and R-sector both using CPDLC) in accordance with Table 5-24.
                         Table 5-24 Transfer from T-sector to R-sector both using CPDLC

              Step        Requirements

              3 DL        Communication transfer with VCI by data link (CPDLC ON)

                     a    Case A (VCI only)                            Case B (Concatenated VCI)

                          Open messages are maintained as per          As Case A, but the transferring
                          5.2.2.3.2.                                   Controller concatenates an instruction
                                                                       UM135 CONFIRM ASSIGNED LEVEL
                          The T-sector Controller instructs by data
                                                                       with the transfer instruction (VCI).
                          link (VCI) the flight crew to contact or
                          monitor the R-sector on the R-sector         Note: Case B does not apply when there
                          voice channel with no CPDLC                  is only a change of frequency within a
                          termination as per 5.2.2.4.1.                sector.

                     b    Case A (VCI only)                            Case B (Concatenated VCI)

                          The flight crew acknowledges the             As case A, except the flight crew enters
                          instruction to transfer voice to the T-      its currently assigned level and the
                          sector as per 5.2.2.4.1.                     aircraft downlinks this concatenated with
                                                                       the WILCO (DM0+DM38).
                          Open messages are maintained as per
                          5.2.2.3.2.                                   Note: Case B does not apply when there
                                                                       is only a change of frequency within a
                                                                       sector.

              3           Communication transfer with VCI by voice (CPDLC OFF)
              VOICE

                     a    Case A (VCI only)                            Case B (Concatenated VCI)

                          The T-sector Controller instructs the        The transfer instruction may also require
                          aircraft via voice to contact or monitor     the flight crew to provide the assigned
                          the R-ATSU on the R-ATSU voice               level.
                          channel.
                          Once the Controller issues the transfer
                          instruction via voice, the Controller does
                          not initiate/respond to any CPDLC
                          message.

                     b    Case A (VCI only)                            Case B (Concatenated VCI)
5-246

        Step      Requirements

                  The flight crew must acknowledge the         When the transfer instruction includes
                  instruction to transfer voice via voice to   the request of the assigned level, the
                  the T-ATSU.                                  flight crew includes the assigned level
                                                               with the WILCO response.
                  Upon flight crew WILCO via voice to
                  the transfer instruction, the flight crew
                  must not respond/initiate transmission of
                  any other operational messages with the
                  T-ATSU.
                  Upon flight crew UNABLE via voice to
                  the transfer instruction, the flight crew
                  and aircraft system continues the
                  capability to exchange operational
                  messages with the T-ATSU.
                  The ATSU System and the aircraft
                  terminate the CPDLC connection as per
                  5.2.10.

        4         Upon WILCO response, the flight crew must contact the Controller on the voice
        VOICE     channel after receipt of DL or voice UM117/UM118/UM275, or monitor the voice
                  channel after receipt of DL or voice UM120/UM121/UM276, as and when
                  appropriate.

        7 (OPT)   When the R-sector is different from the T-sector and the Control Authority identity
                  has changed, the R-sector notifies the aircraft of Control Authority identity by
                  sending a UM282 CURRENT ATC UNIT message using CPDLC-message request.



        9 (OPT)   The T-ATSU notifies the R-ATSU that a given frequency has been selected by the
                  pilot. The R-ATSU can use voice or data link (UM117 CONTACT) to request
                  confirmation of the monitored frequency.

        10        When the R-sector is different from the T-sector, the R-sector enables CPDLC as per
                  5.2.2.6 (with no change of CPDLC connection).
                  Note: When the R-sector is the same as the T-sector local implementations determine
                  whether CPDPC remains enabled.
                                                                                                        5-247

5.2.8         Transfer from T-ATSU to R-ATSU with independent transfer of data and
              frequency communications (by data link or voice)

5.2.8.1        Operating Method
IR-417  Ground and aircraft systems shall conduct the ACM service when the T-ATSU and the R-ATSU
are both using CPDLC with transfer of voice independent of the transfer of CPDLC connection in
accordance with Table 5-25.
                  Table 5-25 Transfer from T-ATSU to R-ATSU with independent transfer of data
                                     and frequency communications (by data link or voice)

              Step      Requirements

              1         The T-ATSU system automatically sends UM160 NDA, authorizing the aircraft to
                        accept a CPDLC connection request from the R-ATSU as per 5.2.2.2.

              1BIS      Transfer of voice frequency is performed independently of the transfer of CPDLC
              DL        connection as per 5.2.12 (―Deferred instruction to change frequency‖).

              1 BIS     Transfer of voice frequency is performed independently of the transfer of CPDLC
              VOIC      connection by voice.
              E

              2         The CPDLC connection is established at the initiation of the R-ATSU using the
                        CPDLC-start service.
                        Note 1: The precise timing of this request and the means by which the request is
                        triggered is outside the scope of this document.
                        Note 2: When the NDA does not request the establishment of the CPDLC connection
                        prior to termination of the CDA connection, this will result in no CPDLC connection.
                        At this point any ATSU System can establish a CPDLC connection.
                        Note 3: Some ATSU Systems consider CPDLC available at this step and may
                        indicate this to the Controller.




              3         The CPDLC connection is terminated at the initiation of the T-ATSU based on local
                        conditions (e.g., automatically detected condition, T-ATSU Controller input) using
                        CPDLC-end request as per 5.2.10.

              5         The aircraft system notifies the R-ATSU that it becomes the CDA as per 5.2.2.5.1.

              6         The R-ATSU optionally notifies the aircraft that it does not support LACKs No
              (OPT)     equivalent.
                        Note: LACK not supported by FANS 1/A aircraft.

              7         The R-ATSU notifies the aircraft of the Control Authority identity by sending a
                        UM282 CURRENT ATC UNIT message using CPDLC-message request.
5-248

                  Step     Requirements

                  8        If the R-sector does not use CPDLC, the R-sector notifies the aircraft that CPDLC is
                  (OPT)    not in use as per 5.2.2.5.2.

                  9        The T-ATSU notifies the R-ATSU that a given frequency has been selected by the
                  (OPT)    pilot. The R-ATSU can use voice or data link (UM117 CONTACT) to request
                           confirmation of the monitored frequency.

                  10       No equivalent.
                           Note: DM99 not supported by FANS 1/A aircraft.




5.2.9             Transfer from a CPDLC-equipped T-ATSU to a non-CPDLC equipped R-ATSU
                  with independent transfer of data and frequency communications
        5.2.9.1          Operating Method
IR-418 Ground and aircraft systems shall conduct the ACM service when the T-ATSU is CPDLC-
equipped and the R-ATSU is not CPDLC-equipped with transfer of voice independent of the transfer of
CPDLC connection in accordance with Table 5-26.
                  Table 5-26 Transfer from a CPDLC-equipped T-ATSU to a non-CPDLC equipped
                                   R-ATSU with independent transfer of data and frequency
                                                     communications

                  Step      Requirements

                  1         The T-ATSU system automatically sends UM160 NDA, authorizing the aircraft to
                            accept a CPDLC connection request from the R-ATSU as per 5.2.2.2.

                  1BIS      The ATSU System and the aircraft terminate the CPDLC connection as per 5.2.12
                  DL        (―Deferred instruction to change frequency‖).

                  1  BIS    Transfer of voice frequency is performed independently of the transfer of CPDLC
                  VOICE     connection by voice.

                  3         The CPDLC connection is terminated at the initiation of the T-ATSU based on local
                            conditions (e.g., automatically detected condition, T-ATSU Controller input) using
                            CPDLC-end request as per 5.2.10.
                                                                                                             5-249



5.2.10          C-ATSU Ends CPDLC Connection
IR-419(ED110B None)Ground and aircraft systems shall conduct provides the requirements for the
ACM service when the C-ATSU ends the CPDLC connection in accordance with Table 5-27.
                                      Table 5-27 C-ATSU ends CPDLC connection

                Step     Requirements

                3        The CPDLC connection is terminated at the initiation of the C-ATSU using CPDLC-
                         end request.
                         See Table 4-8  ATN CPDLC constructs and FANS 1/A CPDLC ACARS IMIs for
                         use of CPDLC-end.



5.2.11          Change of Frequency Requested by the Flight Crew
     5.2.11.1          Operating Method
IR-420  Ground and aircraft systems shall conduct the ACM service using CPDLC with aircrew request
of frequency change in accordance with Table 5-28.
                           Table 5-28 Change of Frequency Requested by the Flight Crew

                Step     Requirements

                1        The flight crew sends the change of frequency request message (DM20 REQUEST
                         VOICE CONTACT or DM21 REQUEST VOICE CONTACT [frequency]) via data
                         link to the ATSU.

                2a       The ATSU processes the received message.

                2b       Case A (Controller is involved)               Case     B     (ATSU/Controller       not
                                                                       differentiated)

                         The Controller is notified of the received    The Controller can be notified of the
                         message.                                      received message.

                3S       A STANDBY response message is optionally sent to the aircraft via data link.

                3U       The Controller selects the response           The ATSU selects the response message
                         message element (UNABLE or the                element (UNABLE or the immediate
                         immediate VCI).                               VCI).

                         The response uplink message is sent via data link to the aircraft.

                                                                       The Controller can be notified of the sent
                                                                       message.
5-250

                Step     Requirements

                         The aircraft processes the received response message(s).
                         When the response to the flight crew initiated exchange is a STANDBY, the flight
                         crew is notified.
                         When the closure response is received, the flight crew is notified.

                3 VCI    Procedure ―Transfers or change of frequency using CPDLC with no change of CPDLC
                         connection‖ applies (section 0).
                         Note. The VCI is sent as a response to the change frequency request.

IR-421

5.2.12          Deferred instruction to change frequency
     5.2.12.1          Operating Method
IR-422   Ground and aircraft systems shall conduct the ACM service using CPDLC for deferred
instruction to change frequency in accordance with Table 5-29.
                                  Table 5-29 Deferred instruction to change frequency

                Step     Requirements

                1        Case A (Controller is involved)                Case B (ATSU System/Controller not
                                                                        differentiated)

                         The Controller selects the deferred VCI        The ATSU Sustem/Controller selects the
                         message element (UM118/121 or                  deferred  VCI    message      element
                         UM275/UM276).                                  (UM118/121 or UM275/UM276).
                                                                        The Controller can be notified of the sent
                                                                        message.

                         The deferred VCI message is sent via data link to the aircraft.

                2a       The aircraft processes the received message.

                2b       The flight crew is notified of the received message.

                3S       A STANDBY response message is optionally sent to the ATSU.

                3U       The flight crew responds UNABLE.
                         The flight crew sends the response message via data link to the ATSU.

                3W       The flight crew responds WILCO.
                         The flight crew sends the response message via data link to the ATSU.

                4        The ATSU processes the received the response message(s).
                                                                                                   5-251


         Step      Requirements

                   Case A (Controller is involved)              Case     B     (ATSU/Controller     not
                                                                differentiated)

                   The Controller is notified of the received   The Controller can be notified of the
                   message(s).                                  received message(s).

         5VCI      In case a WILCO is sent, procedure ―Transfer from T-ATSU Using CPDLC to R-
                   ATSU Using CPDLC With transfer of voice independent of the transfer of CPDLC
                   connection‖ applies (section 5.2.8).

IR-423


5.3      ATC Traffic Clearance (ACL) Service
         This continental data link service describes airborne system/ATSU air-ground data
         communication procedures for operations for the ATN B1 ground system for the
         following:
               Aircrew-initiated reports and clearance requests;
               Controller-initiated delivery of clearances, instructions and notifications to aircraft.
         The ATC Traffic Clearance (ACL) Service is equivalent in ATN and FANS 1/A.
         No additional Interoperability Requirements.
         Note: See sections 4.2.8 and4.2.9 to see accommodation of specific CPDLC messages.
5-252

5.4     Departure Clearance (DCL) Service
        DCL is an air traffic service supported by CPDLC, which provides support for the
        following exchanges:
           Aircrew departure clearance requests and responses to ground; and
           Controller delivery of revised departure clearances to aircraft.


5.4.1   Accommodation of the Departure Clearnace Service
        The ATN ground system can accommodate FANS 1/A aircraft using the departure
        clearance service. The ATN departure clearance service uses the following CPDLC
        messages:
               UM264 [depatureClearance]
               UM325 REVISED
               UM331 [position information] [assigned time] CONTACT [facility function
                ground] [frequency]
               UM311 STARTUP APPROVED [assigned time]
               UM314 EXPECT [clearance type][assigned time]
               UM305 HOLD [direction] AS PUBLISHED
               UM306 HOLD [direction] ON [inboundradial] RADIAL [airway][direction]
                TURNS [legtype] LEGS
               UM224 NO DELAY EXPECTED
        The ATN ground system can accommodate the FANS 1/A aircraft using the departure
        clearance service by sending the following messages.
               UM73 [preDepartureClearance] (UM264 and UM314 Accommodation)
               UM169 [free text] (UM264 Accommodation)
               UM158 ATIS CODE [atisCode] (UM264 Accommodation)
               UM169 [free text] (UM325 Accommodation)
               UM169 [free text] (UM224 Accommodation)
        The following ATN messages are not accommodated in the FANS 1/A departure
        clearance service. These messages are also part of the D-TAXI service.
               UM331 [position information] [assigned time] CONTACT [facility function
                ground] [frequency]
               UM310 STARTUP APPROVED [assigned time]
               UM305 HOLD [direction] AS PUBLISHED
               UM306 HOLD [direction] ON [inboundradial] RADIAL [airway][direction]
                TURNS [legtype] LEGS
                                                                                                           5-253



5.4.2         Departure Clearance Revsions
              The Departure Clearance (DCL) Service revisions are different in ATN and FANS 1/A. In ATN
              the revised departure clearance message UM264 is preceeded by the ATN message UM325
              REVISED. In FANS 1/A the revision parameter in UM73 will always be set to the integer value 1.
              A revision can be accommodated in FANS 1/A by appending a free text message UM169
              ―REVISED‖ to the start of a departure clearance. In ATN only the updated Departure Clearance
              fields will be sent in a DCL revision, in FANS 1/A all mandatory fields will be sent in the revision
              as well as any optional fields that have changed.
IR-424   The ATN ground system shall append the FANS 1/A free text message UM169 ―REVISED‖ to
the start of a revised departure clearance message.
IR-425 The ATN ground system shall always set the PDCRevision field in the FANS 1/A UM73
departure clearance message to the integer value of 1.
IR-426 Note: See sections 4.2.8 and4.2.9 to see accommodation of specific CPDLC messages

5.4.3         Departure Clearance Request
              The departure clearance request is different in ATN and FANS 1/A. In ATN departure
              clearances are requested via the new departure clearance request message DM139
              REQUEST DEPARTURE CLEARANCE [DepartureClearanceRequestData]. In FANS 1/A
              departure clearances are requested using the DM25 REQUEST CLEARANCE message.
              The following concatenated message sequence describes how a FANS 1/A aircraft requests a
              departure clearance from an ATN ground system.
              DM25 REQUEST CLEARANCE

5.5           ATC Microphone Check (AMC) Service
              The AMC service provides controllers with the capability to uplink an instruction for
              aircraft to check that they are not blocking a voice channel. No aircrew acknowledgement
              of the instruction is required.
              The ATC Microphone Check (AMC) Service is equivalent in ATN and FANS 1/A.
              No additional Interoperability Requirements.
              Note: See sections 4.2.8 and4.2.9 to see accommodation of specific CPDLC messages.

5.6           4DTRAD Service
5.6.1         ITBO Service
              The ITBO Service defined in DO-XXX is a subset of the greater 4DTRAD service. A
              FANS 1/A aircraft may participate in the ITBO service using the CPDLC application
              optionally supplemented by ADS-C, given the differences identified above.
              If ADS-C is to be used for ITBO, the FANS 1/A aircraft and the ATS ground system
              must implement the ADS-C application as defined in DO-258A/ED-100A.
              When a FANS 1/A aircraft participates in the ITBO service the time parameters are
              restricted to hours and minutes. This restriction needs to be taken into consideration when
              implementing ITBO for FANS 1/A aircraft.
6-254

6       Guidelines for ATN Ground System Use of FANS 1/A ADS-C Application

6.1     ADS-C Contracts
        Table 6-1 compares the ATN ADS contracts with the FANS 1/A contracts. The threee
        types of ADS-C contrats and the emergency mode are supported by both types of aircraft.


                           Table 6-1      ATN and FANS 1/A ADS-C Contracts

        ATN ADS-C Contract              FANS 1/A ADS Contract         Interoperability Guidance
        [PM-ADS] imposes that           [ED100A/DO258A]               No additional interoperability
        ATN aircraft support at least   implicitly imposes that the   guidance.
        one of the three types of       FANS 1/A aircraft support
        ADS-C contracts.                the three types of ADS
                                        contract.

        Note. See PM-ADS chapter        Note. See ED100A section
        8.                              4.5.1 NOTE.
        ADS-C Demand Contract           Demand Contract               Functionally equivalent.
        ADS-C Event Contract            Event Contract                Functionally equivalent.
        ADS-C Periodic Contract         Periodic Contract             Functionally equivalent.
        [SC-214 ATN INTEROP]            [ED100A/DO258A]             Functionally equivalent.
        imposes that the ATN            implicitly imposes that the
        ground system which             FANS 1/A ground system
        receives any ADS report         which supports periodic
        shall support the               contract or event contract
        Emergency/Urgency mode.         shall support the Emergency
        Note. See 3.2.6.2.1: Upon       Periodic Contract.
        receipt of an ADS report
        that has an emergency
        and/or urgency indication,
        the ATSU System shall
        notify an operator
                                                                                                   6-255


6.2     Uplink Functions
6.2.1   ADS Uplink Messages
        Table 6-2 compares the ATN ADS-C uplink messages with the FANS 1/A ADS uplink
        messages. ADS uplink messages are similar for both types of aircraft, except the abort
        messages defined specifically to terminate the ATN connections, and the ground
        emergency contract that cannot be initiated by ATN ground system.


                        Table 6-2       ATN and FANS 1/A ADS uplink messages

        ATN ADS Uplink                   FANS 1/A ADS Request         Interoperability Guidance
        [0] ADS-cancel-all-contracts-    Tag (1): Cancel All          Functionally equivalent.
        PDU (terminates connection)      Contracts and Terminate
        Note. The aircraft               Connection Request
                                                                      With ATN aircraft, the ground
        automatically terminates the     Note. The aircraft sends a   system has to ―cancel all
        dialogue.                        Disconnect Request with      contracts‖ only when periodic
                                         reason code 8.               and/or event contracts are in
                                                                      place.
                                                                      Note. The connection is
                                                                      automatically closed down by the
                                                                      aircraft when no ADS contract is
                                                                      in place.
                                                                      With FANS 1/A aircraft, the
                                                                      ground system has to ―cancel all
                                                                      contracts and terminate the
                                                                      connection‖ even if no contract is
                                                                      in place.
        [1] ADS-cancel-contract-PDU      Tag (2): Cancel Contract Functionally equivalent.
        (terminates one contract)        Request
         CancelContract = event-         ADS Contract Request
             contract(0) or periodic-        Number
             contract(1)
        Note. The aircraft
        automatically terminates the
        dialogue when no contract
        remains.
        [2] ADS-contract-PDU
                  ADS Contract           Tag (7): Periodic Contract   Functionally equivalent.
                  Request                Request                      See paragraph 6.2.2 for
                   contract-type =                                   additional guideline on demand
                     demand                                           contract.
                  ADS Contract           Tag (8): Event Contract      Functionally equivalent.
                  Request                Request                      See paragraph 6.2.4 for
                   contract-type =                                   additional guideline on event
                     event                                            contract.
6-256

        ATN ADS Uplink               FANS 1/A ADS Request         Interoperability Guidance
                 ADS Contract        Tag (7): Periodic Contract   Functionally equivalent.
                 Request             Request                      See paragraph 6.2.3 for
                  Contract-type =                                additional guideline on periodic
                    periodic                                      contract.
        [3] ADS Provider Abort       No equivalent.               Not equivalent.
                                                                  The ground system cannot issue
                                                                  an abort to the FANS 1/A
                                                                  aircraft.
        [4] ADS User Abort           No equivalent.               Not equivalent.
                                                                  The ground system cannot issue
                                                                  an abort to the FANS 1/A
                                                                  aircraft.
        No equivalent                Tag (6): Cancel              Not equivalent.
                                     Emergency Mode Request       The ground system cannot
                                                                  request an ATN aircraft to cancel
                                                                  the emergency mode.
        No equivalent                Tag (9): Emergency           Not equivalent.
                                     Periodic Contract            The ground system cannot
                                                                  request an ATN aircraft to
                                                                  modify an emergency mode.
                                                                                                  6-257

6.2.2   ADS Demand Contract Request
        Table 6-3 compares the ADS-C Demand Contract Request parameters for ATN and
        FANS 1/A. Same data block types can be requested except for the extended projected
        profile. The ground system requests the projected profile for ATN aircraft or the aircraft
        intent for FANS aircraft resulting in a different data being reported. Aircraft intent cannot
        be requested for a number of way points.


            Table 6-3     ATN and FANS 1/A ADS-C Demand Contract Request variables

        ATN ADS Demand Contract           FANS 1/A ADS Demand        Interoperability Guidance
        Request                           Contract Request
        DemandContractRequest             Tag (7): Periodic ADS      When issuing a Demand
                                          Request                    Contract request, the ground
                                                                     system sets the ADS request tag
                                                                     to (7) periodic.
                                          Tag (11): Reporting Rate   When issuing a Demand
                                          (optional)                 Contract request, the ground
                                           Scaling Factor = 0       system:
                                           Rate = N/A                includes the reporting rate
                                                                          tag in the contract request,
                                                                      sets the Scaling Factor value
                                                                          to (0).
                                                                     Note. The FANS 1/A aircraft
                                                                     does not use the rate parameter
                                                                     in the demand contract request.
        [0] Contract Number               Tag (7): Periodic ADS      Functionally equivalent.
                                          Request                    When issuing a Demand
                                           ADS Contract Request     Contract request, the ground
                                              Number                 system generates a new contract
                                                                     request number.
                                                                     The ATN ground system does
                                                                     not duplicate a contract request
                                                                     number already used for active
                                                                     contract on the same ADS
                                                                     connection.
                                                                     Note. See Table 6-23 for
                                                                     additional guideline on the
                                                                     contract number parameter.
        [1] Aircraft-address (optional)   Tag (17) Airframe ID       When the aircraft address is
                                           Modulus                  desired, the ground system:
                                                                      includes the Airframe ID
                                                                          group tag in the ADS
                                                                          Contract request.
                                                                      may use a modulus different
                                                                          from zero in the demand
                                                                          contract request.
6-258

        ATN ADS Demand Contract         FANS 1/A ADS Demand          Interoperability Guidance
        Request                         Contract Request
        [2] Aircraft-identification     Tag (12) Flight Id           When the aircraft identification
        (optional)                       Modulus                    address is desired, the ground
                                                                     system:
                                                                      includes the Flight ID group
                                                                          tag in the ADS Contract
                                                                          request.
                                                                      may use a modulus different
                                                                          from zero in the demand
                                                                          contract request.
        [3] Projected-profile (optional) Tag (13): Predicted Route   When the projected profile is
                                         (optional)                  desired, the ground system:
                                          Modulus                    includes the Predicted Route
                                                                          group tag in the ADS
                                                                          Contract request.
                                                                      may use a modulus different
                                                                          from zero in the demand
                                                                          contract request.
        [4] Ground-vector               Tag (14): Earth Reference    When the ground vector is
                                        (optional)                   desired, the ground system:
                                         Modulus                     includes the Earth Reference
                                                                          group tag in the ADS
                                                                          Contract request.
                                                                      may use a modulus different
                                                                          from zero in the demand
                                                                          contract request.
        [5] Air-vector                  Tag (15): Air Reference      When the air vector is desired,
                                        (optional)                   the ground system:
                                         Modulus                     includes the Air Reference
                                                                          group tag in the ADS
                                                                          Contract request.
                                                                      may use a modulus different
                                                                          from zero in the demand
                                                                          contract request.
        [6] Met-info                    Tag (16): Meteorological     When the met info is desired, the
                                        (optional)                   ground system:
                                         Modulus                     includes the Meteorological
                                                                         group tag in the ADS
                                                                         Contract request.
                                                                      may use a modulus different
                                                                         from zero in the demand
                                                                         contract request.
                                                                                          6-259

ATN ADS Demand Contract          FANS 1/A ADS Demand         Interoperability Guidance
Request                          Contract Request
[7] Extended-projected-profile   No equivalent.              When the extended projected
(optional)                                                   profile is desired, the ground
                                                             system:
                                                              includes the Predicted Route
                                 Tag (13): Predicted Route
                                                                  group tag or the Aircraft
                                 (optional)
                                                                  Intent Group tag in the ADS
                                  Modulus                        Contract request.
                                 or                           may use a modulus different
                                 Tag (21): Aircraft Intent        from zero in the demand
                                 (optional)                       contract request.
                                  Modulus                   Note. Use of the Predicted Route
                                  Aircraft Intent           Group (2 way-points) or the
                                      Projection Time        Intermediate Projected Intent
                                                             Group (up to 10 way-points) in
                                                             place of the Extended Project
                                                             profile Group is a local matter.
                                                             When requesting the Aircraft
                                                             Intent group, the Intermediate
                                                             Projected Intent group and the
                                                             Fixed Projected Intent group will
                                                             be provided by the FANS 1/A
                                                             aircraft.
                                                             The Fixed Projected Intent
                                                             Group represents the position at
                                                             the requested time in the Aircraft
                                                             Intent group request.
EPPWindow:                                                   See Table 6-23 ATN and
 time-interval, or                                          FANS 1/A ADS variables with
                                                             range and resolution
                                                              for additional guidelines
                                                             EPPWindow parameter.


   number of way points         No equivalent
[8] Eta Min Max Request          No Equivalent               The ground system cannot
                                                             request an ETA min max data
                                                             block from a FANS 1/A aircraft.
6-260

6.2.3   ADS Periodic Contract Request
        Table 6-4 presents the ADS-C Periodic Contract Request parameters for ATN and
        FANS 1/A. Same data block types can be requested except for the extended projected
        profile. The ground system requests the projected profile for ATN aircraft or the aircraft
        intent for FANS aircraft resulting in a different data being reported. Aircraft intent cannot
        be requested for a number of way points.


             Table 6-4      ATN and FANS 1/A ADS Periodic Contract Request variables

        ATN ADS Periodic          FANS 1/A ADS Periodic           Interoperability Guidance
        Contract Request          Contract Request
        Periodic Contract         Tag (7): Periodic Contract      Equivalent.
        Request                   Request
        [0] Contract Number          ADS Contract Request       Functionally equivalent.
                                      Number                     When issuing a Periodic Contract
                                                                 request, the ground system generates a
                                  Note. A contract number of 255 new contract request number.
                                  indiccates an emergency        The ATN ground system does not
                                  contract.                      duplicate a contract request number
                                                                 already used for active contract on the
                                                                 same ADS connection.
                                                                 Note. See Table 6-23 for additional
                                                                 guideline on the contract number
                                                                 parameter.
                                                                 Note. Emergency contract management
                                                                 is outside the scope of this document.
        [1] Reporting-rate        Tag (11): Reporting Rate        When issuing a Periodic Contract
         Reporting time          (optional)                      request, the ground system includes the
                                   Scaling Factor (SF)           reporting rate tag in the Contract
                                                                  request.
                                   Rate
                                                                  In FANS 1/A, if the reporting rate is not
                                                                  provided, the default reporting rate is
                                                                  304 seconds.
                                                                  In ATN, the fastest reporting rate is one
                                                                  second, while in FANS 1/A, the fastest
                                                                  reporting rate is 64 seconds.
                                                                  Note. It is unlikely that the ATN aircraft
                                                                  will meet the 1 second reporting
                                                                  interval.
                                                                  Note. See Table 6-23 for additional
                                                                  guideline on the reporting time
                                                                  parameter
                                                                                        6-261

ATN ADS Periodic         FANS 1/A ADS Periodic           Interoperability Guidance
Contract Request         Contract Request
[2] Aircraft-address-    Tag (17) Airframe ID            When the aircraft address is desired, the
modulus (optional)       (optional)                      ground system includes the Airframe ID
                          Modulus                       group tag in the ADS Contract request.
                                                         Note. See Table 6-23 for additional
                                                         guideline on the modulus parameter.
[3] Aircraft-            Tag (12) Flight Id (optional)   When the aircraft identification address
identification-modulus    Modulus                       is desired, the ground system includes
(optional)                                               the Flight ID group tag in the ADS
                                                         Contract request.
                                                         Note. See Table 6-23 for additional
                                                         guideline on the modulus parameter.
[4] Projected-profile-   Tag (13): Predicted Route       When the projected profile is desired,
modulus (optional)       (optional)                      the ground system includes the
                          Modulus                       Predicted Route group tag in the ADS
                                                         Contract request.
                                                         Note. See Table 6-23 for additional
                                                         guideline on the modulus parameter.
[5] Ground-vector-       Tag (14): Earth Reference       When the ground vector is desired, the
modulus                  (optional)                      ground system includes the Earth
                          Modulus                       Reference group tag in the ADS
                                                         Contract request.
                                                         Note. See Table 6-23 for additional
                                                         guideline on the modulus parameter.
[6] Air-vector-modulus   Tag (15): Air Reference         When the air vector is desired, the
                         (optional)                      ground system includes the Air
                          Modulus                       Reference group tag in the ADS
                                                         Contract request.
                                                         Note. See Table 6-23 for additional
                                                         guideline on the modulus parameter.
[7] Met-info-modulus     Tag (16): Meteorological        When the met info is desired, the ground
                         (optional)                      system includes the Meteorological
                          Modulus                       group tag in the ADS Contract request.
                                                         Note. See Table 6-23 for additional
                                                         guideline on the modulus parameter.
6-262

        ATN ADS Periodic          FANS 1/A ADS Periodic          Interoperability Guidance
        Contract Request          Contract Request
        [8] Extended-projected-   No equivalent.                 When using the extended projected
        profile-modulus                                          profile modulus, the ground system
        (optional):                                              includes the Predicted Route group tag
                                  Tag (13): Predicted Route
         modulus,                                               or the Aircraft Intent Group tag in the
                                  (optional)
                                                                 ADS Contract request.
         EPP Window:              Modulus
                                                                 Note. Use of the Predicted Route Group
           time-interval, or     or                             (2 way-points) or the Intermediate
                                  Tag (21): Aircraft Intent      Projected Intent Group (up to 10 way-
                                  (optional)                     points) in place of the Extended Project
                                   Modulus                      profile Group is a local matter.
                                   Aircraft Intent Projection   When requesting the Aircraft Intent
                                       Time                      group, the Intermediate Projected Intent
                                                                 group and the Fixed Projected Intent
                                                                 group will be provided by the
                                                                 FANS 1/A aircraft.
                                                                 The Fixed Projected Intent Group
                                                                 represents the position at the requested
                                                                 time in the Aircraft Intent group request.
                                                                 See Table 6-23 for additional guideline
                                                                 on modulus and EPP Window
                                                                 parameters.
           number of way         No equivalent                  The ground system cannot request the
            points                                               number of way points from a FANS 1/A
                                                                 aircraft.
        [9] Eta-min-max-          No equivalent                  The ground system cannot request an
             modulus                                             ETA min max data block from a FANS
                                                                 1/A aircraft.
                                                                                                 6-263

6.2.4   ADS Event Contract Request
        Table AP- 1 presents the ADS Event contract request for ATN and FANS 1/A. Only a
        limited number of events are common to both types of aircraft.


                    Table AP- 1 ATN and FANS 1/A ADS Event contract request

        ATN ADS Event Contract        FANS 1/A ADS Event           Interoperability Guidance
        Request                       Contract Request
        Event Contract Request        Tag (8): Event ADS Request Equivalent.
        [0] Contract Number              ADS Contract Request     Functionally equivalent.
                                          Number                   When issuing a Periodic Contract
                                                                   request, the ground system
                                                                   generates a new contract request
                                                                   number.
                                                                   The ATN ground system does not
                                                                   duplicate a contract request
                                                                   number already used for active
                                                                   contract on the same ADS
                                                                   connection.
                                                                   Note. See Table 6-23 for
                                                                   additional guideline on the
                                                                   contract number parameter.
        [1] Lateral-deviation-change Tag (10): lateral deviation   Equivalent event type.
        (optional)                   change (optional)             See paragraph 6.2.4.1 for lateral
                                                                   deviation change event
                                                                   management.
        [2] Vertical-Rate-change      Tag (18): vertical rate      Equivalent event type.
        (optional)                    change (optional)            See paragraph 6.2.4.2 for vertical
                                                                   rate change event management.
        [3] Level-Range-change        Tag (19): altitude range     Equivalent event type.
        (optional)                    change (optional)            See paragraph 6.2.4.3 for
                                                                   level/altitude range change event
                                                                   management.
        [4] Way-point-change          Tag (20): Waypoint change    Equivalent event type.
        (optional)                    (optional)                   See paragraph 6.2.4.4 for
                                                                   waypoint change event
                                                                   management.
        [5] Air-Speed-change          No equivalent                Ground system cannot receive air
        (optional)                                                 speed change indication from
                                                                   FANS 1/A aircraft.
        [6] Ground-Speed-change       No equivalent                Ground system cannot receive
        (optional)                                                 ground speed change indication
                                                                   from FANS 1/A aircraft.
6-264

        ATN ADS Event Contract         FANS 1/A ADS Event          Interoperability Guidance
        Request                        Contract Request
        [7] Heading-change             No equivalent               Ground system cannot receive
        (optional)                                                 heading change indication from
                                                                   FANS 1/A aircraft.
        [8] Extended-projected-        No equivalent, except for   When using an extended projected
        profile-change (optional)      sequencing way-point.       profile change event contract, the
         time-interval, or                                        ground system includes the
                                                                   Waypoint change tag in the ADS
         number of way points         Tag (20): Waypoint change
                                                                   Contract request.
                                       (optional)
                                                                   Using the Waypoint change event
                                                                   will issue the provision of the
                                                                   Predicted Route group.
                                                                   Note. Use of the Predicted Route
                                                                   Group in place of the Extended
                                                                   Projected Profile Group is a local
                                                                   matter.
                                                                   See paragraph 6.2.4.4 for
                                                                   waypoint change event
                                                                   management.
        [9] fom-change (optional)      No equivalent               Ground system cannot receive
                                                                   fom change indication from FANS
                                                                   1/A aircraft.
        [10] trak-angle change         No equivalent               Ground system cannot receive
        (optional)                                                 track change indication from
                                                                   FANS 1/A aircraft.
        [11] level-change (optional)   No equivalent               Ground system cannot receive
                                                                   level change indication from
                                                                   FANS 1/A aircraft.
        [12] vertical-deviation-       No equivalent               Ground system cannot receive
        change (optional)                                          vertical deviation change
                                                                   indication from FANS 1/A
                                                                   aircraft.
        [13] out-of-vertical           No equivalent               Ground system cannot receive out
        boundaries (optional)                                      of vertical boundary change
                                                                   indication from FANS 1/A
                                                                   aircraft.
                                                                                                      6-265

6.2.4.1       Lateral deviation change event
          Table 6-5 presents the ATN and FANS 1/A Lateral Deviation Change Event.
                                 Table 6-5     Lateral Deviation Change Event

          ATN                             FANS 1/A                      Interoperability Guidance
          Request Parameters
             Left Lateral deviation         Lateral deviation         In FANS 1/A, the same threshold
              threshold                       threshold                 is provided for left and right.
             Right Lateral deviation                                   See Table 6-23 for additional
              threshold                                                 guideline on the lateral deviation
                                                                        parameter.
          Event Report Parameters
             Basic Group                    Basic Group               See paragraph 6.3.2.1 for
             Ground vector                  Earth Reference           additional guidance on basic
                                                                        group.
                                                                        See paragraph 6.3.2.2 for
                                                                        additional guidance on ground
                                                                        vector / earth reference group.
          Trigerring Event                                              Equivalent
             when the lateral               when the absolute value
              deviation of the aircraft       of the lateral distance
              relative to the active          between the aircraft's
              route of flight is more         actual position and the
              than the value of               aircraft's expected
              lateral-deviation-              position on the active
              change                          flight plan is greater
                                              than the lateral
                                              deviation threshold
          Reporting Rate                                                Not equivalent
             once every 60 seconds          only one report
6-266

    6.2.4.2       Vertical rate change event
              Table 6-6 presents the ATN and FANS 1/A Vertical Rate Change Event.
                                     Table 6-6     Vertical Rate Change Event

              ATN                         FANS 1/A                         Interoperability Guidance
              Request Parameters                                           Equivalent.
                 Vertical rate               Vertical rate change        Note. See Table 6-23 for
                                               threshold                   additional guideline on the
                                                                           vertical rate parameter.
              Event ADS Report                                             Equivalent


                 Basic Group                 Basic Group                 See paragraph 6.3.2.1 for
                 Ground vector               Tag (14): Earth             additional guidance on basic
                                               Reference Group             group.
                                                                           See paragraph 6.3.2.2 for
                                                                           additional guidance on ground
                                                                           vector / earth reference group.
              Trigerring Event                                             Equivalent.
                 only when the aircraft‘s    If the vertical rate
                  rate of climb is greater     threshold is positive,
                  than the value of            when the aircraft's rate
                  vertical-rate-change         of climb is greater than
                                               the vertical rate
                                               threshold.
                                              If the vertical rate
                                               threshold is negative,
                                               when the aircraft's rate
                                               of climb is less than the
                                               vertical rate threshold
                                               (i.e. the aircraft is
                                               descending)
              Reporting Rate                                               Not equivalent
                 once every 60 seconds       only one report
                                                                                                      6-267

6.2.4.3       Level/Altitude range change event
          Table 6-7 presents the ATN and FANS 1/A Level/Altitude Event.


                                  Table 6-7     Level/Altitude Range Event

          ATN                          FANS 1/A                        Interoperability Guidance
          Request Parameters                                           Equivalent.
             Ceiling level                Ceiling altitude           Note. See Table 6-23 for
             Floor level                  Floor altitude             additional guideline on the
                                                                       level/altitude parameter.
          Event ADS Report                                             Not equivalent, the ground vector
                                                                       is not downlinked.
             Basic Group                  Basic Group                See paragraph 6.3.2.1 for
             Ground vector                                            additional guidance on basic
                                                                       group.
          Trigerring Event                                             Equivalent
             when the aircraft‘s level    when the aircraft's
              is greater than the value     altitude is greater than
              of ceiling, or less than      the altitude ceiling or
              the value of floor            less than the altitude
                                            floor
          Reporting Rate                                               Not equivalent
             once every 60 seconds        only one report
6-268

    6.2.4.4       Way-point change event
              Table 6-8 presents the ATN and FANS 1/A Way-point Event.


                                            Table 6-8     Way-point Event

              ATN                           FANS 1/A                       Interoperability Guidance
              Request Parameters
                 none                         none                       Equivalent.
              Event ADS Report
                 Basic Group                  Basic Group                See paragraph 6.3.2.1 for
                 Projected Profile            Tag (13): Predicted        additional guidance on basic
                                                route Group                group.
                                                                           See paragraph 6.3.2.3 for
                                                                           additional guidance on projected
                                                                           profile / predicted route group.
              Trigerring Event
                 whenever the aircraft‘s      The waypoint change
                  next way-point changes        event is triggered by a
                                                change to the next or
                                                next- plus-one waypoint
                                                (due to a flight plan
                                                change or waypoint
                                                sequence).
              Reporting Rate                                               Equivalent
                 None, sequence of            The waypoint change
                  waypoint                      event trigger remains in
                                                effect for all waypoint
                                                changes.
                                                                                              6-269

6.3     Downlink Functions
6.3.1   ADS Downlink Messages
        Table 6-9 compares the ATN ADS-C downlink messages with the FANS 1/A downlink
        messages.
                     Table 6-9   ATN and FANS 1/A ADS downlink messages

        ATN ADS Messages         FANS 1/A ADS Messages            Interoperability Guidance
        [0] ADS-report-PDU
        [1] ADS-accepted-PDU
            ADSReport            Tag (7): Periodic Report         Functionally equivalent.
             contract-type =                                     See paragraph 6.3.2 for
               demand                                             additional guidance on ADS
                                                                  Report.
            ADSReport            Tag (10, 18, 19, 20) ADS Event   Functionally equivalent.
             contract-type =    reports                          See paragraph 6.3.2 for
               event                                              additional guidance on ADS
                                                                  Report
            ADSReport            Tag (7): Periodic Report         Functionally equivalent.
             contract-type =                                     See paragraph 6.3.2 for
               periodic                                           additional guidance on ADS
                                                                  Report
        [2] ADS-reject-PDU       Tag (4): Negative                Functionally equivalent.
                                 acknowledgement                  See paragraph 6.3.3 for
                                 Note. Following the generation   additional guidance on ADS
                                 of three consecutive Negative    Reject.
                                 Acknowledgements on the same
                                 connection, the FANS 1/A
                                 aircraft shall cancel all
                                 contracts on the respective
                                 connection and terminate that
                                 connection
        [3] ADS-ncn-PDU          Tag (5): Noncompliance           Functionally equivalent.
                                 Notification                     See paragraph 6.3.7 for
                                                                  additional guidance on non-
                                                                  compliance notification.
6-270

        ATN ADS Messages           FANS 1/A ADS Messages                Interoperability Guidance
        [4] ADS-Positive-          Tag (3): Acknowledgement             In the ATN ground system,
        Acknowledgement-PDU        For a valid Demand contract          positive acknowledgement is
                                   request, not containing the          only in use in Event and
                                   Aircraft Intent Group, the only      Periodic contract types.
                                   response shall be the                The ATN ground system would
                                   ―acknowledgement‖ assembled          be able to process the
                                   with the ADS report in the same      ―acknowledgement‖ assembled
                                   ADS downlink message.                with the ADS report.
                                   For a valid Demand contract          When requesting the Predicted
                                   request containing the Aircraft      Route Group from the
                                   Intent Route Group the initial       FANS 1/A aircraft if a ―Positive
                                   response shall be the                Acknowledgement‖ is sent, it is
                                   ―acknowledgement‖. The               always sent with the Demand
                                   acknowledgement is either sent       report.
                                   in a separate ADS downlink           Some FANS 1/A aircraft send
                                   message or assembled with the        the acknowledgement in an
                                   ADS report in the same ADS           ADS message separate from the
                                   downlink message.                    ATS report. Other FANS 1/A
                                                                        aircraft send the
                                                                        acknowledgement assembled
                                                                        with the ADS report in the same
                                                                        ADS downlink message.
                                                                        The ATN ―Positive
                                                                        Acknowledgement‖ is always
                                                                        included in ADS Demand
                                                                        report.
                                                                        See paragraph 6.3.6 for
                                                                        additional guidance on ADS
                                                                        Positive Acknowledgement
        [5] ADS-cancel-positive-   Tag (3): Acknowledgement             Functionally equivalent.
        acknowledgement-PDU        Note. Sent after the receipt of a    See paragraph 6.3.6 for
                                   valid cancel event contract.         additional guidance on ADS
                                                                        Cancel Positive
                                                                        Acknowledgement
        [6] ADS-cancel-negative    Tag (4): Negative                    Functionally equivalent.
        acknowledgement-PDU        acknowledgement                      See paragraph 6.3.3 for
                                   Note. Sent after the receipt of an   additional guidance on ADS
                                   invalid cancel event contract.       Cancel Negative
                                                                        Acknowledgement
        [7] ADS-Provider-Abort-    No equivalent.                       The ground system cannot
        PDU                                                             receive an abort from an
                                                                        FANS 1/A aircraft.
        [8] ADS-User-Abort-PDU No equivalent.                           The ground system cannot
                                                                        receive an abort froman
                                                                        FANS 1/A aircraft.
                                                                                                 6-271

        ATN ADS Messages              FANS 1/A ADS Messages         Interoperability Guidance
        No equivalent.                Tag (9): Emergency Report     Not equivalent.
                                                                    In ATN, the emergency
                                                                    information is downlinked in
                                                                    each ADS-report, not as a
                                                                    separate downlink message.


        No equivalent.                Tag (6): Cancel Emergency     Functionally equivalent.
                                      Mode Indication               In ATN, the cancel indication is
                                                                    downlinked in each ADS-report,
                                                                    not as a separate downlink
                                                                    message.



        The FANS 1/A aircraft may concatenate different ADS reports in a single downlink
        message. The ATN ground system would be able to process multiple different ADS
        reports in a single downlink message.


6.3.2   ADS Report
        Table 6-10 presents the ATN and FANS 1/A ADS reports.
                              Table 6-10 ATN and FANS 1/A ADS reports

        ATN ADS Reports                FANS 1/A ADS Reports       Interoperability Guidance
        ADS report                     Tag (7): ADS report        Functionally equivalent.
                                       Periodic report            When the ADS-report is related to
                                       Or                         an ADS-Demand contract request,
                                       Tag (10, 18, 19, 20) ADS   the ATN ground system processes
                                       Event reports              the ADS report tag (7) as the
                                                                  reception of a Demand report.
                                                                  When the ADS-report is related to
                                                                  an ADS-Periodic contract request,
                                                                  the ATN ground system processes
                                                                  the ADS report tag (7) as the
                                                                  reception of a Periodic report.
                                                                  The ATN ground system
                                                                  processes the ADS report tags (10,
                                                                  18, 19, 20) as the reception of
                                                                  Event reports.
        [0, 1, 2] Basic Information       Basic ADS Group        Functionally equivalent.
                                                                  See paragraph 6.3.2.1 for
                                                                  additional guidance on basic
                                                                  group.
6-272

        ATN ADS Reports               FANS 1/A ADS Reports         Interoperability Guidance
        [3] Contract Number           Not equivalent.              Not equivalent.
                                                                   FANS 1/A does not include the
                                                                   contract number in the ADS
                                                                   Report.
        [4] Aircraft address          Tag (17) Airframe ID group   Functionally equivalent.
                                                                   Note. See Table 6-23 for
                                                                   additional guideline on the
                                                                   aircraft adress / airframe id
                                                                   parameter.
        [5] Aircraft Identification   Tag (12) Flight              Functionally equivalent.
                                      Identification Group         Note. See Table 6-23 for
                                                                   additional guideline on the
                                                                   aircraft id parameter.
        [6] Projected Profile         Tag (13) Predicted Route     Functionally equivalent.
                                      Group                        See paragraph 6.3.2.4 for
                                      Predicted Route Group        additional guidance on Projected
                                                                   Profile / Predicted Route group.
        [7] Ground vector             Tag (14): Earth Reference    Functionally equivalent.
                                      Group                        See paragraph 6.3.2.2 for
                                                                   additional guidance on ground
                                                                   vector / earth reference group.
        [8] Air vector                Tag (15): Air reference      Functionally equivalent.
                                      Group                        See paragraph 6.3.2.3 for
                                                                   additional guidance on ground
                                                                   vector / earth reference group.
        [9] Met info                  Tag (16): Meteorological     Functionally equivalent.
                                      Group                        See paragraph 6.3.2.7 for
                                                                   additional guidance on MET
                                                                   group.
        [10] Extended Projected       Predicted Route Group        The ground system processes the
        Profile                       Predicted Route Group Tag    Predicted Route Group Tag (13)
                                      (13)                         as the reception of Extended
                                                                   Projected Profile Group when it
                                                                   results from an EPP request
                                                                   translated into a Predicted Route
                                                                   Request.
                                                                   Only the next and next+1
                                                                   waypoints are provided.
                                                                   See paragraph 0 for additional
                                                                   guidance on EPP / Predicted
                                                                   Route.
                                                                                    6-273

ATN ADS Reports           FANS 1/A ADS Reports        Interoperability Guidance
                          Tag (22): Intermediate      The ground system processes the
                          Projected Intent Group      Intermediate Predicted Intent
                                                      Group Tag (22) and the Fixed
                                                      Projected Intent Group tag (23) as
                          And
                                                      the reception of Extended
                                                      Projected Profile Group when they
                          Tag (23): Fixed Projected   results from an EPP request
                          Intent Group                translated into an Aircraft Intent
                                                      request.
                                                      The Intermediate Projected Intent
                                                      group and the Fixed Projected
                                                      Intent group are provided by the
                                                      FANS 1/A aircraft.
                                                      If Intermediate Projected Intent is
                                                      used, then up to the next 10
                                                      waypoints are provided
                                                      Intermediate Projected Intent
                                                      group does not contain waypoint
                                                      where there is no change of
                                                      altitude or speed or track
                                                      (heading).
                                                      See paragraph 6.3.2.6 for
                                                      additional guidance on EPP /
                                                      Intermediate Project Intended
                                                      Group.


[11] Emergency-urgency-   No equivalent               No equivalent
status                                                The emergency information is
                                                      received from a FANS 1/A
                                                      aircraft in ADS emergency reports
                                                      through the establishment of an
                                                      emergency contract.
6-274



    6.3.2.1       Basic Group / Basic ADS Group
              Table 6-11 presents the ATN Basic Data Block / FANS 1/A Basic Group.
                                  Table 6-11 Basic Data Block / Basic ADS Group

              ATN – Basic                    FANS 1/A – Basic                 Interoperability Guidance
              Parameters                                                      Equivalent
                 ThreeDPosition                                              Latitude, Longitude,
                 Latitude                      Latitude                     Altitude/level, timestamp range
                                                                              and resolution different.
                 Longitude                     Longitude
                                                                              FOM data is different.
                 Level (OPTIONAL)              Altitude
                 Time                          Timestamp
                                                                              Note. See Table 6-23 for
                 FOM                           FOM
                                                                              additional guideline on latitude,
                 Position accuracy             Position accuracy            longitude, level/altitude,
                 Multiple units operating      TCAS Health                  timestamp, position accuracy
                                                                              parameters.
                 Acas operational              Navigation System
                                                 Redundancy


              Note. When an ADS report       When either the latitude or
              is received with the           the longitude for a position
              FOM/position accurancy=0,      are invalid, both shall be set
              the ATN ground system          to -180°. In the Basic
              shall disregard the position   Group, the FOM shall also
              and timestamp.                 be set to 0.
                                             When the timestamp is
                                             invalid, in the basic ADS
                                             Group, the FOM shall also
                                             be set to 0.

    6.3.2.2       Ground Vector data block / Earth Reference Group
              Table 6-12 presents the ATN Ground Vector Data Block / FANS 1/A Earth Reference
              Group.
                                   Table 6-12 Ground Vector / Earth Reference

              ATN – Ground Vector            FANS 1/A – Earth                 Interoperability Guidance
                                             Reference
              Parameters                                                      Equivalent
                 Track                         True Track                   Note. See Table 6-23 for
                 Ground-speed                  Ground speed                 additional guideline on track,
                                                                              ground speed and vertical rate
                 Vertical rate                 Vertical rate
                                                                              parameters.
                                                                                              6-275

6.3.2.3       Air Vector data block / Air Reference Group
          Table 6-13 presents the ATN Air Vector Data Block / FANS 1/A Air Reference Group.
                                  Table 6-13 Air Vector / Air Reference

          ATN – Air Vector            FANS 1/A – Air Reference Interoperability Guidance
          Parameters                                            Equivalent
             Heading                    V, S, True Heading    Note. See Table 6-23 for
             Air speed                  Mach Speed            additional guideline on heading,
                                                                air speed and vertical rate
             Veritcal Rate              Vertical Rate
                                                                parameters.



6.3.2.4       Projected Profile data block / Predicted route Group
          Table 6-14 presents the ATN Projected Profile Data Block / FANS 1/A Predicted route
          Group.
                         Table 6-14 Projected Profile data block / Predicted Route

          ATN – Projected Profile     FANS 1/A – Predicted      Interoperability Guidance
                                      Route
          Parameters                                            Functionally equivalent.
             Next Way-point:            Next Way-point:       Note. See Table 6-23 for
             Position                   Position              additional guideline on position
                                                                and time parameters.
             Name (OPTIONAL)            No equivalent
             ETA (OPTIONAL)             ETA
             Next+1 Way-point:          Next+1 Way-point:
             Position                   Position
             Name (OPTIONAL)
             ETA (OPTIONAL)
6-276



    6.3.2.5       Extended Projected Profile data block / Predicted route Group
              Table 6-15 presents the ATN Extended Projected Profile Data Block / FANS 1/A
              Predicted route Group.
                  Table 6-15 Extended Projected Profile data block / Predicted route Group

              ATN – Projected Profile    FANS 1/A – Predicted route       Interoperability Guidance
              Extended Projected Profile Predicted Route Group:
                                          Predicted Route Group Tag
                                          (13)
              For each waypoint (up to   For next waypoint and next + 1   If Predicted Route Group is used,
              128 waypoints)::           waypoint                         then the comparison can be done
                                                                          only for the data provided, up to
                                                                          the next 2 waypoints.


                  Position                   Position                     Latitude, Longitude,
                         Latitude             Latitude                    Altitude/level, ETA timestamp
                                                                          range and resolution are different.
                         Longitude            Longitude
                                                                          See paragraph 6.4 for parameter
                         Level                Altitude
                                                                          range and resolution differences.

                  Name                       Not equivalent.
                  ETA                          ETA (at next waypoint
                                               only)


                  Estimated Speed            Not equivalent.
                  Vertical Type              Not equivalent.
                  Lateral Type               Not equivalent.
                  Level Constraints          Not equivalent.
                  Speed restrictions         Not equivalent.
                  RTA                        Not equivalent.
              Gross mass                 Not equivalent.
              Gross mass at TOD          Not equivalent.
              Speed schedule             Not equivalent.
              Trajectory intent status   Not equivalent.
                                                                                                   6-277

6.3.2.6       Extended Projected Profile data block / Intermediate Projected Intent Group
          Table 6-16 presents the ATN Extended Projected Profile Data Block / FANS 1/A
          Intermediate Projected Intent Group.
          Table 6-16 Extended Projected Profile data block / Intermediate Projected Intent
                                                    Group

          ATN – Projected Profile      FANS 1/A – Intermediate          Interoperability Guidance
                                       Projected Intent
          Extended Projected Profile    Intermediate projected intent   See paragraphs 6.3.2 for the use of
                                        tag (22)                        intermediate projected intent tag
                                                                        (22).

          For each waypoint (up to     Up to 10 waypoints               If Intermediate Projected Intent is
          128 waypoints)::                                              used, then the comparison can be
                                                                        done only the data provided, up to
                                                                        the next ten waypoints.
              Position                     Position


                    Latitude                 No equivalent            For the Extended Projected Profile,
                    Longitude                No equivalent            the ATN ground system may
                                                                        convert the information provided
                    Level                    Altitude
                                                                        in the Intermediate Projected
                                              Distance from previous   Intent Group into LAT/LON
                                               waypoint                 reference.
                                              True Track from
                                               previous waypoint
              ETA                          Projected time
              Estimated Speed              No equivalent
              Name                         No equivalent
              Vertical Type                No equivalent                The Intermediate Projected Intent
                                                                        Group may include waypoints
                                                                        (ATC compulsory waypoint and
                                                                        pilot/ company-inserted waypoint)
                                                                        and vertical profile points. The
                                                                        way point type is not identified in
                                                                        the intermediate projected intent
                                                                        report.
                                                                        Intermediate Projected Intent
                                                                        group does not contain waypoint
                                                                        where there is no change of
                                                                        altitude or speed or track
                                                                        (heading).
              Lateral Type                 No equivalent
              Level Constraints            No equivalent
              Speed restrictions           No equivalent
6-278

              ATN – Projected Profile    FANS 1/A – Intermediate      Interoperability Guidance
                                         Projected Intent
                  RTA                         No equivalent
              Gross mass                 No equivalent
              Gross mass at TOD          No equivalent
              Speed schedule             No equivalent
              Trajectory intent status   No equivalent




    6.3.2.7       MET data block / Meteorological Group
              Table 6-17 presents the ATN MET Data Block / FANS 1/A Meteorological Group.
                                 Table 6-17 ATN Ground Vector / Earth Reference

              ATN – MET                   FANS 1/A –               Interoperability Guidance
                                          Meteorological Group
              Parameters                                           Not Equivalent
                 Wind Speed                  Wind Speed          Note. See Table 6-23 for
                 Wind direction              V, S, True Wind     additional guideline on wind
                                               Direction           speed, air speed and vertical rate
                                                                   parameters.
                 Wind quality Flag           No equivalent
                 Temperature                 S, Temperature
                 Turbulence                  No equivalent
                 Humidity                    No equivalent
                                                                                                             6-279

6.3.3           ADS ATN Reject / FANS Negative Ack
                Table 6-18 presents the ATN and FANS 1/A ADS reject.
                                Table 6-18 ATN ADS Reject / FANS 1/A Negative Ack

        ATN ADS Reject             FANS 1/A ADS Negative Ack                     Interoperability Guidance
        [3] ADS reject             Tag (4): Negative acknowledgement             Functionally equivalent.
           ADS contract Number       ADS contract Request Number               ATN aircraft use the contract type
                                                                                 to associate the reject data with the
                                                                                 contract whereas the FANS aircraft
                                                                                 use the contract number.
                                                                                 Note. See Table 6-23 for additional
                                                                                 guideline on wind speed, air speed
                                                                                 and vertical rate parameters.
           Emergency Urgency         No equivalent
           Reject Details            Reason                                    FANS aircraft provide more
                                                                                 detailed reason on the reject cause.

           ADS service               No equivalent
            unavailable
           Undefined                 Duplicate on request group tag (1)
                                      Duplicate reporting rate tag (2)
                                      Event contract request with no data
                                       (3)
                                      Improper operational mode tag (4)
                                      Non-matching cancel contract
                                       number (5)
                                      Matching existing contract request
                                       number (6)
                                      Undefined contract request tag (7)
                                      Undefined error (8)
                                      Not enough data in request (9)
                                      Floor altitude >= ceiling altitude (10)
                                      Vertical rate change threshold equal
                                       to 0 (11)
                                      Aircraft intent projection time
                                       parameter equal to 0 (12)
                                      Lateral deviation change threshold
                                       equal to 0 (13)
6-280

        ATN ADS Reject          FANS 1/A ADS Negative Ack                  Interoperability Guidance
           Maximum-capacity-      No equivalent                          When the aircraft receives an ADS
            exceeded                                                       service request while the maximum
                                                                           number of ADS connections are
                                                                           established:
                                                                            the FANS 1/A aircraft denies
                                                                                service by sending a
                                                                                Disconnect Request
                                                                                (IMI=DIS) with reason code 1,
                                                                            The ATN aircraft sends the
                                                                                reject reason Maximum-
                                                                                capacity-exceeded with the
                                                                                identity of the ground systems
                                                                                it is connected to.
           Invalid-waypoint       No equivalent
           No equivalent          Extended Data (only for reasons 1, 2   The ground system ignores the
                                    and 7):                                extended data.
                                   Duplicate optional message group
                                    tag
                                   Duplicate reporting Rate tag.
                                   Undefined contract request tag
                                                                                            6-281


6.3.4   ADS ATN Cancel Positive Ack / FANS Positive Ack
        Table 6-19 presents the ATN and FANS 1/A ADS Positive Ack.
               Table 6-19 ATN ATN Cancel Negative Ack / FANS 1/A Positive Ack

        ADS ATN Cancel Positive     FANS 1/A ADS Positive      Interoperability Guidance
        Ack                         Acknowledgement
        [3] ADS Cancel Negative     Tag (3): Acknowledgement   Functionally equivalent.
        Ack                                                    Note. ATN Neg Ack is not used for
                                                               contract rejection (see ADS
                                                               Reject).
           No equivalent              ADS Contract Request   Functionally equivalent.
                                        Numbe


           Request type               No equivalent
           Cancel-event-contract
           Cancel-periodic-
            contract



6.3.5   ADS ATN Cancel Negative Ack / FANS Negative Ack
        Table 6-20 presents the ATN and FANS 1/A ADS Negative Ack.
              Table 6-20 ATN ATN Cancel Negative Ack / FANS 1/A Negative Ack

        ADS ATN Cancel Negative FANS 1/A FANS Negative         Interoperability Guidance
        Ack                     Ack
        [3] ADS Cancel Negative     Tag (4): Negative          Functionally equivalent.
        Ack                         acknowledgement            Note. ATN Neg Ack is not used for
                                                               contract rejection (see ADS
                                                               Reject).
           No equivalent              ADS contract Request   Functionally equivalent.
                                        Number


           Request type               No equivalent
           Cancel-event-contract
           Cancel-periodic-
            contract
           Reject Reason              Reason
           No-such-contract           Non-matching cancel
                                        contract number (5)
6-282



6.3.6   ADS Positive Acknowledgement
        Table 6-21 presents          the    ATN     ADS     and   comparable    FANS 1/A        positive
        acknowledgement.
                  Table 6-21 ATN and FANS 1/A ADS positive acknowledgement

        ATN ADS Positive              FANS 1/A ADS Positive          Interoperability Guidance
        Acknowledgement               Acknowledgement
        [5] ADS Positive              Tag (3): Acknowledgement       Functionally equivalent.
        Acknowledgement
           ADS contract Request          ADS Contract Request      ATN aircraft use the contract
            Number                         Number                    type to associate the reject data
            (OPTIONAL)                                               with the contract whereas the
                                                                     FANS aircraft use the contract
                                                                     number.
           Request Type:                 No equivalent
           event contract,
           periodic contract,
           demand contract,
           cancel event contract,
           cancel periodic
            contract,
           cancel all contracts.
        




6.3.7   ADS Non-Compliance Notification
        Table 6-22 presents the ATN ADS and cFANS 1/A non-compliance notifications.
                 Table 6-22 ATN and FANS 1/A ADS non-compliance notification

        ATN ADS Non-Compliance             FANS 1/A ADS Non-         Interoperability Guidance
        Notification                       Compliance Notification
                                           Message
        Non-compliance notification        Non-Compliance            Functionally equivalent.
                                           Notification Tag (5)
        Contract number                    ADS Contract Request      In the FANS 1/A, the ADS
                                           Number                    contract request number is used
                                                                     to identify what type of contract
                                                                     the ADS Non Compliance
                                                                     Notification refers.
                                                                     Note. See Table 6-23 for
                                                                     additional guideline on the
                                                                     contract number parameter.
                                                                                           6-283

ATN ADS Non-Compliance          FANS 1/A ADS Non-              Interoperability Guidance
Notification                    Compliance Notification
                                Message
Emergency Urgency               No equivalent                  The emergency information is
                                                               received from a FANS 1/A
                                                               aircraft in ADS emergency
                                                               reports through the
                                                               establishment of an emergency
                                                               contract.
EPP Limitations                 No equivalent                  FANS 1/A Intermediaite
 epp-tol-range-difference                                     Projected Intent request does not
                                                               include tolerance range,
 epp-waypoint-difference
                                                               waypoint, reporting/monitoring
 epp-reporting-window-                                        window.
   difference
 epp-monitoring-window-
   difference
Ncn type contract not           Number of Message              The ATN ground system would
supported                       Groups                         use the ADS number of message
                                Note: The “Number of           groups received in the Non
                                Message Groups”                Compliance Notification to
                                corresponds to the number      identify the number of on-
                                of on-request groups or        request groups or events which
                                events that cannot be          cannot be provided.
                                complied by the FANS 1/A
                                aircraft.
                                Each message group is
                                identified by a
                                group/Event Tag.
                                The repetition of the First
                                Message Group variable
                                gives the list of on-request
                                groups or events tags that
                                are not in compliance.
     Demand-ncn                Group Tags               Equivalent for data block
    For each data block, ―not   For each data block,     supported by both ATN and
    available‖ indication                                FANS1/A.
                                 Block Tag
                                 ―not
                                    available/undefined‖
                                    indication
                                 Parameters (see below)
6-284

        ATN ADS Non-Compliance      FANS 1/A ADS Non-               Interoperability Guidance
        Notification                Compliance Notification
                                    Message
              Event-ncn            Event Tags               Equivalent for event supported
                                     Event Tag              by both ATN and FANS1/A.
                                     For each data block,
                                        ―not
                                        available/undefined‖
                                        indication
                                     Parameters (see below)
            Periodic-ncn
           SEQUENCE OF
           notsupportedReportType   Group Tags
                                    For each data block,
                                     Block Tag
                                     ―not
                                        available/undefined‖
                                        indication
                                     Parameters (see below)
           supportedReportingRate   No equivalent                   The default reporting rate
                                    When indicating that the        applies.
                                    FANS 1/A aircraft is not
                                    able to support the
                                    requested reporting rate,
                                    First Message group value
                                    contains the reporting rate
                                    tag (11) and the first bit of
                                    the following octet is set to
                                    1.
           No equivalent            Parameters                      The FANS 1/A aircraft also
                                    For each message group          indicates which parameters
                                    (one for each on-request        within each optional group
                                    groups or event that cannot     cannot be provided.
                                    be complied with):              The ATN ground system may
                                    - number of parameters,         ignore the number of parameters
                                                                    and parameter number provided
                                    - parameter number.
                                                                    in the Non-compliance
                                    Note: The FANS 1/A              notification.
                                    aircraft also indicates
                                                                    Use of these parameters is a
                                    which parameters within
                                                                    local matter.
                                    each optional group cannot
                                    be provided.
                                                                                                6-285


6.4   Parameter Range and Resolution
      Table 6-23 compares the ATN and FANS 1/A ADS-C variables with range and
      resolution.
           Table 6-23 ATN and FANS 1/A ADS variables with range and resolution

      ATN ADS variables with       FANS 1/A ADS variables       Interoperability Guidance
      range and resolution         with range and resolution
      Aircraft address             Airframe ID                  Equivalent
       24-bit ICAO ID              24-bit ICAO ID
      Aircraft Identification      Flight Identification        Equivalent
       String SIZE (2..7)          String SIZE (8)
      Air Speed:                   Mach:                        The FANS 1/A variable does not
      Either                          Range: 0 to 4.095        contain IAS.
       Mach                           mach                     The FANS 1/A mach variable has
                                                               smaller range and finer resolution.
         Range: 0.5 to 4 mach         Resolution: 0.0005
                                       mach
         Resolution: 0.001
          mach
         Ias
         Range: 0 to 1100 knots
         Resolution: 1 knot
         Mach and Ias


      Contract Number              Contract Number              Equivalent.
       Range: 0.255                Range: 0.255

                                   Note. The value (255) is
                                   reserved for the emergency
                                   periodic contract.
      EPP Window:                  Tag (21): Aircraft Intent
       Time-interval:             (optional)
         Range: 15 min to 20       Aircraft Intent
          hours                         Projection Time
                                                             The FANS 1/A variable has smaller
         Resolution: 15 minutes      Range 0 – 255 minutes range and finer resolution.
                                      Resolution: 1 minute
         Number of waypoints:
         Range: 1 to 128                                       No equivalent. The ground system
                                                                shall be aware that only up to 10
         Resolution: 1
                                                                way-points can be reported by the
                                                                FANS 1/A aircraft and for a
                                                                maximum projected time of 255
                                                                minutes.
6-286

        ATN ADS variables with     FANS 1/A ADS variables       Interoperability Guidance
        range and resolution       with range and resolution
        Ground Speed               Ground Speed               The FANS 1/A variable has a
           Range: -50 to 2200        Range: 0 to 4095 knots different range;
            knots                     Resolution: 0.5 knot
           Resolution: 0.5 knot
        Heading                    True Heading                 The FANS 1/A variable has a
           Range: 0.05 to 360        Range: -180 to           different heading reference and a
            degrees                    179.912°                 finer resolution.
           Resolution: 1 degree      Resolution: 0.08789°
        Lateral Deviation          Lateral Deviation Change     The FANS 1/A variable has smaller
        Threshold                  Threshold                    range and finer resolution.
           Range: 0.5 to 150 NM      Range: 0.125 to 31.875
                                       NM
           Resolution: 0.5 NM        Resolution: 0.125
        Latitude:                  Latitude:                    When using the Predicted route
         Range: -90 to +90          Range: -90 to +90           group or the Intermediate Projected
                                                                Intent group, the ATN ground
         Resolution: 0.1 seconds    Resolution: 0.00172
                                                                system would process the FANS
                                    degrees
                                                                range and resolution for the
                                   Default value: -180 (with    Latitude variable.
                                   FOM set to 0)
                                                                When using the Latitude variable,
                                                                the ATN ground system would not
                                                                use the Latitude variable when set
                                                                to default value.
                                                                The ATN variable has finer
                                                                resolution.
                                                                The algorithm to convert range and
                                                                resolution is a local matter.
                                                                The translation of the default value
                                                                is a local matter.
                                                                                         6-287

ATN ADS variables with     FANS 1/A ADS variables       Interoperability Guidance
range and resolution       with range and resolution
Level:                     Altitude:                    When using the Predicted route
 Range: -750 to +100000     Range: -131,072 to +        group or the Intermediate Projected
                            131,068                     Intent group, the ATN ground
 Resolution: 10 feet
                                                        system would process the
                            Resolution: 4 feet
                                                        FANS 1/A Range and resolution for
                           Default value: -131,072      the Altitude variable.
                                                        When using the Level variable, the
                                                        ATN ground system would not use
                                                        the Altitude variable when set to
                                                        default value.
                                                        The FANS 1/A variable has greater
                                                        range and finer resolution.
                                                        The algorithm to convert range and
                                                        resolution is a local matter.
                                                        The translation of the default value
                                                        is a local matter.
Longitude:                 Longitude:                   When using the Predicted route
 Range: -180 to +180        Range: -180 to +180         group or the Intermediate Projected
                                                        Intent group, the ATN ground
 Resolution: 0.1 seconds    Resolution: 0.00172
                                                        system would process the FANS
                            degrees
                                                        Range and resolution for the
                           Default value: - 180 (with   Longitude variable.
                           FOM set to 0)
                                                        When using the Longitude variable,
                                                        the ATN ground system would not
                                                        use the Longitude variable when set
                                                        to default value.
                                                        The ATN variable has finer
                                                        resolution.
                                                        The algorithm to convert range and
                                                        resolution is a local matter.
                                                        The translation of the default value
                                                        is a local matter.
Modulus:                   Modulus:                     No additional interoperability
 Range: 1 to 255           Range: O to 255            guidance.
 Resolution: 1             Resolution: 1
                           Default value: 255
                           Value 0 is to de-select a
                           group.
Position accuracy:         Position accuracy:           FOM values other than 0 are not
 Range: 0 to 7             Range: 0 to 7              used by continental data link
                                                        services.
 Resolution: 1             Resolution: 1
                           Default value: 0
6-288

        ATN ADS variables with      FANS 1/A ADS variables        Interoperability Guidance
        range and resolution        with range and resolution
        Reporting rate:             Report interval:              When using the ADS Periodic
         Seconds:                    Scaling factor 01:           contract, the ATN ground system
                                                                  would process the FANS range and
           Range: 1 to 59              Range: 1 to 64
                                                                  resolution for the Reporting Interval
           Resolution: 1 second        Resolution: 1 second       variable.
         Minutes:                    Scaling factor 10:           When using Reporting Interval
           Range: 1 to 120             Range: 8 to 512            variable, the ATN ground system
           Resolution: 1 minute        Resolution: 8 seconds      would not use the Reporting
                                                                  Interval variable when set to default
                                     Scaling factor 11:
                                                                  value.
                                       Range: 64 to 4096
                                                                  FANS 1/A variable range is greater.
                                       Resolution: 64 seconds     The translation of the default value
                                                                  is a local matter.
        Track                       True Track Angle:             The FANS 1/A variable has a
           Range: 0.1 to 360          Range: -180 to            different heading reference and a
            degrees                     179.912°                  less resolution.
           Resolution: 0.05           Resolution: 0.08789°
            degree
        Vertical Rate               Vertical Rate:                The FANS 1/A variable has a larger
           Range: -30000 to           Range: -32752 to          range but a less resolution.
            30000 feet/min              32752 feet/min
           Resolution: 10 feet/min    Resolution: 16 feet/min


        Distance:                   Distance:                     When converting the Intermediate
          Range: 1 to 8000           Range: 0 to 8191.750         Projected Intent group to the
                                                                  extended projected profile group,
          Resolution: 1 nautical     Resolution: 0.125 NM
                                                                  the ATN ground system would
          mile                      Default value: 8191.750       process the FANS range and
        Note: Not used in the ATN   NM                            resolution for the distance
        INTEROP Standard.                                         parameter.
                                                                  When using the ETA variable, ATN
                                                                  ground system would ignore the
                                                                  default value of the ETA variable.
                                                                  ATN variable resolution more
                                                                  restrictive.
                                                                  The ―Distance‖ variable is provided
                                                                  in the Intermediate Projected Intend
                                                                  group.
                                                                                       6-289

ATN ADS variables with     FANS 1/A ADS variables        Interoperability Guidance
range and resolution       with range and resolution
ETA:                       ETA:                          When using the ETA variable, the
 Time:                      Range: 0 to 16382            ATN ground system would convert
                                                         the ETA variable Hour-Minute-
  Hours:                    Resolution: 1 second
                                                         Second.
    Range: 0 to 23         Default value: 16,383 sec
                                                         When using the ETA variable, the
    Resolution: 1                                        ATN ground system would ignore
  Minutes:                                               the ETA variable when set to
    Range: 0 to 59                                       default value.
    Resolution: 1                                        In the FANS 1/A INTEROP
                                                         Standard, ETA is the estimated time
  Seconds:
                                                         to go from the timestamp provided
    Range: 0 to 59                                       in the Basic data group.
    Resolution: 1
Projection time:           Projected time:               FANS 1/A variable range is greater
 Range: 1 to 240            Range: 0 to 16382            and resolution is finer.
 Resolution: 1 minute       Resolution: 1 second
                           Default value: 16382
Timestamp:                 Timestamp:                    When using the Timestamp
 Date:                      Range: 0 to 3599.875         variable, the ATN ground system
                                                         would convert the timestamp
   Year:                    Resolution: 0.125 seconds
                                                         variable in Hour-Minute-Second.
    Range: 1996 to 2095    Default value: FOM set to 0
                                                         When using the Timestamp
    Resolution: 1 year                                   variable, the ATN ground system
   Month:                                                would ignore the Timestamp
    Range: 1 to 12                                       variable when FOM is set to 0.
    Resolution: 1 month                                  FANS 1/A timestamp variable
                                                         provides time seconds relative to
   Day:
                                                         current hour.
    Range: 1 to 31
                                                         The date variable can be provided
    Resolution: 1 day                                    using local source.
 Time:
   Hours:
    Range: 0 to 23
    Resolution: 1 hour
   Minutes:
    Range: 0 to 59
    Resolution: 1 minute
   Seconds:
    Range: 0 to 59
    Resolution: 1 second
6-290

        ATN ADS variables with        FANS 1/A ADS variables         Interoperability Guidance
        range and resolution          with range and resolution
        Not used in the ATN           True Track angle               When using the Intermediate
        INTEROP Standard.               Range: -180° to              Projected Intent group, the ATN
                                        +179,912°                    ground system would process the
                                                                     FANS Range and resolution for the
                                        Resolution: 0,08789°
                                                                     True Track angle variable.
                                      Default value: valid bit set
                                                                     When using the True Track angle
                                      to 1
                                                                     variable, the ATN ground system
                                                                     would ignore the True Track angle
                                                                     variable when set to default value.



6.5     Timers
        Table AP- 2 presents the ATN ADS technical timers and comparable FANS 1/A timers.
                                 Table AP- 2 ATN and FANS 1/A ADS timers

        ATN ADS Timers                 FANS 1/A ADS Timers            Interoperability Guidance
        t-DC-1 (demand contract        No equivalent.
        request)
        t-DC-2 (demand contract        No equivalent.
        request+report)
        t-EC-1 (event contract         No equivalent.
        request)
        t-EC-2 (cancel contract        No equivalent.
        request)
        t-PC-1 (periodic contract      No equivalent.
        request)
        t-PC-2 (periodic report)       No equivalent.
        t-PC-3 (cancel contract        No equivalent.
        request)
        t-LI-1                         No equivalent.
        The connection is closed by Inactivity timer               Not equivalent.
        the aircraft when no contract 16 minutes.
        is in place.
                                      If the connection has been
                                      established and does not
                                      have a valid contract for
                                      sixteen consecutive minutes,
                                      the FANS aircraft terminates
                                      the connection.
                                      6-291




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Appendix A MEMBERSHIP
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                                                                                  Appendix A
                                                                                         A-1
                                   Appendix A     MEMBERSHIP


               RTCA Special Committee - 214/EUROCAE Working Group - 78
            Air Traffic Services (ATS) Safety and Interoperability Requirements


                        FANS 1/A – ATS INTEROPerability Standard
Chairmen:
Appendix B HISTORY AND TERMS OF REFERENCE OF SC-214/WG-78
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                                                              Appendix B
                                                                     B-1
      Appendix B     HISTORY AND TERMS OF REFERENCE OF SC-214/WG-78

B.1   Introduction


B.2   Terms of Reference
Appendix C IMPROVEMENT SUGGESTION FORM
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                                                                                          Appendix C
                                                                                                 C-1
                            Appendix C       IMPROVEMENT SUGGESTION FORM


Name:      Company:
Address:
City:                                            State, Province:
Postal Code, Country:                            Date:
Phone:                                           FAX:
Email:
Document: ED-            /DO-            Revision        Sec:           Page:         Line:
[ ]      Documentation error (Format, punctuation, spelling)
[ ]      Content error
[ ]      Enhancement or refinement
Rationale (Describe the error or justification for enhancement):




Proposed change (Attach marked-up text or proposed rewrite):




Please provide any general comments for improvement of this document:




Return completed form to:
RTCA, Inc.                                 OR                 EUROCAE
Attention: DO-                                                Attention:   Secretary-General  ED-___
1828 L Street, Northwest, Suite 805                           102        rue        Etienne     Dolet
Washington, D. C. 20036-4001 USA                              92240       Malakoff      -    FRANCE
Email: info@rtca.org                                          Email: eurocae@eurocae.com
Appendix D
D-2




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                                                                           Appendix D
                                                                                  D-1
           Appendix D   Interoperability Requirements Traceability Table1


    DO-305 IR              SC-214 FANS INTEROP IR

    IR-1                   IR- 1

    IR-2                   IR- 2

    IR-3                   IR- 3

    IR-4                   IR- 4




1
  Editor’s note: Table to be updated during final review and comment period after SC-214
.validation period.

				
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