Your Federal Quarterly Tax Payments are due April 15th Get Help Now >>

Preventing electromagnetic interference Designing the electronic by hedongchenchen


VO LUM E 5 6
               J O U R N A L
                               NU MB ER 1, 2 00 1

Preventing electromagnetic interference
    Designing the electronic checklist
     The importance of crew briefings
P re s i d e n t

                                            ICAO Journal
1st Vi c e - P re s i d e n t
2nd Vi c e - P re s i d e n t
3 rd Vi c e - P re s i d e n t               The magazine of the International Civil Aviation Organization
S e c re t a ry
  S e c re t a ry General           VOL. 56, NO. 1                                                              J A N U A RY / F E B R U A RY 2001
T. Chérif                           FEATURES
J.L. Bacarezza                       4 The radio frequency spectrum used by civil aviation faces growing interference
AUSTRALIA                              from numerous sources.
J. Aleck
BOTSWANA                             7 A PANS-OPS amendment that will become applicable in late 2001 includes
K.J. Mosupukwa                         human factors-related provisions for aircraft operations.
A.M. Cunha                          14 The development of an automated weight and balance verification system
CAMEROON                               enables the detection of unsafe aircraft loadings prior to take-off.
T. Te k o u
CANADA                              17 Designers of an electronic checklist made a special effort to ensure the
G. Richard
CHINA                                  automated cockpit tool would not introduce new possibilities for errors .
Y. Zhang
                                    21 A new educational initiative is bringing air safety seminars to regions where
J. Hernández López                     maximum safety gains may be achieved.
M. Molina Martínez                  22 The investigation of SilkAir Flight MI 185’s crash in December 1997 yielded
EGYPT                                  very little data on which to draw conclusions.
M.A.A.A. Elbagori
FRANCE                              24 A DC-10 equipped as an eye hospital is regularly flown to developing
M. Peissik                             countries on an intensive humanitarian programme.
J.F. Dobelle (as of 12 Feb. 2001)
GERMANY                             27 Early diagnosis of age-related vision problems is the key to corrective action
Dr. H. Mürl                            that allows pilots to continue flying safely.
A.P. Singh
I NDONESIA                          ICAO UPDATE
J. Sjioen                           30 An ICAO committee has recommended further measures for reducing aircraft
                                       noise and engine exhaust emissions.
G.L. Cornado
JAPAN                               COVER
K. Okada
KENYA                               In recent years the level of electromagnetic interference experienced by aviation has
S.W. Githaiga                       grown dramatically. The increasing pressure on the utilization of the radio frequen-
                                    cy spectrum requires that special measures be taken to preserve the interference-free
R. Abdallah
ME X I C O                          operation of essential radiocommunication and radio navigation services.
R. Kobeh González                   Cover photo by Roy Ooms/Masterfile
M.A. Kraan
NI G E R I A                        Editor: Eric MacBurnie                                                     Production Clerk: Sue-Ann Rapattoni
D.O. Eniojukan                      Editorial Assistant: Regina Zorman                                         Design Consultant: Rodolfo Borello
NORWAY                              THEOBJECTIVES of the Journal are to provide a concise account of the activities of the International Civil Aviation
O. M. Rambech                       Organization and to feature additional information of interest to Contracting States and the international aero-
PA K I S TA N                       nautical world.Reproduction in whole or in part of all unsigned material is freely authorized. For rights to repro -
S.N. Ahmad                          duce signed articles, please write to the editor. Published nine times annually in English, French and Spanish.
PA N A M A                          OPINIONS EXPRESSED in signed articles or in advertisements appearing in the ICAO Journal are the author’s or
R.E. García de Paredes              advertiser’s opinions and do not necessarily reflect those of ICAO. The mention of specific companies or products
R U S S I A N F E D E R AT I O N    in articles or advertisements does not imply that they are endorsed or recommended by ICAO in preference to oth-
V.P. Kuranov                        ers of a similar nature which are not mentioned or advertised.
SA U D I A R A B I A                SUBSCRIPTIONS: $25 (by surface) and $35 (by air) per year. Single copies available for $3 (by surface) and $5 (by air).
S. Al-Ghamdi                        Prices in US funds. For subscription and circulation inquiries contact ICAO Document Sales Unit, telephone (514)
SE N E G A L                        954-8022; fax (514) 954-6769; e-mail: sales_unit@ The catalogue of ICAO publications and audio-visual train-
 –                                  ing aids is available at ICAO’s website or may be obtained through ICAO’s Document Sales Unit.
S LOVAKIA                           NOTICE: ADVERTISERS have been advised that it is preferable to publish advertisement text in the language of each edi-
O. Fabrici                          tion. Those advertisements which do not appear in the language of each edition do so at the insistence of their sponsors.
S PA I N                            ADVERTISINGREPRESENTATIVE: Richard Brown, Gordon Kresic; Victor Brown Associates Corp., 15 Zorra St., Toronto,
L. Adrover                          O n t a r i o, C anada M8Z 4Z6. Te l e p h o n e : (416) 259 -96 31. Fa c s i m i l e : (416) 259-96 34. E-m ail addr ess:
UN I T E D K I N G D O M  
D.S. Evans                          OTHER CORRESPONDENCE should be addressed to: The Editor, ICAO Journal, Suite 1205, 999 University St.,
U N I T E D S TAT E S               Montreal,Quebec, Canada H3C 5H7. Telephone: (514) 954-8222. Facsimile: (514) 954-6376;
E.W. Stimpson                       Published in Montreal (Canada).Second-class mail registration No. 1610.ISSN 0018 8778.
U R U G U AY                        TO C O N TAC T ICAO H EADQUARTERS: telephone: (514) 954-8219; facsimile: (514) 954-6077; e-mail address:
C.A. Borucki               Website:

RF spectrum used by aviation faces growing
interference from non-aeronautical sources
With increased pressure on RF spectrum utilization from all radio sources, special measures
will have to be taken to preserve the interference-free operation of essential aeronautical
radiocommunication and radio navigation services.

                                                 Since the 1970s the level of interference   Sources of interference
             ROBERT WITZEN                    from non-aeronautical sources has risen            The most common source of interfer-
             ICAO SECRETARIAT                 dramatically. Twenty years ago, exclusive      ence is the RF energy from unwanted
                                              bands were available for aviation use, and     emissions from an interfering transmitter

        OR many year s ICAO has               the relatively low utilization of the radio    falling on the operating frequency (or
        addressed the problems of elec-       frequency (RF) spectrum by all radio serv-     within the RF bandwidth) of aeronautical
        tromagnetic interference with         ices meant that relatively few interference    receivers. Normally, the level of these
essential aeronautical radiocommunica-        cases were documented. During the last         emissions decreases as the frequency
tion and radio navigation services. In the    two decades, however, the increased shar-      separation between the interfering signal
late 1970s and early 1980s various world-     ing of the aeronautical spectrum with non-     and the “victim” receiver increases. A
wide meetings held by ICAO reviewed           aeronautical services has introduced a         special case however, is for spurious
the problems related to the ef fects of       number of new potential sources of harm-       emissions on harmonics of the RF carrier
harmful interference from non-aeronau-        ful interference. In addition, the generally   frequency, which can exhibit relatively
tical sources, and developed a number of      increased use of spectrum by all radio         high signal levels at a great distance
recommendations for further action.           services and the explosive growth in the       from the carrier frequency. As an exam-
   The International Telecommunication        telecommunications industry (e.g. mobile       ple, the fourth harmonic of 27 megahertz
Union (ITU) has also taken action, having     telephones) means that interference from       (MHz) can cause interference at 108 MHz
developed several reports and recom-          systems operating outside the aeronautical     (ILS localizer) and the fifth at 135 MHz,
mendations concerned with protecting          bands is more likely. Yet a third factor is    which is used in air-ground voice safety
aeronautical services. A recommendation       the introduction of new aeronautical sys-      communications.
now under development by an ITU study         tems that make use of the RF spectrum             Another source of interference comes
group, on the “protection of safety servic-   for communications and navigation. This        from increased frequency sharing. Since
es from unwanted emissions,” includes a       requires that special measures be taken        the early 1990s, aviation has been forced
number of important aspects to be con-        by aviation to avoid mutual interference       in a significant number of cases to share
sidered when addressing the protection        between aeronautical systems on board          spectrum with non-aeronautical services.
of safety ser vices.                          an aircraft.                                   This situation arose as a result of modifi-
                                                                                             cations to the table of frequency alloca-
                                                                                             tions established by the ITU at world
                                                                                             radiocommunication conferences. Norm-
                                                                                             ally, compatibility between the aeronau-
                                                                                             tical and non-aeronautical ser vices is
                                                                                             maintained through the development of
                                                                                             appropriate ITU-R recommendations or
                                                                                             by special provisions or footnotes to the
                                                                                             frequency table of the radio regulations.
                                                                                             These provisions place certain constraints
                                                                                             on the incumbent or the incoming ser-
                                                                                             vice, or both. An example is the use of
                                                                                             the bands between 1164-1350 MHz by
                                                                                             the radionavigation satellite service.
Since the 1970s the level of interference from non-aeronautical sources has risen dra-
matically. Use of the band 100-108 MHz by the FM broadcasting service, for example,          These bands are used by aviation for dis-
may cause interference to an ILS or VOR system operating just above 108 MHz.                 tance measuring equipment (DME) and

4                                                                                                                       ICAO JOURNAL
                                                                                                   AE RO NAUT ICAL C OM M UNI CAT I O N S

radar systems, which need priority in        (e.g. cellular phones or broadcasting of the adverse impact of this type of
protection over the radionavigation satel-   transmitters). There are also systems in i n t e rf e rence is under way, and ICAO is
lite ser vice. In principle, any form of     operation that make use of RF signals considering the need for further action.
sharing increases the interference level     but which are not intended to radiate
and restricts full use of the spectrum by    electromagnetic energy, such as micro- Protection margin
aviation.                                    wave ovens, TV cable distribution sys-                   In general, interference is acceptable,
   The third source of interference is the   tems and cer tain medical equipment. but only up to the level where it becomes
effect of the utilization of frequency       These systems can also interfere with harmful. The ITU radio regulations
bands, adjacent to aeronautical bands,       the reception of radiocommunication describe inter f e rence as “the ef fect
where radio systems are in operation         and radionavigation signals through unin- of unwanted energy due to one or a
using relatively high-power signals. An      tended leakage of RF energy. In the ITU combination of emissions, radiations or
example is the use of the band 100-108       radio regulations, provisions have been inductions upon reception in a radiocom-
MHz by the FM broadcasting service,          made for these systems to operate in munication system, manifested by any
which may cause interference to an           certain frequency bands allocated to the performance degradation misinterpreta-
instrument landing system (ILS) or very      category “industrial, scien-                                       tion or loss of information
high frequency omnidirectional radio         tific and medical (ISM) Minimum desired field strength              which could be extracted in
range (VOR) operating just above 108         equipment”.                                               Signal   the absence of such unwant-
MHz. Measures to protect ILS and VOR                Radiation limits from                                       ed energy.” Furthermore,
were one of the main topics discussed at     ISM equipment were deve- Interference threshold                    harmful i n t e rf e rence is
the ITU regional broadcasting confer-        loped by the International                    Protection           defined by the regulations
ence in the early 1980s. Given the tech-     Special Committee on                              margin           as a condition “that endan-
nical complexity of the problem, it was      Radio Interference (CISPR)                                         gers the functioning of a
not until 1995 that an ITU recommenda-       and are described in Inter-                   Aggregate            radio navigation ser vice or
tion on this matter could be approved.       national Electrotechnical                                          other safety services or seri-
   The work of ITU world radiocommu-         Commission (IEC) stan-                                             ously degrades, obstructs
nication conferences and meetings of         dard CISPR 11 and 28.                                              or repeatedly interr upts a
ITU radiocommunication sector study          These limits do not always                                         radiocommunication ser v-
                                                                                Signal A   Signal B
groups is extremely important in setting     comply with ICAO’s posi-                                           ice operating in accordance
the conditions for a safe and efficient use   tion on the need to protect Calculating the impact of with these regulations.”
of the spectrum. Recent meetings focused     safety services. Further- multiple interfering signals                 When studying the ef fect
on protection for the following systems:     more, the limits apply for                                         of interference, due consid-
• the microwave landing system (MLS)         measurements that take place at ground eration must be given to the cumulative
from satellite feeder links;                 level while most interference measured effect that may be present at the receiver
• radar systems on-board aircraft at 15      above ground level is stronger. This input. In assessing models for predicting
gigaher tz (GHz) from satellite feeder       occurs because the attenuation of RF interference, it is therefore necessar y to
links;                                       energy through the roof of a building is consider the protection margin that a
• airpor t sur veillance radar at 15 GHz     generally less than that through the specific interfering signal leaves in con-
from satellite feeder links;                 walls. Also, aircraft experience the junction with other inter fering signals.
• global navigation satelli te system        cumulative effect of RF interference In order to secure the safe operation of
(GNSS) from the mobile satellite service;    from various sources, something that is aeronautical systems, the summation of
• DME from radionavigation satellite         ver y dif ficult to measure on the ground all interfering signals must not exceed
systems;                                     and is not considered in the radiation the interference threshold level (see fig-
• primar y radar from radionavigation        limits set by CISPR.                                  ure). When the protection margin is
satellite systems; and                            A relatively new source of inter fer- zero, there is no adequate protection of
• MLS from radionavigation satellite sys-    ence includes the various personal elec- the safety ser vice. Interference thresh-
tems.                                        tronic devices that passengers bring on old levels are determined by ICAO or by
   Studies now under way at ITU are look-    board an aircraft. These include elec- aviation industr y organization such as
ing at several of these issues, with the     tronic equipment such as computer ARINC, RTCA or the European Organi-
scope to be expanded.                        games, por table computers and radio. zation for Civil Aviation Equipment
   The potential sources of interference     Cell phones are a major problem because (EUROCAE).
identified above are from radio systems      these transmitting devices could seriously               This principle has been suppor ted by
that are intended to radiate electromag-     i n t e rf e re with on-board navigation and many ITU recommendations. An aero-
netic energy to provide radio ser vices      communications equipment. Assessment nautical safety margin, var ying from six

NUMBER 1, 2001                                                                                                                              5

to 10 decibels (dB), has been used in          may not exceed the sensitivity thres-      order to assess compatibility between
recommendations that establish a model         hold or the particular interference thres- FM broadcasting stations and aeronauti-
for assessing the protection for various       hold of the relevant receiver.             cal systems operating between 108-137
aeronautical safety-of-life systems.              The specific geometry of the interfer-  MHz. The work that took place in the
                                               ence situation may also have a significant  Limited European Group on Broad-
Interference models                                                                       casting and Aeronautical Compatibility
                                               effect on the permissible level of interfer-
     ICAO provisions describe the ef fect of   ence. Normally, for aeronautical systems   (LEGBAC) provides the basic interfer-
i n t e rf e rence in the form of a desired to that are used during the en-route phase    ence assessment method and is used by
undesired (D/U) signal protection ratio.       of flight, the minimum separation dis-     many administrations in Europe.
The desired signal strength considered is      tance between an external interfering sig-    Television cable carrier systems. Cable
the minimum signal level required of a         nal and an aircraft can be set at about 300carrier systems originally operated in the
given aeronautical system throughout its       feet (100 metres). For systems used dur-   frequency band below 108 MHz. The
coverage area. The undesired or                                                                        introduction of the use of fre-
interfering signal is the maxi-                                                                        quencies in the band 108-137
mum signal level that can be                                                                           MHz by these cable carrier
expected from the interfering                                                                          systems is of concern because
system which in most cases is a                                                                        of the potential of co-frequency
system with the same character-                                                                        interference to essential aero-
istics; an example of this would                                                                       nautical ser vices.
be a desired non-directional                                                                              Normally, properly installed
radio beacon (NDB) signal                                                                              and maintained cable carrier
encountering interference from                                                                         systems do not radiate much
another NDB operating on the                                                                           electromagnetic energy. How-
same frequency but geographi-                                                                          ever, malfunctioning of the
cally positioned in such a way                                                                         system may result in a signifi-
that no harmful interference is                                                                        cant amount of electromag-
caused.                                                                                                netic energy being radiated.
     The signal protection require-                                                                    Such cases are also not always
ments which are used during                                                                            quickly dealt with and the
the frequency assignment plan-                                                                         result may be interf e rence
ning process for aeronautical                                                                          in the aeronautical systems,
systems cannot, directly, be                                                                           notably ILS or VOR, for a par-
applied to external interfering Various electronic devices that passengers bring on board an ticularly long period of time.
sources. The signal protection aircraft may cause interference with communications and                    The best solution would be
ratio required to ensure, for navigation equipment. Cell phones are a major concern.                  to prohibit the use by cable
instance, the safe operation of an                                                                    systems of frequencies falling
ILS in the presence of an FM broadcast- ing the final approach and landing phase within the aeronautical safety alloca-
ing signal is different from that required of a flight, however, this minimum sepa- tions, but this might not be practicable in
in the presence of another ILS operating ration distance is normally 100 feet, and is all cases. ICAO would suppor t the estab-
on the same or adjacent channel.               related to the obstacle clearance surface. lishment of practices and enforcement
     Normally in the case of systems that                                                 procedures that would provide a high
provide continuous wave (CW) signals, Specific cases of interference                      degree of assurance that excessive levels
such as NDB, ILS or VOR, the protection           FM broadcasting stations. This type of of electromagnetic energy would not be
from interference from external sources interference can occur at any point within radiated from the cable distribution sys-
can be expressed in the form of a D/U the ser vice volume of an ILS or VOR, and tems.
signal ratio. The actual value of the pro- manifests itself around a broadcasting            Signaling systems for power line distri -
tection ratio, as described above, depends station. The volume of the area affected bution systems. Where these systems
upon the particular characteristics of the can be large, with an irregular shape.                                    continued on page 34
interfering signals. In cases where the           The interference model for FM com- Robert Witzen is a Technical Officer in the Communi-
transmissions of the radiocommunication patibility is described in detail in an ITU cations, Navigation and Surveillance (CNS) Section of
                                                                                          the Air Navigation Bureau at ICAO headquarters,
or radionavigation systems are not con- recommendation (ITU-R Recommend- Montreal. Mr. Witzen is Secretary of the Aeronautical
tinuous, such as in voice communications ation IS. 1009). The provisions of this ICAO atCommunications Panel (AMCP), anderepresents
                                                                                                  meetings of the International Tel communi-
or DME, the interference in many c a s e s recommendation are generally used in cation Union.

6                                                                                                                         ICAO JOURNAL
                                                                                                                   SA FE TY RE GU LAT I O N

Amendment to PANS-OPS includes human factors
related provisions for aircraft operations
A PANS-OPS amendment which is expected to become applicable in November 2001 will
introduce guiding principles for the development and implementation of standard operating
procedures incorporating human factors requirements.

                                             assessment included the U.S. National              The PANS-OPS also requires that the
       CAPT. DANIEL MAURINO                  Aeronautics and Space Administration            SOPs followed by operators give specific
             ICAO SECRETARIAT                (NASA) aviation safety reporting system         guidance on using on-board technology,
                                             (ASRS), the U.K. Civil Aviation Authority       and call for the utilization of ground-

       PROPOSED amendment to the (CAA) mandator y occurrence reporting                       based aids such as distance measuring
         Procedures for Air Navigation system (MORS), the Australian Bureau                  equipment (DME) to help achieve an
          Services — Aircraft Operations of Air Safety Investigation (BASI) sys-             optimum approach slope descent during
(PANS-OPS) will establish a number of tematic incident analysis model (SIAM),                a non-precision approach.
human factors-related provisions for and the safety databases kept by three                     Stabilized approach procedure. The pri-
flight procedures. The proposal to revise major airlines: British Air ways, Air               mary safety consideration in the devel-
Volume I of the PANS-OPS* is expected France and KLM.                                        opment of the stabilized approach proce-
to become applicable in November 2001.          The evaluation of all this information       dure is the ability to maintain the
    The underlying reason for adopting made it possible to focus on concerns of              intended flight path depicted in the pub-
human factors-related amendments to statistical significance. From this starting              lished approach procedure without
safety regulations, initially to the techni- point, the ICAO Secretariat drafted pro-        excessive manoeuvring. According to the
cal annexes to the Convention on Inter - visions for discussion by the ICAO Flight           proposed change to the PANS-OPS, the
national Civil Aviation (Chicago, 1944) Safety and Human Factors Study Group.                parameters for the stabilized approach
and now to PANS-OPS, is to develop reg- The draft provisions were then submitted             should be defined by the operator’s SOPs
ulator y provisions that are based on the to the ICAO Air Navigation Commission,             and should also be published in the
proactive application of human factors which approved the proposal to amend                  company operations manual. The details
knowledge to aircraft and system design, the PANS-OPS in January 2001.                       provided for each aircraft type should
certification, personnel licensing, train-                                                   include the range of speeds, minimum
ing and operations. The integration of Safety concerns                                       power settings, range of attitudes and
human factors knowledge with safety             The proposal to include human fac-           configurations. The details also need to
regulation anticipates that human error tors-related provisions in the PANS-OPS              provide the crossing altitudes deviation
is inevitable but manageable in an opera- responds to six specific areas of concern.         tolerances, maximum sink rate and the
tional environment.                          These are: non-precision approaches             point at which checklists and crew brief-
                                             including multiple step-down fixes; sta-        ings must be completed.
The amendment process                        bilized approach procedure; standard               The proposed change to the PANS-OPS
    Before developing the proposed human operating procedures (SOPs); the use                calls for cer tain elements of a stabilized
factors provisions, ICAO first reviewed and design of checklists; the conduct of              approach to be spelled out in the opera-
the PANS-OPS to identify a broad list of crew briefings; and the safety of aero-             tor’s SOPs. As a minimum, the SOPs need
potential safety concerns that could be drome surface operations.                            to indicate that all flights should be stabi-
addressed. It then reviewed the safety lit-     Non-precision approaches. The PANS-          lized at 1,000 feet height above threshold,
erature to narrow down the list of con- OPS requires that non-precision approach             and must be stabilized at 500 feet height
cerns to those of an operational relevance. design provide the optimum final                  above threshold.
This process was supported by an exten- approach descent gradient of 5 per cent or              The proposal further requires that an
sive examination of industry databases (in a constant approach slope of 3 degrees.           operator’s SOPs call for a go-around in
excess of 1,300 reports were reviewed).      This results in a rate of descent of 300 feet
                                                                                             * PANS-OPS Volume I, Flight Operations, describes
   In addition to reviewing information per nautical mile. The information pro-              operational procedures that are recommended to
                                                                                             States as guidance for flight operations personnel.
from ICAO’s own accident and incident vided in approach charts should display                PANS-OPS focuses on those procedures where inter-
data reporting (ADREP) system, the the optimum constant approach slope.                      national uniformity is desirable.

NUMBER 1, 2001                                                                                                                                7

the event of an unstable approach or an        feedback. This is encouraged to foster           system malfunctions or emergencies,
approach that becomes destabilized at          standardization and compliance with the          and guard against any weaknesses in
any point. It also recommends that oper-       SOPs and to evaluate the reasons for any         human performance during moments of
ators reinforce this policy through pilot      non-compliance.                                  high workload. The checklist for abnor-
training.                                         Checklists. The proposed amendment            mal or emergency situations ensures a
    Standard operating procedures. The         to the PANS-OPS defines the operator’s           clear allocation of duties to be performed
PANS-OPS requires that operators estab-        responsibility for establishing checklists       by each flight crew member and acts as
lish SOPs that provide crews with guid-        as an integral part of the standard operat-      a guide in troubleshooting, decision mak-
ance in carrying out flight procedures by       ing procedures. Checklists depict sets of        ing and problem solving. This type of
safe, ef ficient, logical and predictable      actions relevant to specific phases of oper-     checklist ensures that critical actions are
means. Under the proposed amendment,           ation (e.g. engine star t, taxi, take-o ff ) ,   taken in a timely and sequential manner.
SOPs should unambiguously express              and actions that relate to safety. They              There are many factors to consider
each task including the timing and             provide a framework for verifying air-           when deciding the order of items on a
sequence. They would spell out by              craft and system configuration that              checklist. They need to fall in the order
whom the task is to be conducted, how it       guards against inattention.                      of system activation, flight deck location
is to be performed, what sequence of              The proposed amendment makes a                and operational environment (i.e. the
actions it will consist of, and what type of   distinction between normal and abnormal          duties of other operational personnel
feedback is to be provided                                                                                   such as cabin crew and dis-
(i.e. verbal call-out, instru-                                                                               patchers must be consid-
ment indication, switch posi-                                                                                ered). Operator policies, such
tion, etc.). There is also the                                                                               as a requirement for single-
requirement that the design                                                                                  engine taxi, may impinge on
of SOPs take into considera-                                                                                 the logic of a checklist. Veri-
tion:                                                                                                        fication and duplication of
• the nature of the operator’s                                                                               critical configuration-related
e n v i ronment and type of                                                                                  items, so that they are checked
operation;                                                                                                   in the normal sequence and
• operational philosophy, in-                                                                                again at the end of the flight
cluding crew coordination;                                                                                   phase for which they are crit-
• training philosophy, includ-                                                                               ical, must be built into the
i n g human per f o rm a n c e                                                                               checklist. In abnormal and
training;                                                                                                    e m e rgency checklists the
• the operator’s corporate culture, in-           Briefings serve to build a plan                most critical items are completed first.
cluding the degree of flexibility to be                                                             Although the duplication of critical
                                                  of action and transmit it to all
built into SOPs design;                                                                         items is found in the optimal checklist,
• the levels of experience of different
                                                  crew members, and also promote                such duplication should not exceed two
user groups such as flight crew, aircraft         effective error management                    items. Critical items should be verified
maintenance engineers and cabin atten-                                                          by more than one flight crew member. A
dants;                                         or emergency checklists. It specifies that        most important consideration contained
• resource conservation policies such as       normal checklists should aid crews in            in the PANS-OPS proposal establishes
fuel conser vation or wear on power-           configuring the aircraft and its systems         that the number of items in checklists
plants and systems;                            by providing a logical flow in cockpit           should be restricted to those critical to
• flight deck automation, including flight       checks, and a logical sequence of actions        flight safety.
deck and systems layout and supporting         to meet all flight deck operational                  Checklist interruption has been iden-
documentation;                                 requirements, including those involving          tified as a factor in safety occurrences.
• compatibility between SOPs and oper-         external activities such as aircraft refu-       For this reason, the proposed PANS-OPS
ational documentation; and                     elling or push-back. They also should            revision establishes that SOPs should
• procedural deviation during abnormal         allow mutual monitoring among crew               include techniques to provide the step-
or unforeseen situations.                      members and ser ve to keep all flight            by-step, uninterr upted completion of
    The PANS-OPS also recommends that          crew members in the information loop,            checklists. SOPs should unambiguously
flight operations personnel be involved        facilitating crew coordination.                  indicate the actions required by flight
in the development of SOPs, and that              Abnormal and emergency checklists             crews who experience interruptions. In
operators establish a formal process of        should aid flight crews in coping with           addition, the PANS-OPS establishes that

8                                                                                                                          ICAO JOURNAL
                                                                                                                    S AFE T Y RE GU L AT I O N

checklist responses should portray the         Transportation Safety Board (NTSB)            extremely unreliable process.
actual status or value of the item being       study identified failures in monitoring          The proposed revision to the PANS-OPS
checked (e.g. switch on, lights off). They     and challenging in 84 per cent of 37          also lays down several principles to be con-
should avoid non-specific responses            major U.S. accidents between 1978 and         sidered when establishing crew briefings.
such as “set,” “checked” or “completed.”       1990, highlighting the importance of          First, a briefing should be short, with not
   Checklists should be coupled to spe-        flight crew errors that go unchallenged.      more than 10 items. If more than 10 items
cific phases of flight, but should avoid
tight coupling with a critical phase of
flight (e.g. completion of the take-off
checklist while on the active runway).
SOPs should dictate a use of checklists
that allows the opportunity to detect and
recover from an incorrect configuration.
   Lastly, the PANS-OPS proposal estab-
lishes some basic principles of typogra-
phy to be obser ved in checklist design.
Layout and graphical design should
obser ve the principles of legibility of
print and readability under all lighting
conditions. If colour coding is used, it
should conform with industry standards.
For example, green headings identify
normal checklists while yellow is associ-
ated with system malfunctions and red is
                                               PANS-OPS establishes that preflight briefings must include both flight and cabin
reser ved for emergency checklists.            crews. Combined flight and cabin crew briefings should focus on crew coordination
Colour coding, however, should not be          as well as aircraft operational issues.
the only means of identifying normal,
abnormal and emergency checklists.                The proposed change to the PANS-           are necessary, it may be preferable to per-
   Crew briefings. Deficiencies in crew        OPS would make it an operator’s respon-       form parts of the briefing before sequential
briefings have been identified by various        sibility to have crew briefings as an inte-   phases of the flight. A briefing should also
authoritative sources as underlying safe-      gral part of the SOPs. Crew briefings         be simple and concise, yet foster an under-
ty occurrences. A repor t by a Flight          communicate duties, standardize activi-       standing of the plan of action. Third, brief-
Safety Foundation (FSF) task force indi-       ties, ensure that a plan of action is         ings should be interactive, wherever possi-
cated that during the period 1984-97           shared by all, and enhance crew situa-        ble using a question-and-answer format,
crew briefings had been a factor in 37         tional awareness. The proposed change         and they need to be scheduled so that
per cent of the approach and landing           further specifies that operators shall        there is no interference with operational
accidents and serious incidents that it        establish a requirement for separate          tasks. Lastly, the continual repetition of
had studied. The U.K. CAA published a          briefings for the flight and cabin crews,     recurring items should be done with care,
report, Global Fatal Accident Review,          plus a combined briefing for both flight      since briefings that become routine recita-
1980-1996, which indicated that failures       and cabin crew members.                       tions do not refresh prior knowledge and
in monitoring and challenging were con-           The amended PANS-OPS would estab-          are ineffective.
sidered a factor in 47 per cent of the acci-   lish that briefings should aid crew mem-         The proposal also recommends that
dents analysed. A study by the Universi-       bers in performing safety-critical actions    any intended deviation from the SOPs
ty of Texas Aerospace Crew Research            by refreshing knowledge and by con-           required by operational circumstances
Project completed in March 1995 report-        structing a shared mental picture of the      should be included as a specific briefing
ed on the causal relationship between          situation. Briefings ser ve to build a plan   item.
specific crew resource management              of action and transmit it to all crew mem-       The proposed change to the PANS-
(CRM) behaviours to accidents and inci-        bers, and also promote ef fective error       OPS addresses the application of crew
dents. Its analysis of 51 classic human        management. They prepare crew mem-                                        continued on page 34
factors-related airline accidents between      bers for responses to foreseeable haz-        Daniel Maurino is a Technical Officer in the Personnel
1970 and 1995 found that deficiencies in       ards. Without briefings, and under the        Licensing and Training (PEL/TRG) Section of the Air
                                                                                             Navigation Bureau at ICAO headquarters, Montreal.
crew briefings contributed to 37 per cent       pressure of time and stress, retrieving       Capt. Maurino is the coordinator of the ICAO flight
of the occurences. Lastly, a U.S. National     information from memor y may be an            safety and human factors programme.

NUMBER 1, 2001                                                                                                                                   9

New system allows for detection of unsafe
aircraft loadings shortly before take-off
The development of an automated system has made it practical to check a cargo aircraft’s weight
and balance moments before departure. Under an innovative arrangement proposed by its
manufacturer, the technology can be installed and operated at no cost to the aeronautical authority.

                                                 Urgent need                                   Qatar, with the report of a cargo shift or
            WALTER M. YOUNG                         In August 1997 a jet freighter crashed     CG problem causing substantial damage
         EMERY WINSLOW SCALE CO.                 just yards beyond Miami Airpor t, send-       to the aircraft.
                (UNITED STATES)                  ing shock waves through Miami and the         • In 1991 a Lockheed 382B/100 Her-
                                                 air cargo industr y. Following the acci-      cules crashed in Luanda with 10 fatali-

        LTHOUGH sophisticated methods            dent, the U.S. Federal Aviation Admini-       ties. Unofficial sources cited cargo shift
         have long been used to calculate        stration (FAA) stated that greater focus      or CG problems as the cause. The plane
           weight and balance for cargo          would be placed on aircraft loading prac-     was destroyed.
 aircraft, the ability to verify a safe weight   tices including such factors as training      • In 1989 a Boeing 747 reported a prob-
and balance has been lacking. The only           for the cargo handlers and the weighing       lem on take-off, turned around and landed
way to know if an aircraft has a safe            and loading of cargo.                         with minor aircraft damage. The cause of
weight and balance is to weigh it just              A number of accidents and incidents        the problem was overloading by over
prior to take-off. Until now, however, this      over the years have pointed to a need for     7,300 pounds, plus a lateral imbalance of
has been regarded as impractical and             verifying aircraft weight and balance         over 18,700 pounds.
well outside the reach of present-day            prior to take-off, including the following:      There are ample reasons to be con-
scale technology.                                • In Januar y 1996 the crash of a cargo       cerned about cargo aircraft safety. Each
   In mid-1999, Emery Winslow Scale Co.          plane in Kinshasa, Zaire resulted in 237      possible breach of safety needs to be
developed, installed and certified a first-      fatalities on the ground; no official         identified and effectively neutralized.
of-its-kind automatic aircraft weight and        reason was given as the cause of the             The Flight Safety Foundation (FSF)
balance verification system (AAWBVS),            accident, but an out-of-tolerance centre-     has cited a number of concerns related
demonstrating its practicality and effec-        of-gravity (CG) or overloading was sus-       to air cargo operations. An ar ticle in an
tiveness on various cargo aircraft includ-       pected.                                       FSF publication of March 1999 noted
ing the Boeing 747.                              • In July 1993 a Boeing 747 crashed in        that one of the key hazards which is
                                                                                               specific to cargo operations is a CG
                                                                                               location that is out of limits. The
                                                                                               Foundation pointed out that in many
                                                                                               cases the flight crew, while being ulti-
                                                                                               mately responsible for aircraft safety,
                                                                                               has no practical way of verifying the air-
                                                                                               craft’s weight and balance before take-
                                                                                               off. It also noted that it can be difficult
                                                                                               to control the quality of the cargo load-
                                                                                               ing process.
                                                                                                  From the beginning of the air cargo
                                                                                               business, weight and balance was
                                                                                               known to be a critical safety component.
                                                                                               In ever y case, methods of computing
                                                                                               safe weight and balance have depended
                                                                                               on two factors: the use of high perform-
                                                                                               ance precision weighing equipment,
An aircraft is shown positioned for a weight and balance reading at Bogota                     and the good judgement of operating
Airport. The weighing process can be completed within 30 seconds.                              personnel.

14                                                                                                                        ICAO JOURNAL
                                                                                                                                    SA FE TY T ECH NO LOGY

Roadside systems                                three nose wheel scales rated up to 70,000                        engines running and ready for departure.
   For well over 50 years, federal agen-        pounds each. The purpose of this weigh-                           Building on experience with the Boeing
cies in many countries have re q u i re d       ing system was to obtain weight informa-                          weighing system, Emer y Winslow sub-
that trucks and all sorts of road vehicles      tion for the total aircraft plus the weight                       mitted a bid and received a contract from
be weighed. Today, these weighing sys-          on each main gear and nose wheel gear.                            ICAO to produce such a system.
tems are capable of handling vehicles up        The system computer and software calcu-                             Since neither the flight crew nor
to 200 feet long, with a standard capacity      lated the aircraft centre-of-gravity and the                      responsible ground operating personnel
of 200,000 pounds and special capacities        mean aerodynamic chord, and processed                             can readily verify the aircraft’s weight
in excess of 500,000 pounds. These              and stored all data for future use.                               and balance before take-off, one of the
weighing systems are highly accurate
and will instantly measure the weight of         Aircraft scale                                         Scale House                                Control tower
                                                                  Digital weight                                                     PC/AAWBVS
                                                 (Weighbridge)    indicators                                                          software
each vehicle axle, the total weight of the                                                                                                       Laser printer
                                                       A                                          PC/AAWBVS
vehicle and, in some instances, the trailer                                                        software
centre-of-gravity.                                     B                           multiplexer

                                                       C                                                                                          Security office
   The reason for these roadside weigh-                                                                                              PC/AAWBVS
                                                                                   Total weight           Wireless network            software
ing systems is to prevent untimely and                 D                           display
                                                                                                           RF transceiver                         Laser printer
expensive damage to highways caused by                 E
overloaded trucks. Although not fre-
quently mentioned, another reason for           A schematic representation of the AAWBVS instrumentation and RF communications
vehicle weight control is that overloaded       from the scale house to the control tower and security office. The automated system can
                                                handle cargo aircraft as large as a Boeing 747.
or poorly balanced trucks pose a signifi-
cantly higher risk of an accident. The reg-        The system accuracy specification                              primary weighing system design consid-
ulatory agencies of many countries have         was 0.1 per cent of the applied weight                            erations has been to develop a highly
invested large sums to install roadside         from 10 to 100 per cent of system capac-                          practical, user-friendly system for all spec-
weighing systems, and it is not uncom-          ity. When calibrated and cer tified by                            ified aircraft including the Boeing 747.
mon for one weighing system to service          Boeing, each of the nine scales per-                              This could only be achieved if the aircraft
more than a thousand trucks in a day.           formed to an accuracy many times better                           can be weighed conveniently and swiftly.
   The verification of over-the-road vehicle     than called for in the specifications.                            Thirty seconds were allotted for the
weight and balance has long since been             The experience gained in developing                            weighing cycle, a process that begins as
justified by transportation authorities, allo-   the Boeing weight and balance system                              soon as the aircraft enters the weighing
cating in excess of U.S. $5 million dollars     solved many problems, such as the need                            system and is completed when the crew
for one state-of-the-art weighing station.      to achieve high accuracy and deal with                            is given clearance to exit the system.
With so much at stake, is it not substan-       jet fuel hazards and corrosive solvents as                           Also included in the ICAO specifica-
tially more urgent to have the weight and       well as a temperature variance of 70                              tions was the requirement to develop
balance of cargo aircraft certified “safe”       degrees Celsius. What it did not resolve                          training programmes for the system
before authorizing a departure?                 were the effects of weighing aircraft out-                        operators and for maintenance staff.
                                                doors, fully fuelled and loaded, with the                            The ICAO contract called for a system
Boeing weighing system                          engines running. Moreover, it did not                             featuring a cluster of weighing platforms
   For many years Emery Winslow                 provide for a quick processing time.                              sized and positioned to handle cargo air-
researched the possibility of weighing          Such issues were addressed a few years                            craft ranging in size from the Convair
aircraft in a manner similar to that used       later when developing an aircraft weigh-                          240 to the Boeing 747, with a maximum
in weighing ground vehicles — safely,           ing system to ICAO specifications.                                system load of 400,000 kilograms. The
efficiently, swiftly and accurately.                                                                              system was to be fitted with a data acqui-
   In 1993 Boeing’s commercial aircraft         ICAO specifications                                               sition and control processor. Also
division requested a custom designed               In 1995, on behalf of the civil aviation                       required was a display in the control
weighing system for its 777, 767 and 747        administration of Colombia, ICAO devel-                           tower and near the weighing station
models. Emery Winslow, with guidance            oped specifications for an automatic air-                         itself to indicate the aircraft’s weight and
from Boeing, engineered, manufactured,          craft weight and balance verification                             status. A ser vice life of at least 15 years
installed and certified an 800,000-pound         system for installation at Bogota’s El                            was required for scales that could oper-
multi-weighbridge weight and balance            Dorado International Airport.                                     ate reliably in conditions including water
system. The system was comprised of six            The specifications called for a system                          inundation, shock, vibration and large
main gear scales, two 300,000-pound and         which could weigh a large variety of cargo                        temperature variations. Radio frequency
four 200,000-pound weighbridges, and            aircraft, fully fuelled and loaded, with                          interference (RFI) noise and electromag-

NUMBER 1, 2001                                                                                                                                                     15

                                                                                             Bogota AAWBVS
                                                                                                 The AAWBVS installed in 1999 at the
                                                                                             Bogota Airport consists of four main
                                                                                             gear weighbridges, each having a design
                                                                                             capacity of 150,000 kilograms, and one
                                                                                             nose gear weighbridge having a design
                                                                                             capacity of 50,000 kilograms. The total
                                                                                             weighing system capacity is 400,000 kilo-
                                                                                             grams, with a digital readout in 20-kilo-
                                                                                             gram increments.
                                                                                                 The weighbridge platform is a struc-
The automated aircraft weight and
                                                                                             tural steel framework with a reinforced
balance verification system installed                                                        concrete deck, supported on hydrostatic
at Bogota’s airport in 1999 consists                                                         100,000-kilogram load cells. The plat-
of four main gear weighbridges hav-
                                                                                             forms have been designed to accept
ing a design capacity of 150,000 kilo-
grams and a nose gear weighbridge                                                            loads up to 50,000 pounds per wheel and
with a capacity for 50,000 kilograms.                                                        300,000 pounds per tr uck in the case of
The platform is a structured steel                                                           the B777 main gear, and up to 35,000
framework with a reinforced con-
crete deck supported on hydrostatic                                                          pounds per wheel for the B747 nose gear.
100,000-kilogram load cells (right).                                                             The computers and software display
                                                                                             the reading of each scale, calculate the
netic emissions were not to cause unac-            In developing the AAWBVS, the obvi-       total weight and centre-of-gravity, com-
ceptable performance degradation.              ous remedy was to make system relia-          pare the actual results against database
   The ICAO contract required that the         bility, zero downtime and low cost of         limits, and store the transaction data for
software for the system display data           ownership high on the system specifica-       future analysis.
from each weigh scale as well as the           tion list.                                        The computer located in the scale
total aircraft weight and calculate aircraft       To meet such stringent requirements,      house transmits weight data via a wire-
CG and the nose and main gear weight           Emer y Winslow engineers utilized an          less RF network to computers in the con-
distribution. The software also had to         alternative technology known as Hytro-        trol tower and security of fice where
compare the results with permissible val-      nics, a technology that has been suc-         aircraft data is displayed and stored (see
ues kept in a computer database, store         cessfully used in road vehicle scales for     figure, page 15). The display data
data for fur ther analysis, and provide the    decades. It is a technology that features     include take-off weight limits, aircraft
basis for a go/no-go decision deter-           the combination of hydrostatic load cells     identification (model, tail number,
mined by aircraft loading limits. Finally,     and state-of-the-art electronic instru-       owner, manufacturer and flight number),
the software was required to maintain a        mentation.                                    runway conditions (air temperature,
log of overloaded aircraft.                        The non-electronic hydrostatic load       wind speed and direction), weight on
                                               cell has several advantages. It cannot be     each gear, and a comparison of total air-
Durability critical                            damaged by power surges, static               craft weight and CG with database limits.
   The conventional modern scale uti-          charges or lightning, and remains oper-       The system also provides archival stor-
lizes electronic load cells and electronic     ational even when it is fully submerged       age of the aircraft type, measured
components to sense and measure                in water. The load cell is unaffected by      weights, calculated values, time and
weight. However, cargo scales and the          RFI and electromagnetic interf e re n c e     date. Finally, it provides an aircraft
AAWBVS are installed outdoors and are          and remains operational in a tempera-         weight and balance check (green screen
subject to the damaging effects of light-      t u re range of minus 32 degr ees to          if the weight and balance is within range,
ning, power surges, corrosion, shock           100 degrees Celsius. It is constructed        red if out of limits).
loading, rodents and flooding. These           of grade 304 stainless steel for high             The actual cost of an AAWBVS depends
environmental factors are known to             corrosion resistance. The load cell is        on the range of aircraft to be weighed and
cause thousands of electronic load cell        electrically inert and safe for use in haz-
                                                                                                                          continued on page 34
failures ever y year at a substantial cost     ardous areas. It is designed to weigh
                                                                                             Walter M. Young is Chairman and CEO of the Emery
to users. Even greater than the cost of        unevenly distributed loads (as in an
                                                                                             Winslow Scale Co., of Seymour, Conn., United States.
the replacement parts is the downtime,         AAWBVS) without a negative ef fect on         Readers may obtain more information about the sys-
                                                                                             tem described in this article by contacting the author
when repair work in certain areas of the       accuracy, and is capable of absorbing         by phone at (203) 881-9333 (ext. 22). The e-mail address
world may require days or even months.         shock loads.                                  is

16                                                                                                                              ICAO JOURNAL

Today’s electronic checklists reduce likelihood
of crew errors and help prevent mishaps
Automation on the flight deck produces some important benefits but can also bring training
challenges, mode confusion and new possibilities for errors. With this in mind, designers
of a modern electronic checklist made a special effort to ensure this automated cockpit
tool would not introduce new error modes.

                                              Paper checklist error modes                   MD-82 at Detroit in which the take-of f
           DANIEL BOORMAN                        From the early days of aviation, it was    was attempted with the flaps and slats
  BOEING COMMERCIAL AIRPLANE GROUP            recognized that pilots were prone to          retracted. The U.S. National Transport-
             (UNITED STATES)                  making operational errors. The omission       ation Safety Board (NTSB) found a pri-
                                              of a procedural step at a critical phase of   mary cause to be the flight crew’s failure

          HE intr oduct io n of di gi tal     operation, such as before take-off, could     to accomplish the taxi checklist. The
        autopilots, fl ight management        have catastrophic results. There f o re ,     crew had experienced many distractions
        computers, electronic displays and    pilots adopted written checklists to          during the taxi out, and they inadver-
airframe system monitoring and alerting       ensure that the required actions were         tently omitted the taxi checklist. They
devices 20 years ago represented the          accomplished.                                 read the before take-off checklist prior to
first phase of digital automation tools          C heckl ist s also evol ved for non-       departure, but only the taxi checklist
in civil aviation. Almost immediately,        normal conditions. Non-normal check-          contained the item, “Flaps ... Set.” Thus,
the interfaces became the subject of a        lists embody procedures to follow in          a paper checklist error mode is identified:
great deal of scrutiny and some criti-        abnormal situations or in emergencies.        Normal checklist is skipped. It can be stat-
cism, producing a variety of new insights     Crew checklists are now universally           ed with certainty that had the crew been
on automation.                                employed in commercial and military avi-      using an automated checklist tool that
   Automation experts today generally         ation and space flight, and are increasingly   prevents the skipping of a normal check-
agree that the new tools — designed to        used in many other complex vehicles and       list, the tragedy would have been averted.
improve efficiency, reduce workload and        industrial and medical processes.                Similarly, other paper checklist error
decrease errors — have been substan-             Although the use of a paper checklist      modes were identified through accident
tially successful in achieving their goals,   provides a great safety increase over no      and incident analysis, a review of safety
but at the same time have resulted in a       checklist at all, using a paper checklist     literature, and training obser vations.
new categor y of errors, sometimes more       is not an error-free method. Consider         Figure 1 lists the paper checklist error
perplexing to flight crews than the           the 1987 crash of a McDonnell Douglas         modes. Most of these error modes can
errors they prevent.
   Starting with a clean sheet of paper,
in the early 1990s Boeing engineers
developed the 777 electronic checklist
(ECL) with a clear awareness of the
problems and risks associated with the
introduction of a new flight deck auto-
mation tool. The particular challenge of
the ECL is to design an error-reduction
tool while ensuring the new human-
computer interface (HCI) has an ab-
solute minimum of new error modes.
The approach used to design this tool,
                                              The electronic checklist developed for the Boeing 777, which entered service in
which benefited from lessons learned          1996, was developed with the primary objective of reducing or eliminating paper
from earlier automation designs, is de-       checklist errors.
scribed below.

NUMBER 1, 2001                                                                                                                       17

be found in the chain of events of one or                    However, this was an early ECL proto-                        good judgement. In some cases, deviation
more serious civil aviation accidents.                       type and most of the new error modes                         from checklists ... may be necessary.”
   The Boeing 777 ECL, which was intro-                      found are no longer associated with the                      Indeed, a study has shown that most pilots
duced into service in 1996, was developed                    tool. Other airframe manufacturers and                       apply their judgement and occasionally
with the primary objective of reducing or                    avionics suppliers have developed auto-                      deviate from checklists rather than act as
eliminating paper checklist error modes.                     mated checklist tools employing various                      “ideal executants”.
The 777 ECL addresses most of the error                      methods.                                                        To accommodate the Boeing philoso-
modes listed in Figure 1. Some of these                                                                                   phy, the 777 ECL was designed with the
errors are prevented by the ECL, while                       Design and operational philosophy                            same degree of operational flexibility as a
the probability of other errors is sub-                         The Boeing two-pilot flight deck design                    paper checklist. But an operational phi-
stantially reduced. Ancillary operational                    and training philosophy developed for the                    losophy by itself cannot lead directly to a
benefits of the ECL include a decreased                      757 and 767 in 1978 includes the idea that                   detailed design, so more specific human-
cognitive workload and shorter checklist                     automation and other flight deck features                     centered criteria were developed.
completion times.                                            are tools that aid the pilot. The tools
   Experimental verification of ECL effi-                    should be used to the extent appropriate                     Minimizing new error modes
cacy is incomplete, although the feedback                    for the operational context. The philoso-                       The primar y function of the ECL
from airlines on the error prevention                        phy behind checklist use has long been                       interface is the reduction of checklist
modes has been very positive. An unpub-                      expressed in the Boeing quick reference                      use errors during critical flight opera-
lished Boeing simulator study of ECL per-                    handbook (QRH), which states: “check-                        tions, so it is exceedingly important to
formance found a 46 per cent decrease in                     lists cannot be created for all conceivable                  prevent the introduction of new error
errors as compared to paper checklists.                      situations and are not intended to replace                   modes that negate the benefits of the
                                                                                                                          tool. Applying the principles of human-
Figure 1. Paper checklist error modes and corrective features contained in the B777 ECL                                   centred automation design should result
                                                                                                                          in a consistent, predictable, transparent
 PAPER CHECKLIST ERROR MODE                                  777 ECL FEATURE
                                                                                                                          and error-tolerant HCI. In addition to
 Both Normal and Non-normal Checklists
                                                                                                                          these considerations, Boeing’s specific
 One or more items are skipped in checklist                  Current line item box jumps to incomplete item.
                                                                                                                          strategy needed to focus on identifying
                                                             “CHECKLIST COMPLETE”indication will not display
                                                             until all items complete                                     and eliminating the potential sources of
 Place is lost in checklist when crew distracted by          Automatic place holding when returning to an                 new errors. Several aspects of this strat-
 higher priority task or checklist                           incomplete checklist                                         egy are described below. It was found
 Incorrect switch is selected                                Sensed line items will not turn green                        that carefully heeding these considera-
 Excessive psychomotor workload due to holding,              Panel mounted display and one-hand cursor controller         tions throughout the design and test of
 turning/marking pages,recovering dropped or                 (this includes a disadvantage:lack of portability; pilot
 misplaced paper checklist                                   cannot move checklist along with visual scan)                the new system resulted in a minimum
 Checklist is misread or unreadable due to poor              Display readable in any lighting condition                   of new error modes.
 illumination                                                                                                                The frequency-of-use dichotomy. An HCI
 Normal Checklists (NC) Only                                                                                              which includes both frequently and infre-
 NC is skipped                                               Next normal checklist in sequence always displayed           quently used functions presents a chal-
 NC is not initiated                                         Not prevented.Checklist is displayed later when ECL          lenge and an opportunity to automation
                                                             next accessed,providing error feedback
                                                                                                                          designers, especially when the infre-
 Non-Normal Checklists (NNC) Only
                                                                                                                          quently used functions tend to be
 Incorrect NNC is accomplished for the annunciated           Correct NNC automatically placed in queue when
                                                                                                                          employed in high workload, high-stress
 condition                                                   airplane system fault message displayed
                                                                                                                          conditions. This situation may be referred
 NNC is skipped or left incomplete                           Checklist queue lists incomplete or unaccessed checklists.
                                                             Amber “NON-NORMAL” indication displayed                      to as the “frequency-of-use dichotomy.”
 Incorrect steps are accomplished in a branching checklist   Current line item box moves to next step in correct             There are two types of checklists: those
                                                             branch.Incorrect branch displayed in cyan                    for normal operations and those for non-
                                                             (cyan indicates inapplicable items)
                                                                                                                          normal situations. An example of a normal
 Steps to be accomplished later in flight are not             Deferred line items automatically attached to Approach
 accomplished                                                or Landing checklist                                         checklist from the ECL is shown in
 Operational notes or revised limitations following a        Notes automatically collected for review at any time;        Figure 2. Normal checklists are structured
 malfunction are forgotten                                   must be reviewed to complete Approach checklist              as a simple list of items to be confirmed,
 Wrong steps accomplished when multiple related              Correct steps are collected in single checklist.             and are used on ever y flight, typically
 failures have conflicting or redundant actions               Consequential checklists inhibited
                                                                                                                          when the aircraft is fully serviceable.
 Excessive cognitive workload in multiple failure case       ECL cognitive workload and accomplishment times
 leads to omitted NNC or other errors                        lower than paper                                             Flight crews quickly become very familiar
                                                                                                                          with this type of electronic checklist.

18                                                                                                                                                   ICAO JOURNAL

    Non-normal checklists can be more items in the normal course of accom- several steps in a typical sequence.
complex (Figure 3 illustrates a typical plishing the approach checklist, thus Design options included automating the
non-normal checklist from the ECL). requiring no unique skills or knowledge entire sequence, or breaking it into two
They employ inter face elements to help to avoid checklist use errors.                                                                                                     or more user-initiated sub-sequences.
users navigate through decision
points in “branching” procedures,
                                                NORMAL MENU                                 RESETS NON-NORMALMENU                                                               NORMAL MENU                              RESETS NON-NORMALMENU
keep track of required time delays
between steps, and remind users of                                    BEFOR E TA K E O F F                                                                                                            BEFOR E TA K E O F F
actions that must be taken later in the         APU SELECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OFF                                 RADAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ON
                                                AUTOBRAKE SELECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . RTO                                                   TAKEOFFCLEARANCE . . . . . . . . . . . . . . . . . . . . . RECEIVED
flight. Non-normal checklists are used                                                                                                                                   1                                                                                                                           1
                                                AUTOTHROTTLE SWITCHES . . . . . . . . . . . . . . . . . . . . ARM
when the aircraft is experiencing one          s TAKEOFF DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SET
or more system failures. The oper-             s DEPARTURE BRIEFING . . . . . . . . . . . . . . . . . . . COMPLETE
                                               s CABIN CREW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WARNED
a ting environment is unpredictable
                                                FLAPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
since the possible combinations of fail-                                                                                                                                 2                                                                                                                           2
                                                 ---------------------- ENTERING RU N WAY ---------------------
ures, although unlikely to occur, are
                                                LANDING LIGHT & STROBE SWITCHES . . . . . . . . ON
nearly infinite.                                TRANSPONDER SELECTOR . . . . . . . . . . . . . . . . . . . . TA/RA
    Given the high reliability of modern                                                                                                                                                              CHECKLISTCOMPLETE
transpor t aircraft, flight crews rarely                        ITEM                                             CHKL CHKL                                          NON-               ITEM                                                  CHKL CHKL                                          NON-
                                              NORMAL OVRD NOTES OVRD RESET NORMAL                                                                                             NORMAL OVRD NOTES OVRD RESET NORMAL
use the non-normal checklist outside
of recurrent training. Infrequent use       Figure 2. Example of a two-page normal checklist from the B777 ECL. Normal checklists
leads to decreased proficiency, and are structured as a simple list of items to be confirmed.
error-inducing factors grow in a situa-
tion that combines rusty skills, high            This strategy must be applied early in                                                                                       Boeing was faced with this choice
stress, high workload and unpredictable the design process because it involves when examining the task flow associated
operating conditions.                        identifying the functional requirements with a per vasive failure condition, such
    The primar y strategy for addressing for the often used and infrequently used as a fire or uncontained engine failure.
this issue is to maximize the common interfaces, and manipulating both to cre- The condition may lead to multiple con-
elements between the often used and ate the maximum number of common sequential system failures. The crew
infrequently used interfaces. In the elec- interface elements.                                                                                                             alerting system displays a list of fault
tronic checklist, many of the interface          Other automated interfaces on the messages of var ying levels of urgency.
elements found in the non-normal check- flight deck are also subject to the fre- Figure 4 shows the sequence of activities
list are encountered daily when using quency-of-use dichotomy. For example, that the flight crew is trained to accom-
the normal checklist. On the rare day the flight management computer (FMC) plish for multiple failure indications on a
when an emergency occurs, the user is contains features which are used on a Boeing aeroplane with paper checklists.
presented with a predominantly familiar daily basis, such as normal FMC descent                                                                                               The sequence of messages displayed
interface. The normal and non-normal from cruise altitude. It also contains fea- on the list is a result of simple logic
checklists have, for example, identical tures which are used infrequently and based on the predetermined aler t level
screen layout and colour conventions, under potentially stressful conditions, and the order in which the messages
page bar and function keys. Menus are such as engine-out cruise driftdown. On were activated. In most cases, if the
accessed in the same way and most line current Boeing aircraft, these tasks are flight crew accomplished the checklists
items function in the same way.              accomplished using different flight man- in a sequence identical to the alert mes-
    Functions unique to the non-normal agement modes and procedures. Training sage display sequence, they would safe-
checklists are minimized, but when and potential errors associated with the ly deal with the non-normal conditions.
required are linked to the normal check- driftdown task could be reduced using the The automation designer might choose
lists whenever possible. The “deferred line strategy described above.                                                                                                      to simply automate the entire task flow
item” function, for example, accommo-            Over-automation and range of opera - and present checklist line items on a dis-
dates a non-normal checklist containing tions. An automated tool has been play in the automated sequence. The
crew actions which must be accomplished described as “a device that carries out problem with this high level of automa-
later. The deferred line items are automat- more or less independently a task that tion is that it cannot accommodate the
ically copied from the non-normal check- would other wise require increased entire range of potential operations.
list to the end of a designated normal human attention or ef fort.” In many Sometimes the operating conditions
checklist, usually the approach checklist. cases, the ECL designers were presented require the crew to choose a sequence of
The user encounters the deferred line with a manual method that consisted of actions different from the sequence the

NUMBER 1, 2001                                                                                                                                                                                                                                                                            19

                                                                                                                                                                                              queue, the user selects the check-
       NORMAL MENU                  NON-NORMALMENU
                                   RESETS                                                  NORMAL MENU                  RESETS        NON-NORMALMENU
                                                                                                                                                                                              lists to be accomplished in the
                    OUTFLOW VA LVE FWD                                                                OUTFLOW VA LVE FWD                                                                      desired sequence. From step 7, the
        C o n d i t i o n : Forward outflow valve auto mode failed.                       FWD OUTFLOW VALVE MODE                                                                              process is largely automated as the
       FWD OUTFLOW VALVE MODE SWITCH . . . OVRD                                          SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MANUAL
                                                                          1                                                                                                              1
                                                                                                                                                                                              ECL displays the correct check-
       Cabin altitude continues to cl i m b :                                            NOTE:Do not move forward outflow
                         Ye s                     No                                      valve until final approach.                                                                          lists for the failure conditions and
                                                                                                                                                                                              the pilots are assisted through the
                                                                                         --------------- Deferred Items -------------
            Position outflow valv e fully cl o s e d .                                                                                                                                        checklist by the error-reducing
                                                                                     ==> APPROACHChecklist
       N O T E: Use aft outflow va lve to control
            cabin pres sure.
                                                                                     At patte rn altitude:
                                                                                                                                                                                         2    agent.
       Cabi n altit ude s tabi lised :                                                   FWD OUTFLOW VALVE CONTROL . . . . . . . . OPEN                                                         Divergence from the manual
                         Ye s                     No                                        Position outflow valv e fully open
                                                                                            fo r landing.
                                                                                                                                                                                              method. When of fered a clean
                Wa it 30 s econ ds.
                                                                                                                                                                                              sheet of paper to design a new tool
                           ITEM                CHKL CHKL            NON-                           ITEM NOTES CHKL CHKL                                                             NON-      such as the electronic checklist,
     NORMAL OVRD NOTES OVRD RESET NORMAL                                          NORMAL OVRD                                                   OVRD RESET NORMAL
                                                                                                                                                                                              the designer naturally seeks to cre-
 Figure 3. An example of a two-page non-normal checklist. Non-normal checklists employ more ate the optimum solution and is
 complex interface elements and are used when aircraft experience one or more system failures. justifiably resistant to any con-
                                                                                                                                                                                               straint from existing paradigms.
automation would have applied.                                              first made of the range of possible oper- However, this tendency can lead to a
     There are many potential scenarios in ations. In some cases the range can be design that is excessively divergent from
which the operational context exceeds bounded with reasonable cer tainty, and the manual method.
th e rang e that automation rules can consultation with airline pilots often                                                                                                               Under high stress, humans have
accommodate. The aviation environment expanded the estimated range of poten- reduced memory and cognitive capacity
is complex and tremendously variable, tial operations. Whenever the range and tend to respond to strong stimuli
an d on ly h uma n                                                                                                    exceeded the ability with well-learned or “over learned”
operators have the Figure 4. Sequence of activities for multi- to create an effective responses. Pilots are trained repeatedly
                                            ple failure indications on a Boeing aircraft
ability to assimilate with paper checklists                                                                           HCI for all opera- over their careers in the use of paper
unexpected and in-                                                                                                    tions, manual inter- checklists to handle emergencies. Thus,
congr uent informa-                                                                                                   vention was retained, a strong stimulus such as an engine fire
                                              1. Attention: Aural alerts or visual scan call atten-
t i o n , co m b i n e i t                       tion to alert message display area                                   allowing the crew to indication may elicit the behaviour the
with experience and                           2. Fault Assessment: Pilot not flying (PNF) reads                        apply their expertise pilot has most frequently been trained to
                                                 lists of fault messages-literal understanding of
knowledge, and use                                                                                                    and exercise control use rather than the behaviour appropri-
reason to determine                           3. Procedure availability assessment: PNF deter-                        when required.                                                   ate to the current context. By maximiz-
the best course of                               mines which messages have associated checklists                                To return to the ing commonality with the paper
action. When design-                          4. Recall items assessment/execution (rule-                             example shown in checklist, however, this human tendency
                                                 based): Pilots identify any failures that require
ers assume a narrow                              immediate action (checklists that include “recall                    Figure 4, the elec- can be used to advantage and errors,
range of operational                             items”); if none:                                                    tronic checklist auto- including errors in the use of checklists,
conditions they may                           5. Root cause assessment (knowledge-based):                             mates steps 1 through can be minimized.
                                                 Pilots use their expertise and available indica-
no t p ro vi de the                              tions to determine root cause-contextual under-                      3 (shaded) by dis-                                                   The 777 ECL was designed with a
required opportunity                             standing of faults leads to situation awareness                      playing a concise list high degree of commonality with the
                                              6. Action planning: Based on understanding of root
for human inter-                                                                                                      of checklists to be manual method in both the normal and
                                                 cause,and level of urgency indicated by alerting
vention in the auto-                             system (warning messages displayed in red,cau-                       accomplished, called non-normal interfaces. Layout, appear-
mated s e q u e n c e ,                          tions in amber, advisories amber and indented)                       the checklist queue. ance, line item indentation and other
                                                 pilots determine which failure conditions require
shifting the locus                               checklist accomplishment and in what sequence                        The queue is pre- visual characteristics are similar to a
of c o n t rol inappro-                       7. Execution: PNF locates first non-normal check-                        sented in the same paper checklist. Most nomenclature is
priately to the auto-                            list in the handbook                                                 default priority se- common to the paper environment. Most
                                              8. Execution: First non-normal checklist is accom-
mation.                                          plished
                                                                                                                      quence as the alert- important is that the procedural flow and
     To protect against                       9. Execution: Continues through last non-normal                         ing system message crew coordination was unchanged. In an
ECL over-automa-                                 checklist                                                            list (warnings, then e m e rg e n c y, the pilot flying (PF) could
tion, a conservative                                                                                                  cautions, then advi-                                                                       continued on page 36
approach was taken. When sequences of sories). Steps 4 through 6 involve knowl-
                                                                                                                                                                                       Daniel Boorman is a Technical Fellow at The Boeing
steps could be automated or a logical edge and cognitive processes that exceed Co., Seattle. This article is an adaptation of a paper
assumption of crew intent could be the capability of any automated agent, so presented at the Human-Computer Interaction in
                                                                                                                                                                                       Aeronautics 2000 conference held in Toulouse, France
imbedded in the tool, an evaluation was they remain manual. From the checklist in September 2000.

20                                                                                                                                                                                                             ICAO JOURNAL
                                                                                                                T RAI NING P ROGR AM ME S

Safety seminars planned for regions where
maximum safety gains may be achieved
A new educational initiative is bringing air safety seminars to different parts of the world.
The specialized programme is designed to attract professionals who may be unable to attend
formal training courses because of their cost and location.

                                             also provide some programme funding.           teaching. For the most part, members
             JIM STEWART                     To minimize the cost of participation,         who are asked to participate in the out-
                (CANADA)                     there are no registration fees or a formal     reach programme have some formal
                                             social programme. The volunteer instruc-       training as a teacher. The Society has

          HE International Society of Air    tors — who are responsible for preparing       also established an in-house quality con-
       Safety Investigators (ISASI) will     their own lesson plans, preparing their        trol panel of professional investigators to
        conduct the first of a planned
series of educational seminars designed
to address regional training needs in
Prague, Czech Republic from 7 to 10 May
   The non-profit seminar, an effort by
ISASI to provide an educational work-
shop to a broader community of air safe-
ty investigators, will be hosted by the
Ministr y of Transpor t and Communic-
ations of the Czech Republic, and is sup-
por ted by ICAO.
   The innovative format of the Prague
workshop and possible future work-
shops is the inspiration of the “reachout”
                                             The first in a planned series of ISASI “reachout” air safety seminars will convene in
programme, an ISASI initiative. The new      Prague in May 2001.
format provides high quality, inexpen-
sive training opportunities for individu-    own handout material and providing a           review and certify teaching tools before
als and organizations that are unable to     full range of services to those attending      presentation. The panel’s task is to con-
par ticipate in the more costly regular      the workshops — are not paid for their         firm the technical accuracy of the prod-
seminar programme conducted by ISASI.        time.                                          uct and ensure that it includes the latest
The plan is to hold such seminars in            With over 1,500 individual members          information available.
areas where the greatest gains in acci-      representing the world’s top exper ts in          The underlying principle of the ISASI
dent prevention may be achieved.             accident investigation and aviation safety,    programme is to respond to the needs of
   Unlike a typical seminar programme,       ISASI has a large pool of potential            the particular area in which the workshop
an ISASI “reachout” seminar does not         instructors to call upon. Having promoted      is being held. ISASI plans to advertise the
include a call for papers or an agenda       aviation safety through professional sem-      availability of the programme to States
filled with a variety of speakers. The pro-   inars and workshops since 1968, it is able     through various means. Current plans
gramme is developed following a specific      to provide expertise on virtually any safety   call for workshops to be held in sev-
request from local organizers, and is pre-   subject and will be able to design and         eral regions including Africa, par ts
sented by ISASI volunteers. Each seminar     deliver a tailor-made workshop to any area     of Asia, Eastern Europe, Central and
is designed to be a structured, training     of the globe.                                  South America, and ISASI is encouraging
workshop.                                       In selecting instructors, ISASI relies
                                                                                                                          continued on page 36
   ISASI “reachout” seminars are sup-        on members who have displayed a tech-
                                                                                            Jim Stewart is the Air Safety Coordinator (Canada) for
ported by corporate members, which           nical knowledge of the subjects to be
                                                                                            the Air Line Pilots Association (ALPA) International. He is
arrange air travel for the instructors and   taught and have a record of successful         also the chairman of the ISASI “reachout” programme.

NUMBER 1, 2001                                                                                                                                     21

Indonesian agency issues report on SilkAir
Flight MI 185 crash in December 1997
The investigation of SilkAir Flight MI 185’s rapid descent into the Musi River from a cruising
altitude of 35,000 feet yielded very little information on which to draw conclusions. Safety issues
on which the investigation focused concerned the areas of flight operations, flight recorders,
human factors and control system malfunctions.

                                                 proceed directly to PARDI.2 The air traf-      site and only six positive identifications
        NATIONAL TRANSPORTATION                  fic controller instructed MI 185 to standby,   were made. The wreckage had penetrated
           SAFETY COMMITTEE                      to continue flying directly to Palembang        deep into the river bottom, and the
                   (INDONESIA)                   and to report when reaching FL 350. At         destruction was such that mainly small
                                                 0853:17, MI 185 reported reaching FL           mangled parts were recovered from the

         N 19 December 1997, a SilkAir           350. Subsequently, the controller cleared      river. Parts of the rudder skin and the out-
         Boeing B737-300 aircraft, regis-        MI 185 to proceed directly to PARDI and        board sections of the horizontal stabilizer
         tration 9V-TRF, was on a sched-         to report when abeam Palembang.                were recovered on land; the part furthest
uled commercial international passenger             At 0905:15, the cockpit voice recorder      away was found about four kilometres
flight under instrument flight rules (IFR),        (CVR) ceased recording. According to           from the main impact site.
routing Singapore-Jakarta-Singapore.             the Jakarta air traf fic control (ATC) tran-
   The flight from Singapore to Jakarta           script, at 0910:18 the controller informed     Accident analysis
operated normally. After completing a            MI 185 that it was abeam Palembang.               The investigation was extremely diffi-
normal turnaround in Jakarta, the aircraft       The controller instructed the aircraft to      cult and challenging because of the
departed Soekarno-Hatta International            maintain FL 350 and to contact Singapore       degree of destruction of the wreckage,
Airport for the return leg with 97 passen-       Control when at PARDI. The crew                the difficulties presented by the accident
gers, five cabin crew and two cockpit             acknowledged this call at 0910:26. There       site and the lack of information from the
crew.                                            were no fur ther voice transmissions           flight recorders during the final moments
   At 0837:13 (1537:13 local time) the           from MI 185. The last readable data from       of the accident sequence.
flight (MI 185) took off from Runway 25R          the flight data recorder (FDR) was at              The analysis was drawn from facts
with the captain as the pilot flying. The         0911:27. Jakarta ATC radar recording           compiled in the engineering and systems,
flight received clearance to climb to            showed that MI 185 was still at FL350 at       operations, and human factor aspects of
35,000 feet or flight level (FL) 350 and to       0912:09. The next radar return, eight sec-     the investigation.
head directly to Palembang.1 At 0847:23          onds later, indicated that MI 185 was 400         Analysis on the engineering and sys-
the aircraft passed FL 245. Ten seconds          feet below FL 350, and a rapid descent         tems aspects started with the aircraft
later, the crew requested permission to          followed. The last recorded radar data at      structural and systems integrity, includ-
                                                 0912:41 showed the aircraft at FL 195.         ing trajectory and flutter analysis studies.
 FLIGHT MI 185 REPORT                            The empennage of the aircraft subse-           The results of tear down and examina-
 The text of this article comprises extracts     quently broke up during the descent and        tion of the actuators were analysed to
 from the Indonesian National Transportation     the aircraft crashed into the Musi River       determine the positions and conditions
 Safety Committee (NTSC) final report on the      delta, about 50 kilometres (30 nautical        of the control surfaces, engines and
 SilkAir Flight MI 185 crash into the Musi
                                                 miles) north-north-east of Palembang at        other related systems. Special attention
 River near Palembang, South Sumatra,
 Indonesia on 19 December 1997.                  about 09:13. The accident occurred in          was also given to the issues arising from
   The full accident report published by the     daylight and in good weather conditions.       previous Boeing 737 accidents (e.g. the
 Department of Communications of the Re-         The sequence of events is shown in the         Colorado Springs and Pittsburgh acci-
 public of Indonesia on 14 December 2000         accompanying figure.                            dents), especially on the issue of the rud-
 includes several appendices including offi-
                                                    The aircraft was completely destroyed       der power control unit (PCU). The stop-
 cial comments on the draft final report by
                                                 by impact forces, and none of the 104 per-     page of the flight recorders was analysed
 other States which participated in the inves-
 tigation.                                       sons on board survived. Very few human         based on the electrical wiring diagrams
                                                 remains were recovered from the crash          as well as on-ground and in-flight tests

22                                                                                                                         ICAO JOURNAL
                                                                                                                                      ACC IDE NT R EPO RT

performed in the United States and in         trim actuator, the rudder trim and feel                      2. Audio spectral analyses on ATC com-
Singapore. The maintenance aspect was         centring unit, the standby rudder PCU,                       munications and the accident CVR indi-
analysed in the last part of the engineer-    the aileron PCUs, the elevator PCUs, and                     cated that the last communication from
ing and systems section.                      the horizontal stabilizer jack-screw com-                    MI 185 at 0910:26, occurring at a position
   The investigation of the operations        ponents, revealed no indications or evi-                     approximately abeam Palembang, was
aspect covered general factors of the oper-   dence of pre-impact malfunctions.                            performed by the first officer.
ation of the flight such as flight crew, air
traffic control, weather, navigation, com-       F/O:“SilkAir 185        CVR stopped                          FDR stopped
munication, flight trajectory and condi-         maintaining 350”         recording                            recording
                                                   (0853:17)            (0905:15.6)                          (0911.33.7)
tions based on CVR, FDR as well as radar                                                                                                  Radar points
                                                                                        Unrecoverable FDR data 6.3s
                                                                                                                                      Time interval = 8 sec)
data, and flight simulation exercises. The
analysis focused on the possible system
failures and their effect to the aircraft
descent trajector y as suggested from
                                                       PIC:“Go back for a while F/O:“SilkAir 185          Last readable    Last radar point at
radar data points. The descent technique                   finish your plate        Roger ...”               FDR data            35,000 ft
that arises from emergency situation and                      (0904:57)            (0910:26)               (0911:27.4)        (0912:09.2)
recovery from such extreme descent was
also discussed.                                 • Note:all times are based on FDR UTC                          Last radar point at 19,500 ft (0912:41.2)
   The investigation of the human factor
aspect of the accident took into consider-    Sequence of events on 19 December 1997 (all times based on FDR UTC).
ation all available background data of the
flight crew, and the results of the analysis   6. Examination of the 370 kilograms of                       3. The examination of the flight deck
in the other areas. The analysis covered      recovered electrical wires, connectors                       noise and sounds concluded that the
general human performance issues, the         and circuit boards showed no indication                      metallic snap recorded on the CVR was
human factor aspects of the CVR and           or evidence of cor rosion, shorting, bur n-                  made by a seatbelt buckle hitting against
ATC recordings, as well as specific           ing or arcing in these wires or parts.                       a metal surface.
human factor issues.                          7. The CVR stopped recording at                              4. Based on flight simulations, it was
                                              0905:15.6 and the FDR stopped record-                        observed that the simulated descent tra-
Accident investigation findings               ing at 0911:33.7. The examination of the                     jectory resulting from any single failure
   Following are the findings related to       CVR and FDR showed no malfunction of                         of flight control or autopilot system
engineering and systems.                      the units. The stoppages could be attrib-                    would not match the radar data.
1. There was no evidence found of in-         uted to a loss of power supply to the                        5. Based on the same flight simulations,
flight fire or explosion.                       units. However, there were no indica-                        it was also observed that the trajectory
2. From flutter analysis and wreckage          tions or evidence found to conclude on                       shown by the radar data could have been,
distribution study, the empennage break-      the reason for the stoppages due to the                      among other possibilities, the result of
up could have occurred in the range           loss of power. The cause of the CVR and                      the combination of lateral and longitudi-
between 5,000 and 12,000 feet altitude.       FDR stoppages and the reason for the                         nal inputs together with the horizontal
3. Examination of engine wreckage indi-       time difference between the stoppages                        stabilizer trim input to its forward manu-
cated that the conditions of the engines      could not be concluded.                                      al electrical trim limit of 2.5 units.
at impact were not inconsistent with high     8. The inspection of the aircraft mainte-                       Following are the findings related to
engine rotation speed. No indications         nance records did not reveal any defects                     human factors.
were found of in-flight high energy           or anomalies that could have affected the                    1. Both pilots were properly trained,
uncontained engine failures. Therefore,       airworthiness of the aircraft or that may                    licensed, and qualified to conduct the
the engines were considered to be not a       have been a factor contributing to the                       flight.
factor contributing to the accident.          accident.                                                    2. There was no evidence found to indi-
4. Examination of the actuators of flight      9. The horizontal stabilizer trim was                        cate that the performance of either pilot
and ground spoilers, trailing and leading     found to be in the 2.5 units position,                       was adversely affected by any medical or
edge flaps, as well as engine thrust          which matched the forward limit of the                       physiological condition.
reversers, indicated retracted or stowed      manual electrical trim.                                                                  continued on page 33
positions of the respective systems.             Following are the findings related to
                                                                                                           1. Coordinates (02.52.7S, 104.39.2E)
5. Examination of the main rudder PCU         flight operations.                                            2. Air traffic control repor ting point (00.34.0S,
                                                                                                           104.13.0E) north of Palembang in the Jakarta FIR
(including the servo-valve), the yaw          1. Weather and air traffic control were                       near the boundar y with the Singapore FIR. At PARDI,
damper modulating piston, the rudder          not factors contributing to the accident.                    flights are transferred over to Singapore ATC.

NUMBER 1, 2001                                                                                                                                                 23

DC-10 flying eye hospital travels worldwide
on intensive humanitarian programme
A former airliner equipped as a modern eye hospital is regularly flown to developing countries with the
goal of saving sight through hands-on training, public health education and improved access to eye care.

                                               lion people, 90 per cent of whom live in         With the aid of the DC-10 flying eye
PAUL F. HASSEN • VICTOR SOTENBERG              developing countries, will become blind      hospital, hundreds of volunteers, inex-
            ORBIS INTERNATIONAL                next year.                                   haustible teamwork and unprecedented
                                                                                            generosity, ORBIS spearheads a global

       McDonnell Douglas DC-10 con-            Saving sight worldwide                       e ff o rt to end avoidable blindness.
       verted into a flying eye hospital          The leading cause of blindness world-
          in 1994 is being flown to several    wide is cataract, a condition which          From aircraft to hospital
countries each year on a humanitarian          impacts 18.9 million people, followed by        ORBIS converted a Douglas DC-8 pas-
mission to prevent blindness and pro-          trachoma, onchocerciasis, and glaucoma.      senger jet into the world’s first flying eye
vide hands-on training for medical pro-        In addition, there are 1.5 million blind     hospital in 1982. In 1994, the DC-8 was
fessionals.                                    children, mainly in Africa and Asia. In      retired and replaced with a McDonnell
   The world’s only flying eye hospital,       developing countries, blindness in chil-     Douglas DC-10-10ER wide-body aircraft.
the for mer ai rliner features a fully         dren is usually caused by conditions            The second production model built,
equipped teaching facility and is piloted      which cause scarring of the cornea such      the ORBIS DC-10 started its career as a
and staf fed by volunteers. It visits devel-   as vitamin A deficiency, measles, con-       test aircraft in the DC-10 certification pro-
oping countries regularly to bring prac-       junctivitis and harmful traditional eye      gramme. Subsequently, it was operated
tical hands-on training to local eye           medicines.                                   by five different airlines including Laker
doctors, technicians and health care              Perhaps the most startling fact is that   Air ways, American Trans Air, Air Hawaii
workers and to restore sight to thou-          the treatments available for the preven-     and Novair, a division of the Rank
sands of patients, often children.             tion and cure of blindness are among the     Organization. ORBIS acquired the air-
   The humanitarian ser vice has been          most successful and cost-effective of all    craft from Rank for $14 million in 1992,
provided by a nonprofit organization,          health interventions. Millions can be        substantially less than the $25 million ask-
ORBIS International, since 1982. There is      cured with techniques routinely prac-        ing price as a result of effective negotiat-
a great need for such work: some 7 mil-        ticed in many countries.                     ing by A.L. Ueltschi, the chairman and
                                                                                            president of FlightSafety International
                                                                                            and chairman of the ORBIS International
                                                                                            board of directors.
                                                                                               Powered by three General Electric CF6-
                                                                                            6D engines and equipped with extra fuel
                                                                                            capacity, the aircraft was ideal for ORBIS’s
                                                                                            needs. Having logged only 35,000 hours of
                                                                                            flying time and about 10,000 cycles, the
                                                                                            DC-10 had sufficient remaining life to be
                                                                                            cost effective to operate.
                                                                                               Originally built in a single class, econ-
                                                                                            omy configuration, the aircraft interior
                                                                                            was gutted from the top of the vertical sta-
                                                                                            bilizer to the bottom of the airframe hull.
                                                                                            It was steam cleaned and repainted where
                                                                                            appropriate. The pneumatic, hydraulic,
The ORBIS DC-10 hospital includes a complete ophthalmic operating suite and                 electrical, air conditioning and environ-
other essential medical facilities, plus a 52-seat classroom which doubles as a travel
compartment. The lower level of the aircraft houses a technical training and main-          mental systems were restored to like-new
tenance centre.                                                                             condition. Some structural components

24                                                                                                                     ICAO JOURNAL
                                                                                                              H U M A N I TAR IA N P R OGRA M MES

also were replaced and the airframe was comprise the international medical staff                            The DC-10 usually arrives at its desti-
modified to bring the floor panel deflec- aboard the flying eye hospital. In addition, nation a day or two before the start of a
tion tolerance to 0.0001 inch, as required three leading ophthalmologists from programme. Soon after, the crew begins
by the precise nature of laser eye surgery. around the world join the crew each week the process of transforming the aircraft
As a result, the DC-10’s modifications to lead the teaching and surgical activities. into an eye hospital. Equipment and sup-
brought the aeroplane to tolerances                  Flying the aircraft is the responsibility plies are unpacked, interior walls assem-
unheard of in most commercial aircraft.           of a cadre of volunteer pilots from United bled and the medical areas cleaned and
   The DC-10 flying eye hospital includes Airlines, the founding airline sponsor of sterilized. The aircraft remains parked
a complete ophthalmic operating suite ORBIS. The dedicated group of veteran for the next three weeks, while teaching
featuring a four-bed pre-operation and pilots receives complimentar y ground and surger y is under way.
recovery room, subster-                                                                                                     DC-10 pro g r a m m e s
ile room and operating                                                                                                   begin with a screening of
                                                                                    Substerile room
room. Also included are                                                                                                  patients suggested by local
a multi-media control                                                                                                    oph thalmologists. T h e
room, examination and                                         Operating room                                             o p hthalmologists and the
                                     Conference room
laser treatment ro o m ,                                                                                                 ORB IS medi cal te am
conference room, and a                                                                                                   select patients whose con-
                                Audio visual room
52-seat classroom which                                                                                         Comm.    di t ions make the best
doubl es as the cre w                                                                                                    cases for demonstrating
c o m p a r t ment duri ng                                                                                               advanced surgical tech-
                                                                                                Recovery room
travel. During modifica-                                                                Corridor                         niques. Patients who are
tion, the DC-10 lower                                                              Laser treatment room                  not selected for surger y
galler y was outfitted as                                                                                                receive a diagnosis and
a biomedical engineer-                                                  Technical services                               local ophthalmologists are
ing work area.                                                   Classroom                                               offered advice about treat-
   The aircraft carr i e s                                                                                               ing them.
enough equipment to be        A view of the recovery room situated near the rear of the DC-10. The room                     In the DC-10’s operat-
                              serves as a pre- and post-operative holding area, and is used to instruct
independent while on          local nurses on topics such as pre- and post-op patient care.                              ing room, local doctors,
the ground, including                                                                                                    nurses, anesthesiologists
auxiliary air conditioners, a water purifi- school and full-motion simulator training and biomedical technicians work side-by-
cation system and an oxygen generation at United’s Denver facility, as well as side with ORBIS faculty in performing
system. Two LD-3 containers have been additional training from ORBIS.                                   s u rg e ry. Video cameras, including one
modified to carry a 400-Hz, 90-KVA gen-               United also provides a flight mechanic inside the surgical microscope, capture
erator plus two 60-cycle diesel generators. who travels with the aircraft to keep its the procedures for simultaneous viewing
   The two-year conversion project was systems running smoothly.                                         in the aircraft’s classroom, where as
completed at Mobile Aerospace Engin-                 Each year the DC-10 visits 10 destina- many as 50 local ophthalmologists
eering in Alabama. ORBIS staff served as tions in the developing world for a three- obser ve the operations on three televi-
prime contractor, with Runge Industries week programme. The 2001 itinerar y sion screens. Signals can also be beamed
providing cabinetry, Schwartz Engineering includes stops in China, Costa Rica, Cuba, to an auxiliar y classroom inside the air-
completing structural work, and Avionics Ethiopia, Guinea, India, Mongolia, Peru, por t terminal or other nearby structure.
Engineering performing electrical work. and Trinidad and Tobago. Last year, the                             Videotapes are left with local partner
Total cost of the conversion was more than aircraft stopped in Bulgaria, China, Cuba, institutions to be reviewed and used in fur-
$15 million and required the expertise of India, Myanmar and Uzbekistan.                                ther training. Doctors and technicians also
more than 100 aircraft professionals.                The itinerary is developed in response gain hands-on experience in the use and
   In July 1994 the DC-10 flying eye hos- to invitations from national ministries of maintenance of ophthalmic equipment.
pital arrived in Beijing, China for a three health and local ophthalmology associ-                          After surgery patients receive care in
week medical programme and the offi- ations in conjunction with ORBIS pro- the DC-10’s recover y room, attended by
cial retirement of the DC-8.                      gramme offices and resources. Technical ORBIS nurses and their local counter-
                                                  considerations include evaluation of the parts. ORBIS doctors work with local col-
The flying eye hospital                           runway length, width and strength (PCN), leagues to ensure that patients receive any
   A crew of 25 health care professionals, and the availability and suitability of fuel, necessar y follow-up treatment after sur-
including ophthalmologists, nurses, anes- security, parking areas and ground sup- gery. Three months after each mission, an
thesiologists, and biomedical engineers port equipment.                                                  ORBIS doctor, staff ophthalmologist and

NUMBER 1, 2001                                                                                                                                      25

nurse return to the area to examine each      nurses transfer skills to their local col-           vibration — for the developing countries
patient as part of the organization’s com-    leagues during surgical programmes and               where it operates. ORBIS also helps
mitment to quality care.                      during nursing programmes that empha-                establish eye banks and cornea donation
                                              size topics such as infection control and            campaigns so doctors may per f o rm
Beyond the aircraft                           primary eye care. Other local hospital               corneal transplants.
   During the past several years, ORBIS       programmes help prepare community                       Since the first mission in 1982, ORBIS
has opened programme of fices in Ban-         health care workers to carr y out public             has completed over 460 programmes in
gladesh, China, Ethiopia and India. These     awareness campaigns, and hospital admin-             80 countries. More than 55,000 ophthal-
new offices, staffed by local public health    istrators to institute practices for quality         mologists, nurses, biomedical engineers,
professionals, enable the organization to     control.                                             anesthetists and other health care work-
                                                                                                           ers have par ticipated in ORBIS
                                                                                                           programmes. Worldwide, more
                                                                                                           than 23,500 patients have been
                                                                                                           directly treated by ORBIS doc-
                                                                                                           tors and more than 9 million peo-
                                                                                                           ple have received eye care from
                                                                                                           ORBIS-trained doctors.

                                                                                                      A helping hand
                                                                                                          E x t r a o rd i n a r y people and
                                                                                                      p a r tnerships have made the
                                              The DC-10 laser/examination room (left) contains
                                                                                                     work of ORBIS possible. Some
                                              independent slit lamp and laser stations, allow-
                                              ing ORBIS personnel to examine patients before 275 leading ophthalmologists
                                              and after surgery and to teach laser techniques from the United States, Canada,
                                              to host-country doctors. A corridor on the port
                                                                                                     Europe and around the world
                                              side of the aircraft links several of the rooms,
                                              with a large window to allow viewing of surgery volunteer to share their surgical
                                              performed in the operating room (above).                skills and knowledge with local
                                                                                                      doctors in the countries where
focus its ef forts in regions where there        The ORBIS Taiyuan Training Centre ORBIS operates. Whether on the aircraft
is a high incidence of avoidable blind-       in Shanxi, China provides a year-round or in local hospitals, the doctors who
ness and a willingness to develop quality     location for ophthalmic training. The demonstrate their surgical techniques
eye-care systems.                             curriculum focuses on the most preva- and share their knowledge are the hear t
    From these country of fices, working      lent blinding diseases in the region, of the ORBIS programme.
with local ophthalmologists, government       while addressing the training needs of          More than 250,000 corporations, foun-
officials and private industry, ORBIS is      ophthalmologists, nurses, biomedical dations and individuals around the world
forging a collaborative plan that assess-     technicians, administrators and other provide the financial resources necessary
es the root causes of blindness and iden-     health care workers. Fellowship pro- to fund the $26 million annual budget. The
tifies a range of interventions designed      grammes allow ophthalmologists in global airline and travel industries have
to strengthen the eye care system in the      developing countries to obtain specialist been major supporters of ORBIS. In addi-
region.                                       training in top teaching hospitals and tion to the founding airline sponsor,
    ORBIS also conducts more than 50          medical schools around the world.           United Airlines, other supportive air carri-
hospital-based continuing education and          Making sure that a new surgical tech- ers include Air Macao, American Airlines,
primary eye care programmes each year,        nique takes root often entails more than Cathay Pacific Air ways, Delta Airlines,
ensuring that its work has a sustainable      continuing education. Doctors must Delta Air Lines, Northwest Airlines and
impact. During hospital-based surgical        have the tools to put these techniques Virgin Atlantic Airlines.
programmes, ORBIS doctors demon-              into practice. Besides providing training                                    continued on page 38
strate techniques for treating those eye      on the use, repair and maintenance of
diseases of greatest concern to their local   biomedical equipment, ORBIS frequently Paul F. Hassen is the Director of Communications at
                                                                                          ORBIS International. Victor Sotenberg is the organiza-
colleagues. Technology programmes             helps to secure or locate affordable and tion’s Senior Flight Operations Officer.
                                                                                             More information about ORBIS is available at the
provide an opportunity for a host coun-       appropriate medical supplies and tech-
                                                                                          organization’s website ( To obtain
try’s biomedical technicians to master        nology including microscopes, lasers information about volunteering or to make a donation
the repair and maintenance of basic and                                                                                International,
                                              and phacoemulsification machines — to ORBIS, contact: ORBISYork, NY 10036;330 West 42nd
                                                                                          Street, Suite 1900, New                     tel. (212) 244-
advanced ophthalmic equipment. ORBIS          used to extract cataracts by ultrasonic 2525; e-mail:

26                                                                                                                                ICAO JOURNAL
                                                                                                                       AV I ATI ON ME DI CINE

Early diagnosis is the key to correcting
age-related vision problems among pilots
The most widespread vision problem among those over age 40 is presbyopia, the difficulty of focusing
on close objects that is considered one of the first indications of aging.

                                                  In a young person, the lens is clear         Individuals who had the highest dis-
     STANLEY R. MOHLER, M.D.                   and flexible, and— with the help of the tant visual acuity while they were in their
        WRIGHT STATE UNIVERSITY                ciliary muscle, which aids in focusing— 20s typically experience presbyopia
             (UNITED STATES )                  its shape changes, depending on the dis- sooner than those who — at the same
                                               tance of the object being viewed. To view age — had poor distant vision because of

         GING brings gradual changes to        a nearby object, the ciliar y muscle con- myopia, also known as nearsightedness.
           the structure of the eye and the    tracts and the lens becomes rounder and This relatively early onset of presbyopia
            quality of vision. These changes   optically stronger; to view a distant occurs because people who see excep-
can result in problems ranging from            object, the ciliar y muscle relaxes and the tionally well at a distance have more
d i f ficulty focusing on close objects to     lens becomes thinner.                        focusing ability to see distant objects.
dry eyes and diseases such as glaucoma            Throughout a person’s life, lens cells Conversely, some people with a small
and macular degeneration. In many              die, and as they                                                          degree of myopia
instances, early diagnosis of vision prob-     do, they are com-                                                         continue to see near
lems makes it possible to correct the          pacted in the outer                                                       objects clearly for
problems so that pilots can continue to        portions of the lens.                                                     several years after
fly safely.                                    Eventually, the ac-                                                       their 40 t h b i rt h-
     The eye of a person with normal           cumulation of dead                                                        day because their
vision functions this way: light enters the    cells makes the                                                           myopia allows them
cornea (the transparent dome on the            lens less flexible.                                                       to focus at near dis-
eye’s surface) and the pupil (the black           Typically, as peo-                                                     tance without the
area in the centre of the eye), which is       ple age, the decline                                                      use of correction.
surrounded by the iris (the round,             in flexibility of the                                                        The first symp-
                                                                         Diagram of the human eye
coloured part of the eye). The iris con-       lens makes it less                                                        toms of presbyopia
trols the amount of light that enters the      capable of becom-                                                         are obser ved when
eye, allowing more light in when the sur-      ing rounder; as a result, the eyes are less an individual tries to read small print in
roundings are dark and less when they          able to focus on nearby objects. This dim light. This is because in dim light,
are bright. The light then passes              condition — the most common age- the pupil of the eye enlarges so that the
through the lens, which focuses light on       related change in vision — is known as retina can receive more light; as the
the retina, the eye’s innermost lining,        presbyopia, which generally becomes pupil enlarges, however, some focusing
which senses the presence of light. The        apparent to people in their early 40s, power is lost. (The red light used in
retina translates the image into electrical    although the exact age at which presby- older aircraft to maintain adaptation to
impulses, which travel along the optic         opia occurs and the extent to which it darkness during cockpit operations at
ner ve to the brain. The eyeball is made       develops vary from one person to another. night makes focusing even more difficult
up of two fluid-filled segments: the ante-     Presbyopia is a natural par t of the aging because red light has the longest wave-
rior or front segment, between the             process and cannot be prevented. In length in the visual spectrum, and focus-
cornea and the lens, is filled with fluid      many instances, the ability to focus on ing the eyes is more difficult than it
called the aqueous, which provides nour-       near objects continues to deteriorate would be using white light.) Eventually,
ishment to the lens, and the posterior or      gradually until about the age of 60; by as presbyopia progresses, small print
back segment, between the lens and the         the time most people reach 50, they also becomes difficult to read even in bright
retina, is filled with a clear gel known as    have lost much of their ability to focus
                                                                                             This text is an adaptation of an article appearing in
the vitreous. Together, the fluids help        on intermediate-distance objects (about       Human Factors & Aviation Medicine (Vol. 47, No. 5,
the eyeball retain its shape (see accom-       the distance from a pilot’s eyes to an air-   September-October 2000), a publication of the
                                                                                             Flight Safety Foundation.
panying figure).                               craft instrument panel).

NUMBER 1, 2001                                                                                                                                  27

light. The extra effor t involved in read-            correct near vision (many people prefer              opia by implanting a four-piece “scleral
ing small print can cause eye fatigue                 half-moon eyeglasses that allow distant              expansion band” in the sclera, the white
after prolonged reading or near the end               vision over the top of the frame), bifocals          part of the eye. The procedure is the
of a long flying workday.                             to correct both near vision and distant              subject of clinical testing in the United
   The physiological changes in the eye               vision, trifocals to add a third segment of          States and in Canada and has not been
that accompany presbyopia preclude                    correction for intermediate vision, or pro-          approved by either government.
“empty field myopia,” also known as                   gressive lenses, which include a range of               In the United Kingdom, implantation
“space myopia,” a condition that can                  corrections from those for distance at the           of the scleral expansion band has been
affect pilots when they search for other              top of the lenses to those for viewing               approved by the government, but the
air traffic in hazy skies or for approach             near objects at the bottom and which                 U.K. Civil Aviation Authority (CAA) indi-
lights during a low-visibility instrument             lack lines between viewing segments.                 cated that the CAA’s Medical Division
approach. Empty field myopia occurs                      Bifocal contact lenses also can be pre-           has not assessed any applicants for pilot
when the eye looks into an “empty” visu-              scribed, but civil aviation regulations in           medical cer tificates who have under-
al field, such as fog, haze or extreme                most countries do not permit pilots to               gone the procedure.
darkness, and the lens tends to adjust to             wear bifocal contact lenses; there f o re ,             Tony Evans, M.D., head of medical
a focal point about three metres to six               presbyopic pilots who wear contact lens-             standards and certification for the U.K.
metres (10-20 ft) in front of the eye. In             es to correct their distant vision general-          CAA, cautioned against any type of sur-
low-visibility, low-ceiling approaches, if            ly wear eyeglasses over their contact                ger y on a healthy eye because of possi-
empty field myopia is present, a few more              lenses to correct their near vision.                 ble complications or side ef fects.
seconds than usual may be required to                    Civil aviation regulations in most coun-             Several other procedures for correct-
recognize the sudden appearance of the                tries also prohibit use of monovision con-           ing presbyopia are being studied, includ-
runway environment. Empty field                       tact lenses, which correct for near vision           ing:
myopia cannot occur, however, if the                  in one eye and for distant vision in the             • anterior ciliar y sclerotomy, in which
lens does not become rounder because                  other eye, because they may inter fere               incisions are made in the sclera to create
of mature presbyopia — an advantage                   with the lens-wearer’s depth perception              more room for the ciliar y muscles to
for older pilots.                                     and distant imaging.                                 work;
   P resbyopia can be cor rected with                    In some countries, a surgical proce-              • the use of small-diameter corneal
eyeglasses — either reading glasses to                dure has been used to correct presby-                inlays, small lenses that are inser ted into
                                                                                                           the cornea to create a bifocal vision cor-
                                                                                                           rection; and,
         Guidelines for choosing multifocal eyeglasses
                                                                                                           • implantation of multifocal intraocular
  There are several aspects to consider in            tion to, the usual near-vision segment at            lenses to replace the eyes’ natural lenses.
  the choice and fitting of multifocal eye-           the bottom, while pilots who wear trifo-
  glasses. For example, the pilot’s seating           cals may want eyeglasses with an inter-                 Unlike presbyopia, which is experi-
  position affects the optimum positioning            mediate segment that is wider than usual             enced by vir tually ever yone, other con-
  of the two segments of bifocal eyeglass-            to allow them to see the complete                    ditions, such as cataracts or glaucoma,
  es. The fit of bifocals should be adjusted          instrument panel without moving their                tend to develop most often in older peo-
  so that the wearer can see the instru-              heads.
                                                                                                           ple, but they also may occur in those
  ment panel without interference with dis-              Changes from single-vision eyeglass-
  tance vision. Presbyopic pilots who fly             es to bifocals, or from bifocals to trifo-           who are much younger.
  more than one type of aircraft may need             cals, can temporarily distort peripheral                Cataracts often are associated with age-
  a different pair of eyeglasses for each             vision and depth perception and can                  related changes in the protein structure
  type.                                               temporarily alter the visual cues that a
                                                                                                           that cloud the normally transparent tissue
     Pilots of aircraft with wide instrument          pilot typically receives during take-off,
  arrays or large navigational charts may             landing and flight manoeuvres. Pilots                in the eye’s lens. Cataracts generally
  prefer bifocals with a larger reading seg-          should be aware that objects initially               develop after age 50, and most develop
  ment than usual. Bifocals with smaller              may appear to be larger or smaller than              slowly, with symptoms that include
  near-vision segments allow for peripheral           their actual size and that the visual scene          blurred vision, a loss of colour-perception
  distance vision around these smaller seg-           may appear to slant.
                                                                                                           acuity, glare, double vision, halos around
  ments.                                                 Finally, pilots with presbyopia should
     Pilots who typically view an instrument          be aware that use of red light in the                objects and a need for more light to see
  panel through the upper portion of their            cockpit at night complicates viewing of              clearly. In their early stages, cataracts
  eyeglasses may prefer bifocals that are             near objects. If red light is unavoidable,           sometimes can be treated with a change
  designed with a near-vision segment at              the pilot may need a near-vision seg-
                                                                                                           in eyeglass prescription; when cataracts
  the top of the lens instead of, or in addi-         ment with increased power.
                                                                                                           become severe, however, surger y is
  Guidelines were derived from a U.S. Federal Aviation Administration publication, Vision Impairment and
  Corrective Considerations of Civil Airmen, published in December 1993 (DOT/FAA/AM-93/21).
                                                                                                           needed to replace the clouded lens with
                                                                                                           an artificial one.

28                                                                                                                                    ICAO JOURNAL
                                                                                                                     AV I ATI ON ME DI CINE

   In addition to aging, other factors        examinations by eye-care specialists condition that can cause blindness if the
appear to increase the likelihood of          (ophthalmologists, who are physicians retina is not reattached promptly by sur-
developing cataracts, including cigarette     specializing in treating the eyes, or ger y or laser therapy. If the retina
smoking; diabetes; galactosemia, an           optometrists, who are specialists in exam- detaches, visual distor tions may be
inherited disorder that interferes with       ining the eyes and                                                   accompanied by flash-
the metabolism of milk; exposure of           prescribing cor-           In most countries civil aviation          es of light and the
unprotected eyes to intense sunlight;         rective lenses). In                                                  appearance of a shad-
                                                                         regulations do not permit pilots
exposure to high levels of ionizing radia-    more advanced                                                        ow over par t of the
                                                                         to wear bifocal contact lenses
tion, such as X-rays used at aircraft main-   stages, blind spots                                                  field of vision in the
tenance facilities, and to high levels of     — areas in the                                                       affected eye. Success-
industrial microwave radiation; and spe-      field of vision where there is no sight — ful treatment generally results in the
cific physical injuries to the eye, such as   develop.                                     pilot’s return to duty.
being struck by a baseball, a bullet frag-       Another type of glaucoma is angle-clo-       Another age-related ailment is degen-
ment or a dart.                               sure (acute) glaucoma, whose symptoms eration of the macula, which destroys
   Preventive measures that may help          may include pain in the eyes, blurred the central vision. Causes var y, but age-
mitigate formation of cataracts include       vision, a loss of peripheral vision and the related macular degeneration is the lead-
sunglasses that provide protection            appearance of coloured rings around ing cause of legal blindness among
against the ultraviolet wavelength in sun-    lights.                                      people over age 55. Two forms of the dis-
light, goggles or some other form of eye         People who are considered to be most ease exist: “dr y” macular degeneration
protection to guard against injury, proper    at risk for developing glaucoma are and “wet” macular degeneration.
control of diabetes and avoiding exposure     black; older than 65; ver y near-sighted;       Dry macular degeneration occurs
of unprotected eyes to high-energy            or have diabetes, a family history of glau- when the macular tissues become thinner
sources of heat and light (such as are        coma or an elevated level of intraocular and the light-sensing cells in the macula
experienced by welders and glass-             pressure. Not everyone with slightly ele- disintegrate. In some instances, dry mac-
blowers). Some specialists believe that       vated intraocular pressure has glaucoma, ular degeneration progresses into wet
vitamins A, C and E and the mineral sele-     but high pressure can indicate that the macular degeneration and new blood ves-
nium also may lower the risk of develop-      individual is at risk of developing glauco- sels may grow, often leaking blood and
ing cataracts. (The vitamins are              ma and should be examined regularly by fluid beneath the macula, a process that
antioxidants, which counteract the harm-      an eye specialist. Ultimately, treatment accelerates damage to the macula. The
ful effects of “free radicals,” naturally     may be necessar y to lower the pressure. wet form of the disease accounts for
occurring molecules that can damage              With age, the gel-like consistency of about 90 per cent of blindness associated
cells in the eye and other parts of the       the eye’s vitreous may become more with macular degeneration.
body.)                                        water y, and the vitreous may shrink.           The most common early symptoms of
   Another eye disease that occurs most       Shrinkage may lead to separation of the macular degeneration are blurred vision
often among people older than 40 is           vitreous from the retina. (Normally, the and an inability to see clearly the details
glaucoma, which increases pressure            two touch in three places: around the of objects in the centre of the field of
inside the eye (intraocular pressure) and     anterior border of the retina; in the mac- vision. Peripheral vision generally is not
damages the optic nerve. The disease is       ula, the centre of the retina that contains affected. Other symptoms include the
a result of a blockage of the passages        the greatest concentration of light-sensi- apparent distortion of straight lines, with
that allow drainage of aqueous fluid in       tive cells and processes the details in the objects in the centre of the field of vision
the eye, but the exact cause of the block-    centre of the field of vision; and at the sometimes appearing more distorted
age can var y. If untreated, glaucoma can     optic ner ve disc.) In many instances, than objects in the peripher y; appear-
lead to blindness. If detected in its early   separation of the vitreous from the reti- ance of a dark blurred area or a white
stages, glaucoma can be controlled —          na — called vitreous detachment — can area at the centre of the field of vision;
usually with eye drops or other types of      cause distor ted vision and the appear- and changes in colour perception.
medication but sometimes with surger y        ance of spots that seem to float across         There is no cure for macular degener-
— without fur ther loss of vision. Vision     the field of vision. These “floaters” by ation, but early detection of the disease
lost because of glaucoma cannot be            themselves are normal and do not con- may allow for treatment that can slow
restored.                                     stitute a medical problem.                   t he pr o g ress of t he d isease or can
   There are several types of glaucoma,          In other instances, however, when the                                 continued on page 37
including open-angle (chronic) glauco-        vitreous shrinks, the retina is torn and Stanley R. Mohler, M.D., is a professor, Vice Chairman
ma, which — in its early stages — has no      vitreous gel seeps beneath the retina. and Director of aerospace medicine at Wright State
                                                                                           University School of Medicine in Dayton, Ohio, United
symptoms and can be detected only in          This may lead to retinal detachment, a States.

NUMBER 1, 2001                                                                                                                                29
CAEP recommends further measures for reducing
aircraft noise, engine exhaust emissions
A committee of aviation and environmental experts meeting         guidance material on effective land-use planning, and a pro-
at ICAO headquarters in Montreal from 8 to 17 January has         posal for new take-off noise abatement procedures.
recommended stricter noise standards and new emissions               On aircraft engine exhaust emissions, CAEP called for the
procedures. The comprehensive series of recommendations           further development of the elements necessary for an emis-
made by the Committee on Aviation Environmental Protection        sions trading programme. Such a programme would be consis-
(CAEP) will be considered by the ICAO Council in the near         tent with the Kyoto Protocol to the United Nations Framework
future, and certain aspects are expected to be taken up at the    Convention on Climate Change (UNFCCC), which recognizes
ICAO Assembly to be held this fall.                               ICAO as the global instrument through which industrialized
                                                                          countries can pursue the limitation or re d u ction of
                                                                          greenhouse gas emissions from international aviation.
                                                                          The committee also recommended additional work in
                                                                          the area of voluntary mechanisms, and the possible
                                                                          use of charges to address emissions. In addition,
                                                                          CAEP recommended that the global air navigation plan
                                                                          include methodology for analysing the environmental
                                                                          benefits of implementing advanced communications,
                                                                          navigation, surveillance and air traffic management
                                                                          (CNS/ATM) systems, and it called for publication of an
                                                                          ICAO circular on operational opportunities to minimize
                                                                          fuel use and reduce emissions. The circular would
                                                                          emphasize the best industry practices for minimizing
Gerard Bekebrede, the CAEP member from the Netherlands, served as
                                                                          fuel consumption.
Chairman of the fifth meeting of CAEP. He is pictured with ICAO Council
President Dr. Assad Kotaite and Jane Hupe, Secretary of CAEP and a           CAEP also adopted an action plan on emissions to
technical officer in the Operations and Airworthiness (OPS/AIR) Section provide a route map for the next five to 10 years.
of the ICAO Air Navigation Bureau.                                           “The conclusions and recommendations of CAEP
                                                                          will greatly assist the ICAO Council in formulating new
   The ICAO committee, meeting for the fifth time since its        policies and adopting new standards for aircraft noise reduc-
formation in 1983, endorsed the concept of a balanced             tion, as well as developing procedures to limit or reduce
approach to noise mitigation made up of four distinct but         greenhouse gas emissions from civil aviation,” stated ICAO
complementary elements, namely the reduction of noise at          Council President Dr. Assad Kotaite. The new policies, stan-
source, improved land use planning and control, a wider use       dards and procedures, he added, “will support Contracting
of noise abatement operational procedures and operating           States and the air transport industry in achieving maximum
restrictions for the noisier aircraft types.                      compatibility between the safe and orderly development of
   A major recommendation arising from CAEP’s meeting was         civil aviation and the quality of the environment.”
the introduction of a new noise standard which is 10 decibels        The CAEP meeting was attended by 200 participants from
lower than the current Chapter 3 standards in Annex 16 to the     a number of Contracting States and interested organizations.
Convention on International Civil Aviation. The new standard      The results of the meeting will be disseminated at a world-
would apply after 1 January 2006. Chapter 3 standards were        wide colloquium on the environmental aspects of aviation that
adopted in 1977.                                                  will convene in Montreal this April.                            s
   The meeting identified a number of technical options for
possible operating restrictions on Chapter 3 aircraft, and the
issue will continue to be addressed in CAEP as part of the
                                                                  ICAO presents position
balanced approach that has been adopted. The ICAO Council         at WTO meeting
will review the outcome of the CAEP meeting in March and          ICAO represented the aviation community at a recent meeting
will make recommendations on policies related to noise            of the World Trade Organization (WTO) which focused on the
reduction at the forthcoming ICAO Assembly.                       air transport sector. ICAO provided substantive information to
   Other major recommendations on the noise problem               the WTO Secretariat in advance of the meeting, held in
focused on procedures for the re-certification of existing air-    Geneva on 4 December, and also presented a paper to dele-
craft in light of the new standard, the implementation of more    gates on ICAO’s role in facilitating air transport liberalization.
stringent noise standards for helicopters, the publication of        The WTO is the international agency overseeing the rules of

30                                                                                                                  ICAO JOURNAL
trade between nations. The Council for Trade in Services of          ICAO Council appointment
the WTO is currently reviewing developments in the air trans-
                                                                                             Aloísio Marques da Cunha has been
port sector and the application of the air transport annex of
                                                                                             appointed the Representative of Brazil
the General Agreement on Trade in Services (GATS). At pres-
                                                                                             on the Council of ICAO. Mr. Cunha’s
ent, GATS coverage of air transport is limited to aircraft repair
                                                                                             tenure commenced on 8 November 2000.
and maintenance, selling and marketing, and computer reser-
                                                                                                Mr. Cunha’s career in aviation began
vation services, but WTO members are considering the addi-
tion of other air transport services such as aircraft fuelling,                              with his graduation from the Brazilian
ground handling, airport services (defined as “air terminal and                               Air Force Academy in 1974, where he
runway capacity”), express package and all-cargo services,                                   earned a bachelor degree in aviation
                                                                          A.M. Cunha
and non-scheduled charter services.                                         (Brazil)         technology. He was trained as a fighter
  The paper ICAO presented to the meeting pointed out that                                   pilot and served as a squadron leader.
the organization is recognized as the worldwide body for set-        Mr. Cunha flew for the Brazilian Air Force over a 20-year period,
ting global safety, security and environmental standards for         reaching the rank of Colonel after 30 years of total service.
international air transport, and that the close linkage among           Beyond his experience as a pilot, Mr. Cunha is a specialist
the regulatory issues in civil aviation illustrates a need to keep   in the fields of aviation safety and information technology. He
regulatory reform of all aspects under the same global               completed several courses in Brazilian educational institutions
umbrella. ICAO informed the delegates that it will continue to       and after graduation from the Brazilian Civil Aviation Institute
play an active role in achieving air transport liberalization with   served as a Flight Inspector specializing in the Boeing 737.
the paramount objective of ensuring that safety is not com-             Mr. Cunha has held several senior posts. He was appointed
promised by economic considerations.                                 head of the Aeronautics Information Technology Centre, located
   Until now the WTO has simply reviewed the applicability of        in Rio de Janiero. Later he headed the Accident Prevention and
the GATS to the air transport sector, but the negotiating            Investigation Division within Brazil’s Civil Aviation Department,
process is expected to start in earnest during 2001. With this       where he also oversaw the Aviation Security and Facilitation
in mind, the ICAO Council is currently considering the con-          Division. Last year Mr. Cunha was assigned to the Brazilian
vening of a worldwide meeting of ICAO Contracting States to          International Air Navigation Commission, where he dealt with
address issues and policy options in the field of international       international air transport policy as well as negotiations for bilat-
air transport regulation.                                        s   eral and multilateral agreements.                                  s

NUMBER 1, 2001                                                                                                                         31
New polar air routes                                               network, and to lend assistance where this may be necessary,
                                                                   Dr. Kotaite indicated.
to reduce flight times                                                 The membership of the steering group is comprised of
A high-level steering group set up in 1998 to coordinate the       high-level officials from Canada, China, Finland, Germany,
establishment of polar air routes has reached an agreement         Iceland, Japan, Mongolia, Norway, the Russian Federation,
on a new air route structure over the North Pole that will cut     the United States and the International Air Tr a n s p o r t
distances on flights linking North America and Europe to Asia       Association (IATA). It has met four times to coordinate the
and the Pacific region.                                             international civil aviation community’s requirements for safe,
   The informal group, chaired by ICAO Council President Dr.       economic and operationally sound polar operations.           s
Assad Kotaite, agreed at a meeting in Paris on 24 January on
a route structure that will result in significantly shorter flight
                                                                   Airline traffic and load
times and more convenient flight schedules. By reducing fuel
consumption, the new routes are expected to benefit the
                                                                   factors reach new highs
environment and provide considerable economic advantages           Preliminary airline traffic figures for 2000, released by ICAO at
to airlines and their passengers.                                  the close of the year, point to an 8 per cent increase in the total
   Dr. Kotaite hailed the unique spirit of cooperation among       tonne-kilometres performed on domestic and international
member States of the high-level steering group known as            scheduled services. The growth for international scheduled
ITASPS. “States have made considerable effort to address           traffic carried by the world’s airlines is estimated at 10 per
not only the technical and operational challenges, but also        cent.
national and political matters of a delicate and often complex        Statistics supplied by ICAO’s 185 Contracting States indi-
nature,” he stated.                                                cate that the world passenger-kilometres performed rose by 8
   “It is now possible to open highly advantageous routes to       per cent in total traffic and by 10 per cent on international
all international aircraft operators on a non-discriminatory       services. Passenger capacity was kept in check, leading to
basis, while reducing fuel burn and producing considerable         the highest ever average passenger load factors of 71 per
economic benefits to the entire civil aviation industry and the     cent for total traffic and 72 per cent for international services.
flying public,” he added.                                           According to the preliminary data, the number of passengers
   A number of successful demonstration flights over the North      carried worldwide on scheduled services exceeded 1.6 billion
Pole have been carried out in recent months, confirming the         for the first time.
operational and economic viability of polar flights to accom-          Scheduled freight traffic showed increases in tonne-kilome-
modate safely the consistent demand for intercontinental air       tres performed of some 10 per cent for all services and 11 per
traffic between the two regions, separated by extreme harsh         cent internationally. Freight carried worldwide on scheduled
climatic conditions above the Arctic circle. The demonstration     services reached some 31 million tonnes.                         s
flights helped evaluate whether there was sufficient flexibility to
plan different flight paths on a daily basis, and to take advan-    ICAO audit database helps
tage of optimum prevailing meteorological conditions.              define safety priorities
   ICAO will continue to closely monitor the progress of imple-
                                                                   ICAO has begun an analysis of safety oversight audit results
mentation of polar routes and further expansion of the route
                                                                   with the objective of identifying possible solutions to safety
                                                                   concerns. The analysis, carried out by the Safety Oversight
                                                                   Audit Section at ICAO headquarters, will make it possible to
                                                                   define safety priorities at the national, regional and global levels.
                                                                      The audit analysis, based on a database of the findings of
                                                                   safety oversight audits of Contracting States, including dif-
                                                                   ferences from the ICAO standards and recommended prac-
                                                                   tices (SARPs), will allow ICAO to assess the need for possible
                                                                   changes to the SARPs and to related guidance material so
                                                                   that these can keep pace with civil aviation developments
                                                                   occurring in States.
                                                                      One of the ongoing comparisons to be made focuses on
               MONTREAL CONVENTION                                 the types of difficulties experienced by Contracting States in
  The Montreal Convention of 1999 was ratified by Mexico            five specific areas: legislation and regulation; organization of
  on 20 November 2000, bringing the number of ratifications         the civil aviation authority; personnel licensing and training;
  to seven. To mark the occasion, Roberto Kobeh González,          the operation of aircraft; and the airworthiness of aircraft.
                                                                   Such information will enable States, ICAO and other organi-
  the Representative of Mexico on the Council of ICAO, is
                                                                   zations to set priorities in efforts to address safety oversight
  pictured with ICAO Secretary General R.C. Costa Pereira
                                                                   system critical elements.
  (left) and Dr. Ludwig Weber, Director of the ICAO Legal
                                                                      ICAO, which has been conducting safety oversight audits
  Bureau. The Montreal Convention was adopted in May
                                                                   for Contracting States since March 1999, completed audits
  1999 as the new regime to govern air carrier liability, and
                                                                   for 82 States in 2000, bringing the total number of audited
  will enter into force after it has received 30 ratifications.
                                                                   States at year’s end to 131.                                      s

32                                                                                                                    ICAO JOURNAL
Achievements of 2000 span all                                          10. From the data available to the NTSC there was no evidence
                                                                       found to indicate if the mortgage policy taken out by the PIC
areas of ICAO’s activities                                             in connection with his housing loan had any relevance to the
An agreement reached by the civil aviation administrations of          accident.
China and Viet Nam at a meeting at ICAO headquarters in                   Final remarks. The NTSC investigation into the MI 185
December culminated in a year of significant achievements in            accident was a very extensive, exhaustive and complex investi-
all areas of ICAO’s work programme, ICAO Council President             gation to find out what happened, how it happened, and why it
Dr. Assad Kotaite noted in a year-end message. China and Viet          happened. It was an extremely difficult investigation due to the
Nam agreed to a three-year trial of a revised route structure          degree of destruction of the aircraft resulting in highly frag-
and airspace organization over the South China Sea during a            mented wreckage, the difficulties presented by the accident site
meeting on 7 December (see story, November/December 2000,              and the lack of information from the flight recorders during the
page 22).                                                              final moments of the accident sequence.
   The many accomplishments of ICAO last year, as in the                  The NTSC accident investigation team members and partici-
past, are “the result of a methodical application of the guiding       pating organizations have performed the investigation in a thor-
principles contained in the Convention on International Civil          ough manner and to the best of their conscience, knowledge and
Aviation,” the Council President emphasized. The Convention,           professional expertise, taking into consideration all available data
signed at a conference in Chicago in 1944, “remains the cor-           and information recovered and gathered during the investigation.
nerstone for the safe and orderly development of international            Given the limited data and information from the wreckage
civil aviation.”                                                       and flight recorders, the NTSC is unable to find reasons for the
    Dr. Kotaite praised the Chicago Convention as an exem-             departure of the aircraft from its cruising level of FL 350 and the
plary global regulatory framework that, even after 56 years,           reasons for the stoppage of the flight recorders.
                                                                          The NTSC has to conclude that the technical investigation
still provides workable solutions to the intricate issues faced
                                                                       has yielded no evidence to explain the cause of the accident.
by ICAO and the world aviation community. “I have no doubt
                                                                          NTSC recommendations. Following are recommendations
that it can guide international civil aviation effectively in the
                                                                       to manufacturers:
21st century,” the Council President added.
                                                                       • It is recommended that the ICAO Study Group on Flight
   In addition to the historic agreement between China and
                                                                       Recorders (FLIREC) Panel undertake a comprehensive review
Viet Nam, there were notable achievements for ICAO in impor-
                                                                       and analysis of flight data recorders and cockpit voice recorders
tant areas such as safety, aviation security, the handling of the      systems design philosophy applied by aircraft and equipment
Y2K challenge, continued protection of the radio frequency             manufacturers. The purpose of the review and analysis would be
spectrum, environmental matters, and policy making related             to identify and rectify latent factors associated with stoppage of
to the economics of airports and air navigation services.       s      the recorders in flight, and if needed, to propose improvements
                                                                       to ensure recording until time of occurrence.
                                                                       • It is recommended that, to facilitate the recover y of flight
Accident report                                                        recorders after impact into water, a review of the flight recorders’
continued from page 23                                                 design philosophy be undertaken by the equipment manufactur-
3. Interviews with respective superiors, colleagues, friends and       ers to ensure that the underwater locator beacons (ULB) are fit-
family revealed no evidence that the flight crew members had            ted to the flight recorders in such a manner that the ULB would
changed their normal behaviour prior to the accident.                  not be separated from the recorders in an accident.
4. There was no evidence found to indicate that there were any         • It is recommended that the ICAO FLIREC Panel recommend
difficulties in the relationship between the two pilots either during   aircraft and equipment manufacturers to include recording of
or before the accident flight; or that the pilots had been experi-      actual displays as observed by pilots in particular for CRT type
encing noteworthy difficulties in any personal relationships            of display panels.
(family and friends).                                                  • It is recommended that a review of the flight crew training syl-
                                                                       labi be undertaken by aircraft manufacturers to include recovery
5. Until the stoppage of the CVR, the pilots conducted the flight
                                                                       from high speed flight upsets beyond the normal flight envelope.
in a normal manner and conformed to all requirements and
                                                                       The purpose of developing the additional training is to enhance
standard operating procedures.
                                                                       pilot awareness on the possibility of unexpected hazardous
6. Although a flight attendant had been in the cockpit previously,
                                                                       flight situations.
after the last meal service and until the stoppage of the CVR,
                                                                       • It is recommended that a review of aircraft autoflight systems
there was no indication that anyone else was in the cockpit            be undertaken by aircraft and equipment manufacturers to pro-
other than the two pilots.                                             vide all passenger aircraft with autoflight systems that could
7. In the final seconds of the CVR recording the pilot-in-com-          prevent an aircraft from flying beyond the high speed limit of its
mand (PIC) voiced his intention to leave the flight deck; however       flight envelope. It is also recommended that such autoflight sys-
there were no indications or evidence that he had left.                tems limit the rate of descent of the aircraft to a certain value
8. Interviews and records showed that in 1997 the PIC had              that is operationally safe.
experienced a number of flight operations related events, one of           General recommendation:
which resulted in his being relieved of his line instructor pilot      • It is recommended that a regional investigation framework for
(LIP) position.                                                        cooperation in aircraft accident investigations be established to
9. The PIC was involved in stock-trading activities, but no con-       enable fast mobilization of resources and coordination of activi-
clusions could be made indicating that these activities had influ-      ties to support those States that do not have the resources and
enced his performance as a pilot.                                      facilities to do investigations on their own.                     s

NUMBER 1, 2001                                                                                                                          33
                                                                          establish a fee programme for each AAWBVS transaction. The
Electromagnetic interference                                              amount of the fee and the collection method would be mutually
continued from page 6                                                     determined by the aeronautical authority and Emery Winslow.
operate in the frequency range of operational NDBs, interference              Conclusion. As concern for overall aircraft safety grows, the
to NDB reception is experienced. The problem can be solved                challenge will be to embrace newer and better safety measures,
through coordination between the various authorities involved.            especially when the safety measure is available at an affordable
   ISM equipment. Special frequency bands have been designated            price.
by the ITU for use by industrial, scientific and medical systems. Of           The newly developed automatic aircraft weight and balance
concern to the protection of aeronautical services is the level of        verification system provides an opportunity to improve safety
spurious or unwanted emissions that is allowed for this equipment.        for cargo aircraft in a way not previously thought practical.
   Conclusion. As a result of the increasing use of the radio                 The benefit to cargo aircraft is the elimination of the unstabi-
frequency spectrum by all radio ser vices, interference from              lizing and dangerous effects of an out-of-tolerance CG, an over-
non-aeronautical sources is expected to grow. Special meas-               loading or any ir regularity in cargo distribution.
ures, both at ICAO and ITU, will be necessar y to enable                      The value of eliminating the ever lurking danger of unsafe air-
expanded use of the RF spectrum by all radio ser vices while              craft weight and balance is difficult to express in dollars or even
                                                                          adequately explain with words. Safety simply should not be com-
preserving interference-free operation of essential aeronautical
                                                                          promised. As a means to further enhance cargo aircraft safety,
navigation and communication services.                           s
                                                                          pretake-off weight and balance verification is worthy of careful
                                                                              Although improved safety is the issue, there are also residual
Weight and balance verification                                            benefits that accrue to users of AAWBVS. For example, the
continued from page 16                                                    information provided by the AAWBVS can be a useful tool for air
the site and soil conditions. Although the cost may be considered         cargo executives in achieving operational improvements. It can
substantial, the ability to avoid just one accident could well be worth   be used to improve the quality of the cargo handling and load-
the investment.                                                           ing process. And there are also the beneficial effects of an
                                                                          improved weight and balance on aircraft operating efficiency
    An AAWBVS can be acquired by aeronautical authorities
                                                                          and aircraft maintenance.                                        s
under a number of arrangements. It can be purchased outright
and installed by others under Emery Winslow’s supervision, or
purchased outright on a turnkey basis.
   To assist in those instances where the outright purchase of an         PANS-OPS amendment
AAWBVS would be difficult or infeasible, an innovative alternative         continued from page 9
provides for the weighing system to be installed and certified at an       briefings, establishing that the operator must implement flight
airport at no cost to the aeronautical authority. Under this arrange-     and cabin crew briefings for specific phases of operations. In
ment, the system is operated in return for fees paid by air cargo         addition to actual conditions and circumstances, briefings need
carriers. In addition to installing, calibrating and certifying the       to address special aspects of operations. For flight crew, briefings
AAWBVS, training is provided for the maintenance and operating            shall be conducted for at least pre-flight, departure and arrival
personnel on a continuous basis at the manufacturer’s expense. In         operations. Cabin crew briefings must be conducted prior to the
return for these services, the aeronautical authority must agree to       first departure of the day, and must also be conducted following
establish a regulation requiring that all cargo carrying aircraft         changes of aircraft type or crew, and before flights involving a
pass over the AAWBVS prior to take-off, and must also agree to            stop of more than two hours.
                                                                             The PANS-OPS establishes that preflight briefings must
                                                                          include both flight and cabin crews. Combined flight and cabin
                                                                          crew preflight briefings should focus on crew coordination as
                                                                          well as aircraft operational issues. This would include any
                                                                          unser viceable equipment or abnormalities that may affect oper-
                                                                          ational or passenger safety requirements as well as essential
                                                                          communications, emergency and safety procedures, and
                                                                          weather conditions.
                                                                             Flight crew departure briefings should prioritize all condi-
                                                                          tions relevant to the take-off and climb phase. The conditions
                                                                          that need to be covered include the runway in use, aircraft con-
                                                                          figuration and take-off speeds; departure procedure and depar-
                                                                          ture route; navigation and communications equipment set-up;
                                                                          aerodrome, terrain and performance restrictions, including
                    SEMINAR IN NAIROBI                                    noise abatement procedures; take-off alternate; items included
  ICAO conducted a seminar on the aeronautical telecom-                   in the minimum equipment list; review of applicable emergency
  munication network (ATN) and global navigation satellite                procedures; and applicable call-outs.
  system (GNSS) at its regional office in Nairobi from 24 to                  Flight crew arrival briefings prioritize all conditions relevant
  27 October 2000. Lecturers came from ICAO, Eurocontrol,                 to the descent, approach and landing. The conditions covered
  the U.S. Federal Aviation Administration (FAA) and SITA.                for these phases of flight include terrain restrictions and mini-
                                                                          mum safe altitudes during descent; the arrival route; instrument

34                                                                                                                           ICAO JOURNAL
or visual approach procedure and runway in use; operational           duces provisions for aerodrome surface operations. The proper
minima; aircraft configuration and landing speeds; navigation          means to implement such provisions is through the development
and communications equipment set-up; missed approach proce-           of operator SOPs that specifically address aerodrome surface
dures; alternate aerodrome and fuel considerations; review of         operations. The PANS-OPS, therefore, establishes that operators
applicable emergency procedures; and applicable call-outs.            must ensure flight crews are aware of the risks inherent in aero-
   Cabin crew briefings performed by the senior cabin crew mem-        drome surface operations. A review of risk factors should include
ber should prioritize conditions relevant to the departure. The       the vulnerability to human error arising from heavy workload, vig-
briefing for cabin crew needs to cover the assignment of take-off      ilance decrement or fatigue, as well as the potential distractions
and landing positions; a review of emergency equipment; passen-       associated with performance of flight deck tasks and the failure to
                                                                      use standard phraseology in aeronautical communications. Safety
gers requiring special attention; a reminder to perform a silent
                                                                      is especially vulnerable to this last factor. Frequency congestion as
review (i.e. the self-review of individual actions required in the
                                                                      well as operational considerations may adversely affect the
event of emergencies); a review of potential emergencies; security
                                                                      issuance or read-back of ATC clearances, leaving flight crews and
or service-related topics that may impact on passenger or crew
                                                                      controllers open to misunderstandings.
safety; and any additional information provided by the operator,
                                                                         SOPs specific to aerodrome surface operations must consider
including review of new procedures, equipment and systems.            the risk factors listed above, and be associated with the following
   Aerodrome surface operations. Concerns about the safety of         operations:
aerodrome surface operations are widespread around the indus-         • runway intersection take-offs;
try, despite efforts to address them. As an example, statistics for   • line up and wait clearances;
1999 released by the U.S. FAA indicate that 295 runway incur-         • land and hold short clearances (not currently an ICAO proce-
sions had been reported as of 30 November 1999. The same sta-         dure);
tistics indicate that flight crew performance was a factor in 61       • take-offs from displaced runway thresholds;
per cent of these occurrences, while ATC operational errors           • hazards associated with runway crossing traffic; and
accounted for 25 per cent and pedestrians and vehicles were           • hazards associated with runway crossing traffic in case of
involved in 14 per cent. There is no evidence of significant pro-      closely spaced parallel runways.
gress in solving safety issues at aerodromes. Furthermore,               The risk factors associated with aerodrome surface operations
industry sources indicate that operators have not implemented         should be addressed by SOPs that require the timely acknow-
specific standard procedures for ground operations.                    ledgment of ground movement instructions and ensure standard
   Not surprisingly, the proposed revision of the PANS-OPS intro-     phraseology is used for acknowledging all clearances to enter,

NUMBER 1, 2001                                                                                                                          35
land on, take-off from, hold short of, cross or backtrack on the            A potential source of confusion for users of displayed infor-
runway in use. The SOPs should also require the use of aircraft          mation is the fact that any of it physically could be controlled by
exterior lights for manoeuvring on aerodrome surfaces.                   the computer behind the display and might be variable.
   The future. One of the objectives of the forthcoming PANS-            Contrast this with paper and its unchangeable print, which
OPS amendment is to develop human factors-related provisions             clearly cannot adapt to var ying conditions and therefore must
in support of the operational procedures in the PANS-OPS,                be scrutinized for applicability to the current context. The prob-
Volume I. The amendment therefore aims at establishing guiding           lem with display interpretation occurs when the user has nei-
principles without delving into specific implementation issues.           ther knowledge nor a clear indication of which information is
   A significant volume of information is available throughout the        static and which is variable. A display by its nature has an
industry concerning implementation issues, and therefore existing        implied intelligent agent behind it.
guidance materials will be reviewed when expanding on the                   Many cockpit displays present a combination of static, pilot-
human factors-related provisions. These guidance materials               input and automatically controlled information with no coding to
include the Preparation of an Operations Manual (ICAO Document           reveal under which categor y each indication belongs. Some
9376), the Manual of All-Weather Operations (ICAO Document               pilots appear to draw the general conclusion, perhaps uncon-
9365) and the Manual of Procedures for Operations Inspection, Cert -     sciously, that “the computer is smart; the displayed information
ification and Continued Surveillance (ICAO Document 8335).       s        must be right; I’ll just follow it.”
                                                                            In the case of the 777 ECL, Boeing provided a simple mental
                                                                         model: ECL text is a static emulation of a paper checklist. The
Electronic checklist design                                              colour coding and the current line item box that leads the pilot
                                                                         through the checklist are the primar y expressions of the intel-
continued from page 20
                                                                         ligent agent behind the display.
make all of the same callouts and receive all of the same
                                                                            Conclusion. The first phase of digital automation tools in
responses, whether the pilot not flying (PNF) was using paper
                                                                         civil aircraft flight decks — today’s autopilots, flight manage-
or electronic checklists. An example is the text displayed when
                                                                         ment computers and displays — has taught us that automation
the ECL logic has ensured that all line items on all pages of a
                                                                         is not free. It can come with a hidden price tag of training chal-
given checklist are complete. The name of the checklist and the
                                                                         lenges, unexpected mode confusion and new error modes.
words “checklist complete” are displayed. The PNF can read
                                                                         Using lessons from this experience, the 777 ECL is an example
the announcement directly from the display.
                                                                         of new automation that was carefully designed to avoid new and
   The implied intelligent agent. Early prototype testing of the elec-
                                                                         potentially confusing error modes. As such, the considerations
tronic checklist revealed that many pilots react to an electroni-
                                                                         used in the ECL design process may be useful for the next
cally displayed instruction in a more compulsory manner and
                                                                         phase of flight deck automation.
treat it less critically than instructions printed on paper. In 777
                                                                            As traf fic density increases, demands on automation will
training, specific coaching is sometimes required to remind the
                                                                         change and increase substantially. But new and more capable
captain that he or she is the final judge as to which procedures to
                                                                         automated agents of the future cannot require a more complex
carry out, and when. There may be several factors behind this
                                                                         mental model for the operator. Simple, elegant solutions must
effect. One potential factor was addressed in the ECL design.
                                                                         be found to address complex problems. Automated tools
                                                                         should include more effective interfaces for infrequently used
                                                                         features and more manual entr y points to account for the
                                                                         tremendous variation in the aviation environment. Automated
                                                                         functions, especially those for which the manual method is
                                                                         retained as an alternative, should be familiar to the user from
                                                                         the outset. Automation can, and should, be far less error prone
                                                                         than it is today, par ticularly during those rare moments of
                                                                         emergency when familiar, intuitive tools are the pilot’s best
                                                                            Boeing and Airbus Industrie electronic checklist tools are in
                                                                         service today, reducing crew errors and undoubtedly preventing
                                                                         mishaps. Future automation can benefit from the lessons of
                                                                         recent design experience.                                        s

                                                                         Air safety seminar
                                                                         continued from page 21
                MEETING IN MEXICO CITY
                                                                         countries in these and other areas to host and participate in an
  The ninth meeting of the Caribbean/South American                      outreach programme. Once the needs of a particular State or
  Regional Planning and Implementation Group (GREPECAS)                  area have been identified, the ISASI staff will design and deliver
  Air Traffic Services Subgroup held at the ICAO Regional                 a workshop that responds to those needs.
  Office in Mexico City from 25 to 29 September 2000 was                     “Reachout Prague” will consist of a two-day general session
  attended by 24 participants from 12 States and from three              that will introduce a number of safety topics. The general ses-
  international organizations.                                           sion will be followed by two days of more detailed workshops
                                                                         conducted on three themes: airline safety management, acci-

36                                                                                                                          ICAO JOURNAL
dent investigation, and emergency response planning. Each of
the volunteer instructors — from Australia, Canada and the          Age-related vision problems
United States as well as from ICAO — has between 35 and 40          continued from page 29
years of relevant experience. ICAO is providing support for the     reduce its severity. Treatment for wet macular degeneration
workshop from its Montreal headquar ters, and its regional          sometimes involves surgery or laser therapy to remove the new
office located in Paris is promoting participation in the semi-     blood vessels generated by the disease.
nars through its contacts with States in the region.                   Research has indicated that the progress of macular degen-
   “Reachout Prague” has been designed to address the partic-       eration may be accelerated by unprotected exposure to bright
ular safety concerns identified by the Czech Republic, and is       sunlight or exposure to tobacco smoke. Hypertension or high
intended for safety investigators from countries located in the     blood pressure also may make some forms of macular degen-
central and eastern par ts of Europe. Contracting States that       eration worse, especially for individuals with wet macular
have been encouraged to send representatives to the Prague          degeneration. Medication used to treat hypertension may slow
seminar include Albania, Armenia, Azerbaijan, Belarus, Bosnia       the progress of macular degeneration. Other research has sug-
and Herzegovina, Bulgaria, Croatia, Czech Republic, Estonia,        gested that the severity of the disease may be reduced or its
Georgia, Hungary, Kazakhstan, Kyrgzstan, Latvia, Lithuania,         onset delayed by the consumption of fresh fruits and green,
Moldova, Poland, Romania, Russian Federation, Slovakia,             leafy vegetables or of vitamins C and E.
Slovenia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan.           Aging also can be accompanied by changes in the quality and
One non-contracting State, the Federal Republic of Yugoslavia,      quantity of the tears that lubricate the eyes. Tears typically
as well as the Interstate Aviation Committee (IAC), have also       become more water y, and more of them are required to keep
been invited to participate in the seminar.                         the eyes properly lubricated. In instances of dry eye syndrome,
   It is hoped that holding the ISASI workshops in a number of      the tear glands fail to manufacture enough tears, and as a result
locations worldwide will benefit areas having high accident         the eyes may itch or burn. If untreated, the cornea may be sub-
rates by leading to improved accident investigations, higher        ject to infections and may eventually become scarred, some-
quality reporting and analysis of incidents, and reduced risk.      times resulting in a loss of vision. Researchers estimate that 75
   Enquiries from civil aviation administrations about arranging    per cent of people over age 65 will experience dry eye syn-
for a future ISASI workshop may be directed to ISASI headquar-      drome, which has many causes, including environmental effects
ters (tel. 703-430-9668; fax 703-430-4970; email;   (wind, intense sunlight and extremes of temperature), the nor-
website: Corporations and organizations that are    mal aging of tear glands, decreased sensitivity of the cornea,
interested in becoming sponsors of the ISASI programme may          excessive evaporation of tears, specific medications (including
also contact ISASI headquarters.                               s    antibiotics, diuretics, antihistamines and anti-diarrheals) and

NUMBER 1, 2001                                                                                                                    37
                                                                                                          specific diseases (including Sjöögren’s syndrome, which is char-
Promoting the Development of                                                                              acterized by dr yness of the mucous membranes). Special eye
International Civil Aviation                                                                              drops or a home humidifier may be recommended. In some
                                                                                                          instances, specialized surgery may be necessary to partially
The International Civil Aviation
Organization, created in 1944 to promote                                                                  block the punctum structure (i.e. the eye’s tear drain) so that
the safe and orderly development of civil                                                                 tears remain in the eye.
aviation worldwide, is a specialized agency of                                                               Sensitivity to light, wind or changes in temperature can
the United Nations. Headquartered in Montreal,
ICAO develops international air transport stan-
                                                                                                          cause the eyes to produce too many tears. Sunglasses or other
dards and regulations and serves as the medium for cooperation                                            forms of eye protection may correct the problem. In other
in all fields of civil aviation among its 186 Contracting States.                                          instances, excess tears are a result of an eye infection or a
                                                                                                          blocked tear duct, conditions that require the attention of an
Afghanistan               Democratic Republic        Latvia                      Saint Lucia
Albania                     of the Congo             Lebanon                     Saint Vincent and           The eyes may also be affected by a number of diseases that
Algeria                   Denmark                    Lesotho                       the Grenadines         are most common among older people, including diabetes.
Angola                    Djibouti                   Liberia                     Samoa
Antigua and Barbuda       Dominican Republic         Libyan Arab                 San Marino               For example, diabetes can lead to diabetic retinopathy, in
Argentina                 Ecuador                      Jamahiriya                Sao Tome and Principe    which new blood vessels may grow and then break, with blood
Armenia                   Egypt                      Lithuania                   Saudi Arabia
Australia                 El Salvador                Luxembourg                  Senegal                  leaking into the vitreous. When blood clouds the vitreous,
Austria                   Equatorial Guinea          Madagascar                  Seychelles               light is prevented from passing through to the retina, and
Azerbaijan                Eritrea                    Malawi                      Sierra Leone
Bahamas                   Estonia                    Malaysia                    Singapore                images can be distor ted or vision can be lost. Laser treatment
Bahrain                   Ethiopia                   Maldives                    Slovakia                 often is effective.
Bangladesh                Ferderal Republic of       Mali                        Slovenia
Barbados                    Yugoslavia               Malta                       Solomon Islands
                                                                                                             Several other eye ailments are common among older
Belarus                   Fiji                       Marshall Islands            Somalia                  people:
Belgium                   Finland                    Mauritania                  South Africa
                                                     Mauritius                   Spain
                                                                                                          • Eyelid problems include drooping eyelids, blinking spasms or
Belize                    France
Benin                     Gabon                      Mexico                      Sri Lanka                an inflammation of the rims of the eyelids. Often, these prob-
Bhutan                    Gambia                     Micronesia                  Sudan                    lems can be treated with medication; in other instances, sur-
Bolivia                   Georgia                     (Federated States of)      Suriname
Bosnia and                Germany                    Monaco                      Swaziland                gery is needed;
 Herzegovina              Ghana                      Mongolia                    Sweden                   • Temporal arteritis often begins with a severe headache, a sen-
Botswana                  Greece                     Morocco                     Switzerland
Brazil                    Grenada                    Mozambique                  Syrian Arab Republic     sation that blood vessels in the temple are swollen and pain in
Brunei Darussalam         Guatemala                  Myanmar                     Tajikistan               the scalp when the hair is brushed. Other symptoms typically
Bulgaria                  Guinea                     Namibia                     Thailand
Burkina Faso              Guinea-Bissau              Nauru                       The former Yugoslav      involve pain in the jaw, chewing muscles and tongue while eat-
Burundi                   Guyana                     Nepal                         Republic of            ing or speaking; double vision; and blurred vision. Early diag-
Cambodia                  Haiti                      Netherlands                   Macedonia
Cameroon                  Honduras                   New Zealand                 Togo                     nosis and medication can prevent vision loss; and,
Canada                    Hungary                    Nicaragua                   Tonga                    • A diminished supply of blood to the peripheral retina can
Cape Verde                Iceland                    Niger                       Trinidad and Tobago
Central African           India                      Nigeria                     Tunisia
                                                                                                          result from diabetes, hypertension, arteriosclerosis (a disease of
 Republic                 Indonesia                  Norway                      Turkey                   the arteries characterized by a thickening and hardening of
Chad                      Iran (Islamic              Oman                        Turkmenistan
Chile                       Republic of)             Pakistan                    Uganda
                                                                                                          their walls) or medications that restrict the diameter of the
China                     Iraq                       Palau                       Ukraine                  blood vessels. The resulting impairment of visual function could
Colombia                  Ireland                    Panama                      United Arab Emirates
                                                                                 United Kingdom
                                                                                                          lead to decreased overall vision during darkness, especially
Comoros                   Israel                     Papua New Guinea
Congo                     Italy                      Paraguay                    United Republic          above 5,000 feet, and increased difficulty locating other aircraft
Cook Islands              Jamaica                    Peru                         of Tanzania             during daylight.
Costa Rica                Japan                      Philippines                 United States
Côte d’Ivoire             Jordan                     Poland                      Uruguay                     In many instances, regular eye examinations can help
Croatia                   Kazakhstan                 Portugal                    Uzbekistan               detect eye problems in their early stages. Early detection
Cuba                      Kenya                      Qatar                       Vanuatu
Cyprus                    Kiribati                   Republic of Korea           Venezuela                can lead to early treatment and, in some cases, elimination of
Czech Republic            Kuwait                     Republic of Moldova         Viet Nam                 the problem.                                                   s
Democratic People’s       Kyrgyzstan                 Romania                     Yemen
 Republic of Korea        Lao People’s               Russian Federation          Zambia
                            Democratic Republic      Rwanda                      Zimbabwe

ICAO Headquarters                Eastern and Southern                 North American, Central
                                                                                                          Flying eye hospital
                                 African Office                        American and Caribbean Office        continued from page 26
999 University Street            Nairobi, Kenya                       Mexico City, Mexico
Montreal, Quebec                 Sitatex: NBOCAYA                     Sitatex: MEXCAYA                    The generosity and goodwill of airport directors, airlines, ground
Canada H3C 5H7                   Facsimile: 011-254-2-226-706         Facsimile: 011-525-203-2757
Telephone: 514-954-8219          Telephone: 011-254-2-622-395         Telephone: 011-525-250-3211
                                                                                                          handlers and governments throughout the world also has been a
Facsimile: 514-954-6077          E-mail:           E-mail:   key component to the success of ORBIS. Fees for landing, parking
Website:            European and North Atlantic Of fice   South American Office                and ground handling are often waived or discounted to help
                                 Paris, France                        Lima, Peru                          ORBIS focus its limited resources on saving eyesight.
                                 Sitatex: PAREUYA                     Sitatex: LIMCAYA
REGIONAL OFFICES                 Telex: 616 766 ICAO FRANCE           Facsimile: 011-51-1-575-0974           Other major ORBIS supporters include Alcon Laboratories,
                                                                      Telephone: 011-51-1-575-1646
                                 Facsimile: 011-33-1-46418500
                                                                                                          AlliedSignal, Berkshire Hathaway Inc., CibaVision Corp., Federal
Asia and Pacific Office            Telephone: 011-33-1-46418585
Bangkok, Thailand                E-mail: Western and Central                    Express, FlightSafety International, La Haye Laboratories
Sitatex: BKKCAYA                                                      African Office                       (Neoptyx), Pharmacia, Ronald McDonald House Charities,
Telex: TH87969 ICAOBKK           Middle East Office, Cairo, Egypt      Dakar, Senegal
Facsimile: 011-662-537-8199      Sitatex: CAICAYA                     Sitatex: DKRCAYA
                                                                                                          Standard Chartered Bank, and The Boeing Co.
Telephone: 011-662 537-8189      Facsimile: 011-202-267-4843          Facsimile: 011-221-823-6926            ORBIS volunteers and suppor ters have recognized a com-
E-mail:                          Telephone: 011-202-267-4841          Telephone: 011-221-839-9393       E-mail:       E-mail:            mon stake in eliminating needless blindness. From their vision
                                 Web Site:
                                                                                                          emerges a new future for people’s lives.                        s

                          N E W P U B L I C AT I O N S
                          FROM ICAO

Designators for Aircraft Operating Agencies,                             Comprehensive Aeronautical Telecommunication
Aeronautical Authorities and Services                                    Network (Document 9739)
(Document 8585)                                                          1st edition, 2000; 760 pages
115th edition, December 2000; 226 pages                                  Available in English
Published in English, French, Russian and Spanish                        Order No. 9739...$191
Order No. 8585/115...$60
                                                                         Handbook on the International Airways
Safety Oversight Audit Manual (Document 9735)                            Volcano Watch (Document 9766)
1st edition, 2000; 167 pages                                             1st edition, 2000; 125 pages
Available in Arabic, Chinese, English, French,                           Available in English, French, Russian and Spanish
Russian and Spanish                                                      Order No. 9766...$32
Order No. 9735...$43
                                                                         Regional Differences in International Airline
                                                                         Operating Economics, 1997 (Circular 280)
Location Indicators (Document 7910)
                                                                         2000; 56 pages
98th edition, October 2000; 188 pages
                                                                         Available in English, French, Russian and Spanish
Published in English, French, Russian and Spanish
                                                                         Order No. CIR280...$18
Order No. 7910/98...$49
                                                                         Manual of Airport and Air Navigation Facility
The World of Civil Aviation, 1999-2002                                   Tariffs (Document 7100)
(Circular 279)                                                           2000 edition; 663 pages
2000; 142 pages                                                          Published in English, French, Russian and Spanish
Available in Arabic, English, French, Russian, and Spanish               Order No. 7100...$200
Order No. CIR279...$50
                                                                         Digest of Statistics No. 480
Digest of Statistics No. 484                                             On-flight origin and destination
Airport Traffic, 1999.                                                    Year and quarter ending 30 September 1999.
Series AT-No. 40; 287 pages                                              Series OFOD-No.91; 151 pages
Published in English, French, Russian and Spanish                        Published in English, French, Russian and Spanish
                                                                         Order No. DIG480...$60
Order No. DIG484...$76

                                                                         National Plan for CNS/ATM Systems
Legal Committee
                                                                         (Circular 278)
Report of the 31 st Session (Document 9765)
                                                                         Guidance Material
Montreal, 28 August-8 September 2000
                                                                         2000; 166 pages
2000; 233 pages
                                                                         Available in Arabic, English, French, Russian and Spanish
Available in Arabic, English, French, Russian and Spanish
                                                                         Order No. CIR278...$42
Order No. 9765...$59
                                                                         Manual of Aircraft Accident and Incident
Convention on International Civil Aviation                               Invesitgation (Document 9756)
(Document 7300)                                                          Part l - Organization and Planning
8th edition, 2000; 111 pages                                             1st edition, 2000; 63 pages
Published in English, French, Russian and Spanish                        Available in Arabic, English, French, Russian and Spanish
Order No. 7300...$29                                                     Order No. 9756P1...$17

               To order documents or obtain a complete list of ICAO publications and audio-visual training aids, contact:

        Document Sales Unit, International Civil Aviation Organization, 999 University St., Montreal, Quebec, Canada H3C 5H7
              Telephone: 514-954-8022 • Facsimile: 514-954-6769 • Sitatex: YULADYA • E-mail:

                          The 2000 edition of the Catalogue of ICAO Publications and Audio-Visual Training Aids
                                          can be found at ICAO’s website (

To top