Summary of RTCA Meeting

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					RTCA Paper No. 211-10/SC220-020         SC-220 8th Plenary Minutes                      Dick Hess, Secretary

                       Summary of RTCA Meeting
                       SC-220 7th Plenary Minutes
                  RTCA Paper No. 211-10/SC220-020
Meeting Location:                     Meeting Date:
Wichita Airport Hilton                October 12-14, 2010
Wichita, KS


The first day was dedicated to wrapping up review and resolution of all remaining comments to the draft
MOPS. The draft document was amended to incorporate resolutions for all comments. At the end of the
day, the group reached consensus that all remaining comments had been resolved. The draft is to be
submitted to RTCA for final review by November 1, 2010.

The next two days were devoted to review of the draft Part 23 installation guidance, which are not reported

Discussions for the Draft MOPS

The agenda for the MOPS included:
     Resolve all remaining comments on the draft
     Review Sections 2.3 and 2.4 to ensure all tests can be accomplished without the need for installing
        the system on an aircraft
     Review Section 3.0 to make sure it includes all appropriate guidance
     Consider a new proposal to define equipment classes.

The FAA had commented at the 7th Plenary that the draft MOPS were missing performance standards.
Since then, the FAA held numerous internal coordination meetings and concluded that the structure and
content of the draft are acceptable provided that guidance was added to assure that control law gains are
correctly configured. The group added provisions for this. For systems where gains are loaded to software
from a configuration module, a CRC with self test would be acceptable. For systems with hardware
configuration straps, extra straps to detect a broken or shorted wire would be acceptable. It is recognized
that these methods may not detect all errors, but they should at least detect a single error.

One FAA comment was that references to FAR should be moved to the Installed Performance section. The
group considered Part 21, Subpart O (Technical Standard Order Authorizations). We replaced FAR
references in Section 2.2 with the terms “airplane” and “rotorcraft”. We also moved references to AC
23/25.1309 to Section 3.

We discussed a proposal to establish four classes of equipment functions covered under this MOPS: class
A, autopilot; class B: yaw damper; class C; flight director; and class D: autothrottle/autothrust. The group
agreed to adopt the proposal, providing that the classes apply to functions, not line-replaceable units. A
simple wing leveler would be classified as an autopilot. Helicopter stability augmentation functions that
remain operational when the autopilot is disengaged are considered part of the helicopter autopilot, under
class A.

We discussed whether a new TSO would replace the existing ones, or provide an option. The group felt that
the existing ones are too much trouble, and should be rescinded for new products.

We agreed to include the definition and discussion of the equipment functional classes in Sections 1.1 and
2.2. It was noted that the draft uses various terms when referring to an “autopilot”, whereas TSO-C9c uses
RTCA Paper No. 211-10/SC220-020          SC-220 8th Plenary Minutes                       Dick Hess, Secretary

the term “automatic pilot”. It was suggested that we use the term “autopilot” throughout the MOPS, and
link it to the term “automatic pilot” in the definitions section.

We changed the title of Section 1.5 to “AFGCS Functions and Modes”. We changed the title of Section 1.7
to “Aircraft Categories”. In Section 1.9b we replaced the term “bench” to “lab”, since “bench” might be
considered slang, and because we did not intend to imply an iron bird is necessary. We changed the title of
Section to indicate it only applies to rotorcraft.

We considered removing Section 1.9c “Installed System/Equipment Tests” since it seemed obvious, but did
not because it was included in the RTCA template.

We considered removing Figure 1.4-1 since it includes a level of detail not necessary for the requirements
of Section 2.2. In the end, we decided to retain the figure since it is referenced in the document.

In Section 2.1, we changed the term “TSO Approval” to “TSO Authorization”.

In Section 1.8d, we decided to add GNSS to the list of examples of navigation sensors.

We decided to reword a number of requirement so that they do not imply a requirement that rests with the
pilot (“The pilot shall…”).

We discussed deleting a requirement in Section 2.1.1 that installation of the equipment should not impair
the airworthiness of the aircraft, since it seems overly broad. We left it in since it is included in the RTCA
template, though we changed the wording a bit. The same question and resolution applies to Section 2.1.3.

There was a proposal to remove references to FARs since they are considered installation rules, and it is
sometimes difficult to show compliance on the equipment level. We agreed to replace all references to Part
23/27/29 with “airplane” or “rotorcraft”.

In Section 2.1.4 and other places where the requirement implies an evaluation on the aircraft, we decided to
add the phrase “if installed”.

We decided to use wording that allows a manufacturer to follow either DO-178B or later version.

In Section there was a comment that the requirement for the autopilot to disengage for
significant force levels could not be evaluated unless installed. We decided to leave in the comment since
the mechanism could be tested; evaluation of whether the force levels were “significant” should be left to
installation tests.

We discussed the need to clarify Section 2.4.4 to indicate the intent to test the equipment, not its integration
with the aircraft.

We discussed a proposal to add more requirements specific to the servo; it was eventually withdrawn. We
discussed whether a manufacturer could seek a partial TSOA on a servo by itself; this would be handled
similarly to what has been done to date.

There was a proposal in Section to add words indicating the manufacturers responsibility to include
appropriate external wiring in the environmental test chamber. We left it unchanged since DO-160 already
addresses this.

We agreed to add a maximum autopilot disengage time to Section of 500 milliseconds.

It was proposed to add a note to 2.2.9 indicating three acceptable means to respond to overspeed – alert and
disengage, alert and provide speed protection, or alert only. Draft test procedures don’t address the last two
of these. We did not adopt the proposal, since this is installation related.
RTCA Paper No. 211-10/SC220-020         SC-220 8th Plenary Minutes                       Dick Hess, Secretary

We discussed a proposal to add requirements for the manufacturer to define servo authority limits, but did
not since all servos are inherently limited anyway, and the installation should address any safety

We declined to include a proposed statement that MOPS performance may be affected by an associated
advisory circular, since it seems obvious.

We agreed to be consistent throughout the document regarding which revision of DO-160 to reference.

In Section 3.2, we agreed to add a requirement that the installation manual indicate the hardware and
software development assurance levels.

In Section, it was proposed to remove any examples of what the installer might have to verify, so
that it can’t be misread as a requirement. We added a requirement for the manufacturer to provide
information on configuration settings of the gains.

In Section 3.2.3, we added a requirement for the manufacturer to provide instructions to avoid command
polarity reversals. We added examples of EMI shielding techniques and moved it to the Electrical
installation section. We deleted examples of installation instructions in the second paragraph of Section

In Appendix C, we used the term “guidance cues”, and made several formatting changes.

We discussed why the draft does not include pitch and roll attitude control limits. The reason was that we
do not want to prohibit systems from providing unusual attitude recovery features, nor do we want to
require systems to control aircraft to arbitrary minimum attitudes that may not be recoverable on all aircraft
and flight conditions.

We decided to use the term “command” in lieu of “guidance” when referring to autopilot in the mode

In Section 1.5.4, we generalized the wording to not imply that an FMS must use a roll steering interface to
an autopilot.

We discussed a proposal to add a requirement on how to deal with multiple autopilots regarding pilot
indication of which sensors are in use by each. We decided to not include this requirement since it appears
to be an installation issue.

In Section, there was a proposal to allow automatic autopilot engagement when the purpose is to
perform an emergency maneuver such as TCAS RA.

In Section, we clarified that an autothrottle/autothrust system may automatically engage to
prevent a hazardous underspeed condition.

In Section 2.2.11, we considered adding a clarification that the design of any emergency descent feature
should avoid unintended activation.

At the end of the first day, the group agreed to accept the draft MOPS as amended.

The rest of the meeting was spent reviewing the draft Part 23 installation guidance white paper. Minutes on
this activity are not recorded here.

Following Meetings
The group set a tentative date for the next Plenary for the week of February 14, 2011 at Clearwater FL.
The leadership team will present the MOPS to the PMC, December 8 th at Washington DC.
RTCA Paper No. 211-10/SC220-020            SC-220 8th Plenary Minutes                 Dick Hess, Secretary

Certified as a true and accurate summary of the meeting.

Bill Nolte     Co-Chair             /s/                         Date    10/26/2010

Sherif Ali     Co-Chair              /s/                         Date    10/26/2010

Peter Skaves     Designated Federal Official        /s/          Date    10/26/2010
RTCA Paper No. 211-10/SC220-020    SC-220 8th Plenary Minutes                    Dick Hess, Secretary

     In Attendance     Title                                    Company                         Phone          e-Mail
1    Sherif Ali        Staff Application Engineer               GE Aviation                     319-432-3120
2    Jim Brady         Aerospace Engineer                       FAA ACE-111                     816-329-4132
3    Khaled Eltohamy   Technical Manager                        Honeywell                       602-436-0773
4    Jay Hardymon      Autopilot Systems Engineer               Avidyne                         319-360-9072
5    James Harris      Sr. Staff Engineer                       Bell Helicopter Textron         817-280-5262
6    Dick Hess         Technical Director                       Universal Avionics              425-602-1519
7    Lee Nguyen        Aerospace Engineer                       FAA AIR-130                     202-385-4656
8    Bill Nolte        Staff Engineer, Certification            Honeywell International, Inc.   602-436-3770
9    Peter Skaves      Avionics Specialist                      FAA CSTA                        425-802-0395
10   John VanHoudt     ASE                                      FAA ASW-111                     817-222-5167

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