IFATCA The Controller - 2nd Quarter 1980

D 21003 F

JOURNAL OF AIR

In this Issue:

OF THE INTERNATIONAL TRAFFIC

CONTROLLERS

FEDERATION ASSOCIATIONS

2/80

Design for the Future Female Air Traffic Controllers Air Traffic Control Stress and its Effects

FRANKFURT

AM

MAIN

2nd

Q U A R T E R 19 8 0

VOLUME

19

D M 4,-

STILL USING FIRSTGENERATION ATCEQUIPMENT? PnlCt~dural Control

--

(no radar)

Watch supervisor. trying to decipher recently arrived flight plan

l'rl'p,Hing flight

NOTAM,

progrt•,~ ,trips

-~-Ill•-

MET rl·p,)rt,

(,trip

rrinta)

Bril'fing d(''"- with

-

ATC centre in the old day~?~Ot

nnirsC' not-it's

.:i

All' & "OTA~,1,

print in~ otlice in th(' 16th n•ntury.

No reason.

Automated Air Traffic Control systems used to be something for big airports and resourceful administrations only. Only they had the knowledge and money to specify and buy them and the skilled staff to operate and keep them running.

Not so any more. In these days of soaring aircraft operating costs you will be surprised to find that prices of modern, reliable ATC systems-probably the most efficient tool for reducing flying times-are in fact going down. And they are as easy to maintain as to operate. Reason: standardization.

Introducing Datasaab's AIRWATCH Automated ATC systems ' Datasaab's new series of AIRWATCH systems-based on many years' experience from tailor-made centres-are designed to suit all types of traffic anci environment. AIRWATCH standardization also means modularization, allowing adaptation to specific needs and ensuring system expansion at low cost as traffic grows.

AIR\NATCH ~y~tem, range tn,m ,l single PP! .:-ystem to lar~e centrt·s. Thl"y te.Jlllrl' rnw, synthetic or mixL'd prc-~cntation ol l'SR and SSR sig11~1lslrom one or more r,1dar ,tatilm~ and numcrolls contrullN IJcilitic·~. including

tull l.ibL•b.

• AIRVVATCH IO00 is an <1utonomous. lm,:•CIJ:,t radar di~pl~1ys.y~tem \vith a built•in micro-pro<.:e$sor. his dl'signl'd tvr small ATC Cl'nlrC's (rnd contrnl lowers.

• AIR WATCH 2000 is ,bi~ned tor small and mrdiunH,ized cent rt'~. Dli.11 computers. opl•rating in paralld. pruvidl' Vl'ry hi~h rt·liability.

• All{WATCH 3000 is designed tor mrdium to largesized ATC centres. System ~Hchitl'cturc is C'Xtremely tlt>xible. OutSttinding nperatiunal [,,------------~] tl~,1ture:-include tr<Kking ot J.11 .-...----~-~ typrs ol tli~ht Jnd IYl\lSaicpresen• L.-..

I~ tali1,.m trom multiple radar sources. '-------------jointly own,·d by the Swedish Government and Saab-Scania AB

For more information contact: Datasab AB, Interactive Data Systems, S-17586 Jarfalla, Sweden. Tel. lnt + 46 8 362800 • Telex 17892 datsaab s

IFATCA

JOURNAL

OF

AIR

TRAFFIC

CONTROL

THECONTROLLER Frankfurt am Main, June 1980

Volume 19 • No. 2

pro

Publisher: International Federation of Air Traffic Controllers' Associations, P. 0. B. 196, CH-1215 Geneva 15 Airport, Switzerland.

a

Officers of IFATCA: H. H. Henschler. President. Daniel Oudin. Vice-President (Technical). A. Avgoustis.

Vice-President (Professional) and "Interim Editor", Pat O'Doherly, Vice-President (Administration), H. Wenger, Treasurer, E. Bradshaw. Executive Secretary.

Secretariat: 6 Longlands Park, Ayr KA7 4RJ Ayrshire, Scotland, United Kingdom Tel.: 0292 42114 Editor: A. Avgoustis 5 Athens Str .. Ayios Dhometios Nicosia. Cyprus Managing Editor: Horst Guddat POB 600 209 D-6000 FrankfurVMain-60 Telefon (06 11) 21 08 86 22 Publishing Company, Production, Subscription Service and Advertising Sales Office: Verlag W. Kramer & Co., Bornheimer Landwehr 57 a, 6000 FrankfurVMain 60, Phone 434325 and 492169, BHF-Bank No. 3-03333-9.

Postscheckkonto Frankfurt 1105-601,Rate Card Nr. 7.

Tower Controller Miss Aziza Jouini of Tunis/Carthage Airport. Female Air Traffic Controllers in their "unusual" professional environment. See article on page 13.

Printed by: W. Kramer & Co., Bornheimer Landwehr 57 a, 6000 FrankfurVMain 60 (Federal Republic of Germany).

Subscription Rate: DM 6.- per annum for members of IFATCA; DM 16,- per annum for non-members (Postage wi II be charged extra).

CONTENTS

Contributors are expressing their personal points of view and opinions, which may not necessarily coincide with those of the International Federation of Air Traffic Controllers' Associations (IFATCA).

Design for lhe future

5

SST operations

10

Female Controllers in an all-male environment .........................

.

13

IFATCA does not assume responsibility for statements made and opinions expressed, it does only accept responsibility for publishing these contributions.

From the ILO desk .................................................

.

16

Design of an Air Navigation Services System .........................

.

17

Low Level Wind Shear .............................................

.

21

Aviation

.

26

.

28

.

29

..... .......... ...... ........ .

31

Contributions are welcome as are comments and criticism. No payment can be made for manuscripts submitted for publication in "The Controller". The Editor reserves the right to make any editorial changes in manuscripts, which he believes will improve the mate• rial without altering the intended meaning.

Written permission by the Editor is necessary for re• printing any part of this Journal.

Law Part 2 ...............................................

US Army Air Traffic Controllers

.....................................

On the ICAO scene: ADISP .........................................

Air Traffic Control stress and its effects News from the Federation

..........................................

News from Member Associations

........... ....... .... ..... .... .... .

33 37

....................................................

38

Cartoons: Helmut Elsner.

This could also happen to me . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

41

Photos: ANSA, Archive, FAA. Goodwood Data Systems, H. Guddat. Hollandse Signaalapparaten, Philips, Software Sciences.

Voice logging in ATC - 25 years of progress

....... .... .. .......... .

42

............. .. .... ...... .... .. .

43

Advertisers In this Issue: Datasaab (inside cover).

AEG-TELEFUNKEN (page 2). Thomson-CSF (page 4).

Philips ELA (page 8), IAL (page 11). CP Air (inside back cover), Selenia (back cover).

News from Corporate Members

..... .... ...... .... ...... ............ .

47

TAIL PIECE - Where does the money go? . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48

Universal News

ATC Operational

Information

Display

AIR TRAFFIC CONTROL - an important sector for communications and data systems.

Through the use of automated data processing AEG-TELEFUNKEN ATC systems assure. optimum safety in air traffic.

,...

641.006

~t

~

ATC Systems made by

AEG-TELEFUNKEN

EDITORIAL

Controller Training Who Benefits?

....................... ········· ................ .

Around the world air traffic control is being provided by controllers who, so their employers and States responsible assure the user, are trained to meet or exceed standards set by the International Civil Aviation Organization, ICAO. Why then is it that users, pilots in particular, note a different quality of service offered in various countries?

Much of this difference, of course, is a reflection of the equipment, or lack of it, controllers have available to them in order to ensure safe and efficient air traffic control.

However, even when similar equipment is in use the quality of service may be different. The training of controllers in many cases is done on a national basis in institutes which should follow ICAO criteria but are sometimes tailored to fit national priorities and in the process, to save funds, corners may be cut, operational controllers do double duties as instructors, skimping reduces quality.

IFATCA is concerned that air traffic controllers anywhere should receive only the best relevant training. The Federation has a detailed and comprehensive policy on the most important role which training must be afforded in the career of a controller. To achieve the full implementation of our policy is a major aim.

For various reasons, not the least of which is concern expressed by our members, the Executive Board some time ago implemented a programme to determine on an international basis the need for additional and adequate training for controllers and the availability of such training with the aim to eventually match supply and demand. The needs indicated range from basic radar training, language training, to electronic data processing. Any training required is available elsewhere. The problem on the surface in bringing supply and demand together is that training often costs money - and must be requested by Governments.

Proper training constitutes a sizeable investment, an investment which must be protected by ensuring that those who have received the training are offered an acceptable

career and working conditions. Proper training, however, is also a necessity as equipment is introduced to replace outdated tools - without it the controller would somewhat resemble the rider of a bicycle who is given a sportscar without any driver education. It is evident that again resources would be wasted.

It must also be stated that a number of Governments will make various kinds of training available at no, or minimal, cost on the request of other Governments and that ICAO is expanding its facilities worldwide.

Finally, there is one kind of training less formalized, less costly, and of short duration, but nevertheless most valuable to all - the familiarization flight. It enables the controller to observe in person the workload during all phases of a flight on the flight deck, aircraft performance and limitations, and allows an exchange on problems experienced on the ground and in the air - it fosters understanding between the two groups which rely on each other, pilots and controllers. Who then benefits from adequate training for controllers? Everyone.

Controllers - because it allows them to perform their responsibilities in the most efficient manner; Employers - because it allows them to live up to their commitments to aviation; Pilots - because it results in a more realistic approach to their needs; Air Lines - because a more efficient service means fewer delays and increased fuel savings; All those who fly - because they are entitled to the safest and most efficient air traffic control wherever tt1ey travel.

Is the provision of training to controllers a good investment? No doubt it is. Together with adequate equipment, proper career and working conditions, it is one of the cornerstones of the safe and expeditious air traffic control IFATCA stands for.

HHH

3

far andwide THOMSON-CSF has demonstrated its ability to design, devise, supply and install consistent, effective, highperformance air traffic control and air space surveillance systems.

CONSISTENT - because THOMSONCSF, leading European group in the field of professional electronics, develops and manufactures almost all the components which make up the completed

Countries whichuse THOMSON.CSF air trafficcontrol,navigationaland landingaid equipment:

systems, including <:letection, transmission, communications and information processing units.

EFFECTIVE- because the experience we have acquired over 20 years of profile design in the most varied contexts means that we can offer tried and true solutions for your every need, however complex or exacting.

HIGH-PERFORMANCE - because THOMSON-CSF's research laboratories and technical experts are in the forefront of all important research into aeronautical and defence networks.

Our active development policy ensures that THOMSON-CSF products set the pace in their respective fields.

TI-IOMSON-CSF DIVISIONDRS-TVT

40, rue Grange-Dame-Rose - BP 34

92360 MEUOON-LA-FORET (F)TEL.(1) 630.23.80

UES%Ei~ f [lf\ THEflJTLIRE

by Bob Adderley Principal Aviation Consultant, Software Sciences Ltd. Corporate Member of IFATCA

BALANCE

AVAILABLE

USER

RESOURCES

REQUIREMENTS

WITH

SYSTEM

ARCHITECTURE

Air Traffic Control Systems throughout the world commonly provide safety but impose delays upon airspace users.

Technology can do anything - at a price! But far too often we specify technical performance to the n'th degree without reference to the dynamic demands upon the ATC system and without regard to the ingenuity, capability and status of the controllers.

System Architecture is a technique to achieve the correct balance between user requirements technological capability financial constraints compatibility with other systems human resources This paper describes how System Architecture can be applied to ATC Systems: to define the user requirements to translate them to technical performance specifications to combine controller and technological capability to provide the appropriate ATC service with the right people at the right time at the right place at the right price

Introducing System Architecture It is a primary objective of Air Traffic Services to provide Safety and Expedition for all users of the airspace. Yet it is increasingly evident that, for a number of reasons, at certain times, within certain areas, delays are manifest and/or even safety is prejudiced.

I should like to examine some of these reasons and to ider.tify individual factors, or collective circumstances that contribute to this 'System Failure'. More constructively I should like to describe a technique of System Architecture that seeks to optimise the application of available resources to match the demands of the operational environment.

As we shall see, System Architecture embraces attaining the correct balance between: • user requirements • technological capability • financial constraints • compatibility with other systems • human resource·s

Bob Adderley is employed by Software Scienes Limited, of Farnborough as Principal Aviation Consultant.

He is a member of the Royal Aeronautical Society (MRAeS), a Member of the British Association of Aviation Consultants (MBAC) and currently President of the London Region of the Guild of Air Traffic Control Officers (GATCO).

He has twenty years experience as a Controller and Supervisor at high intensity Airfields and Area Radar Units and as an Airspace Planner of civil and military procedures.

For nine years he has worked as a Systems Analyst and Designer on aviation projects in Canada, the USA, and ten European countries. Many of these projects have been concerned with the analysis of ATC capabi lily and the definition and design of equipment and procedures to improve the safety and expedition of ATC systems.

On the above photo Bob is shown giving his presentation at the 1979 Annual Conference of I FATCA.

5

SYSTEM

REQUIREMENTS

only a sub-system of the air transporation system and as such needs to provide compatibility throughout the world.

Finally, even the architect yields to certain human factors in designing his inanimate building. When we consider the dynamic nature of the Air Traffic System and the critical role played by the conlroller, we must allow for both human capability and human nature. We must arrange to take advantage of our unique and flexible decision making processes, without abusing, or failing to recognise, the status and rewards that should be commensurate with such responsibility.

ARCHITECTURE

,....

RESOURCES

I

I

FINANCE

Numbers

The Elements of the ATC Problem

ond Roles

of USERS

I

I T

SERVICE STRUCTURE FACILITIES

C H

N 0

L

CAPABILITY

C A

E H

p

u

A

M A N

B I

L

0

I

G y

T y

System Architecture Applied to ATC The term architecture is more familiar to us when applied in defining the design specification of a building. This application remains as useful analogy when considering the term 'architecture' in the context of the air traffic control system.

We all understand that, when an architect designs a building, his basic considerations are: What is the building to be used for? and How many people are going to live or work in it?

From this point the architect then takes considerable efforts to provide appropriate facilities, in terms of the number of rooms, and their functions, to serve the particular requirements of the ultimate users. In a similar way, system architecture evaluates the differing role's and numbers of the future users of its system, and seeks to design the facilities and performance to match their needs.

Clearly, the building architect has to have considerable knowledge of the limitations and cost effectiveness, of the building materials that are available. But, in Air Traffic System terms, technology has achieved the dubious advantage of being able to provide virtually anything at a price. Certainly there are a number of technical solutions anxiously awaiting problems; and the initial problem is to correctly identify the most cost-effective solution.

So clearly, finance i's a significant, and indeed, usually the major constraint, and the architect necessarily attempts to achieve the most effective results within a stated budget. However, what constitute·s effectiveness, in house building terms, may merely be subjective or aesthetic appeal, or even the whim of the lady of the house. In system terms it should be positive calculations and quantifications of the way in which the system will respond to user demands.

Whilst the architecture of a building is important in itself, it is a generally accepted concept that it ·should blend with its environment and not be a monument to its architect and a contradiction of surrounding practice. In a dynamic system, such as Air Traffic Control, there is even greater importance that it should not be an autonomous system - "with no connection with the firm next door" - but it needs to be completely compatible with adjacent systems in order to achieve a uniformity of communication and service. Indeed, to be correct, the Air Traffic System is 6

In basic terms, in this case, the problem is to specify an Air Traffic Control Service which provides safety and expedition for the users of its airspace.

The ·starting point is to measure the demand. Logical though this may be, historically the development of ATC systems has followed a pattern of system capability trailing demand, with inevitable consequences of delays and/or reductions in safety standards. Exceptionally, in isolated cases, the reverse has been true, with National fortunes being invested in complex and sophisticated solutions to serve trivial requirements. More commonly, limited resources of money, machines and manpower are wasted by senseless duplications and overlapping capability, at the expense of inadequate capability elsewhere. Often this is because of historic demands or political, or civil versus military biased prejudices. Typical of this is the proliferation of primary radars so commonly introduced to flood the ether with a profusion of pulses and un-coordinated procedures.

Quantifying the demand is not merely extracting such inanimate statistics as the number of aircraft on the National Civil Register. It involves a detailed evaluation of the actual flight path's flown, with consequential assessment of distribution in terms of timings, geography, routes, levels, types, performances, etc. Such values need further analysis to provide detailed quantifications of ATC work-loads and system performance. This can be

THE

AIRCRAFT

ELEMENTS

OF

THE

ATC

PROBLEM

ATC SECTORISATION

AIRSPACE STRUCTURE

Numbers

Types Roles

Missions

CURRENT DISTRIBUTIONS

PATTERNS OF

Timings

DEMAND

Geographic Routes Levels

PREDICTIONS

FUTURE PATTERN OF DEMAND

done by techniques of computer based Fast Time Simulations, as described later.

Far too often, not only is the problem of excess demand not recognised until it occurs, but the situation is exacerbated by attempting to solve the problem in term·s of its present size, instead of recognising that, by the time a solution is introduced, the problem will almost certainly have increased.

So measurement of the demand must include a prediction factor. Once again, this should not be merely a numerical con·stant, bul should seek to take account of future variables such as new aircraft types and performance characteristics. The need to recognise user requirements applies equally to current activities. Investigation often demonstrates that certain procedu•es are followed, not because ATC or the user wants them, but, because many years ago they were introduced, e.g. to serve the Dakota and the NOB, and no one has been bold enough to change them. The most u·sual example of this is the location of holding areas for airports.

Now I have said a lot about the need to quantify and describe the demand, because this is one half of the problem. The other half is to apply our available resources as effectively as possible to serve this demand.

Essentially these resources are vested in our technology, as limited by financial constraints, and as enhanced by: a) human ingenuity to devise practices and procedures to best utilise our airspace (strategic control) and by b) human capability to provide the decision making processes upon which our pre·sent ATC concepts are based (tactical control).

Also, as already indicated there is the need for compatibility with adjacent systems. Indeed to provide standardisation for users this compatibility should be common to all ATC systems.

In practice, strategically, this means conformity with ICAO standards and practices and, tactically, it should achieve rapid and reliable data transfers perior to and/or coincident with each and every transfer of control.

In summary with respect to the elements of the problem, I suggest that, in many areas: a) too little is known of the dynamic nature of the demand and in some cases not even the time and route distributions have been measured yet alone predicted b) too little: is predicted of the workloads that will be imposed upon ATC c) technological solutions abound but are often misapplied d) financial resources are, and always will be limited, but they could be more effectively deployed e) human resources are often mis-directed and even abused.

Defining the Operational Requirement Hi'storically ATC systems have developed by applying human ingenuity and capability and progressively adding evolutionary or distinct stages of technology.

Most note-worthy examples are: a) W/T replaced by RTF b) introduction of primary radar c) application of SSR d) automated Flight Plan Processing (FPPS) e) processed displays f) automated radar data processing (RDPS) However cost, complexity and novelty, are not necessary yardsticks ot improved efficiency. For instance, although Flight Plan Processing Systems were hailed as the 'greatest invention since sliced bread' they were in fact merely number crunchers and did little if anything, to increase ATC system capability which, of course, is dictated primarily, by ·separation standards, and secondly, by sector workloads.

This tells us that we should pay due regard, not merely to the technical specification of our black-boxes (which tend to be extraordinarily comprehensive) but, more particularly, we should

THE

OPERATIONAL

REQUIREMENT

r------------------7 I I

,--------,

I

FUTURE PATTERN OF DEMAND

ATC RULES

COMPUTER FAST-TIME

AIRSPACE ROUTE STRUCTURE

I

BASED SIMULATION

Sector Workloads

Arrival Delays Ocporture

I I

Comms Workloods

Delays

No. in Stack Holding Os

Prox.i mi ty Counts

REDESIGN

SPECIFY

COMMS LOADING

COMPUTER POWER

RADAR COVERAGE

consider how the equipment contributes to the user and total system requirements.

Now the u·sers of the system range from the comprehensively equipped civil air transport aircraft, to the less well endowed population of general aviation and military aircraft. In fact, a significant proportion of aircraft carry sophisticated communications and navigation devices, such as INS or Air Navigation (R Nav) equipment. They do this because of the non-standardisation of ATC performance throughout the world. For instance, they may need to use it whilst crossing the Oceans or over Africa, but find it redundant within the complex VOR based route structures of Western Europe.

Conversely individual ATC systems have to handle aircraft with differing standards of navigational capability and thus have to gear their separation standards to the lowest capability.

In between the aircraft, with it's navigational and communication fit, providing ability to comply with ATC instructions, and the controller with his display/information and communication equipment that enables him to make and communicate tactical decisions, is a strategic route structure and ATC sectorisation.

This route structure and its associated procedures, conventionally aligned upon VORs, i's the key to ATC capability and consequential safety and delays. Invariably the number and even the alignment of routes are constrained by political and military factors. Sometimes investigation of the antecedents of these factors indicates historic justifications that no longer remain valid. More frequently the investigations reveal long established procedures that now actually detract from present day aircraft navigational or flight performance.

Thus a sensible preliminary to defining the performance required from ATC equipment is to test and optimise the route structures and procedures. This can be done by computer based fast time simulation techniques, which can apply present or predicted traffic demands to current or optimised route structures.

The outputs from these simulations provide analyses of s:.ich measurements of system performance as:

7

I

WHENPHILIPS INTRODUCED THEIRFIRSTGENERATION VOICELOGGING SYSTEM AN AIRPORT WASSIil~ A SIGHTSEER'S PA~ADIS

AVIATION HASPROGRESSEDSINCE THEN ANDNOWTHERE ·sA FOURTHGENERATION PHILIPSVOICE LOGGING SYSTEM 1954: An airport was a place where Convairs, Dakotas and Super Connies lined up like taxis and children spent their Saturdays watching those planes in fascination. In those days, tower control had an overall view of the field and ground movements could be observed directly.

At that time air traffic control was becoming a fast growing international concern. That's when Philips introduced their first generation Voice Logging System.

Now airports are no longer a sightseer's paradise. They've become part of an ongoing complex operation. With all communications clearly recorded on multi-channel Philips voice loggers at over 120 airports around the world. Now, after 25 years of progress and proven reliability we're introducing our fourth generation VLS. Because we aim to keep pace with the times.

For further information write to: Philips Industries Electro-Acoustics Division Prof. Ree. Dept. - HBS 2 Eindhoven, The Netherlands.

OVER25 YEARS

ij

OF PROGRESS VoiceLoggingSystems

PHILIPS

• sector workloads • holding queues • communications workloads • arrival delays • conflict/proximity counts • departure delays • numbers of aircraft in stacks These results can be used both to redesign procedures and validate operational (sector) organisation and to assist in the specification of such aspects of equipment performance as: • radar coverage and capacity • communications loading and distribution • computer power and respon·se At first, this may seem to be a complex way of designing a system and defining equipment specifications.

But you will appreciate that the alternative - and one that undoubtedly you will have experienced - is to provide a system with new equipment that may prove to be unnecessarily complex, or inadequate, for a traffic demand; and procedures that have not been tested.

The results of inadequate system design can prove to be technically and/or economically disastrous and, in operational terms, spell delays, discord and even disasters.

Thus a very basic rule, before preparing the technical equipment specification - or worse still, of simply buying off the shell - i's to prepare an Operational Requirement. That Operational Requirement should not be dictated by current chaos, or guesses of impending doom, but should be derived from scientific techniques of evaluating future user requirements and proposed operational solutions.

TRANSLATING OPERATIONAL

TO

TECHNICAL

REQUIREMENTS

LIMITED FINANCE

ABUNDANT TECHNOLOGY

OFF THE SELF

NEW DESIGN

'

TECH PERFORMANCE

r~-,---'7 I

/

/

I I

I

I IL _____

I

I I

I

'----,->-----✓

/

-;(

I

_J

HUMAN CAPABILITY

Translating Operational to Technical Requirements System Architecture continues from its role of preparing a scientifically based operational requirement, to translating it to a Technical Specification.

In ·some cases there will be a off-the-shelf black-box or even complete system that will match or nearly match the operational requirements. For instance, to repeat the system in an adjacent FIR. Usually this provides considerable advantages in such terms as compatibility, known performance and reliability, and almost certainly in costs. This is becau·se the technical design and development costs do not have to be repeated.

But there are considerable pit-falls in purchasing an off-theshelf system merely because of such reasons as: a) 'it works splendidly in Country X' and b) 'our problem·s are less than theirs, therefore their system will handle our traffic without difficulty' Unless the off-the-shelf system does genuinely match the operational requirements, such a course of action invites disaster, or at least considerable technical and financial efforts, and/or operational disruption or inadequacy.

Therefore in principle system architecture begins at the beginning and meticulously translates operational requirements firstly to broad technical designs and secondly to detailed technical performance specifications.

You are all aware that there are radars - and radars - and that there are displays - and displays. This question of standards applies to every component in the system and i's ultimately reflected in the system performance, reliability and availability. Thus they need to be specified to a standard that will provide a predetermined degree of service, as influenced by the financial resources available. This balance between performance and cost is an important function of the System Architecture.

As already mentioned there is the need to design for compatibility with adjacent and other International systems. This should be part of the Operational Requirement but it has to be resolved in the Technical Design and of course is complicated where adjacent one-off or autonomous systems already exist.

But, as you all know, unless system can communicate rapidly and freely with system, the flow of air traffic cros'sing FIR boundaries is inevitably constrained.

Earlier ATC systems were essentially pure hardware, but now with the impact of automation there is a significant element of

-------1

OPERATIONAL REOUI REMENT

SYSTEM SPECIFICATION

software. Indeed the software costs can amount to as much as two-thirds of the total cost of a data processing system. For those of you who remain uncertain of the relationship between hardware and software, a useful analogy is to consider a tape recorder as hardware and the tape as software. The recorder determines the acoustic quality of output but it i's the tape that dictates whether you hear Handels' Messiah or the 'Top of the Pops'.

Thus the design and production of the software is absolutely critical lo the performance and capability of an automated system.

In translating an operational requirement to a technical specification, systems Architecture is involved both in designing software applications, functions and performance, and in ensuring that the appropriate computers and man-machine interfaces, such as displays and input devices, will serve the user requirement.

At this stage, user requirement is quoted in two contexts. In the first it means the ATC service provided by the system to users of the airspace. In the second context it means that the display and input devices themselves will provide suitable interfaces with the controllers in terms of the volume and nature of information they interpret and originate.

For the controller is currently a critical element of the ATC system and it is essential that the system is designed and implemented to take advantage of his skills. Therefore the system architecture provides both the ergonomic designs of hardware to match man's physical proportions, and the software designs to present display and input techniques appropriate to the application of those skills when under-taking ATC procedures.

It is when all these design aspects are neglected that we so often see the mi·s-application of controller's capability and consequential degradation of the ATC system.

9

Not the end - but the beginning As I have already indicated our technical capability has over taken our financial resources, yet still we flounder and waste men and machines. This is because so very often we specify the technical performance of ATC equipment to the 'n'th degree without previously relating it to the demands of the dynamic operational system.

Certainly we mu·st invest in new ideas and new techniques amongst which must be new tools and display techniques to assist with problems ranging from strategic traffic management to tactical conflict resolution.

But we must beware of electronic sledge-hammers that crunch, but do not cure our problems. For although we may be faced with some tough nuts to crack, the problem is not a parochial one.

IFATCA contributes to a world-wide air transport ·system. The elements that comprise that system must be evaluated and matched by System Architecture, so that the men can be provided with effective machinery to provide expedition and safety to all users of the airspace, as part of the Design for the Future.

■

SST Operations-Operational Requirements Since the original resolution passed at the IFATCA Brussels Conference 1964, almost every other IFATCA conference, resolved on continuing the study of Supersonic Transport and the effects. on the Air Traffic Control System.

1978 Conference required Standing Committee I to provide policy for the 1979 Conference. It is interesting to note that the Operational Requirements considered by IFATCA in 1964 were the same as those on current Operational Requirements published in ICAO Circular 126 - AN/91. The following Operational Requirements were adopted as IFATCA policy on SST operations for the use of the Air Traffic Controller:

1. IFR Operation That SST aircraft, when in transonic and supersonic phases of flight, operate in accordance with the Instrument Flight Rules.

2. Clearance for transonic phase That the ATC clearance relating to a transonic at least to the end of that phase.

phase extend

3. Establishment of longitudinal separation That longitudinal separation, where it is to be applied to SST aircraft intending to follow the same or diverging tracks during the transonic and supersonic phases of flight, be established by appropriate timing of the start of transonic acceleration, rather than by speed restrictions applied in supersonic flight.

4. Size and shape of FIRs and CTAs

That the size and shape of Flight Information Regions and Control Areas should be consistent with the need to obviate frequent transfers of control or change of communication channels.

5. Separation of SST from other flights That an SST flight during the transonic and supersonic phases of flight be provided with air traffic control service ensuring separation from all other known flights.

6. Cruise Climb That air traffic services be capable of authorizing cruise climb for SST aircraft in supersonic flight.

7. Clearance for transonic accelaration/decelaralion That ATC clearances to SST for transonic accelaration and for deceleration/descent from supersonic cruise be issued sufficiently early to permit completion of necessary preparations before commencing these phases of flight.

8. Early notification of expected terminal delay That SST aircraft be informed of expected terminal delay sufficiently early before intended descent to permit absorption of such delay by most economical means.

9. ATC imposed deviation from flight plan That ATC imposed deviations from the intended flight path of an SST aircraft during the transonic and supersonic flight 10

phases be kept to a minimum and that, if such deviation becomes necessary, the associated ATC clearance take due account of the operational constraints of the aircraft in those flight phases.

10. Issuance of transonic acceleration clearance That the ATC clearance relating to a transonic acceleration phase, whenever practicable, be issued at the point of departure. In any case however, such clearance shall be issued not later than 5 minutes before the aircraft is required to commence acceleration.

11. Flight information to en-route SST fllghts That information on destination weather, the operational status of facilities associated with the runway in use, and the runway conditions, be provided to SST aircraft by the appropiate area control centre or flight information centre upon request, prior to commencement of deceleration/descent from supersonic cruise.

12. Fuel penalties al take-off That procedures be developed to minimize between engine start and take-off.

fuel

penalties

13. Transonic and supersonic Information in flight plan That the flight plan to be submitted for an SST flight provide, within the existing flight plan format, the specific information on transonic and supersonic flight phases necessary for ATS purposes.

15. Descents due to cosmic radiation That procedures be developed to faciliate ATC handling of SST descents from supersonic cruise necessitated by solar cosmic radiation.

17. ATS authorization of en-route absorption of terminal delay That air traffic services be capable of authorizing SST aircraft to absorb the whole or part of notified terminal delay by descending early and cruising at a reduced speed for the latter portion of the flight and of crediting the aircraft with the time absorbed when determining the landing order.

18. Air-ground communications That rapid and efficient air-ground communications able during all phases of SST operations.

be avail■

In the hills surrounding Bath lies a fine 18th century manm: It's almost hidden by the green and blossom of the English summet But at Bailbrook College the air is full of drama.

IAL is putting an ATC student through his paces.

It's all happening on our digital air traffic control radar simulatoc A choice of% different aircraft can be displayed Ranging from the smallest fixed wing or rotary to the largest and fastest civil and military types, it can simulate any type of radar installation in the world today.

At Bailbrook the student learns to handle the unexpected with the same calculating precision as the everyday. Because one day many lives could be held in the balance of his judgement

In the past 21 years over 2,000 ATC students from 75 countries have graduated through IAL. Training courses include air traffic control services, electronic engineering and telecommunications, communications operations, meteorology, science and mathematics, teaching techniques and English language.

These courses are specially tailored to meet the individual needs of overseas governments and organisations.

At Bailbrook College, it's no accident we've built a reputation for happy landings. Can you think of a better place to develop askill?

Im

THEHIGH Tl:CHNOLOGYTASKFORCE

AVIATION SYSTEMS AND SERVICES· COMMUNICATIONS SYSTEMS •COMPUTER SYSTEMS AND SERVICES· WORLDWIDE Contact: ThePrincipal.!AL.BailbrookCollege. London !badWest.Bath.England. BAl 7JO.Telephone:Bath (0225)858941.Telex:4441221AL G.

A FEMALE AIR TRAFFIC CONTROLLER the pilot's empathic guardian angel.

...

and what happens when angels control angels?

Do we have to face excessive frequency congestions?

12

Female Controllers in an all-male environment

by A. Avgoustis

Though women nowadays find their way through, in some countries, air traffic control still remains a predominantly male profession. Despite attractive terms offered in the field with good prospects of promotion and fringe benefits, women seem to be hesitant to breach the conventional barrier which stands before this new and unknown, or possibly uncomfortable environment.

This article attempts to examine in the first instance legislative measures assumed by states towards the abolition of any discriminating grounds that may stand in the way of a complete equality of the two sexes in the employment system; and in the second instance it reveals the position of the woman and her feelings having to work in such a predominantly male environment, through statements made by the ladies themselves.

A great number of countries have during the past few years, through series of legislative acts abolished any discrimination based on sex, either directly or indirectly, by reference to marital or familiy status. Statistics in these countries show that at the beginning of our century, the proportion of occupations without any women workers was relatively constant at around 9 % which fell down to 2 % by the early 1970s. On the contrary all-female jobs have increased during this period of time from 9 to 12 %. Data presenting the emergence of one sex in occupations previously dominated by the other sex showed some changes. Early in the century almost half of all men were employed in all-male occupations eventually this number to be occupied in jobs where male outnumbered female employees, by at least 9 to 1. As far as women were concerned, during the same period under review the majority of women were employed at typically female jobs. A breakdown by occupation, even at the present day, may reveal that a great many of the occupations in which women are over represented are typically "feminine", eg. maids, nurses, canteen assistants, sewing machinists, cooks, waitresses, housekeepers, etc, in the sense that they draw skills exercised on an unpaid and non-specialist basis within the home. However, occupational patterns of men and women obviously show a noticeable change since the commencement of the second half of this century.

Before I force myself away from such generalities and enter into our world, i.e. aviation in general and air traffic control in particular, I feel it is necessary to run through briefly a small number of legislative acts enacted by different administrations in their drive towards equality in employment.

United States for instance has by the Equal Employment Opportunity Act of 1972 prohibited discrimination in employment on the basis of race, colour, relegion, sex or national origin. This was followed by another act in 1978 banning sex discrimination on the basis of pregnancy and requiring employers who have general health insurance and medical disability plans to provide coverage for childbirth, pregnancy and related medical conditions. Despite these U.S. public enactments, under the United States Constitution, sex discrimination is not yet prohibited. Constitutional changes require a two/third state ratification. To allow time for such ratification to be effected by American States the US Senate had recently extended by three years the seven-year ratification period, which expired at the end of 1979.

The Council of European Communities adopted in 1976 a directive on the implementation of the principle of equal treatment for men and women as regards access to employment, vocational training, promotion and working conditions. The principle to be applied is that "there shall be no discrimination whatsoever on grounds of sex either directly or indirectly by reference in particular to marital or family status."

The most outstanding example towards the absolute elimination of sex discrimination in employment is witnessed in the Swedish government's recent measures and directions to all government agencies which are required to submit annual progress reports on the adherence of such agencies to the provisions of the law of equality between men and women. It has also established a special board which provides guidelines for helping companies to comply with statutory regulations. The formal prohibition of sex discrimination in the Swedish civil and public Services was established in 1976. In the same year the Central Administration of the Swedish Telecommunications was directed by the Government to start an experimental programme with a view to breaking the practice of assigning men and women to different job categories within the administration. A joint working group, known as the BREAK Committee was set up to carry out the programme and in November 1978 submitted an evaluation of its findings to the Government.

The jobs selected for the project were those which are traditionally dominated by either sex. The female dominated jobs were, telephone operators, directory, inquiries, sales and technical drawing. The male-dominated jobs were, telephone and exchange installation, line and plant maintenance and telephone and exchange maintenance.

During the two-year trial period, 106 individuals were either recruited for or transferred to an occupation dominated by the opposite sex. Briefly the following was the result: Women: The majority of women, most of whom had previously worked in traditionally female jobs were enthusiastic about their new job and felt that they had better career opportunities, more diversity and greater responsibility. Only a very small number asked to return to a typically female job.

Men: Out of 25 male participants only 8 said they enjoyed their new environment. The majority criticised the monotony, the limited scope of advancement, the lack of responsibility and the low pay. Most of the men participat13

ing in the project were new recruits and only three applicants came from the establishment. The majority of the men said they will stay at the job until they find another job, more "manly" with better possibilities for advancement.

Having gone through this introductory, in my opinion, informative note, let us examine our world, the air traffic control world and what women controllers feel about their job as air traffic controllers and how do men and the rest of the world look upon them. Indeed, air traffic control from its inception has been and continues to be a predominantly male job and in some countries it still remains closed to female personnel. Japan, for example, until the close of 1979, when the tradition had come to an end, had kept its doors closed to female controllers - there are more than 5000 air traffic controllers in Japan timidly employing the first half dozen or so from the 113 female applicants.

Eurocontrol - the agency established by some European countries to provide air traffic control in their airspace - still remains closed to female controllers, though alleged that this is purely coincidental.

Powered flying is comparatively older than the establishment of air traffic services units. Even the beginning of scheduled passenger flying which may go back to the first quarter of the century could not have necessitated their use. During the first half of the century women were not permitted employment either in the cockpit or in the control room. The nearest they could get at the time was the serving of coffees or meals on board aircraft when scheduled passenger flights began operation. The first break in the cockpit tradition came in 1953 when Marie Athanasova of Balkan Airways (Bulgaria) became the firstever woman co-pilot of a passenger aircraft. Balkan Airways example was followed in the coming years by many airlines but present day statistics still show the cockpit as a man's world with a long way to go before a fair number of women are attracted or admitted to such employment.

With air traffic control, military control units had the privilege of using female control personnel first during the period of World War Two. It is argued that civilian women controllers joined air traffic control after women pilots did, in 1953. This assumption, cannot, unfortunately, be disputed for the simple reason that controller employment statistics do not provide for sex classification. Where, however, women were permitted into the air traffic control services they joined in greater numbers than women pilots.

Nonetheless, the profession does not seem to appeal to a good percentage of women with some places, though equal employment rights exist, not envisaged to attract many women applicants in the near future. The United States Air Traffic Control Agencies claim the greatest number of women controllers with European countries showing a very small number - steadily decreasing - in proportion to their male counterparts. Greece, for example, employs two women controllers out of a total of three hundred; in Cyprus, though the country's constitution secures equal employment opportunities for both sexes, there seems to be either a reluctancy on the part of the government to encourage women applicants or the latter fail to understand their capabilities in this rather new environment.

In an effort to uncover what lies behind this "unpopularity" or "unattractiveness" of the profession to women, questions posed and statements made by practicing women controllers generally meant to reflect their feelings working in an all-male environment; questions concentrated on popularity of the profession and on the effects on their family and social life. The result of this unique questionnaire is an excellent picture of professional spirit 14

and dedication despite the fact that the background is tinted with uncomfortable situations for the ladies concerned.

CROWDED SKIES (The Dallas Fortworth Control Tower Newsletter), edited by a high spirited, hard-working Richmond K. Murry, devoted its entire August, 1979 issue to statements made by five American female controllers, with four of whom I had the opportunity to communicate with, in order to make up this article. These are Jill Finan, Loretta Harris, Susan Powers and Brenda Young. Rich comments on the statements made in his CROWDED SKIES may be summarised in these few words: "The girls had a lot to say and said it beautifully. I feel that we are all male chauvinists to some degree and a little constructive criticism shouldn't hurt long."

Let us now see what the ladies have to say.

Jill Finan, who works at Atlanta Center, married to an air traffic controller says of her marriage: "this controller/ controller marriage poses a unique situation, since we both have the problems of shift work and different days off. As a result, it seems that most of our friends are fellow controllers."

Jill

Finan

Brenda Young, who works at Memphis Center - is also the editor of HIGH COTTON, Memphis ARTCC's newsletter - speaks of her first experience when she moved away from hometown to Memphis Center. "I was somewhat embarrassed," Brenda says, "to work in a 'conventionally male environment', but as time passed and I became more familiar with my cohorts and new surroundings of ATC, it became less and less a problem." On social life Brenda, admits that shift work does affect her social life; "I have to make my social plans on my Saturdays and Sundays whether they happen to be a Monday and Tuesday or Thursday and Friday for that rotation, but so does everyone else that I work with," she concludes.

Loretta Harris, who has been a controller for four years now undergoing radar training at Dallas Forth Worth Air Traffic Control Center, and at the same time attends the University of Texas aiming for a degree in Management, is married and has a girl aged 5. "Shift work," Loretta says, "does to some degree affect my family lire.

It creates hardships in trying to maintain a normal household working irregular hours. Most of my social activities involve fellow air traffic controllers, because they understand the hours and it's easier to plan activites with someone whose days off are concurrent with yours."

Susan Powers, believes that there was a big change for her when she moved into air traffic control after being a school teacher in "a primarily female environment". Susan

says that, "working rotating shifts and changing days off every six weeks adds very little to one's social life whether male or female. 'Normal' friends hesitate to call as they think you might be sleeping. Garden clubs and other women's groups are no more a problem for a controller than for any working woman. Regarding both family and friends, "Susan continues," an individual working as a controller can do exactly what she makes time to do, just as anyone does."

Embarrassingly, Jill Finan, speaks of male controllers' behaviour towards their female colleagues. This is how she describes such behaviour in her statement to CROWDED SKIES: "Something really happened to me the other day. As a female who is a controller at Atlanta Center, I found myself assigned to a sector with three other women. Yes we were all female: the D controller, the radar controller, a radar trainee, and I, the tracker.

"But the unusual thing was not that the sector was staffed by females. After all there are more women than ever working in air traffic control. Since I was hired on five years ago, the number of women on the boards has more than quadrupled. So it stands to reason that more and more women are going to be staffing sectors and positions together, right?

"No, the strange thing was the reaction from our brother controllers. Every man who passed that sector had something to say. Of course, being experienced in dealing with our male counterparts, we let all the remarks bounce off. When we were not busy separating airplanes we applied the comments with some of our own. But this repartee stretched into hours, it got less and less funny.

"It's not that I am sensitive. After five years as a controller, sensitivity is a forgotten emotion. But after you hear, Oh, my God, an unmanned sector!' two hundred times, it isn't cute any more. Some of the remarks even touched on the obscene, (I've heard of combined sectors, but never a split one!) And when the assistant chief on duty strolled over to say, 'Now I've seen everything. It's time to retire!' that's when I began to wonder.

"You see, I was in attendance at the Miami PATCO Convention, where the delegates passed a resolution supporting equal rights. I was extremely pleased and proud that my brother and sister controllers could take such a stand. But now I wonder if the attitude demonstrated at the Convention was taken back to the individual facilities.

"There are never insulting remarks made when three or four men are working a sector, even when those men are the weakest controllers in the area. But get two or three women on a sector, even the two or three women who are the best controllers in the facility, and you're fair game for everyone passing by who wants to impresse his buddies with his wits. That, to me, is not equal treatment.

In fact, it's downright degrading.

"I went through my training, my checkout and my baptism by fire like everybody else. With some people - not everyone - I had to work a little harder to prove that I could do the job. I thought I had proven it. I thought I could car-ry the title 'Controller' without having the word female tagged onto it. It looks like I may have been wrong.

"So I ask my brothers at every facility to think about their attitudes. When you see a woman performing her duties at a sector or position, don't just see her as a female. She is a controller. A controller just like yourself.

And I think that is the highest recognition any of us - no matter what sex - can hope to achieve."

Karen Harrison's opinion on the issue of treatment of women controllers by male colleagues does not seem to be very much different than Jill's. This is what Karen has to say: "Of course you are treated differently as a woman.

Despite the increasing number of women controllers, there still lingers the conventional image of wide-eyed feminine naivete. As soon as a woman enters a field which demands competitive and aggressive action one or two things happen: 1, if a woman takes the aggressive attitude thought to be necessary to be a good controller the men label her a castrating bitch; 2, if a woman tries to sit back and use passive compiant behaviour, she finds herself being told that she can't respond to the competive atmosphere and that she cannot handle the pressure of the job. So you are torced to find your own compromise somewhere in the middle, which is difficult because the while you feel like you are on trial, not just as an individual but also as a representative of women."

Karen concludes her remarks by saying: "We were born male and female - we had no choice. We all had to become controllers by working hard and wanting it bad enough. I am not proud of being something over which I had no choice, but I am proud of being a professional air traffic controller. Like everyone else, I had to do it myself."

Loretta Harris of Fort Worth Center says: "If you have spent any lenght of time in an Air Traffic Control Facility, you've probably heard one or all of the following comments: 'Women shouldn't be air traffic controllers; women should stay at home and raise families; women aren't smart enough to be air traffic controllers; women can't stand the pressure'. The pressures are definitely on. You hear opinions from everyone trying to explain why women are not meant to be air traffic controllers. If God didn't want me to do what I'm doing, he would not have given me this ability. It becomes desperately necessary that you respond only to your feelings and abilities."

Loretta continues by saying that the major obstacle for acceptance of female controllers into the air traffic control world is "lack of aggressiveness. Many people," Loretta says, "feel that to be aggressive is 'unladylike'. This feeling must be overcome, because self assertiveness becomes a vital role to female controllers. Women can be aggressors, when the job demands it, and we must be. This problem stems from culture norms imposed upon us by our society. We have been told for generations that women are not capable of competing in a male-orientated society ... We have reached that juncture where women are becoming aware of their individuality and capabilities and are stepping out to pursue them. A woman's place is anywhere she wants to be and some of us have chosen our place to be Air Traffic Controllers."

Concluding Loretta admits: "We must however, be realistic. We cannot expect our male counterpart to change overnight. They won't." Finally, Loretta urges her worr:en colleagues to work together to accomplish their common goal - safety in aviation.

15

Susan Powers on the other hand, seems to have anticipated some kind of "kidding" as she was married to a Memphis controller before she joined air traffic control.

Susan says: "I was the first woman controller to work at Memphis Tower since World War II; therefore I was quite a novelty in the Memphis area for a while. Controllers and pilots alike joked with me and about me being a female in an all male environment .... I realized," Susan continues, "from the beginning I was entering their world and I would be the one who would have to make the majority of the adjustments and compromises." As to the question whether she felt embarassed working in an all male environment Susan said: "only if I let it be".

employment relationship with their female counterparts, who, had it not been for their dedication, could have been forced out of the air traffic controller's profession. However, there may be a possibility that the ladies misjudge their male colleagues bearing in mind that "remarks" could be nothing more than boastful jesting. Furthermore, hoping that I do no injustice to them, I would draw their attention to Susan Powers definite approach to the problem when she says: "I have found that men will be men ... And yes, thank goodness for being treated different by the male controllers. Any woman who thinks she is one of the guys or has to be, she is only kidding herself."

■

Brenda Young admits also that when she joined air traffic control, she knew she will be working with male controllers, generally and conditioned herself "to try and cope with the situation". Being a woman, Brenda says, "doesn't necessarily make promotions or life more difficult," yet she admits that "every day comments are made about your ability or lack of it; sometimes you feel that you may never be totally accepted by your brother controllers .... Naturally," she continues, "you receive daily a shower of comments such as 'you'll never make it' or someone hands you the employment section of the newspaper want ads."

From the ILO Desk:

Brenda Young

Despite the unfitting attitudes of the male controllers, women controllers seem to be content with their jobs and happy that they chose the controller's profession. Brenda Young says: "In summary I feel very fortunate to be where I am in my career field and wouldn't trade it for anything."

Susan Powers says: "Learning to control airplanes from the ground up at Memphis International was not the easiest thing I have ever tackled - graduate school was a piece of cake compared to all of the learning I had to accomplish here at Memphis Tower. It has proved well worth the effort.

I like being an air traffic controller and have enjoyed my experience as a rotational EPDS for the past year. I am still learning."

Recalling Karen Harrison's statement, "I am proud of being a professional controller," and Loretta Harris's, "A woman's place is anywhere she wants to be, and some of us have chosen our place to be air traffic controllers," compel us to conclude that the ladies' dedication to the profession is equal to, if not greater than that of, their male counterparts. Dedication to be envied by a great number of us.

As a conclusion one must therefore admit, judging from the statements made by the ladies above, that Rich Murry's observation that "we are all male chauvinists" reflects a somewhat unorthodox approach of the male controllers 16

ILO Meeting of Experts - Outcome The Chief of the Industrial Sectors Branch, Sectoral Activities Department of the International Labour Office (ILO), has notified IFATCA and Organizations as well as Government-Members that the Governing Body of the Office at its 211th session, last November, considered the Report and Conclusions of the ILO Meeting of Expert's on problems Concerning Air Traffic Controllers, which took place in Geneva in May, 1979 (see THE CONTROLLER issues 2/79 and 3/79) and took the following decisions: 1. The Governing Body took note of the Report and authorised the Director General to communicate it: (i) to the governments of member States, informing them that it had taken note thereof and requesting them to transmit it to the employers' and workers' organisations concerned; and (ii) to the international government organisation·s concerned, in particular the World Health Organisation (WHO), the International Civil Aviation Organisation (ICAO) and the non-governmental international organisations with consultative status, 2. The Governing Body requested the Director-General to draw the attention of the governments of member States to paragraph 1 of the Meeting's conclusions, in which the governments of all ILO member States are urged to ratify and apply the Freedom of Association and Protection of the Right to Organi·se Convention, 1948 (No 87), the Right to Organise and Collective Bargaining Convention (1949) (No. 98) and the Labour Relations (Public Service) Convention, 1978 (No. 151) as their provisions embody the principles which should be recognised as applicable to air traffic controllers.

3. The Governing Body authorised the Director-General, when Communicating the Meeting's Report to the international organisations concerned: (i) to draw the attention of the World Health Organisation to paragraphs 12, 13, 25 and 35 of the Meeting's Conclusion·s; and (ii) to draw the attention of the International Civil Aviation Organisation to paragraphs 12, 13, 25, 41 and 45 of the Meeting's Conclusions.

4. The Governing Body authorised the Director-General to collaborate with the World Health Organisation, the International Civil Aviation Organisation and other appropriate international bodies in exploring and pursuing the action to be taken on the conclusions adopted by the Meeting.

5. The Governing Body authorised the Director-General to take account of the Meeting's Report and Conclu'sions when considering future ILO action in this field and planning the future work programme of the Office.

6. The Governing Body decided to take the request formulated in paragraph 52 of the Meeting's Conclusions into account when considering future proposals for the agenda of the International Labour Conference.

Mr. Renaud's letter concluding confirms that the Report and Conclusions have been communicated as directed by the Governing Body of the Office.

■

The Design of an Air Navigation Services System

by F. W. Fischer Director ANSA Corporate Member of IFATCA and H. Fischer Air Navigation Consultant Flugsicherung-System-Beratung

Introduction The purpose of this article is to present briefly and in key words the conditioning factors for the design of an air navigation services system related to its safety, capacity and capability.

The matter also goes hand in hand with the modernization and upgrading of present air navigation service·s systems. We therefore find it suitable to present our considerations on this subject, since it is our objective to assist aviation authorities, organizations and institutions in the development of new or the modernization and upgrading of existing air traffic services systems, services and equipment to promote air safety in air navigation.

The recommendations and conclusions presented herein have been elaborated in close cooperation with system planners, evaluators, engineers, air traffic controllers and airspace users. They have been drawn with the knowledge of insiders on the problems arising in the design of such systems in mind. We have been influenced in our conclusions by ICAO considerations and theories.

the implementation of air traffic services system functions, such as conflict alert and conflict prediction, for provi'sion of proper air traffic services to the airspace users, especially during upgraded instrument operations (IFR); the adaptation of the navigation system to the requirements of the airspace users (VOR, DME, Area Navigation Procedures); the modernization respectively implementation of new air traffic service·s equipment including radar and flight plan data processing with corresponding state of the art display equipment, and the installation respectively modernization of the necessary voice and data communication links.

Reasons for the development of new or the upgrading and modernization of present air navigation services systems are available worldwide and in great number.

lflTERFACE

General Considerations The construction re·spectively upgrading of airports and the implementation of airplanes meeting specific transportation requirements should go and do normally go hand in hand with the implementation respectively modernization of the air navigation services systems.

An extended national air navigation services system does constitute an extension of the ·safety of air traffic due to the increased number of flights controlled and the type of aircraft utilized safely under that system.

Since air traffic control is not isolated for one country, the air navigation services system must be compatible with the adjacent systems in neighbouring countries and with their system function·s.

In order not to infringe safety within the national system and when changing from the national to foreign systems, interfaces must be provided for the exchange of flight data on such international flights.

Such system interfaces constitute an encounter of different technologies with respect to the exchange and the coordination of flight plan and flight progress data and present a major problem in system communication and coordination of functions.

Therefore different technologies of an air navigation services system with those of neighbouring countries have to be made to fit.

In addition to the internal improvement this implies a modernization of a system for adaptation in respect to the technology and the status of the adjacent systems, if traffic is to cro'ss borders. Of course, with increasing national traffic rates the air navigation services system must also meet additional and different conditions of air traffic control. These additional conditions require for instance: the reorganization of the airspace structure with the corresponding air traffic services routes, especially in the terminal control areas; the implementation of air traffic flow control procedures for the economic distribution of traffic along routes and in terminal areas;

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One ·set of arguments presented by industry results in the sale of as much hardware as possible. The other, brought forward by the International Civil Aviation Organization and its offices, constitutes a general demand for more safety. Related to national interests, neither of both sets of arguments normally meets the actual requirements.

Based on the experience of the members of the Advi'sory Group - Air Navigation Services, coming from the industry, the national air navigation services administrations and the military (air traffic control and air defense), the process of setting up a concept for an air navigation services system must be seen under the following aspect's: safety of air traffic by control in the national airspace and national safety.

Safety of Air Traffic in the National Airspace The requirement for air traffic control stems from the requirements and demands of national civil and military air traffic, international air traffic of national companies and international air traffic of international companies.

17

Based on the demands of these airspace users and their requirements a concept for a national air navigation services system can be set up.

But of what use is the best national (non - ICAO) air navigation services system with an own tailored set of rules, if the pilot is used to other air navigation services and air traffic control rules, entering the country from a neighbouring state and is unable to get on well with the now implemented new system?

National Safety Based on the experience with air navigation ·services systems in the western hemisphere, in which mostly a separation of military air surveillance systems and military and civil air navigation services systems are customary, one can say that due to this fact problems have been created in these countries.

A new concept should therefore combine the demands of the individual users to build an integrated joint technical system for reaons of safety, costs and efficiency.

With the available knowledge in the industry the set-up of a proposal for an air navigation services system i's possible. However, a significant system layout conforming to the actual requirements can only be achieved in close cooperation with the system operator.

To allow an impression of our ideas we enter into a few particulars on basically necessary ·system elements. It is to be said before-hand that air traffic control is possible in two different ways: air traffic control on a procedural basis, i. e. monitor and control based on available flight plans and revisions (position reports) only or air traffic control on a radar basis, i. e. the system places to the control personnel's disposal continuous and accurate positional information on aircraft movements through the use of radar.

To what extent the main point of system effort is to rely on, the one or the other possibility, is dependent on the type and amount of traffic at times. In most ca·ses a mixture of these two air traffic control system possibilities seems to be advisable. It requires for instance careful study, if a complete radar covernge should have to be provided in case of a high traffic volume along routes only.

In the consideration of reasons and requirements for the plans of an enhancement of air navigation services systems one must refer to ICAO policy, since each contracting state of ICAO is responsible for the provision of air traffic services in its territory under article 2 of the convention.

Arso, based on the air navigation plans and their corresponding conditions to be met, detailed concepts are set forth for the provision of facilities, services and procedures required for international air navigation within specified areas.

It se,ems to be a good guideline that planning should be directed towards facilitating implementation of essential improvements for existing and anticipated operations in a region and that planning for facilitie's and services in addition to meet the operational requirements, should consider the need for 'Efficiency in Operation' and 'Economy in Equipment and Personnel' with due consideration on capability for future expansion without major re-design or replanning.

The planning should take into account the need for adequate numbers of qualified and competent personnel to be an integral part of the system, to supervise, maintain and operate air navigation facilities and services in the fields of alerting service, flight information ·service, air traffic control service, aeronautical information service, aeronautical telecommunication service, as well as meteorology and search and rescue.

There seems to be a need to accommodate the air navigation services systems to meet the requirements of present and future air traffic. Reliability, accuracy and speed of the system must match present and future needs. Improvements in the provision 18

of air traffic services are however largely dependent upon developments in related fields, particularly in. navigation equipment and modern data processing elements. The introduction of high performance aircraft in common airspace environments requires an upgraded air traffic control system.

The objective should, therefore, be the provision of a well balanced air traffic control system that meets the demand of the predicted growth of its air traffic through the year 1995, maintaining and guaranteeing an improved level of safety, an optimum use of its available airspace and solving existing shortcomings and problems of an operational and technical nature.

Since then the coordination problems could be solved, this could result in an extension and upgrading of air traffic services, namely the provision of positive air traffic control service, in areas, where at present only flight information service can be provided or the air traffic control service does not meet the requirements of present air traffic.

In this context the exchange of available aircraft position (radar), flight plan and flight progre·ss data constitute a problem, which can best be solved by application of automated data processing. The implementation of automated air traffic control system functions should, however, be approached very carefully.

Fundamental importance have modern system functions like 'Conflict Prediction' and 'Active Air Traffic Flow Control'. And by all means should it be planned to maintain a principle of 'Unity of Control' in the commonly used airspace, despite the possible neces·sity to maintain two separate technical systems (military air surveillance & defense and air navigation services). Disobeyance of this principle will multiply technical complexity and system cooperation.

Unity of control should be defined as all aircraft within a given portion of the airspace being under the control of only one functional air traffic controller team (airspace sector personnel) at any one time.

Since satisfactory operation of any air navigation services system is totally dependent on the total and effective structure, 'the principles, objectives and characteristics' of the future air navigation services system require vital human, operational, technical, managerial, organizational and environmental considerations to be examined.

Firm intentions and decisions of the air navigation services authorities are required and must be stated as a re·sult of considerations covering long term planning to implement a future air navigation services system.

The government decisions could most appropriately set down under three headings: Operational Philosophy Safety Considerations General Communications Considerations

Operational Philosophy The air navigation services system should be pre-planned in such a way that it only requires minimum intervention during periods of normal operation, based on airborne navigation and regionally centralized management of control for positive control of all traffic.

Now, what is a 'system'? A system in the commonly accepted understanding is defined as a composite of equipments, skills and techniques capable of performing or supporting an operational role or both. A complete system therefore includes all equipment, related facilities, material, software, services and personnel required for its operation and support to the degree that it can be considered a self-sufficient unit in its intended operational environment.

The air navigation ·services system consists of sub-systems, which perform specific operational functions. Main system elements, respectively subsystems are: the weather subsystem the notices to airmen subsystem the navigation sub·system

Ali<

consist

TRA~r1c

of Hardware,

SERVICES

Software

;;ys·1 l'MS

and Liveware

as integral

parts

Hardware Metalware or articles, as tools, hinges, cutlery or utensils; any mechanical, electrical or electronic computer equipment.

Software locks,

ATS SOf'TW/1.RE

The program and programming support necessary to put a computer through its assigned tasks, as distinguished from the actual machine; any aspect of an apparatus not specifically connected with its hardware.

Live..,are People and procedures directly engaged in the operation or a system. They instruct and control the system by overriding or making decisions, ..,hich the system either has not made or are unsatisfactory.

TO FULFIL THIS TASK IN ATS-SYSTEMS MAN NEEDS THREE CATEGORIES OF DATA, FLIGHT PLAN & FLIGHT PROGRESS, RADAR AND AERONAUTICAL INFCRMAT!ON DATA.

the voice and data communication subsystem the direction finding subsystem the flight plan and flight progress data subsystem the radar data subsystem the aeronautical information data subsystem the personnel, training and simulation subsystem the system monitoring and control subsystem the logistic support subsystem Such a system consists of machine and man. It should be the major task of this yet incomplete machine (the different equipments in their proper configuration) to expedite the flow of data in the system. In order to fulfil his system function and operational tasks man needs information and data. More traffic means more data. Equipment is manufactured to accept much more data than man can handle himself. Therefore these data must be p1esented to him in a suitable way to enable him to act as human interface, besides hi's major role of 'Commanding and Controlling·, i. e. managing th system.

Every system concept proposal should therefore contain an operational part and a technical part.

Safety Considerations The management, the control of common air traffic within defined airspace should be the sole responsibility of one control team. Segregation of control should be avoided, technically and operationally.

Mathematical and practical evaluations of system element accuracy, reliability and de'sired level of safety should result in quality standards to be applied by all sub-agencies or units.

System planning, design and layout should cover sufficient reserve and back-up elements to guarantee fail-safe quality and operation during predictable peaks and/or abnormalities under due consideration of human engineering.

Optimum monitoring of all aircraft positions independent of all airborne navigational systems in use to meet anticipated levels of safety in terminal areas and control areas requires introduction of an upgraded radar service. It should be technically assisted by modern operational system functions, such as 'Conflict Alert'.

Con~traints on the ground component's of the system due to meteorological or environmental affects should be negligable.

General Communications Considerations All voice communication circuits and their channels should be static free and reliable to such an extent that this important subfunction maintains required quality at all times, especially during aircraft emergencies.

Essential sub'systems of the total system should be able to automatically detect and indicate malfunctions as soon as they occur to allow corrective direct human intervention.

The common system should have the ability to detect inadvertent infringements by other airspace users, friend or foe, by applying non-cooperative methods and equipment of detection. This means consistent employment of advantages offered by application of data processing methods and equipment especially in the radar and data communication fields.

The ground/ground exchange of vital information and coordination data between national and foreign system managements should be rapid and instantaneous, using on-line computer/computer links for transmission, processing and display of such data, if traffic so warrants. This proves to be true in emergency situations of any kind requiring immediate and continuous access to stored static, semi-dynamic or dynamic data, which cannot inadvertently be erased, falsified or lo'st.

Recommendations Any innovation of procedures, facilities and techniques employed in future air traffic services, resp. air traffic control systems should be judged, if they result in success or failure.

System upgrading and sub'sequent application of automation should foster the decision making and problem solving function.

The air traffic controller should be able to take advantage of offered new and better system capabilities to assist in his ultimate task in guaranteeing the safe, efficient and orderly flow of air traffic under his control at any time.

The introduction and application of automated aids and their subsequent functional capabilities should be carefully planned

19

considering a gradual handover to avoid a shock that may result from sudden confrontation with super-sophisticated systems or elements thereof.

Automated aids should never re·sult in the restriction of the controllers freedc-rn to carry out or maintain his responsibility.

Concentrated effort will be required to analyze, define, specify and design in order to fulfil the important requirements of the human interface considering human engineering principles to assist in reliable, quick error-free and effort-free access to transmi'ssion and transfer of information between equipment and man.

Negligence in fulfilment of this important requirement may, for example, result in an increase of routine input tasks on the one hand and result in reduced decision making capability on the other, when greater traffic, because of unsolved system philosophy so warrants.

The controllers environment plays an important role in determining his efficiency and, therefore, the efficiency of the whole system. Proper and concentrated analysis is required in regard to ergonomics, i. e. essential manual data input and subsequent processing, transmission, routing and display functions to keep the system economic and going.

Description of Present System Determination of Present Sy'stem Shortcomings Performance of a System Functional Analysis on: Air Navigation Services and Air Traffic Services Air Navigation Services and Air Traffic Services Subsystem:, Airspace Organization Internal and External System Environment, Topography Weather Conditions Air Traffic and Message Traffic Airports Power Air Conditioning General Standards, General and Detailed System Functions Man versus Equipment Functions Control Procedures and Methods Present Equipment and Layout of Working Positions System Life Cycle, Reliability, Availability and Maintainability Communications Network Air Traffic Controller Proficiency Judgement and Valuation of the Present System

CRITICAL - EXTENT

Abilily

DECISIONS

OF >1Ul0M.ATION

Government Commitments, Plans and Proposals -

Construction of a General Planning Concept Determination of Operational Philosophy system Safety Role of

of

Controller

to

Pi101 and

take

?

Controller

over

Redundancy

?

'~

Requirements

?

The basic layout of the system should be developed to allow adaptability and capability to suit any control task, including live and synthetic training. Sound scientific principles in the early design stages, coupled with comprehensive evaluation trials during development, construction and implementation phases should en·sure that a system trained controller is enabled to apply the aids offered by the system to assist and support his freedom of decision making, which is based on professional skill and application of know-how even in emergency situations.

It is evident that modern automated techniques can influence the nature of the task of any controller to such an extent that additional stress is placed upon him.

The application of primary and secondary surveillance radar in enroute and terminal control environments result in increased positional accuracy and increased traffic handling capability, as well as more efficient movement of aircraft.

At least for the first phase of an automated sy·stem it can be recommended to employ automated radar data proces'sing and display techniques and an upgraded flight plan and flight progress data processing with incorporated system growth potential for further upgrading and extension to presently exotic system functions, such as DABS/ADSEL or NAVSTAR/GPS. The system should therefore be extended ·step by step using proven hardware and software, following the requirements of present and future airspace users. Experience gained by other air traffic control authorities shows that it is not recommendable to introduce unproven system techniques.

With these considerations in mind we consider the following steps necessary for the successful implementation of new or upgraded air navigation services systems: 20

Extension of Air Traffic Services Reorganizations of the Airspace Air Traffic Controller and other Personnel's Job Descriptions Determination of Air .. Navigation Services Subsystems and Extensions Weather Subsystem Notices to Airmen Subsystem Navigation Sub'system Voice and Data Communication Subsystem Direction Finding Subsystem Radar Subsystem (incl. Conflict Alert) Flight and Flight Progress Data Subsystem (incl. Conflict Prediction) Aeronautical Information Data Sub'system Personnel, Training and Simulation Subsystem System Control and Monitoring Subsystem Logistic Subsystem Equipment Working Positions, Units, Facilities (Description and Layout) Implementation Schedule Costs Documentation Proposals on Project Management System Test's and Evaluations Change Control and Reviews System Concept Proposal Presentations to Operators Determination of Human Factors System Validation.

Present System Descriptions items of:

should

cover

all aspects

and

airspace organization air navigation service·s air navigation services system and subsystems system environment and special problem areas.

Therefore questionnaires should be used as checklists in the preparation of present system description documents and in gathering information and data.

For the layout of working positions human engineering criteria must be applied in design and development in order to: achieve required performance by operators, control maintenance personnel minimize skill, personnel requirements and training time

and

achieve required reliability of human interfaces (man - equipment) and foster de'sign standardization within the system.

The job descriptions must be related to the air traffic services to be provided the ·system functions to be performed the operational tasks to be fulfilled and the working position duties to be performed.

General requirements, which must be fulfilled in this connection are: proper allocation of functions (job descriptions) human engineering design requirements fail-safe design anthropotechnical requirements heating, ventilation and air conditioning requirements.

Documentation should be in such a way that computer assi'sted System Validation Procedures can be applied.

As Computer Sciences Corporation (CSC) in the USA stated, any proposed system concept should be based on descriptions of the present situation, present system shortcomings and operational requirements. A system concept should briefly summarize the scope of the system and how, when and where it will

be defined, developed, concepts of: WHAT WHAT HOW HOW WHAT HOW HOW HOW HOW WHAT WHEN WHERE

procured

and utilized,

by stating

the

the system replaces the system must ultimately be it will be specified it will be developed components comprise ii it will be tested it will be costed it will be integrated the system development cycle will be controlled standards will be applied or developed each step is to be accomplished each step is to be accomplished

It should identify studies required to complete concepts and specifications. It should also briefly identify areas of responsibility for each part or step in the system development.

This necessary sequence of events in planning a system is often neglected by air navigation services authorities. A variety of air navigation services consultants is offering services of this kind and should be engaged in the preparatory works of system construction and extension.

All of us should, however, keep in mind that IT IS A MANSYSTEM! ■

Low Level Wind Shear*) Editor's Note

=

The following article is intended to provide guidance for recognizing the meteorological situations that produce !he phenomenon widely known as low level wind shear. It describes procedures for detecting and predicting this phenomenon as well as pilot techniques that minimize its effects when inadvertently encountered on takeoff or landing.

,, ., w~J MAX HAZARD ZONE

Background Wind shear is best described as a change in wind direction and/or speed in a very short di'stance in the atmosphere.

Under certain conditions, the atmosphere is capable of producing some dramatic shears very close to the ground; for example, wind direction changes of 180 degrees and speed changes of 50 knots or more within 200 feet of the ground have been observed. It has been said that wind cannot affect an aircraft once it is flying except for drift and groundspeed. However, studie·s have shown that this is not true if the wind changes faster than the aircraft mass can be accelerated or decelerated.

The most prominent meteorological phenomena that cause significant low level wind shear problems are thunderstorms and certain frontal systems at or near the airport.

Meteorology Thunderstorms: The winds around a thunderstorm are complex (Figure 1). Wind shear can be found on all sides of a thunderstorm cell and in the downdraft directly under the cell.

The wind shit! line or gust front associated with thunderstorms can precede the actual storm by 15 nautical miles or more.

Consequently, if a thunderstorm is near an airport of intended takeoff or landing, low level wind shear hazards may exist.

Fronts: The winds can be significantly different in the two air masses which meet to form a front. While the direction of the winds above and below a front can be accurately determined, existing procedures do not provide precise, current measurements of the height of the front above the airport. The following ") Adapted from the FAA Advisory Circular

<'IGURE l.

THUNDERSTORM HAZARDZONES

is a method for determining the approximate height of the wind shear associated with a front.

(1) Wind shear occurs with a cold front just after the front pa·sses the airport and for a short period thereafter. If the front is moving 30 knots or more, the frontal surface will usually be 5,000 feet above the airport about three hours after the frontal passage.

(2) With a warm front, the most critical period is before the front passes the airport. Warm front shear may exist below 5,000 feet for approximately six hours. The problem ceases to exist after the front pas'Ses the airport. Data compiled on wind shear indicates that the amount of shear in warm fronts is much greater than that found in cold fronts.

(3) Turbulence may or may not exist in wind shear conditions. If the surface wind under the front is strong and gusty, there will be some turbulence associated with wind shear.

Strong Surface Winds: The combination of ·strong winds and ·small hills or large buildings that lie upwind of the approach or departure path can produce localized areas of shear. Observing the local terrain and requesting pilot reports of conditions near the runway are the best means for anticipating wind shear from this source. This type of shear can be particularly hazardous to light airplanes.

Sea Breeze Fronts: The presence of large bodies of water can create local airflows due to the differences in temperature 21

between the land and water. Changes in wind velocity and direction can occur in relatively short distances in the vicinity of airports situated near large lakes, bays or oceans.

Mountain Waves: These weather phenomena often create low level wind shear at airports that lie downwind of the wave.

Altocumulus standing lenticular (ACSL) clouds usually depict the presence of mountain waves, and they are clues that shear should be anticipated.

Detecting Wind Shear Airplanes may not be capable of safely penetrating all intensities of low level wind shear. Pilots as well as controllers should, therefore, learn to detect, predict, and avoid severe wind shear conditions. Severe wind shear does not strike without warning.

It can be detected by the following methods: a) Analyze the weather during preflight.

(1) If thunderstorms are observed forecast at or near the airport, be alert for the possibility of wind shear in the departure or arrival areas.

(2) Check the surface weather charts for frontal activity. Determine the surface temperature difference immediately across the front and the ·speed at which the front is moving. A 10° F [5° CJ or greater temperature differential, and/or frontal speed of 30 knots or more, is an indication of the possible existence of significant low level wind shear. b) Be aware of pilot reports (PIREPS) of wind shear. Airmen's Information Manuals recommend that pilots report any wind shear encounter to Air Traffic Control. This report should be in specific terms and include the loss/gain of airspeed due to the shear and the altitude(s) at which it was encountered. A simple report is extremely important so that the pilot of the next airplane in sequence can determine the safety of transiting the same location. Reporied shear that causes airspeed losses in exces·s of 15 to 20 knots should be avoided. Reported shears associated with a thunderstorm should also be avoided due to the speed which some storms move across the ground. The storm movement can cause one aircraft to encounter an airspeed increase which may appear harmless where the next aircraft can encounter a severe airspeed loss. c) Assume that severe wind shear is present when the following conditions exist in combination.

(1) Extreme variations in wind velocity and direction in a relatively short time span.

(2) Evidence of a gust front such as blowing dust on the airport surface.

(3) Surface temperature in excess of 80° F. (4) Dew point spread of 40° F or more.

(5) Virga (precipitation that falls from the bases of high altitude cumulus clouds but evaporates before reaching the ground). d) Use the airplane instruments to detect wind shear.

(1) Pilots flying airplanes equipped with inertial navigation system (INS) should compare the winds at the initial approach altitude (1500-2000' above ground level [AGL]) with the reported runway surface winds to see if there is a wind shear situation between the airplane and the runway.

(2) If frontal activity does exist, note the surface wind direction to detP.rmine the location of the front with respect to the airport. If the airplane will traverse the front, compare the surface wind direction and speed with the wind direction and speed above the fror,t to determine the potential wind shear during climbout or approach.

(3) Pilots flying airplanes equipped with a device which reads out groundspeed should compare the airplane··s groundspeed with its airspeed. Any rapid changes in the relationship between airspeed and groundspeed represents a wind shear. Some operators have adopted the procedure of not allowing their aircraft to slow below a precomputed minimum groundspeed on approach. The minimum is computed by subtracting the surface headwind component from the true airspeed on approach.

22

(4) Pilots flying airplanes which do not have INS or groundspeed readouts should closely monitor their airplane's performance when wind shear is suspected. When the rate of descent on an ILS approach differs from the nominal values for the aircraft, the pilot should beware of a potential wind shear situation.

Since rate of descent on the glide slope is directly related to groundspeed, a high descent rate would indicate a strong tailwind; conversely, a low descent rate denotes a strong headwind.

The power needed to hold the glide ·slope also will be different from typical, no-shear conditions. Less power than normal will be needed to maintain the glide slope when a tailwind is present and more power is needed for a strong headwind. Aircraft pitch attitude is also an important indicator. A pitch attitude which is higher than normal is a good indicator of a strong headwind and vice versa. By observing the aircraft's approach parameters - rate of descent, power, and pitch attitude - the pilot can obtain a feel for the wind he is encountering. Being aware of the wind-correction angle needed to keep the localizer needle centered provide's the pilot with an indication of wind direction.

Comparing wind direction and velocity at the initial phases of the approach with the reported surface winds provides an excellent clue to the presence of shear before the phenomenon is actually encountered. e) Utilize the Low Level Wind Shear Alert System (LLWSAS) at airports where it is available. LLWSAS consists of five or six anemometers around the periphery of the airport, which have their readouts automatically compared with the center field anemometer. If a wind vector difference of 15 knots or more exists between the center field anemometer and any peripheral anemometer, the tower controller will let the pilot know the winds from both locations. The pilot then may assess the potential for wind shear. An example of a severe wind shear alert would be the following: "Center field wind is 230 degrees at 7 knots; wind at the north end of Runway 35 is 180 degrees at 60 knots." In this case, a pilot departing on runway 35 would be taking off into an increasing tailwind condition that would result in significant losses of airspeed and, consequently, altitude.

Airplane Performance in Wind Shear The following information provides a basis for understanding the operational procedures recommended in this circular.

Power Compensation: Serious consequences may result on an approach when wind shear is encountered close to the ground after power adjustments have been already made to compensate for wind. Figures 2 and 3 illustrate the situations when power is applied or reduced to compensate for the change in aircraft performance cau·sed by wind shear.

(1) Consider an aircraft flying a 3° ILS on a stabilized approach at 140 knots indicated airspeed (IAS) with a 20-knot headwind. Assume that the aircraft encounters an instantaneous wind shear where the 20-knot headwind shears away completely. At that instant, several things will happen; the airspeed will drop from 140 to 120 knots, the nose will begin to pitch down, and

HEADWIND

TAILWIND OR CALM

FAILURE TO RESTABILIZE POWER AFTER

·,

INITIAL

ADDITION

! · ..

--·--· ----·-·-·-· / -~-

•'-....

INSUFFICIENT INITIAL POWER ADDITION

FIGURE 2.

**•

HEADWINDSHEARING TO TAILWIND OR CALM

HEADWIND OR CALM

f

r-

IAS AND PITCH INCREASE SINK RATE DECREASES

/

* 4f. if 1'

TAILWIND

INSUFFICIENT INITIAL POWER REDUCTION

/

* ~* /' --~ *

• **

\

FAILURE TO RESTA81LIZE/\ POWER AFTER INITIAL REDUCTION

FIGURE 3,

*

*,.*-•__

\

TAILWIND SHEARING TO HEADWIND OR CALM

the aircraft will begin to drop below the glide slope. The aircraft will then be both slow and low in a "power deficient" state. The pilot may then pull the nose up to a point even higher than before the shear in an effort to recapture the glide slope. This will aggravate the airspeed situation even further until the pilot advances the throttles and sufficient time elapses at the higher power setting for the engines lo replenish the power deficiency.

If the aircraft reaches the ground before the power deficiency is corrected, the landing will be short, slow, and hard. However, if there is ·sufficient time to regain the proper airspeed and glide slope before reaching the ground, then the "double reverse" problem arises. This is because the throttles are set too high for a stabilized approach in a no-wind condition. So, as soon as the power deficiency is replenished, the throttles should be pulled back even further than they were before the shear (because power required for a 3° ILS in no wind i•s less than for a 20-knot headwind). If the pilot does not quickly retard the throttles, the aircraft will soon have an excess of power; i. e., it will be high and fast and may not be able to stop in the available runway length (Figure 2).

(2) When on approach in a tailwind condition that shears into a calm wind or headwind, the reverse of the previous statements is true. Initially, the IAS and pitch will increase and the aircraft will balloon above the glide slope. Power should initially be reduced to correct this condition or the approach may be high and fast with a danger of overshooting. However, after the initial power reduction i"s made and the aircraft is back on speed and glide slope, the "double reverse" again comes into play. An appropriate power increase will be necessary to restabilize in the headwind. If this power increase is not accomplished promptly, a high sink rate can develop and the landing may be short and hard (Figure 3). The double reverse problem arises primarily in downcraft and frontal passage shears. Other shears may require a consistent correction throughout the shear.

(3) The classic thunderstorm "downburst cell" accident is illustrated in Figure 4. There is a strong downdraft in the center of the cell. There is often heavy rain in this vertical flow of air.

As the vertical air flow nears the ground it turns 90 degrees and

l Runwoy

FIGURE 4.

DOWNDRAFTSHEAR

becomes a strong horizontal wind, flowing radially outward from the center. Point A in Figure 4 represents an aircraft which has not entered the cell's flow field. The aircraft is on speed and on glide slope. At Point B the aircraft encounters an increasing headwind. Its airspeed increases, and it balloons above the glide slope. Heavy rain may begin shortly. At Point C the "moment of truth" occurs. If the pilot does not fully appreciate the situation, he may attempt to regain the glide slope and lose excess airspeed by reducing power and pushing the nose down.

Then in the short span of time between Points C and D the headwind ceases, a strong downdraft is entered and a tailwind begins increasing. The engines spool down, the airspeed drop·s below V,ef• and the sink rate becomes excessive. A missed approach initiated from this condition may not be successful. Note that a missed aµproach initiated at Point C (or sooner) would probably be successful ·since the aircraft is fast and high at this point.

Note also that the pilot of an aircraft equipped with a groundspeed readout would see the telltale signs of a downburst cell shortly after Point B; i. e., repidly increasing airspeed with decreasing groundspeed.

Angle of Attack in a Downdraft: Downdrafts of falling air in a thunderstorm (sometimes called a "downburst") have gained attention in the last few years due to their role in wind shear accidents. When an airplane flies into a downdraft, the relative wind shifts so as lo come down from above the horizon. This decreases angle of attack, which in turn decreases lift, and the airplane starts to sink rapidly. In order to regain the angle of attack necessary to support the weight of the airplane, the pitch attitude must be significantly increa·sed. Such a pitch attitude may seem uncomfortably high to a pilot. However, a normal pitch attitude will result in a continued sink rate. The wing produces lift based on angle of attack - not pitch attitude. Caution should be observed when a pilot has traversed a downdraft and has pitched up sufficiently to stop the sink rate. If that pilot does not lower the nose of the airplane quickly when it exits the downdraft, the angle of attack will become too large and may approach the stall angle of attack. For these reasons, a flight director which senses angle of attack will be preferable to a f!ight director which calls for a fixed pitch attitude in a downdraft.

However, even an angle of attack based flight director may become ineffective if it has an arbitrary pitch up command limit which is set too low (with respect to the downdraft).

Climb Performance: In the takeoff and landing configurations, jet transports climb best at speeds near V, and Vref (reference speed with landing flaps). respectively. Retracting gear and flaps will even further improve climb performance. However, jet transport airplane manufacturers have pointed out that their airplanes still have substantial climb performance (generally in excess of 1000 fpm) at speeds down to stall warning or stickshaker speed, Vss· Energy Trade: There are only two ways an aircraft can correct for a wind shear. There can be an energy trade or a thru·st change. Historically, most pilots have opted for a thrust change since they had no idea how much an energy trade would benefit thE:lm. Further information on the energy of flight, therefore, is warranted.

(1) The energy of motion (kinetic energy) is equal to 1/2 MV2 where M is the mass of the airplane and V is the velocity. Kinetic energy is directly convertible to energy of vertical displacement (potential energy). More simply put, airspeed can be traded for altitude or vice versa. It is important to note that adding 10 percent to the speed of the airplane results in a 21 percent increase in kinetic energy because of the velocity being squared. This, of course, explains the concern over stopping an aircraft on the available runway when additional speed is added. {2) The following table shows the altitude conversion capability of trading 10 or 20 knots of speed for altitude at various initial speeds. Independent of its mass, the capability of the aircraft to trade airspeed for altitude increa·ses as its initial speed increases.

23

Equivalent Equivalent 20 Knot Change 10 Knot Change From - To Altitude, Ft. Altitude, Ft. From - To 247 150-130 150-140 128 230 140-130 119 140-120 212 130-120 111 130-110 120-110 120-100 195 102 110- 90 177 110-100 93 Trading Altitude for Speed: A pilot caught in low level wind shear who finds he is slower than the normal airspeed (even though he has gone to max. power) could lower the nose and regain speed by trading away altitude. (This is trading potential energy for kinetic energy.) However, data shows that the penalty for doing this is severe; i. e., a large sink rate is built up and a great deal of altitude is lost for a relatively small increase in airspeed. Therefore, at low altitudes this alternative becomes undesirable. It is preferable to maintain the lower airspeed and rely on the airplane's climb performance at these lower speeds than to push the no·se over and risk ground contact. Flight directors which attempt to maintain a given speed (such as V2 + 10, etc.) will automatically call for trading altitude for airspeed if the airplane is below the proper airspeed. Cases have been observed in simulators where following such a flight director will result in the pilot flying the airplane into the ground.

It is the pilot - not the flight director - who should decide if trading altitude for speeds is desirable.

Trading Speed for Altitude: Conversely, a pilot caught in low level wind shear may pull the nose up and trade speed for altitude; i. e., trade kinetic energy for potential energy. If the speed is above V, or V,ef (as applicable), then this trade may well be desirable. If at or below V, or V,ef• such a trade should be attempted only in extreme circumstances. In doing so, the pilot is achieving a temporary increase in climb performance.

After he has traded away all the airspeed he desires to trade, he will then be left with a permanent decrease in climb periormance. In addition, if ground contact is still inevitable after the trade, there may be no airspeed margin left with which to f!are in order to soften the impact. Wind shear simulations have shown, however, that in many cases trading airspeed for altitude (down to V 55 ) prevented an accident, whereas maintaining V,ef resulted in ground impact.

Adding Speed for Wind Shear: The possibility of having to trade speed for altitude in wind shear makes it attractive to carry a great deal of extra speed. However, on landing, if the airspeed margin is not used up in the shear and the airplane touches down at an excessive speed, the airplane may not be able to stop on the available runway. It is generally agreed that if a speed margin in excess of 20 knots above V, 01 appears to be required, the approach should not be attempted or continued.

Difficulties of Flying Near V55 : Above we stated that in simulations, wind shear "accidents" had been prevented by trading speed for altitude all the way down to V55 . There are difficulties associated with flying at or near V55 which should be recognized. These include: (1) The pilot often does not know V,,.

(2) The stickshaker mechanism may be miscalibrated (especially on older aircraft).

(3) The downdraft velocity may vary, which requires a change in pitch attitude to hold speed.

(4) It is hard to fly a precise airspeed in turbulence, which is often associated with wind ·shear.

(5) Turbulence might abruptly decrease the airspeed from v,, to v,.

(6) Pilots have historically had little training in maintaining flight at or near V,,.

Procedures for Coping with Wind Shear The most important elements for the flightcrew in coping with a wind shear environment are the crew's awareness of an impending wind shear encounter and the crew's decision to avoid an encounter or to immediately respond if an encounter occurs.

24

Takeoff: If wind shear is expected on takeoff, the PIREPS and weather should be evaluated to determine if the phenomena can be safely traversed within the capability of the airplane. This is a judgment on the part of the pilot based on many factors.

Wind shear is not something to be avoided at all costs, but rather to be assessed and avoided if severe. Some rules of thumb for coping with wind shear on takeoff follow: (1) An increasing headwind or decreasing tailwind will cause an increase in indicated airspeed. If the wind shear is great enough, the aircraft will initially pitch up due to the increase in lift. The pilot should not trim the airplane at the initial high pitch attitude. After encountering the shear, if the wind remains constant, aircraft groundspeed will gradually decrease and indicated airspeed will return to its original value. This situation would normally lead to increased aircraft performance so it should not cause a problem if the pilot is aware of how this shear affects the aircraft.

(2) The worst situation on departure occurs when the aircraft encounters a rapidly increasing tailwind, decreasing headwind, an/or downdraft. Taking off under these circumstances would lead to a decreased performance condition. An increasing tailwind or decreasing headwind, when encountered, will cause a decrease in indicated airspeed. The aircraft will initially pitch down to the decreased lift in proportion to the airspeed los·s.

After encountering the shear, if the wind remains constant, aircraft groundspeed will gradually increase and indicated airspeed will return to its original value.

(3) When the presence of severe wind shear is suspected for departure, the pilot should delay takeoff until conditions are more favorable.

(4) If the pilot judges the takeoff wind shear condition to be safe for departure, he should select the safest runway available considering runway length, wind directions, speed, and location of storm areas or frontal areas. He should execute a maximum power takeoff using the minimum acceptable flap position. After rotation, the pilot should maintain an airplane body angle which will result in an acceleration to V,+25. This speed and takeoff flaps should be held through 1,000 feet AGL. Above 1,000 feet the normal noise abatement profile should be flown. If preflight planning shows that the airplane is runway length limited, or obstruction clearance is a problem, taking off into even a light shear using the V2+25 procedure should not be attempted. This is because too much of the thrust available for climb is used for acceleration, resulting in the V,+25 flight path falling below the engine-out flight path at V,. This would give insufficient clearance for an obstacle in close proximity to the departure end of the runway.

(5) If severe wind shear is encountered on takeoff, the pilot should immediately confirm that maximum rated thrust i's applied and trade the airspeed above V2 (if any) for an increased rate of climb. Depending on the airplanes' gross weight, pitch attitudes of 15 to 22 degrees are to be expected during this energy trade, especially if a downdraft is present. A sudden decrease in headwind will cause a loss in airspeed equal to the amount of wind shear. At this point, the pilot should quickly evaluate his airplane's performance in the shear. He/she should monitor airspeed and vertical velocity to ensure that an excessive rate of descent does not develop. If it becomes apparent that an unacceptable rate of descent cannot be prevented at V, speed or ground contact appears to be certain at the current descent rate, the pilot should gradually increase the airplane's pitch attitude to temporarily trade airspeed for climb capability to prevent further altitude loss. The trade should be terminated when stickshaker is encountered. The airplane should be held in an attitude that will maintain an airspeed just above the airspeed where the stickshaker was initially encountered. A general rule is to reduce pitch attitude very slightly when stickshaker is encountered.

Further pitch reduction in the shear could result in a large descent rate. As the airplane departs the shear, the pilot should reduce the pitch attitude and establish a normal climb. In several

recent wind shear accidents, the National Transportation Safety Board (NTSB) has found that the full performance capability of the airplane was not used following a severe wind shear encounter. Post accident studie's have shown that, under similar circumstances, had flight techniques of an emergency nature (such as tnose outlined above) been used immediately, the airplane could have remained airborne and the accident averted.

Approach to Landing: Considerations involved in flying an approach and landing or go-around at an airport where wind shear is a factor are similar to those discu·ssed for takeoff.

(1) When wind shear weather analysi's, PIREPS, or an analysis of airplane performance indicates that a loss of airspeed will be experienced on an approach, the pilot should add to the V,ef speed as much airspeed as he expects to lose up to a maximum of V,e1+20. If the expected loss of airspeed exeeds 20 knots the approach should not be attempted unless the airplane is specially instrumented and the pilots are specially trained. The pilot should fly a stabilized approach on a normal glidepath (using an electronic glidepath and the autopilot when available). In the shear when airspeed loss is encountered, a prompt and vigorous application of thrust is essential, keeping in mind that if airspeed has been previously added for the approach, the thrust application should be aimed at preventing airspeed los·s below V,ef· An equally prompt and vigorous reduction in thrust is necessary once the shear has been traversed and normal target speed and glidepath are reestablished to prevent exceeding desired values. Early recognition of the need for thrust is essential. Along with the thru·st addition is a need for a noseup rotation to minimize departure below the glidepath. If the airplane is below 500 feet AGL and the approach becomes unstable, a go-around should be initiated immediately. Airspeed fluctations, sink rate, and glide slope deviation should be assessed as part of this decision.

(2) A pilot's chances of safely negotiating wind 'shear are better if heishe remains on instruments. Visual references through a rain-splattered windshield and reduced visibility may be inadequate to provide him/her with cues that would indicate deviation from the desired flightpath. At least one pilot should, therefore, maintain a continuous instrument scan until a safe landing is assured.

(3) Some autothrottle systems may not effectively respond to airspeed changes in a shear. Accordingly, the thrust should be monitored closely if autothrottles are used. Pilots should be alert to override the autothrottles if the response to increased thrust commands is too slow. Conversely, thrust levels should not be allowed to get too low during the late stages of an approach as thi's will increase the time needed to accelerate the engines.

(4) Should a go-around be required the pilot should initiate a normal go-around procedure, evalute the performance of his airplane in the shear, and follow the procedures outlined in the takeoff section of this article as applicable.

Summary Tne following summarizes the critical steps in coping with low level wind shear.

Be Prepared: Use all available forecasts and current weather information to anticipate wind shear. Al"so, make your own observations of thunderstorms, gust fronts and telltale indicators of wind direction and velocity available to pilots.

Giving and Requesting PIREPS on wind shear are essential.

Request them and report anything you encounter. PIREPS should include: (1) Location of shear encounter.

(2 Altitude of shear encounter.

(3) Airspeed changes experienced, with a clear statement of: ( i) the number of knots involved; (ii) whether it was a gain or a loss of airspeed.

(4) Type of aircraft encountering the shear.

Avoid Known Areas of Severe Shear: When the weather and pilot reports indicate that ·severe wind shear is likely, delay your takeoff or approach.

Know Your Aircraft: Monitor the aircraft's power and flight parameters to detect the onset of a shear encounter. Know the performance limits of your particular aircraft so that they can be called upon in such an emergency situation.

Act Promptly: Do not allow a high sink rate to develop when attempting to recapture a glide slope or to maintain a given airspeed. When it appears that a shear encounter will result in a substantial rate of descent, promptly apply full power and arrest the descent with a no'seup pitch attitude.

■

New Takeoff Clearance System The FAA's National Aviation Facilities Experimental Center (NAFEC) started a six-month feasibility demonstration on September 18 at Bradley International Airport, Windsor Locks, Conn., of a new experimental runway traffic light system designed to give airplanes about to take off added protection from collisions with other aircraft.

The national test center, together with FAA's New England Region, has installed the new system at Bradley International as part of a research and development effort by the Federal Aviation Administration to devise further safety measures that might be needed to prevent airport runway accidents. Commercial and military pilots using Bradley have pledged to cooperate with the evaluation, and the FAA is currently seeking participation by private pilots.

At present, controllers in airport towers direct runway traffic by radio contact with aircraft on the ground. The new, experimental system would be a visual confirmation through green lights of their verbal clearance to take off. It would be the first use of such traffic lights at a regular airport in the nation.

NAFEC Acting Director Joseph M. Del Balzo said the reactions of both pilots and controllers to the Bradley tests would be vital in determining, not only the acceptance of the new traffic lights, but the scope and dimension any such system should take in the future.

The Visual Confirmation of Voice Takeoff Clearance System, dubbed VICON for short, is designed to prevent aircraft collisions on the ground such as the one that occurred March 22, 1977, when two Boeing 747s collided at the airport on Tenerife Island, killing more than 570 people. The probable cause has been attributed to a verbal misunderstanding of takeoff clearance.

The new system consists of clusters of three, pulsing, green lights located at all takeoff positions along the left side of runways. Mounted on 14-inch high, frangible tubes, one or more of the lights will always be visible to pilots of aircraft on the runway or on a taxiway approaching the runway.

Here's how the system works: When a controller clears a pilot for takeoff, he will push a button on an airport tower control panel that will turn on the appropriate lights. If the pilot, awaiting takeoff, does not see the lights, he is expected to check back with the controller.

In some positions the lights will be turned off a·s the departing aircraft breaks an electronic beam across the runway. The remaining lights will be turned off by timers after approximately 30 seconds. The timing can be adjusted as desired to meet different traffic conditions.

NAFEC designed, developed and fabricated the new system.

It also conducted initial testing at the NAFEC/Atlantic City Airport, which is located within the 5,000-acre experimental center, 10 miles northwest of Atlantic City. The Operational evaluation at Bradley International is being done by NAFEC for the FAA's Air Traffic Service.

In the forthcoming evaluation, FAA will ask participating pilots to fill out pre-addressed, postage-paid questionnaires. They will be available from the Bradley Flight Service Station and from fixed base operators at Bradley and nearby airports. They also should be available at airline dispatch offices, or can be obtained by writing Project Office (VICON), ANA-210, FAAINAFEC, Atlantic City, N.J. 08405.

FAA News 25

AVIATION LAW:

Legal Liability of the Controller

by E. McCluskey

Part 2 In addition to any criminal or penal liability resulting from the very fact of an accident as opposed to liability for a deliberate act the controller is faced with a possible civil liability. Civil liability may result from a tort as opposed to a "crime". The tort which would affect the controller most is the tort of negligence. The tort of negligence carries no legal or moral stigma.

A tort is a breach of the legal duty placed on everyone to take care and the breach results in damage undesired by the defendant to the plaintiff. In certain situation·s a person may be liable for the acts of another, even though he himself is not at fault. The commonest example is the liability of an employer for the torts of his servant ii committed in the course of the servant's employment. This liability may arise because the employer himself owes a duty to the plaintiff but this is not always the case for if a servant drives negligently in some countries it is presumed a breach of an implied undertaking in the contract of service to use reasonable care. A servant is a person whose work is subject to the control of another in the way the work has to be done. An act done in the course of a servant's employment is so considered if it is of a class of act which he is expressly or impliedly authorised to do. It makes no difference that the method employed was unauthorised or forbidden or that the act was done negligently or for the servant's own fraudulent purposes.

If however the act is done quite outside the servant's duties the employer is not liable.

Thi's doss not mean as we shall see that the controller can act negligently and just let the employer take the blame. The controller is in all cases also liable for his actions or lack of them. But because the controller like most other servants is likely to be a man of straw unable ever to face enormous damages awarded it is in the interests of the plaintiff to attack the employer first.

The Socialist System Wherea·s the employer might be held liable to pay damages under the Socialist system, the law is quite explicit that the controller is liable under the civil law if any prejudice to the enterprise results from his actions and he is required to make good the damage. This means in effect that the plaintiff will receive damages from the employer and the controller would then be attacked in justice by the employer to recover the damages awarded. Even if he still remained a controller this would be a financial millstone round his neck until his death. Again it is seen that in addition to a statutory penal liability in fact the controller has statutory civil liability. In both fields he is the worst placed of all controllers so that an international limit of liability and international indemnity is most needed in the socialist countries.

International Organisations In reply to the ILO Eurocontrol pointed out that the Organisation assume·s responsibility for damage caused to third parties and is answerable for faults committed by controllers in the 26

performance of their duties. However a controller may be called on to make good all or part of the prejudice suffered by Eurocontrol if he has committed a serious personal fault. Controllers working for international organisations also must be covered by any international protection provided which would either mean the member states of such organi'sations adding a protocol to the conventions setting up the organisations or permitting the organisations to adhere to any convention limiting controllers' liability in the same way as States. In the interests of standardisation the second method is to be preferred.

The Roman Law States As with penal law, the basi's of civil law is the same in all Roman Law States. Nevertheless some States apply the law more leniently than others. Basically if the controller is a civil servant, he should find himself subject to a case law system which tends to be favourable to civil ·servants. There is little interest in suing a controller for damages because he would be unlikely to be able to pay them. Thu·s lawyers would tend to advise plaintiffs to sue the employer. This is the practical side of the question. In Roman Law there is a fundamental distinction called the "separation of powers." The judge has no right to make an evaluation or asses·sment on the working of the Public Service. As soon as a judge in a civil court is faced with this evaluation his authority is superseded by that of the administrative judge. The Civil Servant is not liable with regard to tort committed during the performance of his duty. So financial liability is not an important worry for the controller working under a Roman Law system. If however some personal offence were proved the State could nevertheless turn to the controller for reimbursement of what damages were awarded against the State. This would be the same mill-stone as in the Socialist countries. A personal offence might be something like making a private telephone call and not watching the radar screen. This is known in some Roman Law countries as "grave fault" or in others there must be an amount of "wilful damage" or "gross negligence" before a ca'se would be brought against a controller.

If the controller carries out his work conscientiously and to the best of his ability he runs little real risk of being held liable under civil law. The one main exception to this idea in the Roman Law States in Scotland whose laws have long been influenced by Acts of Parliament based on AngloSaxon ideas.

The Anglo-Saxon System Here again there is variation from State to State. In Canada there i's a fixed maximum limitation of liability. However in some States there is a problem in that the controller may find himself in court anyway. The only way to sue the State is through one of its servants. As in the case of criminal proceedings in the Anglo-Saxon systems there is a great protection in that the burden of proof is on the plaintiff. To sue a controller for negli-

gence it must be proved that he was "under a duty of care" to the plaintiff, that there was a "breach of that duty" and that as a result "the plaintiff suffered damage."

The duty of care means that you must take reasonable care to avoid acts or omissions which you can reasonably foresee would be likely to injure your neighbour. Neighbour in this sense means persons who are so closely and directly affected by your act that you ought rea·sonably to have them in contemplation as being so affected when you are directing your mind to the acts or omissions which are called in question. Generally speaking the standard of care is that of the ordinary prudent man however if a person has set himself up as having particular skill he must exhibit as much skill as is usually found in such persons.

The burden of proof is normally on the party alleging negligence. However the onus is on the defendant when the accident tells its own story, (Res ipse loquitur). The accident must be such as could not in the ordinary course of things have happened without negligence. The facts do not speak for themselve·s where there is an explanation. To take a hypothetical case, a radar controller in controlled airspace gives essential traffic information on traffic one mile ahead and an accident occurs. If both aircraft were under his control there is "res ipse loquitor." If the traffic is explained a·s an unknown aircraft suddenly appearing in radar cover there is no "res ipse loquitor." Under common law the employer, in most cases the State, must take reasonable care to provide competent staff, adequate equipment, a safe place of work and a safe system of working. Failure on the employers part to provide the above renders him jointly liable.

The whole law of tort depends on the burden of proof and then if the case is proved on a number of defence·s in order to reduce dc:mages awarded. One of these is contributory negligence on the part of the plaintiff - in the case of a controller this would be likely to be the pilot or the airline company. Damage must not be too remote and here the judge decides what is remote.

In English Law this is by no means settled and until a judge decides to follow the New Zealand procedure and a ruling is given in the House of Lords fine di'stinctions will continue. Other Anglo-Saxon systems particularly in the British Commonwealth follow New Zealand on this question. Two cases show the difference. In Re Polemis and Furness Withy and Co 1921 stevedores negligently dropped a plank down the hold of a ship. The hold was full of petrol vapour. A spark ignited it and the ·ship was destroyed by fire. It was held that there was liability for the entire loss. In the New Zealand case of the Overseas Tankship (UK)Ltd v Morts Dock and Engineering Co Ltd (The Wagon Mound) 1961, owing to a servant's negligence furnace oil escaped from the defendants' vessel, floated on the water and was carried by wind and tide to a wharf. It was ignited by a piece of smouldering cotton waste and the wharf was severely damaged by fire. It was held that the defendants were not liable as they did not know and could not be reasonably expected to have known that the furnace oil was capable of ignition when spread on water.

There is still inference in the UK that a man intends the natural and necessary consequences of his conduct. Here is an impor:ant point which IFATCA seek's to resolve for controllers under AngloSaxon systems and particularly where damages be unlimited, in requiring a fixed maximum sum probably based on a fixed maximum percentage of salary to avoid any possibility of the extremes of financial hardship.

Hypothetical Case Let us take the hypothetical case of an aircraft accident in which one person is severely injured. If the controller were proved negligent, (remember we are talking of civil negligence), it is fairly certain that damages would be assessed on the injury, but what of the shock caused by the announcement of the news on the injured person's wife? Perhaps she has a weak heart. Perhaps she sees the accident. Perhaps the injured person suffers from haemophilia. Generally the judge must rule as to what the

reasonable man could foresee and the brilliant man is not penalised for foreseeing more than the average man.

Judgements of this nature, though, do vary from State to State and we can compare the case where a lorry ran away down a street. A woman saw it and was terrified for the safety of her children who had just turned round a bend in the road. She was told that a child was injured, suffered shock and died. The defendants were held liable but the Court limited this liability to persons in the vicinity of the accident. Compare this to exactly the same circumstances in another country where the defendants were held not to be liable. As case law is followed in AngloSaxon countries as precedent it can be seen that the amount of liability is quite often a matter of chance.

Another defence in Anglo-Saxon Law is inevitable accident which would possibly cover the case of a radar controller knowing of thunderstorm activity, but not seeing anything of it on his screen, turning an aircraft into a storm area with resultant damage to the aircraft. A further defence is "volenti non fit iniuria., (to the willing person injury is not done). In this case the pilot might opt to continue towards the storm area knowing of the danger and the controller could not be held liable, but he could be liable if he had let his separation run so low that there was no alternative for the pilot but to turn or hit another aircraft.

What is ihe duty laid on the controller in the Anglo-Saxon system? He must take reasonable care to avoid acts or omissions which he can reasonably see would be likely to injure person·s who are closely affected by his acts and he should reasonably have them in mind at the time of the act. Briefly this means all persons in aircraft under his control and all persons likely to wander on to airfields or cross runways with or without permission.

A learner driver need only show the skill of a reasonable learner driver. This applies equally to trainee controllers at all stages of training. However an expert must show the skill of a reasonable expert. An expert i"s liable for negligent misstatement even in the absence of a contractual or fiduciary relationship. Let us suppose that a controller calculates the Atlantic crossing time negligently and issues this time to a rerouted aircraft. Shortage of fuel at the end of the flight might give rise to a cae of negligence. But the controller is dealing with other experts who shculd check the time and the fuel at an early ·stage of the flight. There is also another expert on the ground who should calculate fuel in case of reroute and there are the legal requirements to arrive at destination with enough fuel to divert.

We talked of remoteness of damage. Damage may be considered too remote if the chain of causation is interrupted by an extraneous act if the type of intervention was not such as was likely to be occasioned by the tort itself. Thus a controller releases an aircraft negligently by saying "released on contact."

He then does not answer a position report prior to the boundary report. It is natural that the pilot calls the next centre. Here there is no case of "novus act us interveniens." But a hi-jack is a very definite case of intervention.

Controllers in the Anglo-Saxon systems do have some protection in that a case involving injuries should normally be brought within three years and in any case all cases should normally be brought not later than six years after the tort was committed.

There is still the possibility of the employer taking a case to recover damages from the controller. It is IFATCA policy to try to include such cases arso in the internationally agreed limitation.

Nevertheless where States such as Canada have already come up with satisfactory limits we do not wish such advantage to be lost so that we must proceed as with the precedent for airline liability in that States may give further indemnity but not apply further liability.

Unlike the Roman Law States there is no definite Administrative Law in the Anglo-Saxon countries and most Ministries tend to have an ad hoe disciplinary system. Here again tr.e controller is in need of international protection. Whereas in the Roman Law system the civil judge must stop short "at the door of the ad27

ministration," allowing the administrative judge then to take over, that is to say that disciplinary action if any follows the civil action, in the Anglo-Saxon system Ministrie·s are often quick to blame with the result that by the time a case comes to court a controller may already be known to have been sanctioned by his "poers." This can influence the court and is most certainly likely to happen if the Ministry hires full defence counsel for itself and neither the Ministry nor a union nor association will help the controller with his defence. It mu·st be underlined that controllers in many Anglo-Saxon system countries are paid above the limit for legal aid.

So international agreement is also required that in every case the controller is suspended from duty on full pay pending the results of the civil court case if a civil court case is likely and only afterwards should any disciplinary action be taken.

Military Liability We have already seen that military personnel may claim immunity in many countries simply because they are on duty. Their employers whether military or not 'should not be immune from

liability in the case of accident especially where civil aircraft are being controlled by military personnel. Even if this means requiring the military controller to face the same limited liability as the civil controller in order to be able to get the military authority into court this would seem also a necessary part of an international agreement on controller liability as it is in the interests of the flying public.

Hi-jackers In addition to possible criminal liability to circumnavigate the problem·s of political cases it could be interesting to transfer civil liability to hi-jackers and to add severe prison sentences for those unable or unwilling to pay. Failure to pay can in many countries be considered contempt of court and thus a prison sentence could be applied for a non-political reason. This idea might be worth developing.

We will leave to part three of this article the problem of interpretation of the Law to apply in view of the controller's unique position under several legal systems. We will look al'so at where the court case takes place and its consequences across national boundaries.

■

U.S. Army Air Traffic Controllers The following is a brief on the USA Army Air Traffic Controller given by Jan Welch of U.S. Army Communications and published in the U.S. Army Aviation Digest. Controllers' responsibilities and problems are no different whether these be military or civilians.

EXACTLY WHAT and who is this Army air traffic control person? Ask a dozen people and you will probably get that many answers - similar perhaps - but different. To the civil aviator flying visual flight rules, stuck on top of the clouds or lugging around in marginal VFR conditions somewhere in east Texas, that calm voice on the radio saying "two-one whiskey, radar contact one six miles southeast of airport, turn right heding 350," rates somewhere between mother and God. On the other hand, to the impatient pilot thinking of the miles to go before dark, that same voice saying, "Army 1234 hold present position," is nothing but a dictator.

An objective look at the Army air traffic controller reveals a highly trained professional, whose job routinely requires instant decisions.

Lives and property depend on each decision being correct the first time. There are few second-thought option's in the real ATC world.

Exactly how is an Army air traffic controller created?

The first requirement is a high (105 or better) mental aptitude score. The second is the ability to meet the stringent requirements of a Class II flight physical.

When these two crucial checkpoints are pas·sed, the third step is an intensive 16-week radar and 13-week tower training course at the U.S. Army ATC School, Ft. Rucker, AL. The course of training at the school i's a total immersion package designed to teach everything from how to do it, to how to say it. The common subjects portion of the instruction covers the whole air traffic control spectrum from the viewpoint of both controller and pilot. Some of the more significant areas covered include ATC procedures, FAA rules and regulations, airspace, aviation weather, phraseology and NAVAIDS operation.

The academic instruction is largely self-paced with sound and slide programed text. The usual ratio is 1 instructor for 10 academic students and 1 instructor for 2 practical application students.

Classroom instruction is reinforced with laboratory exercises designed to create a realistic environment for the student. The laboratory equipment looks just like that in general use in Army ATC facilities. Computer-generated problems are solved by the students.

28

Academic and laboratory standards are very high. An overall score of 90 percent is the most common standard applied on the pretest for any block of instruction. Under normal conditions only one phase back for any block of instruction is permitted.

Only after these standards are met is the ·student tested and moved on to the next phase of training. Even after graduation from A TC school, the controller still is not ready to tell aviators what to do.

The new graduate only has a license to continue learning and the chance to complete the fourth and final step to become an air traffic controller.

On assignment to the first facility after graduation, the potential controller finds a real world training situation with even more exacting standards.

Controllers assigned to a tower must complete a minimum of 6 months in training. Then they may be eligible for facility rating test and the issuance of that all-important control tower operator certificate that allows them to control traffic without supervision.

Controllers assigned to the radar environment find themselves with equally stringent training requirements but slightly different time limits.

The Army radar approach controller is allowed 1 year of training time because of the difficulty of the operation. Assignment to a ground controlled approach function allows for a 3-month training period.

The reasons for these exacting standards for Army air traffic controllers are simple. Safety of flight is the paramount one.

Army air traffic control operates largely within the National Airspace System, subject to Federal Aviation Administration standards.

However, under tactical deployment conditions some of the time requirements may be modified to meet operational needs.

If it sounds as though becoming an Army air traffic controller is difficult, it is. It is a challenging, demanding profession in which only the best and most highly motivated Soldiers can endure.

So the next time one of you Army aviators communicaties with an Army air traffic controller, rest assured that you are talking to another professional.

■

On the ICAO Scene: 'Wiiiiiiiiiii ~

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ADISP

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Automated Data Interchange Systems Panel

by Michael Andreou ADISP Member (Cyprus) The ADIS Panel was established on the 2nd of November, 1967 by the ANG (Air Navigation Commission) with Terms of Reference which were later expanded - on the 11th of June 1970 - to cover the interface with telecommunication systems operating at low modulation rates. On the 8th of November 1977 the ANG agreed to revise the Terms of Reference of the Panel to remove the restrictions which had existed in respect of low modulation rates. The amended Terms of Reference of the ADIS Panel are: "To undertake studies as approved by the Air Navigation Commission, related to the technical aspects of Data Interchange in the AFS (Aeronautical Fixed Service) and AMS (Aeronautical Mobile Service) with the object of making recommendations for appropriate Standards, Recommended Practises, Procedures and guidance material."

The ANG at the same time also agreed to add to the Panel's work programme the resolution of recognised problems encountered world wide on the AFS as listed with ASPENN / 3 (Aeronautical Fixed Service Planning Europe North American North Atlantic) - Recommendation No 72 and any others as might subsequently be referred to the Panel by the ANG. In giving the Panel the new mandate and in adding the resolution of current problems of the AFTN to the Panel's work programme to ANG at the abov~ date agreed to expand the membership of the Panel from thirteen to ·sixteen states.

The ADIS Panel develops SARPS (Standard And Recommended Practices) and guidance material required to introduce medium and high modulation rates into the AFTN (Aeronautical Fixed Telecommunication Network) to enhance its capability and capacity beyond that allowed by the low modulation rate system.

The new centre is to be called CIDIN (Common ICAO Date Interchange Network). The Panel deals also with the current problems of the AFTN. The highly technical material being developed by the ADIS Panel is then presented to ANG for final approval.

Eight Panel meetings were held until now, all at ICAO Headquarters (Montreal). The eighth meeting (ADISP/8) took place in June, 1979. The following thirteen states were represented at this meeting (three did not turn up).

1) Australia (Member + One Advi'ser) 2) Belgium (Member) 3) Canada (Member + three Advisers) 4) Chile (Member) 5) Cyprus (Member) 6) France (Member + one Adviser 7) Germany (Member + four Advisers) 8) Netherlands (Member + one Adviser) 9) Spain (Member) 10) Soviet Union (Member+ three Advisers) 11) United Kingdom (Member + two Advisers) 12) United States (Member+ three Advisers) 13) I.A.TA (Member + one Adviser) The work conducted by the Panel at its Eighth Meeting in accordance with the following Agenda, approved by the Air Navigation Commis"sion. The discussions were conducted in English, French, Russian and Spanish, (The Report was issued in English, French and Russian).

1) Development of SARPS or guidance material for the Common !CAO Data Interchange Network (CIDIN).

2) Consideration of the problems associated with the interface of CIDIN with other automated systems and development of any neces·sary solution.

3) Development and consolidation of guidance material on the engineering and planning of the AFTN. 4) Consideration of current problems of the low speed AFTN and development of any necessary solutions.

5) Updating and revision of Annex 10 pertaining to the AFTN. The Panel noted the various items requiring consideration that were identified during the meeting as well as those items of the former work programme that still remained to be completed.

Two working Groups were formed to deal with all those items.

Working Group 1 would carry out the development of CIDIN associated with the finalization of the management structure, interface of CIDIN with Public Data Networks and development of the request/reply data base management systems. Working Group 2 would handle the rest including the study of message prioritie's and any new tasks relating to the AFTN that may be assigned to the Panel. During the Eighth Meeting a very important aspect of the Panel's work concerned the interface to other networks and the use of common carrier channels. The Panel had noted several factors of availability cost and possible introduction of volume based tariffs on common carrier services at previou·s meetings and it had been evident that the recent work on X.25/X.75' Standards by the CCITT (International Telegraph and Telephone Consultative Committee) as well as standardization by the International Organization for Standardization (ISO) may have a major impact on CIDIN in some states. The rapid development and application of multiple access protocols for packet switched networks by the carriers means that both alternate and sometimes primary circuits of the new AFTN could be over the'se called virtual circuits. Satellite channels provided a case in point where in some parts of the world a full time leased circuit could not be justified but the leasing of a virtual circuit from a carrier could be the best means of significantly upgrading the AFTN. The ADIS Panel has invested a great deal of time in developing a CIDIN concept which is well defined but subject to further refinement. It would be necessary to develop a similar concept

Michael Andreou

29

if the X.25/X.75 protocol were adopted for the AFTN. However once such a concept was developed it would be relatively quicker and easier to eliminate faults in the X.25/X.75 protocol as the number of users would be far larger than those that would use a protocol peculiar to the AFTN. The Panel did not come to a definite conclusion as to which direction should they follow at this moment (CIDIN - X.25/X.75) but at ADISP/9 (October 1980) decision must be taken and SARPS to be prepared. SARPS also should be prepared for the following items: a) Optional Heading Field (Additional information such as message type etc.) b) Code Conversion (from ITA2 to IA5 and vice versa). c) Priorities (reduce the number of priority levels). d) Extended Address (Expanding the line of addressing from single line to three lines) e) Long messages (The length of each message to be increased).

By the time of publication of this article, little progress has been made on the above items becau·se there was only one Group meeting since ADISP/8. Another two Group meetings are planned before ADISP/9.

1) Recommendations X.25/X.75 (CCITT) 2) ASPEN/3 Recommendation No. 7 In the course of the meeting a number of problems on the current AFS needing rapid resolution were brought to its attention. These required study as follows. (i) Drafting of low speed ITA-2 controlled circuit protocols for potential optional application to enhance AFTN circuit and message as·surance. (ii) Consideration of possible application of an incoming message acknowledgement procedure, as an option, to low speed ITA-2 circuits of the AFTN. (iii) Review of the continued need for message numbering as a mandatory requirement on low speed ITA-2 AFTN circuits (relates to items (1) and (2) above). (iv) Review existing Annex 10 AFTN provisions and actual present practices applicable to message servicing procedures, with a view to developing improvements including standardization of service message format and phraseology, and definition of the conditions on which generation of service messages are based. (v) Review of existing AFTN message rejection practices with a view to developing guidance applicable to responsibilities for message protection and associated servicing procedures. (vi) Review of and potential improvement of ITA-2 and ICAO-7 AFTN message format and procedures, with a view to: a) expanding the addressing limitation beyond a single line, by providing for a discrete end-of-address signal. b) providing a discrete end-of-text signal. c) providing for address stripping (optionally), so as to limit addresses to those appropriate to the outgoing circuit concerned.

*

ICAO Conference Reviews Current Issues in Air Transport ICAO's second world-wide Air Transport Conference ended three weeks of debate with variou·s recommendations which stressed the need for multilateral solutions on urgent economic problems. The Conference (held from 12 to 28 February) was attended by some 400 delegates from 102 States and nine international organizations.

The Conference provided an opportunity for governments to take stock of current issues in international air transport on the basis of concIu·sions of two panels of experts which have been working since the first Air Transport Conference in April 1977.

In reviewing recent developments on the regulation of aircraft 30

capacity on international routes and the establishment of international fares and rates, the Conference was confronted with the positions of the USA and some other States for a more liberal market and those of many governments for a firmly regulated international market.

The Conference also came at a time of increasing concern over the economic outlook for international airline·s in the face of rising costs, particularly for fuel. In this connection, the Conference made three recommendations - one expressing the need for close attention to the effects of rising fuel prices on airline costs and tariffs, and another urging consultations among States on fuel price stability, fuel availability and conservation.

The Conference also recommended that State's should, as far as possible, ensure adequate fuel supply for approved operations on a non-discriminatory basis at prices current in their respective national markets.

After considerable debate on current capacity regulation practices, the Conference approved for the consideration of States in their bilateral negotiations, a model "pre-determination" clause (in which the governments establi.sh capacity according to market requirements), and referred for further study by the appropriate ICAO Panel the two more liberal-type model clauses known as "free-determination method" (in which capacity is largely left. for the airlines alone to establish in relation to the market forces) and the "Bermuda I type method" (in which airlines determine capacity on the basis of market requirements subject to ex-post facto review by governments).

Eearlier, the Conference after examining a Panel's report on guidelines to distinguish competitive scheduled and non-scheduled services confirmed the Panel's view that the ICAO Council's definition of "a scheduled international air service" did not require revision since it was sufficiently flexible to permit States to classify so-called "programmed charters" a·s scheduled flights subject to the same regulations.

On the subject of international fares and rates, the discussions of the Conference were influenced by recent proposed developments in IATA and by the US Civil Aeronautics Board's decision to permit only limited participation by US airlines in IATA tariff-coordination activitie's. The Conference agreed that unilateral action by governments which may have a negative effect on carriers' efforts towards reaching agreement should be avoided, that international tariffs should be established multilaterally and that the IATA tariff coordination be adopted as a first choice, whenever applicable.

During its consideration of the passenger tariffs for nonscheduled airlines, the Conference approved a set of recommendations to help harmonize ways of establishing and controlling these tariffs. The Conference also adopted recommendations regarding the establishment of international freight rates with due regard to the special nature of freight operations, the role played by freight forwarders and consolidators in setting bulk rates and the liberal attitude of many States towards such operations. In view of the complexity of the air freight market. the Conference noted problems in tariff coordination and enforcement of approved cargo rate·s and recommended consultations among interested parties on the international and national level to do away with malpractices. The Conference found that the problem of enforcement of passenger fares had changed character since the First Air Transport Conference in 1977, primarily because of improved load factors and innovative tariffs. It reconfirmed, however, earlier recommendations on this subject.

The Conference also considered the rules and condition·s associated with international fares and rates, including the currency exchange rates applied. Noting that it was becoming increasingly difficult for the users of air services to know their entitlements and obligations vis-a-vis the carriers, the Conference recommended studies to harmonize and simplify such rules and possibly reduce the differences in average levers of fares and airline costs amongst different regions of the world.

■

Air Traffic Control Stress and its Effects: An Investigation at Manchester Airport

by V. B. Maxwell and J. H. Crump

V. B. Maxwell

INTRODUCTION Investigations into Air Traffic Control (ATC) stress have been carried out in a number of countries, however, confusion about the concept still remains. Part of this confusion has arisen from the wi,:te variety of definitions and methodologies that have been employed in the assessment of ATC stres·s. Furthermore, differences in operating conditions, equipment and management systems between countries and local centres, have often produced conflicting interpretations.

The most extensive and thorough ATC stress and health studie's have been carried out in the U.S.A. Other work has been done elsewhere, although to a lesser extent. The findings from these investigations have given insight into potential sources of ATC stress and their physical and mental health effects. This information can be a useful source of reference for those ATC centre·s where research of this nature has not been carried out.

Therefore, we examine some of the published work on ATC stress and then describe how we are currently carrying out a study on stress and health among controllers in Manchester.')

The studies we describe here apply to Air Traffic Control, although it should be noted that much of this work applies equally to other occupations.

PAST RESEARCH ON ATC STRESS The main focus of ATC stress research has been on the task itself and the effects of shift work. Other factors such as environment, interpersonal relationships, management and individual characteristics have been investigated to a lesser extent.

Task Stress In general, the factor which has been found to be the most consistent predictor of ATC stre·ss is the number of aircraft controlled. In U.S. and European studies, increases in traffic load have been found to correlate highly with increases in heart rate and behavioural response. In one U.S. investigation it was concluded that the number of aircraft controlled momentarily over a short period of time was, "potentially the most important phyEiological stressor in the ATC environment". In another American study investigating health changes in controllers, it was found that controllers who showed significantly elevated systolic and

1) A more detailed review of ATC stress research can be obtained from J. H. Crump, Department of Management Sciences. UMIST, P.O. Box 88, Manchester M60 1OD, England.

J. H. Crump

diastolic blood pressure in response to ATC work were more likely to develop frank hypertension.

Other potential task-related stressors have included radio telecommunications, radar control, input and output of control strips and co-ordination by telephone and word of mouth with other controllers. Although the effect's of varying degrees of workload have been examined, there is still very little known about the nature and consequences of overloading on the controller and his performance. The term "loss of picture" is somet;mes used to describe the situation when the controller's mental representation of the traffic situation becomes distorted or is lost completely. The conditions leading up to loss of picture and the phenomenon itself remain unclear, although French studies relating to the mental strategies adopted when controlling have given some insight into the ways in which the controller copes with increa·ses in workload and the resultant stress. In conditions of increasing workload it has been found that controllers select strategies which take account of successively fewer factors for each aircraft under control. In effect this creates more time, but reduces the quality of information relating to the individual aircraft.

Shift Work Effects Although the ATC task and its effects have been studied extensively, a number of other factors relating to the ATC organisation and environment have arso been investigated.

Probably the most widely researched non-task factor has been shift work schedules. In particular many shift work studies have been carried out in the U.S., where the objectives have been to compare different rotation systems and the effects of heavy and light shifts. No significant differences were found between different rotation systems although differences were found to exist between heavy and light shifts. Those shifts which had higher traffic loading, and were judged to be more difficult, were found to cause more anxiety. Furthermore, differences were found between individual controllers in their response to shift work, indicating differences in subjective adaptation to ATC work.

Organisational and Environmental Stress A number of other organisational and environmental factors have been cited as potential ATC stressors. The·se include lighting, air-conditioning, noise, inadequate equipment, responsibility, and more importantly, relationships with co-workers, supervisors and management, although until recently the impact of these environmental factors on the controller had not been measured. Nevertheless, evidence suggesting their importance has come from U.S. and German attitude studies which have con31

sistently shown controllers to be dissatisfied most with management and supervision. This dissatisfaction ha·s been attributed to the lack of communication and consultation over technical and interpersonal matters. Others sources of dissatisfaction have been career plan deficiency, pay and the lack of advancement opportunities. In contrast, the work itself and busy situations in particular, have been consistently regarded as the greatest sources of job satisfaction. These environmental factors have generally been regarded as possible sources of ·stress, although their impact has only been assessed recently in an extensive study investigating health changes in U.S. Controllers. It was found that controllers who perceived the work environment negatively and who were dissatisfied with their work, co-workers and management, showed a significantly increased risk of developing either psychiatric disorders or mild medical illness. In discussing the implications of these results the authors commented, "it was not so much what they were doing but the context in which they were doing it and the attitudes and feelings they had about their situation, that influenced their risk for health change".

Domestic Stress The ·same American study also gave some insight into the impact that domestic stress can have on controllers. Family relation·ships, domestic difficulties and major life changes have been implicated with health risk in other research areas, but the effect of these factors on controllers has only recently been examined. Again it was found that major stressful life changes and major marital problems were related to psychiatric problems and moderate illness.

Individual Characteristics In the foregoing discussion we have examined the more objective ·stressors, however, a number of less tangible concepts such as age, experience, aptitude, morale and personality have been considered to be important when evaluating controller's subjective response to stress. In particular, personality has been investigated with the aim of identifying characteristics which are desirable for ATC work. Again the most extensive work ha·s been carried out in the U.S., where it has been found that controllers are more "hard-headed" and "practical" in their approach to life and work, compared to the general population. In addition, they are more independent, introverted and have greater emotional control. These findings are not supported by a parallel study carried out in the U.K. by the Civil Aviation Authority, the results of which have not yet been published. Psychophysiological research in the U.S. into the relationship between personality and stress ha·s identified behaviour pattern characteristics which are related to increased risk of Coronary Heart Disease (CHO). This "Type A" Coronary prone behaviour pattern is characterised by extreme competitiveness, aggressiveness, impatience and feelings

of being under the pressure of time and responsibility. "Type B" on the other hand is the opposite exemplified by calm adaptive behaviour. It has been found that controllers who were more "Type A" tended to have a greater incidence of more moderate illness and psychiatric disorders, although in contrast, controllers who were more likely to develop hypertension were found to be more "Type B".

The Long Term Effects of Stress on Health So far we have been examining the short term effects of ATC stressor's and the predictors for long term ill health. A number of investigations have also been conducted into the long term effects of ATC work on health and medical disqualification. These have largely been based on medical licencing records and the self reports of stress related symptoms. U.S. studies indicate that controller's experience increased symptomatology and advancing susceptibility to cardiovascular disease with age. The most consistent findings reveal that cardiovascular and psychiatric disorders are the two most prevalent medical disorders and both exceed general population norms. One U.S. study estimated that, 'Air Traffic Controllers currently on the job have 50 % to 100 % higher prevalence of hypertension than "the average man the same age in U.S. communities". In addition, ATCOs have an even greater risk than other men of developing new hypertension and this risk may be more than 200 % that of other men'.

Despite the weight of evidence indicating increased risk of pathology in controllers, the trend does not seem to be reflected in the statistics for actual disqualification.

In some cases the di'squalification rate for stress linked disorders in European Controllers has been reported to be as low as 0.3 % and 0.5 %.

These findings are clearly contradictory indicating either a discrepancy in the methodologies employed or deficiencies in the sensitivity of the licencing medical examination.

Discussion The majority of scientific evidence that we have regarding ATC stress is taken from U.S. sources. Both physiological and psychological ·studies have been carried out on U.S. Controllers in different ATC centres. The results from these studies indicate that a number of stressors both inside and outside ATC are related to health risk in controllers. In America, the principal health risks from ATC work have been found to be cardiovascular and psychiatric disorders. Elsewhere, research has largely been orientated towards ergonomic assessments of task and workload stress.

An overview of the available evidence suggests that both stress CHO risk are important factors to be con'sidered in the assessment of ATC health, although these can vary according to local conditions. In view of the difficulty of establishing comparability between different locations and countries, we decided to initiate a screening study of stress and CHO ri·sk among controllers at Manchester Airport.

MANCHESTER AIR TRAFFIC CONTROL PROJECT Background

Everything under control ...

32

Part of the task of monitoring controllers' physical and mental health has been the provision of a regular consultative service involving weekly visits to the Civil Aviation Authority Unit at Manchester Airport. This service operated by Dr. V. B. Maxwell, has been de'scribed previously in the Controller, (August 1976, Vol. 13, Nr. 3). Furthermore, a symposium on ATC stress was held at Manchester in 1976. This was very successful and highlighted areas where further research needed to be done. An additional outcome of the symposium wa·s the decision between the writers to collaborate on an interdisciplinary study of possible stress amongst Manchester Controllers.

The Study In the current annual medical examination carried out according to ICAO standards, there is no formal assessment of psychological health and physiological testing is restricted to the measurement of blood pressure, ECG, chest X-ray, obesity, and general examination of the body systems. Therefore, the object of our study was to see whether it would be possible to institute a psychological screening for stress and an improved and more sophisticated medical screening, which would take account of the most commonly accepted CHO risk indicators. The information from this modified screening procedure could then be evaluated to see whether it succeeded in giving any clearer indication of the controllers· present and future physical and mental health risk, and by implication their risk of loss of licence.

A complementary objective of our study was to examine more closely the nature of ATC psychological stress and to e·stablish the nature and strength of its relationship to CHO risk.

The study wa·s started during 1977 with the co-operation of the IPCS, the Guild of Air Traffic Controllers, Management, the CAA Medical Branch and not least the Controllers themselves.

Indeed as a result of the strong relationship built up with the

Controllers in the past, there has been a great deal of enthusiasm and co-operation in the project. Our intention in the design of the practical data collection was to interfere as little as possible with the controllers' normal routine. As such it was decided that interviewing would take place in their homes and any additional medical measures would for most cor.trollers be taken in an extension of the statutory annual medical examination. The psychological assessment of ·stress included interviews with some of the controllers and their wives, as well as a questionnaire administered to the full sample. The physiological assessment included all of the measures taken during the existing annual medical examination and in addition a blood ·sample was taken for biochemical analysis. A major factor considered in designing the project was that it should be simple and inexpensive to apply and lend itself to easy application with large numbers of controllers working in many different types of unit in different parts of the world.

The final sets of data have now been received and are currently being analysed. It is hoped that the results will contribute toward·s a greater understanding of ATC stress and indicate ways in which health risk can be identified and prevented.

■

News from the Federation Executive Board Meeting - Amsterdam, February, 1980.

The Board meeting which was planned to take place at the Casa Della Aviatore, Rome on the 14-16 February was held at the Novotel, Amsterdam instead. A last minute decision to shift the venue from Rome was due mainly to Alitalia's failure to provide the members of the Board with free or reduced rate transport.

"Emergency" arrangements by the Dutch Guild to accommodate the Board in their capital served as a test for the organisers of the 1982 Annual Conference - they have indeed pas·sed with flying colours. The short notice given to the Guild did not prevent them from setting up an ideal venue for the meeting and encourage the Board members to keep Amsterdam as a permanent substitude.

During the ensuing three-day marathon meetings (a total of 30 hours were spent), the Board realised that time is becoming shorter as the Federation expands with its increasing problems.

Consideration is therefore been given to the possibility of adding two extra days to one particular scheduled annual meeting or add the extra days to the post conference Board meeting.

The Agenda Routine business was overshadowed by two important items, THE CONTROLLER printing house and Member-Associations problems. The 1980 Suriname Conference, a major problem on the October agenda had been resolved at the special Frankfurt Board Meeting in December. In fact at the meeting the Board decided, following the use of the postal ballot system, in favour of Suriname as the 1980 venue. (Since, however, the Amsterdam meeting and the time I am writing this item, developments in Suriname forced the Board to shift the 1980 Conference to Toronto, Canada.)

Though Member-Associations' problems were dealt separately, decision as to action and policy to tie followed had to be common. Naturally, the Board leers somewhat embarrassed to note the increased indifference of administrations towards the problems of controllers particularly when they look at controllers' grievances with a suspicious mind. The appalling and inexistent system of air traffic control in the Sudan, the Portugese controllers' strike, and the French government's disciplinary action against controllers were viewed with grave urgency.

Fortunately, the Greek controllers' preliminary court hearing, brought against the controllers by the government and testified

by Greek pilots, was called off by the Attorney General for lack of evidence, shortly before IFATCA's expert witnesses were due to Athens to testify. Cabled protests against government action were sent to the administrations concerned and messages of support were sent to associations involved.

THE CONTROLLER's printing house still remains a pending issue after the Board postponed its decision as to where the journal will be printed as from is'sue 1/81. Despite the fact that the February meeting was expected to reach a decision on the issue, it determined instead to allow the period until the pre-'80 Conference Board meeting for additional details on the offers from the printing houses which responded to IFATCA's request for tenders. There are presently three offers from an equal number of printing houses, from Cyprus, Ireland and Switzerland each with its own merits.

The alarming rate of inflation which forced printing costs to rise tremendously forced the Board to increase subscription rates of the Journal to 8 SFrs for members and 20 SFrs for non-members, keeping advertising rates at the same level.

The only courtesy call the Board was called upon to make was to the Director of the Dutch Air Traffic Services, Mr. J. S. Smit at The Hague - an opportunity for the Board to express in person the appreciation of the Federation for the understanding and assistance granted by the Dutch Government to its con33

of

SC IV in session. Left to right: Peter Grieken, vos Schaap, Egbert Just, Klaus Piotrowski, Emile Schodts and Richard Peeters.

!rollers. The occasion became more characteristic when the first IFATCA President, Mr. L. N. Tekstra joined the meeting for an informal talk and meet the new members of the Board.

Vice President Professional on behalf of the Board; the reorganisation of ATC Agencies for civil and military necessities; etc. On this last item, the Committee thought that they have come to a stalemate stage because the problem as it presently stands cannot found a basis of compromise and no definite policy could be foreseen at this stage. Various existing systems have been examined but none gives an ideal for other countries.

It was, as a result, determined that SC IV would recommend to the next Conference that this item be taken out of the Committee's agenda. It was however the consensus of the members that air traffic control should be carried out by one air traffic control unit in one particular area.

The Executive Board during the Amsterdam Meeting had the privilege meeting Mr. Jan Smit, (Center), Director, Air Traffic Services, CAA.

* SC IV Meeting Tradition has it that Standing Committees (SC's) tend to meet periodically at the different places from where their members come from. This is also true for SC IV whose members come from Germany, France, Switzerland, Belgium and Holland despite the fact that Germany will be the more natural venue, being convenient as well as being the home of its chairman, Egbert Just. The chairman's hometown, Neunkirchen offering an ideal environment with its comparatively warm February weather offered the ideal venue for the Committee's preconference meeting to study and finalise working papers to be submitted to the 1980 Annual Conference of IFATCA. The meeting which took place at the Neunkirchen Hotel "Kurfurst" from the 11th to the ,3th February was attended by Egbert Just (Chairman) and Klaus Piotrowski of Germany, Emile Schodts and Richard Peeters of Belgium, Jos Schaap and Peter N. Grieken of Holland. The French and the Swiss members who constitute subcommittee medical notified the chairman that they could not attend duP. to other commitments. The Executive Board was represented at the meeting by Andreas Avgoustis, the Vice President Professional under whose department SC IV is established.

SC IV (short for Standing Committee Four), ist one of the seven Standing Committees which make up the backbone of the Federation's professional functions. It deals generally with professional and medical matters of concern to the controller and is responsible particularly with the updating and keeping of the IFATCA Handbook (IHB). The handbook covers a variety of subjects that deal with status, working conditions, training and medical standards of the air traffic controller internationally with an abundant number of comparative tables as well as local conditions of service. The information is derived basically from member associations though non-member associations do provide information for the handbook also.

The meeting itself conducted under the expert guidance of the Committee's chairman guaranteed succes·s from the outset.

Members dealt with problems of co-ordination and co-operation with the Executive Board, the presence of the Vice President Professional helped to settle. The Meeting's agenda included such other items as: the questionnaire issued to member associations on the ILO Meeting of Expert"s on problems concerning the air traffic controller; the questionnaire and updating of the IHB; the suggested working paper on the ILO, presented by the 34

The next meeting of SC IV is being fixed for Amsterdam the 1-3 September, 1980.

on

* IFATCA during the past twelve months Report of the Executive Board It was predicted in last year's Report to the Annual Conference, I continue to predict it, problems and struggles in the Profession are, and will be, with us for some time. Why i"s it that a group of professionals at each Annual Conference, and in between these, spend an "inordinate" amount of time deliberating on problems which occur in air traffic control worldwide? Why can we not concentrate more on technical, on medical, on equipment-related matters? We would love to do this but the decision is not ours. Until such time as conditions in air traffic control, and these include all facets ·such as equipment, working conditions, training and work environment, and cannot be separated, - until these conditions have been established in a satisfa:;tory manner, problems, upheavals, struggles will continue to be with us - the Profession is striving towards the achievement of the ·safest and most expeditious air traffic control system worldwide.

If Governments and Administrations were willing to recognise the impact on world and national economy of the importance and responsibility and dedication of Controllers; if the Airline industry, rather than standing aloof as it now does, became involved tor their own benefit; if all other interested parties got together with Controllers - who by accident of history in most cases are in the ·strait-jacket of civil service, which fact is callously exploited by many governments, - to reasonably exchange views and negotiate the quickest route to reach what should be a common goal - the safest, most reliable, most efficient system of air traffic control - then inconveniences to the industry and the air traveller could be effectively minimized.

Until then, however, we can expect to see more of the same, a struggle which - although users complain - is waged on behalf of the airspace user, on behalf of the travelling public, as well as on behalf of the recognition of the Profession and its unique role and responsibilities.

Developments such as: (1) the International Labour Organization's Meeting of Experts on Problems Concerning Air Traffic Controllers in May 1979, (2) the Hearings of the European Parliament on Efficient Air Traffic Control, (3) the programme of the Briti'sh Broadcasting Corporation entitled "Plane Chaos", (4) articles in the aviation journals and press concerning our Profession's problems, all indicate that the sad state of affairs in many areas and countries is being recognized and publicised - our voice of deep concern is no longer the only one in the wilderness.

Within its policie·s the Federation will continue to strive to achieve its stated objectives, in the world-wide context to help and support its Member Associations, to continue to co-operate with organizations and authorities who share our deep concerns.

The old argument of cost will continue to be encountered, yet, adequate equipment and working conditions would pay for themselves in a relatively short term through provision of an efficient sy'stem. We hope that a long-term, all-encompassing view, rather than the past and present shortsightedness, ignorance of the air traffic control environment, tunnel vision, will become the order of the day as has already occurred with more enlightened administrations.

We are certain, moreover, that through cooperation, unity, solidarity, and supreme effort and dedication the Federation will be instrumental in solving the problems, many of which are caused by the pettiness of the administrations, which are still facing our Profession.

ADMINISTRATION - PART A: General: - Outside activities of IFATCA have had to be selectively curtailed. The reasons for this are the shortage of funds, of qualified manpower and time, and the need to develop relevant policies. The Board agreed that just to merely attend a Congress or seminar, medical, technical, or otherwi'se, is not sufficient justification to spend the Federation's funds. An intelligent input, worthwhile returns, and future benefits must form part of this package. Concentration on interchange with Member Associations and IFATCA Regions do, at this time, promise a more immediate benefit, while the Board is establi'shing priorities and working towards involving other agencies in research and studies concerning the Profession.

Again, without the assistance of national authorities, namely those of Canada, Cyprus, France and Ireland as well as a number of concerned air carriers, much of the work and travel carried out by members of the Board would not have been possible. To all these we express our appreciation and our hope of continued assistance and co-operation; they are truly an example to others, they are the enlightened leaders in a field of agencies and companies whose goals should coincide with ours. Eventually the others, the non-co-operative ones, the ones hiding behind rules, regulations, company policies, will become enlightened and accept the fact that the controllers' success and wellbeing is to their benefit.

Executive Board: - Three regular Executive Board Meetings were held between Annual Conferences: June 1979 in London, October 1979 in Tunis, February 1980 in Amsterdam. The February 1980 Meeting was originally scheduled for Rome. However, unavailability of transport from the Italian national airline forced a short-notice change of venue thus preventing the Board from being able to meet with Italian authorities and Member Association. In addition to the above three meetings a Special Board Meeting was held in December 1979 in Frankfurt to consider the air traffic control systems and problems in Europe, long term possible solutions, and the venue for IFATCA '80. The Executive

'

The Executive Board at a Special Meeting in Frankfurt, December 1979.

Board met on this occasion with Members from ANACNA and EGATS. To the airlines who made attendance at these meetings possible, to the host Member Association·s, and their respective authorities, as applicable, goes our sincere appreciation.

There is a need for the Board to be made aware of the activities in which it may be required to participate at a much earlier stage than is the current norm. I refer here in particular to meetings of Standing Committees and Regional Meetings.

Regions and Regional Meetings: - In total the concept of regionalization is progressing in a ·satisfactory manner. There are grey areas concerning the latitude of responsibility of the Regional Councillors: these grey areas are being studied. The Board is grateful to those of the Councillors who are committed and unceaGing in their work on behalf of the Federation, the need for such work in the Regions cannot be overestimated.

The Executive Board again attempted to be present at as many Regional Meetings a·s possible. Of course, distance and lack of travel facilities prevented total success. It was not possible to combine Board Meetings and Regional Meetings, a long-term scheduling programme will be studied.

The Board was represented at the following Regional Meetings: EUR (Vice President, Administration) NGA (President) The Executive Board met with Regional Councillors of EUR and MID during the Board Meetings.

Member Associations: - Throughout the period the Executive Board attempted to provide input and assistance, on their request, to Member Associations. Member Associations are autonomous organizations and, on principle, should originate any request tor Federation involvement. Communications with Member Associations, though still below the acceptable levels where que·stionnaires are concerned, are improving and, we hope, will soon reach the constant and timely exchange necessary.

Personal visits with Member Associations other than those who hosted E3oard Meetings: Canada Pre·sident, Vice President Technical.

Mexico President Netherlands President. Vice President Administration Germany President Suriname Vice President Administration Greece Vice President Professional Cyprus Vice President Professional Standing Committees: - Although, ideally, the Board should be represented by its respective member at meetings of Standing Committees, this again is prevented by travel, time-off, and scheduling of the·se meetings. Questions can be raised on the cost/effectiveness of some Standing Committee meetings, a study on this is continuing, and the financial authority, and restrictions, of the Treasurer must be affirmed.

35

Standing Committee Meetings attended: SC. I. SC. Ill SC. IV

-

4 meetings: Vice President, Technical.

2 meetings: Treasurer 1 meeting: Vice President, Profe'ssional

The Secretariat: - The Board would be remiss not to record its sincere appreciation to the Executive Secretary and his coworkers for the hard and often difficult work they perform under adverse conditions. Ted Bradshaw's willingness to tackle any reasonable request, exotic though it might be and ill-defined, is an immeasurable benefit to the Federation and a credit to his dedication and the Profes·sion.

"The Controller": - Since the appointment of A. Avgoustis as Interim Editor the Journal has regained a professional footing and all printing deadlines are being met. A renewed effort towards attracting increased advertising is however required, and Member Associations are reminded of their responsibilities to the Journal.

Finances: - Though many more Member Associations are paying their subscriptions on time, many are still not fulfilling their financial obligations to the Federation.

Annual Conferences: - All Member Associations are aware of problems which were obvious in the preparation of this year's Conference. Allegations made regarding the willingness to cooperate of the Executive Board are completely unfounded as will be documented in Committee A if required. It must be realized by all who accept the responsibility to host and organize a Conference that it is the Federation's annual showcase and cannot be taken lightly. Personal feelings or preferences have no place in this process, the success of the IFATCA Conference must be the only factor. Thus, certain conditions and timetables must be met. Steps are being taken to ensure this. The Board i's, regrettably, caught in the middle - Directors allocate the Conference to a Member Association and then, when timely information is not forthcoming from the host, request such information from the Board.

Such process reflects on the Federation as a whole and care must be taken that only Member Associations capable of carrying out this ta·sk, when offering to host a Conference should be considered and accepted as organisers of IFATCA Conferences.

It is imperative that the Board as a whole visit a proposed Conference site at least once. To this end we plan that the February Board meeting should be held at the Conference site in the year preceding so that the Board will be able to brief the Directors at a Conference a full year ahead. When a Member Association takes re·sponsibility for Conference it should be one of the conditions that they will arrange the appropriate Board meeting and have as many details as are required by the Board concerning Travel, Accommodation, Secretarial facilities, Press Requirements and other Publicity available to the Board at this meeting.

Corporate Members: - At the time of writing and since the last Conference the following have been accepted as Corporate Members: PHILIPS' TELECOMMUNICATIE

INDUSTRIE B. V. - The Netherlands AMECOM DIVISION, LITTON SYSTEMS, INC. U.S.A. COMPUTER SCIENCES EUROPE S. A. - Belgium E-SYSTEMS ING. MONTEK DIVISION - U.S.A. VWK-AERONAUTICAL CHARTS Germany RAYTHEON CANADA LTD. - Canada DICTAPHONE CORPORATION - USA The drive by the Executive Board to attract more Corporate Members has been completed. More than 220 letters of invitation were sent - re·sults are awaited.

The Board wishes to record its app·reciation to the Corporate Members Co-ordinator, Mr. A. Weijts, for his committed efforts on the Federation's behalf, under sometimes trying circumstances.

Non-Member Associations: - The number of contacts with non-member Associations i's increasing. Happily, as the number of applicants for IFATCA professional membership indicates, the 36

total number of non-member Associations is shrinking. It is imperative that Member Associations, Regional Councillors, and the Board continue to impress on non-member Associations the benefits and advantages of IFATCA membership. Only in unity is success assured.

Relations with International Organizations: - Members of the Board met with representatives or attended Meetings of these Organizations: ICAO ILO MECACON IFALPA

IATA

Vice President, Technical Vice Pre'sident, Professional Vice President, Professional President - Excellent relationship continues to exist between IFATCA and IFALPA. The two Presidents met in January 1980 and affirmed their common goal of increased cooperation at all levels.

President Met with the IATA Director General in May 1979 to exchange views, and direct contact has been maintained.

TECHNICAL - PART B: A post Conference period of about three months was necessary for the Vice President Technical to assimilate the mass of information passed on to him by his predecessor.

The Vice President Technical in his many activities attended all the S.C.I. meetings, (June, August, December 79 and January 80) but was prevented from attending the October 79 meeting as this coincided with the Executive Board Meeting held in Tunis.

This involvement enabled him to keep fully informed and constructively comment on the work programme which included R/T Failure Procedures and Blocking of Frequencies, Beacon Collision Avoidance Systems, Visual Flight Rules, Helicopter Operations, Vertical Separation and Aerosat Communications.

In liaison with S.C.I. Chairman, a continuous co-ordination was maintained in the field of our activities in ICAO Study Groups such as - Surface Movement Guidance and Control Systems, Radio Telephony, Elimination of Ambiguity in RTF Callsigns, Basic Operational Requirements Group.

Though our request to participate in the ICAO Air Traffic Management Group (ATMG) has not been approved it has been necessary to keep fully informed of the Group's programme throughout the year.

Close co-operation was maintained with the Federation delegation and S.C.I. for our participation in the European Fiow Control Meetings.

PROFESSIONAL - PART C: The first period since Conference is marked by two events: the I.L.O. Meeting of Experts on Air Traffic Control and the MECACON '79.

The I.L.O. Meeting of Experts was an opportune time for IFATCA's policy to be introduced to an international body c1nd the Federation's delegation to the meeting was given directions as to how to approach the various problems facing the air traffic controller internationally. The Vice President Professional headed the delegation to the Meeting. A full report on the deliberations and conclusions of the Meeting are given in a separate IFATCA document.

The MECACON (Middle East Civil Aviation Conference) '79 was held in Amman, Jordan. The Vice President Professional together with the Regional Councillor for the Middle East participated at the Meeting and was a member of a special Air Traffic Control Panel on "The Controller's Contribution to Aviation Safety".

During the second period under review, the Vice Pre'sident Professional other than routine business and his attendance at

the Board Meetings in London, Tunis and Amsterdam, attended S.C. IV. Second Meeting which took place at Neunkirchen, Germany, in February.

Because of lack of funds, the Vice President Professional could not attend the special Executive Board Meeting in Frankfurt in December '79. The Vice President Professional could not attend the First Meeting of S.C. IV. October '79 due to unsuitable timing of the Meeting.

CONCLUSION: Taking into account the progress made in the past twelve months, the Executive Board views the future with cautions optimism. The Federation's concerns, regarding medical aspects of the Profession, work environment and conditions as well as the legal liability of the air traffic controller have been addressed at the international level by the International Labour Organization. Neverthele·ss, these concerns have not yet been answered

and require the full and dedicated commitment by all Member Associations.

As always, not all actions and decisions of your Executive Board have met with full approval by all but they were undertaken with only the best interests and results for the Profession and the Federation in mind.

The Federation is growing: a "Fund Special Circumstances" was establi'shed to allow tangible expression of solidarity with less fortunate colleagues, and it is our hope that Member Associations will take full advantage of this opportunity.

IFATCA '80 lies ahead, a Conference which brings together representatives from all facets of the industry. They will learn of our concerns and leave with a deeper understanding of the Profession. It will be another hard-working Conference, one that will allow u·s to reaffirm our basic aims and establish future goals, a Conference which will challenge us to exchange views, experiences, and plans. A Conference which will consolidate our will to succeed.

Much hard work lies ahead of us - let's go and do it!

■

News from Member Associations Austrian ATCA Awarded the "Diplome d'honneur".

By a motion of the President of the Austrian Aeroclub, Dr. Josef Lenz, the annual Conference of the FAI (Federation Aeronautique International) held in Nicosia in October, 1979, awarded the Austrian Air Traffic Controllers' Association the DIPLOME D'HONNEUR for outstanding services, especially afforded to the general aviation in Austria and for the Association'·s continued efforts to promote co-operation between general aviation pilots and controllers in the interest of AIR SAFETY. The award is considered to be the first in the history of the FAI given to a professional air traffic controllers' group.

The award was presented at a formal ceremony to the then President of the Austrian ATCA Mr. Kurt Kihr, by the President of the Austrian Aeroclub Dr. Jo'sef Lenz. At the ceremony, which was held on the 18th December, 1979, the local press, TV and aviation representatives were present to witness the award.

.....~"'': .. ..,,...

-"".',.,, ,

Dr. J. Lenz, President of the Austrian Aero Club (left) presenting the "Diplome d'Honneur" of the FAI to Kurt Kihr, President of the Austrian Air Traffic Controllers Association.

2oth Anniversary of the Luxembourg Guild On the 22nd of January the Luxembourg Guild of Air Traffic Controllers gave a reception to celebrate the occasion of its 20th Anniversary.

Among many invited guests were the director of Luxembourg Airport, Mr. E. Jene, representing the airport authority; representatives of the airline pilots as·sociation, private pilots association and representatives of the unions. IFATCA was represented by Mr. C. A. Enright, Chairman of SC V, from the Eurocontrol Guild.

The Belgian Guild was represented by their president Mr. E. Sermijn and Miss B. Behin.

In his short address the president of the Guild, Mr. C. Baum, thanked the guests for accepting the invitation and made a brief review of the main objectives of the Guild.

In December 1959 ten controllers met to constitute the Luxembourg Guild of Air Traffic Controllers. Only 2 years later they signed the constitution of an international federation as one of the 12 founder members of IFATCA. It is through this Federation that the Luxembourg Guild could realise its first two objectives: i. e. to look for international contacts to allow a permanent update of the evolution of their profession; the second objective was to achieve, with IFATCA, a bond of solidarity among all the air traffic controller associations.

The president al'so mentioned the merits of the Federation in the negotiation on professional conflicts between national associations and their governments. He then reminded guests of the successful help that IFATCA had given to the Luxembourg Guild in 1975.

The Guild has also made all possible efforts to maintain good relation·ships with the neighbouring associations, especially the Belgian Guild where the friendly cooperation and periodical meetings have contributed to a better working atmosphere between the two ATC units .

On a national basis the president offered the ATS authorities close cooperation, hoping that this could lead to the realisation of a beneficial dialogue.

Mr. Enright, on behalf of the Federation thanked the Luxembourg Guild for their invitation and acknowledged the cooperation of the Guild within IFATCA. He emphasised the fact that the Federation and especially SC V will continue to offer all pos37

Enquiries to: Convex 80 International, Room 237, London Air Traffic Control Centre, Porters Way, West Drayton, Middlesex, UB7 9AU England.

■

Universal News DC-9 Test Programme

Members of the Luxembourg Guild posing at the Guild's 20th Anniversary celebrations

sible assistance both to the Guild and to Luxembourg airport authorities particularly on any problems concerning training or procedure·s resulting from the implementation of radar, which is presently under development at Luxembourg.

CONVEX ID ------

INTERNATIONAL---~

The UK Guild of Air Traffic Control Officers: CONVEX 80 Goes International!

Under the heading of CONVEX 80 International the UK Guild is holding another of its well known seminars in October. Probably the most ambitious CONVEX ever undertaken by the Guild.

The conference lasted 2½ days from 22nd-24th October, 1980. The venue is within the boundaries of the airport in the Heathrow Conference Centre at the luxurious Heathrow Hotel. Within the complex there is a large exhibition area which will provide one of the most comprehensive and largest exhibitions of Air Traffic Control equipment and associated products ever seen in Western Europe. The Guild's Corporate Members will all be in evidence and some of the IFATCA Corporate Members are exhibiting in addition to outside industries.

Plans are being finalised to provide an impressive list of speakers from most of the major international bodies in the aviation field as well as airlines and government agencies.

IFATCA is one of the invited speakers for the opening session.

The theme for 1980 is typically emotive "Chaos or Control a conference into the requirements and problems of Air Traffic Control into the 80's". The conference arrangements are slightly different this year in that the subject, under the sub-headings of "The Chao·s" and "The Control", is dealt with in a number of sessions each dealing with various aspects within that sub-heading. As usual audience participation is a major feature of Convex 80 International and will include several open forums at the end of each section. The UK Guild says that it is expecting a big response and has 'slanted the subject to appeal particularly to the developing countries of the world.

In support of the Conference there will be a full ladies programme to keep them occupied while delegates thrash out the problems of the aviation world. The whole Conference is rounded off with a Gala Ball on the Friday night, and is included in the specially reduced registration fees for IFATCA members. Many IFATCA members have attended and enjoyed previous CONVEX's and 1980 will surely be one not to mi'ss.

38

The flight test programme on the McDonnell Douglas DC-9 Super 80 has passed the 400-hour mark on its way toward certification by the Federal Aviation Administration this summer.

The third of the advance technology twin-jets joined the flight test programme recently, making a 3-hour initial flight from the Long Beach Municipal Airport to the Douglas Aircraft Company flight development facility in Yuma, Arizona, where the test programme is headquartered.

The three aircraft in the test programme have flown a total of 403 hours in 214 flights as of March 4.

Painted in the colours of Austrian Airlines, the third test aircraft is the first production-configured Super 80 aircraft, although it will not be equipped with full airline seating during the test programme.

It will be used in the te·st programme to evaluate cruise performance, crew workload and in autopilot and category IIIA instrument landing certification tests.

The first two of the quieter, more fuel-efficient Super 80s already have accomplished a number of objectives in the lengthy and thorough flight test programme.

These have included structural limits tests up to .87 Mach at 35,00 ft, wing and fuselage load tests, demonstrations of flying qualities and manoeuvring ·stability, stall tests, landing- takeoff and cruise performance and noise tests, and calibrations of the new digital flight guidance system and the optional head-up display.

Tests conducted so far have indicated that the Super 80 will meet the goals of being the quietest jetliner in commercial service and providing the lowest fuel consumption per passenger seat mile on any airliner.

The first Super 80, painted in McDonnell Douglas colours, made its first flight on October 18, 1979. The second aircraft, painted in the colours of Swissair, joined the test programme December 6.

Twelve customers have placed 72 firm orders for the DC-9 Super 80, which will enter airline service this summer. McDonnell Douglas has received conditional orders and options for 30 more aircraft.

Customers which have announced purchase of the Super 80, in addition to Swi'ssair and Austrian, are Aeromexico, Air California, Austral Lineas, Aereas of Argentina, GATX Leasing/ McDonnell Douglas Finance Corporation, Hawaiian Airlines, lnex-Adria of Yugoslavia, Pacific Southwest Airlines, Polaris Aircraft Leasing Corporation and TOA Domestic Airlines of Japan.

*

The Airbus during 1979

During 1979 Airbus lndustrie became the world's second civil aircraft seller. During the past year Airbus lndustrie increased its orderbook by 221 (133 new firm orders and 88 options). Of these 92 were for the A300 (70 new firm orders and 22 additional options) and 129 for the A310 (63 firm orders and 66 options).

These figures clearly show that the A310 launch was not detrimental to the A300, since not only the A310 but also the A300 have sold well. Airbus lndustrie also added another twelve customers to its list, passing from 20 to 32.

As a consequence of these sales Airbus lndustrie also secured a 26 0/o market share in US dollar value of all aircraft sales.

If only the wide-body market is considered, Airbus lndustrie sold 42 % by number and 34 % by US dollar value. And considering the total short to medium range aircraft including F28, B737, DC9, etc Airbus lndu'strie took 39 % of that market in US dollar value.

Production Rate As a consequence of increasing sales and in order to r:ope with future market requirements, the decision has been taken to speed up the production rate for the A300/A310 (both aircraft will be produced on the same assembly line). Monthly output, which was at two A300s at the beginning of 1979, is now three.

It will continue to increase, reaching four in 1981, 5.5 in 1982, 6.5 in 1983, 8 in 1984 and 10 in 1985.

This will be achieved by mobilizing the manufacturing resources of Airbu's lndustrie's partners, whose assets total over US$ 7 billion. Huge investments are being made at the partners' plants throughout Europe. Investment of nearly 400 million F.F. is planned for this year (1980) by Aerospatiale in France for the A300/A310 programme. For the coming four years (until 1984) MBB in Hamburg, Germany, is investing OM 400 million to cope with the increased A300/A310 production rate. British Aerospace's commitment to investment in the A300 and A310 programmes will exceed £300 million by 1984. Airbus lndu'strie will also acquire two new Super Guppies in addition to the two at present in use, to feed finished assemblies to the final assembly line at the Aerospatiale facility at Toulouse.

Obviously the number of workers occupied on the programme will also have to be increased. At present some 17,000 people work on the A300 and A310 programmes within the partner companies, and thi's figure will reach 40,000 to 45,000 by the middle of the eighties, This represents less than one third of the total number of employees of the major partner companies, British Aerospace (United Kingdom), Deutsche Airbus (MBB and VFW-Fokker in West Germany) and Aerospatiale in France (over 150,000 in total). This means that the resources within the partner companies and the other aerospace industries throughout Europe will ensure that the production rate increase will not be hampered by human factors!>t A300 Operation By 31st December 1979, 81 A300s had been delivered to 14 airlines, serving some 100 different cities in 43 countries. By mid-December about 380,000 hours have been flown in approx.

267,000 flights and over 50 million passengers have been carried.

The two high time aircraft belong to the Belgian charter carrier T.E.A. (A300B1 with 9,800 flight hours) and the German charter carrier Hapag Lloyd (A300B4 with 9,700 flight hours). The two A300s with the highest number of take-offs are B2s from Lufthansa (8,950 and 8,650). The three top operators in terms of technical dispatch reliability for the four weeks period ending 9th December were Air Inter (100 %), Olympic Airways (99.5 %) and Hapag Lloyd (99 %), The T.E.A. aircraft achieved 100 % dispatch reliability over the 5-month period July-November, averaging over 7¼ hours utilisation per day.

Deliveries in 1979 During the past year, 25 aircraft were delivered to 10 operators. Of these 17 were for six customers already operating A300s: three to Air France, three to Lufthansa, one to Korean Airlines, one to Indian Airlines, four to Thai International and five to Eastern Airlines, and eight to four new customers: two to Olympic Airways, two to Hapag Lloyd, two to Malaysian Airline System and two to Philippine Airlines.

In March of 1979, the A300B4 operated by the Colombian airline Aerocondor was taken back and returned to its Toulouse base, and in April the two A300B2-200 operated by Iran Air also returned to their base at the end of a wet lease agreement.

Four aircraft were delivered during December: one to Eastern Airlines, one to Philippine Airlines, one to Malaysian Airline System, and the first A300C4 to Hapag Lloyd. Eastern Airlines

asked for increased delivery rates and within three months received five additional A300B4-100 instead of the four originally scheduled.

They are now successfully operating 12 of the twin engined wide-bodies, and have now considerably increased A300 operation on their network, serving 14 cities throughout the United State·s, on routes as short as New York - Philadelphia or Miami - Nassau or on transcontinental routes such as Atlanta - San Francisco and Los Angeles. Eastern Airlines considers the A300 as the most economical airliner they have in their fleet of over 250 aircraft, enabling them to make considerable fuel savings.

In November 1979 Eastern Airlines purchased two additional A300s of the shorter range B2 version, raising their total firm orders to 25 (plus another nine options). Two A300B2s were delivered to Eastern in January 1980 for immediate introduction on the New York - Boston shuttle service and, as soon as the much quieter twin engined wide body is authorized into Washington's down town airport, on the New York - Wa'shington National shuttle, one of the busiest and densest traffic routes in the world.

*

FAA Study Shows DC-10 Pylon Fundamentally Sound The Federal Aviation Administration reported that a six-month study shows the DC-10 pylon is fundamentally sound and can ·serve 25 years without failure unless damaged during maintenance.

FAA said it is proposing mandatory modifications to the DC-10 pylon to prevent the kind of maintenance-induced damage that led to the crash of a DC-10 at Chicago's O'Hare International Airport last May 25. Replacement of certain titanium parts with stronger steel parts also would be required.

The review's basic finding is that "the DC-10 wing pylon is of sound design, material, specification, con·struction and performance and, as such, meets all the applicable criteria and certification requirements set forth in the Federal Aviation Regulations".

The study also concluded that maintenance abuse of the type uncovered in the Chicago accident "can render the aft pylon bulkhead unsafe". This part failed as the DC-10 was taking off from O'Hare, causing the left engine to tear away from the aircraft. Investigation showed that the bulkhead had been cracked earlier when the engine and pylon had been removed as a unit, contrary to the manufacturer's recommendations, in a procedure that involved the use of a forklift truck. FAA already has banned the use of this procedure.

39

Based on its analysis of the raw damage tolerance study results, FAA is proposing to relax the stringent inspection schedule for the DC-10 pylon imposed when the aircraft wa·s returned to service last July 13 after 30 days on the ground. The agency would permit the airlines to return to more normal inspection schedules.

Summing up the findings of the study, FAA Administrator Langhorne Bond said: "opinion can never be unanimous en a question like this one. But the study represents the best thinking of the best people we could find in our agency and the Air Force, as well as a special team of aviation experts from outside the Government."

The "damage tolerance study" includes more than 5,000 pages of complicated calculations. McDonnell Douglas Corporation, the DC-10 manufacturer, did the actual work following strict FAA criteria and operating under close FAA supervision. The Air Force's Aeronautical Systems division then reviewed the result's.

So did FAA in consultation with a team of non-Government aeronautical engineers headed by Dr. Raymond Bisplinghoff.

The study concluded that the DC-10 pylon design life is equivalent to approximately 25 years in airline service - longer than the design life of the DC-10 itself.

To deal with the problem of maintenance-induced damage FAA, is publishing a notice of proposed rule-making in the Federal Register on January 25 that would require two basic modification·s.

One would require recessing two bolt heads located near the spot where the aft bulkhead is attached to the wing so they cannot come into contact with the wing attach point.

The other would require the installation of a device that would ensure that the aft bulkhead can be fitted to the wing without damage to the wing or the wing attachment point.

Also required would be the replacement of titanium thrust links in the pylon with steel thrust links. Although the titanium thrust links have a projected useful life of 90,000 flight hours, FAA believes the steel replacements will provide an even higher level of safety.

The study also considered other possible modifications and inspection schedules. The FAA recognizes that there are other views on these proposals and encourages interested person·s and organizations to provide pertinent data for consideration in the development of a final rule.

FAA News Release

* New Fire-Resistant Materials Researchers at the FAA's National Aviation Facilities Experimental Center (NAFEC) are testing new materials and coatings for aircraft evacuation slides that could survive up to 10 times or longer than present slides under certain fire conditions.

In an aborted takeoff of a Continental Air Lines DC-10 at Los Angeles International Airport last March, two main fuel tanks in the left wing were ruptured and the spilled jet fuel caught fire. All the slides and slide-rafts on the left side were unusable due to the extensive fire on that side. Most of the slides on the right side of the aircraft lasted for the prescribed 90-second evacuation time but several failed due to fire and radiant heat before all 184 passengers and 14 crew members were able to get out.

Actual evacuation time was approximately five minutes, according to the National Transportation Safety Board.

Within a month of the accident, NAFEC had started an investigation of the heat resistance of the materials used in the fabrication of aircraft evacuation slides. Results of this early study showed that the two most commonly used materials - neoprene-coated nylon and polyurethane-coated nylon - failed rapidly when exposed to moderate amounts of radiant heat from jet fuel fires.

Samples of inflated slide materials placed nine feet upwind and to the side of free-burning fuel fires failed (deflated) within 29 40

to 45 seconds when exposed to heat fluxes from 0.95 to 2.07 Btu/ ft2-sec. Inflated slide samples placed 18 ft. downwind of the fire failed in 17 seconds.

As a result of this preliminary investigation, FAA's Office of Airworthiness has asked NAFEC to undertake an extensive study of new and coated materials that could be used to make evacuation slides more fire resistant.

Researchers in NAFEC's Fire Safety Branch have already begun evaluations of promising new materials in the laboratory using a new, radiant heat test unit developed at the Center. This year they plan to conduct full-scale tests of aircraft evacuation slides located at varying distances from large, outdoor pool fires of jet fuel. One of the most promising materials tested to date is a neoprene-coated Kevlar which remained intact for 124 seconds under the same test conditions that caused current slide materials to fail in 12 to 15 seconds. The neoprene-coated Kevlar, when sprayed with a reflective aluminium coating, remained usable for five minutes.

NAFEC recently awarded a contract to the B. F. Goodrich Co., to study the feasibility of applying reflective coatings to inservice evacuation slides and slide-rafts when they are deployed and tested for air leaks - approximately every 30 months. Center researchers will test material samples with coatings provided by Goodrich on NAFEC's new, radiant heat laboratory unit. The most promising· of these coatings will then be evaluated here next spring on full-scale slides.

* New Brochures on VFR Flying As in past years the Civil Aviation Authority of Sweden has again published a useful brochure on rules and regulations applicable to VFR flying in Sweden.

New on this market is a very detailed booklet published by the Federal Air Navigation Services Administration of Germany.

It looks to be the most comprehensive publication offered so far by an aviation administration,rin Europe. It has the merit of containing in English and German all rules and procedures for VFR/CVFR flights in and across the Federal Republic of Germany; depicts the airspace structure, puts some light into the jungle of regulations and even leaves you with a smile glancing at Helmut Elsner's cartoons that break up the serious background somewhat.

A similar three-languages brochure appeared in Switzerland these days, published by Radio Swiss. All the above publications aim at improving the knowledge of VFR pilots, inviting them to a thorough preparation of their flights and hopefully contributing to more safety in aviation.

elsnER.

I tell you, Darling, it is really much safer to go by air than using those packed roads with lots of crazy people and cars on them, hmhmh !

This Could also Happen to Me NON~TANDARDPHRASEOLOGY It was not a particularly busy period in the tower. HS748 G-AD was making autoland approache·s on Runway 27. Visibility; good.

Wind; calm. And an excited group of Boy Scouts stood at the back of the small tower being introduced to the mysteries of ATC. Oscar 45, a Sea-Vixen, calls for taxi and is cleared to taxi to Runway 06 - which intercepts 27/09 about midway. As Oscar 45 aµproaches Runway 06 he requests take-off clearance. G-AD is now on short finals to Runway 27 for a touch and go.

"Oscar 45, negative take-off" answer's the controller, turning away from the Sea-Vixen to watch the landing HS748. A continuous chatter provides a background distraction. A slight movement in the corner of his eye draws the attention of the controller to his left where he observes one Sea-Vixen rapidly picking up speed along Runway 06.

"Oscar 45 abort take-off, landing traffic Runway 27" is the frantic message squeezed from a dry throat.

"Tower, Oscar 45 say again" replies the pilot, obligingly rotating and rai'sing the undercarriage in one deft movement.

"Oscar 45 keep it low. Overshooting traffic Runway 27."

"Er roger Tower. Staying low" replies a slightly shaken pilot.

G-AD meanwhile, has overshot with a climbing left turr. to position himself downwind. He makes no comment about the incident until next time on final when he politely asks the controller to confirm that this time he really is cleared to land and if the runway would be exclusively available for him.

Conclusions (i) Use of incorrect phraseology by the controller. The phrase "negative take-off" was interpreted by the pilot to mean "affirmative", or "-tive, take-off". (ii) The pilot did not ensure a thorough visual check before commencing take-off. (iii) Di'straction of the controller by the group in the tower.

P.S. Why did I not use the correct phraseology? - the day before this incident the self:same pilot having been instructed to "hold position" had taxied across an active runway. At the back of my mind was the fact that this pilot did not appreciate .the meaning of the word "hold" so I substituted another phrase which almost had disasterous result's, Stick to standard phraseology - Substitution leads to misinterpretation.

CUVHAHO

IIOPKINS

AIRPORT

outboard of the No 1 engine on the left wing. The vehicle severed approximately 15 feet of the wing almost completely off! The aircraft veered to the left, struck a 'snow fence 150 feet to the left of the runway and tore down 100 feet of fence before stopping.

The vehicle had its' roof and front end smashed in and, continued across the runway, coming to a stop in the grass. A section of the wing 5 feet long and 3 feet wide broke off and was lodged inside the vehicle, resting on the steering wheel and hood.

(Needless to say - the driver was very lucky to survive.)

The vehicle left 59 feet of 'skid marks before it struck the aircraft. This indicated a minimum speed of 35mph when the driver saw the aircraft. The crew of the DH-114 (which was estimated to have touched down 500 feet before impact) only caught a glimpse of the vehicle before it hit them.

One may determine that the "direct cause" of the accident was the Ground controller's failure to hold car 5 short of runway 36L. It may also be found as contributing factors to the accident: a. the driver's failure to look down the runway before crossing; b. excessive speed; c. Cleveland airport's failure to e·stablish a formal training and check-out programme for city vehicle drivers.

The driver, in this case, had one year of employment on the airport prior to the accident.

CLEVELAND HOPKINS AIRPORT ACCIDENT Cleveland airport was landing and taking off on runway 23L as their primary runway, Gallion flight 806 (GCS-806) inbound to Cleveland from the south requested to land on runway 36L, to hold short of 23L. This is a standard procedure for Gallion and, it is almost always approved.

The Approach controller coordinated the arrival with the Local controller in the CAB. The Local controller advised the Ground controller of the arrival and, he acknowledged. All coordination was routine and, was not disputed by any of the controllers after the accident.

At 14:29 Lei, GCS806 reported 2½ miles south of the airport to the Local controller.

At 14:30, a city vehicle (1977 Chevrolet Suburban Van) Car 5, requested clearance from the Ground controller to proceed from the "Tank Plant" taxiway, via "L" - "K" taxiways to the gate area. The Ground controller responded; "That's approved".

At 14:31 Lei, Car 5 struck the DH-114 at the intersection of "K" taxiway and runway 36L. The vehicle struck the aircraft just

PILOT ERROR CITED IN MEXICO CITY CRASH Head of U.S. Federal Aviation Administration investigating team said pilot error appreared to be cause of crash of Western Airlines DC-10 at Mexico City October 31 which killed 72 persons. Official noted investigation di"sclosed no mechanical malfunction or control tower mistakes. He said preliminary findings showed pilot, a 30-year airline veteran, was trying to land when he could not see runway due to fog. Repeated warnings from control tower that he was off course were said to have been issued, but landing was made on runway which was under repair not on a parallel runway on which landing was suppo'sed to have been made. Plane crashed into truck and pilot was among those killed. National Transportation Safety Board studies of 71 fatal accidents show pilot error involved in 63 %.

41

Voice Logging in Air Traffic Control: Over 25 Years of Progress ~ I

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The old way of recording ...

Traditionally, the air transportation industry has led the world in demanding and applying the most rigorous standards of safety and security. These standards can be seen in every aspect of the industry: equipment, maintenance, personnel, training, rules and procedures.

But for the air traffic controller, safety means not only using advanced equipment and observing carefully formulated ruies.

It also means exercising judgement to determine quickly an optimum course of action from interpretation of a constantly changing picture of traffic and condition's.

Like any key personnel whose task combines heavy responsibility with a wide range of discretion in action, both air traffic controllers and pilots may sometimes have to justify their decisions and actions. In ·such cases, it is vital that what was said and done can be proved beyound doubt, to show that the right information was given, the right instrutions were issued and the right action was taken.

Such proof can be provided only by a comprehensive and completely dependable voice logging system, which can unfailingly record every conversation with an air traffic control centre.

Standard equipment The use of voice logging as a means of recording air traffic control messages has become widely accepted since its introduction in the early 1950s. Among the leading suppliers of the necessary recording equipment is Philips, which wa·s one of the pioneers in this field. The company now claims over 25 ye:ars of experience in voice logging, during which time its voice loggers have become accepted as standard equipment at over 120 of the world's major airports.

Over this period, Philips has developed four distinct generations of voice loggers specifically to meet the communications recording needs of the air transportation industry. Successive generations of the equipment have shown increases in both capacity for simultaneous recording on multiple channels, and continuous recording time.

For example, the recently introduced fourth generation voice loggers have a simultaneous recording capacity of up to 44 channels (although smaller configurations are also available with 11, 22 or 33 channels) to meet the needs of centres where large numbers of aeroplanes may be under control simultaneously.

stop to change tape for 24 hours. After this period, changeover to a stand-by tape deck carrying a fresh tape reel takes place automatically, with a 30 minute overlap period, so there is no danger of any loss of recorded information.

A comparison with the early equipment of the mid-1950s illustrate·s the extent of the technological developments that have taken place. The first generation voice loggers in use at that time, for example, had a capacity of up to 15 simultaneous recording channels, and could operate continuously for a maximum of eight hours. In the second generation units, introduced in 1965, the number of recording channels had increased to a maximum of 31, while continuous recording was possible for up to 12 hours.

In addition, neither of these units possessed the comprehensive standby facilities which are taken for granted today as the only way to ensure that the risk of information loss resulting from equipment malfunction is virtually eliminated. This system was first introduced by Philips in its third generation voice loggers, which first appeared in 1974. It was further refined with the introduction of the fourth generation units in 1979 by the adoption of computerized monitoring of all vital recorded functions. A warning is automatically given of any system malfunction, and the built-in monitor panel contains indicators to help pinpoint and correct any fault in the minimum tape. Automatic switchover to the stand-by tape deck takes place when the fault is such as to endanger the security of recording.

Extended service life As well as high reliability achieved by the provision of extensive stand-by facilities, durability and service life are important considerations for equipment of this type where the initial cost has to be amortized over a long operating life. To ensure that this is achieved, the highest possible standards are applied in both design and manufacture so that requirements for both preventive and corrective maintenance are reduced to an absolute minimum.

Although the design lifetime of each Philips voice logger system is ten years in continuous service, operating experience gained in over 35 years as a supplier of these systems shows that the actual lifetime is very often considerably longer.

In fact many systems are still in economic, everyday operation at around the 15 year mark. Full availability of spare parts and service facilities for these early machines is maintained to ensure that they can be kept in continuous service.

These service facilities are available from numerous centres strate:gically placed around the world. Alternatively, training courses can be provided for technicians of larger organisat;ons wi'shing to carry out their own preventive and corrective maintenance.

•

Automatic changeover Continuous recording times have also been steadily extended, so that the latest equipment can operate without the need for a 42

and the new, the Philips way.

The ATC Operational Information Display D. G. Grainger Goodwood Data Systems Ltd. Corporate Member of IFATCA

Introduction The Operational Information Display is a multi-channel, T.V. type information display. This information display will be used by controllers to retrieve operationally required data at their control positions. The data before now has not been readily available (WX sequences) or if it has been available, a filtering process has been required because the data is pertinent to a large number of users and not specific to any one of those users (CCTV or viewgraph).

It is generally accepted that the method now in use in various ATCC's is inadequate as a source of operationally required controller assi'sting information. This method of display has become surfeitted with meteorological and other sundry data leaving little room for Notams, Flow Control, etc. The viewgraph type of display is further restricted because console equipment often blocks the controllers view of the area of projection.

Data The type of data being presented on the information display falls into three main categories: i) information that is sensed automatically, then output to the display (e. g. weather sequences). ii) information that is sensed automatically, then is processed through an algorithm, and i's then output to the display (e. g.

Mean and Now Winds). iii) information that is manually entered and then output to the appropriate display (e. g. ATIS message content).

Purpose The purpose of the Operational Information Display is to consolidate operational information on a Cathode Ray Tube Display (T.V. monitor) in digital form to provide the controllers, data on a ••need to know" bas i's rather than force them to individually filter out the information during the stress of the working environment.

I

ILS RVR NAVAIOS DADS WINO DIRECTION RUNWAY LIGHTING WINDSPEEO

TERMINAL BLOCK

DATA ACQUISITION UNIT

4 TERMINALS

DATA ACQUISITION UNIT

USED r-----,'

--------16 POSSIBLE

I

GOODWOOD :

DAT~

SYSTEMS

C~~lf. TON rl. .. Cf ~NTJ.SU~

LTD

I

CANADA

AES MET

43

GATE ASSIGNMENT

APP

AL

RVR

1LS 24L

A60•B60·

PAR 24A

A60•B60•

GATE

AIRLINE BA101

AC345

23

BA602

,, ,,

AC2J4

BA657

MEAN

NOW

ALT

ACl5'

3,

PA795

70

27/10

28 10

2980

AC567

45

FA177

81

AC678

56

KLSJC

55

AC789

67

08,114

66

"

oesrs

-;;

89

AFl23

88

"

AF234

:.'5-29,'10-30

UL 10825 -121118 2'2910 HU 14835-F 140.20. 4 301;'

2952

AC891

.. ·- 2993

AC9l2

2965

AC135

MX S101200 1502088S - • 879 16 2 2•115•20

AC791

FLOW OHL

BOS • 10 0HWEEN

CA9076C

I\ C ENTERING BOS AREi,

FLOW CNTL YZ • 10' BETWEEN WESTBOUNOS 1200 G'P lLS2.aA US TIL 1600

A TYPICAL PAGE FOR THE TERMINAL CONTROL AT DORVAL, QUEBEC

NOTAMS WEATHER

NOTAMS

1205JS MX 5101200 150E23012 879/34/30/0415•20/9101CF4CU4

OWVORTACUSllL

liU 015• 135/23/11/3014/989

UL GP ll52JR U,,S 1200 - 1600

JN 1200250015• 114/14/5/2412i976/AC1C11

ST EUSTACHE TACAN CHANl10 US TIL APR l72100

OJ 250-015• 143/1918/3215/989/Cll

NO STANDBY POWER FOR RADAR APR 171500 TO 1700

OW 015 105/23/13/11/3017/990/AC/

1500

RADAR US APR171700 TO 2000

SC 015 I tS/19/5/2823•30/933

BAGOTVILLE TACAN CHAN!:13 Al11,1UTH U S DME SVCBL

OEVES YZ

TR 14001S• 140123/11/3017/990/AC/ OEVES YZ PG 200200•015 014/17/9!2327 •33J955/SC212 CC PRSNT HVY DRFTG SNW MSS 015 118/19/512823•301983

ATIS RUNWAY AND FIELD CONDITIONS

flME ATISUL

RNWY & FIELD CONDITIONS

• UL

1205 ,i5

UL 1092S· 127'18'2,2'9l0 All APP

LANDING

ILS?4l.

RNWYS

OEPT

BARE & ORY SNOW COVERED

50°, WITH 3 IN DRIFTS

ICE PATCHES

20~; SANDED

SNOW COVERED

1001 0 WITH 3 IN DRIFTS

24L

PAR 2JR

VFR 24R

28 TAXtWAYS

NOTAMS

SNOW REMOVAL IN PROGRESS ST EUSTACHE TACAN CHAN 110 US TIL APR li2100 OW VORT AC UtS Ttl 1SOO UL GIP ILS 24R US

44

1200. 1600

..

Wl11

"

Specifically, the following information 1) Time 2)ATIS 3) Approach Aids and Landing Runway 4) Approach and Runway Light Settings 5) Wind Direction and Speed 6) Runway and Visual Range 7) Altimeter Settings 8) Weather Sequences 9) Flow Control Restrictions 10) Navigational Facility Unserviceabilities 11) Notams 12) Runway and Field Conditions 13) G,ate Assignments.

is being displayed

-

System Description The system will consist of the following subsystems (figure 1) 1) a display subsystem 2) a data acquisition subsystem 3) a central processing unit with software and programming peripherals The system has been designed so that all elements have redundancy in case of failure.

Display Subsystem The display subsystem consists of a number cluster control units. Each display channel provides: * video converter to give a 20 X 64 array * e 5 X 7 matrix character * a video driver for multiple monitors * keyboard and keypack inputs * lailure information * refresh memories.

* * * *

of GDS-300

The cluster control unit provides: independent channels to each computer data distribution to the video channels overall subsystem control communications options.

Pages A page is the practical number of characters that can be . displayed at any given time on the screen of the monitor. There are two types of pages: primary and secondary. A primary page arises because most control positions have a data presentation differing from another; each primary page has emphasis on information peculiar to that position (figures 2-3). A secondary page normally comprises of all the available information in the system on information of one subject: weather page, A TIS content, Gate Assignments ... (figures 4-8).

Page Format Figure 2 illustrates the present format, for the UL TCU, Dorval sector primary page. The format of the page is divided into four horizontal areas. The top areas display current tactical control information, which the controller needs to know to successfully perform this control function; these are: GMT, Approach Aid, Runway Lights, Approach Lights (including Vasis), Runway Visual Range, Current ATIS, Mean Wind, Now Wind, DADS (Digital Altimeter Display System). The middle area contains the current weather reports - hourly or specials required by Dorval. The lower area contains a message area for UIS facilities, Notams and other messages the collator may deem pertinent to Dorval.

Time appears at the top left corner and is incremented in 5 second intervals. To the right of the time readout is the area reserved for Approach Aid and Landing Runway and is headed by the title APP (there may be more than one currently in-!.lse).

Changes in the APP would be entered from the tower keyboard and would correspond to the current operational requirement.

The selection of the approach aid causes an automatic coupling of the Approach and Runway Lights associated with that runway selection. These appear to the right of the APP indicated by AL and RL. Under the heading of RVR appears the Runway Visual Range and is in a format similar to pre·sent indicators. The alpha character designates the runway position, the numerics t1esignate the RVR readout. If there are more RVR serviced runways than can be conveniently displayed, then the RVR displayed is tied to the selection of the APP similar to the Approach and Runway Lights. The top right position contains the current ATIS code designation.

The horizontal area on the primary page contains wind and altimeter. The MEAN wind in this example. refer's to a twominute average wind - 270 degrees at 10 mph - followed below by the extreme deviations for the two minute period. The Now Wind is the current wind averaged over the last 5 second period.

No deviations are displayed here but they are taken into consideration in the averaging process. The wind information used in the averaging process is sampled from the presently in use analog dials, one sample per second. The altimeter ALT is online value from the new digital altimeter currently being introduced into operational service.

The third horizontal area contains the hourly and special weather reports, which are by site adaption, appropriate to this control position. These sequences are compacted and reform 9 tted for ease of reading and quick retrieval of specific information. The data from the beginning of the sequence to the end of the obstructions to visibility are retrieved and placed by themselves. The temperature and dew point is then displayed by· itself, then the altimeter as reported on the weather sequence is pulled out and placed on the extreme right of the display. Dots are placed in between each sequence grouping in order to ~orrelate the various parts of the sequence with the identifier.

Below the dashed line is an unformatted message area to which pertinent information is routed either automatically sue~ as "HU BEACON U•S", or manually entered and routed ·by keyboard or paper tape reader. This area contain·s Notams of interest to that particular sector. flow control information, unserviceable equipment status will be flashed to and acknowledged by the controller. When the information is no longer current or -of .no further use; the area will be cleared to make room for more pertinent information.

Data Input Information entered into the system is automatic except for three manual positions where extended data entry keyboards are used. The tower input station is limited to modifying its own primary page. the PAR primary page, the gate as'signment page and the ATIS page. The centre input position-collator has access to all pages within the system and can modify any of the pages as he sees fit.

The third position of entry is the Ramp Controller's position.

This position can enter or modify information in the Gate Assignment page only. He can not modify any other page.

Responsibilities The requirements dictated by the new system will not differ significantly from the present responsibilities.

For the tower the keyboard takes the place of teleautograph (electro-writer), telephone and hot-line in various phases of its usage. For the collator (the primary input station), the proposed duties will be: i) monitor and verify the operation of the system. ii) filter and enter data such as Notams, Flow Control, N.A.T. Tracks, and route the·se messages to the appropriate sectors.

Information Retrieval The retrieval of information i) automatic retrieval ii) manual retrieval.

will take place in two ways:

45

The information considered suitable for automatic Time Approach, Basis and Runway Light Settings Runway Visual Range Wind Altimeter Weather Report Sequences, and Monitored Navigational Facilities.

retrieval is:

The information considered not suitable for automatic retrieval, whether because of economics or efficiency of the effort ATIS Code and Content (keyboard) Approach Aid in Use (keyboard) Unmonitored Facilities (keyboard) Notams (paper tape reader) Flow Control Information (paper tape reader) Runway and Field Conditions (paper tape reader) Gate Assignment (keyboard) NAT TRACKS (keyboard).

Data Acquisition Subsystem The Data Acquisition Subsystem will retrieve data automatically from the wind speed sensor, the wind direction sensor, the DADS altimeter, the RVR indicator. This sensor acquired data will be converted to a digital format through a Goodwood Data Systems Data Acquisition Unit.

Data Acquisition Unit DCU/4 This provides: input selection of discrete or byte optically isolated input's communications compatible output modular design field proven reliability built-in test circuitry designed for real time applications.

Central Processing Unit A number of alternatives for the CPU for the Canadian 010 System were: lnterdata Model 70 lnterdata Model 7/16 expanding into 7/32 Data General Nova 2.

Consideration was given to a Digital Equipment PDP11 Model 40. The Ministry of Transport chose the lnterdata Model 70 because of commonality with the Terminal, En route System.

This dual CPU is provided with 64K bytes of core memory and normal programming peripherals.

Page Selection A controller at a sector or radar position will be able to select any one of 10 information pages that are made available to him through site adaption. The selector device is a 16-button keypack or an extended keypack in some instances. For example, depressing button #1 will cause to be displayed the primary page whose information is unique to that sector, depressing #5 will cause the A TIS content to appear ...

Maintenance Features To facilitate the maintenance of the OIDS, a special position is made available in the equipment room. This position, designated Maintenance Control Position (MCP) is equipped with a keyboard, a video monitor and other special features. The MCP is responsible for the maintenance of the equipment. The MCP initializes the system by loading in the "operational" program and bringing the equipment on line. In addition the MCP loads 46

in a number of overlay programs that are used only on a need basis. The overlay·s are used for RVR testing, manual update, memory dump, and data base transfer. The MCP is located close to both CCU's and is supplied with all video signals outputted by the CCU. In this way, the MCP is able to check the video as it is supplied to the video monitors.

Redundancy Features The OIDS system has a number of fail-·soft features that are invoked when various hardware items fail. For example there are two CPU's. One CPU functions as master and the other functions as standby. The data content in both CPU's is maintained at the same level thereby providing a hot standby unit.

When brought up to the standby status, a CPU tests for the presence of the master unit through the use of handshakes.

When the standby unit fails to receive an acknowledgement from the master CPU, the standby unit assumes control of the system.

Additional fail-soft features are provided through the u·se of two CCU's and a special operator position designated Collator. Both CCU's provide "normal" communication paths with the various operator positions. A normal communications path is one that provides an operator position with the capability of making page requests, inputting machine instructions, and similar ta·sks. A CCU contains a separate memory for each video monitor connected to it. When an operator position requests a page of data, the CPU assembles the contents of the requested page in the CCU memory appropriate to the operator position. The video memory is then scanned by the CCU to generate the video signal which then paints the page of data on the monitor :Screen.

To provide operator administered fail-soft features, the Collator is supplied with several back-up pages. In addition to the normal communications, the Collator is supplied by two ·standby pages, one through each CCU. The standby pages are maintained in the CCU's by the CPU and are available as alternate pages in the event of the breakdown of a normal communications path.

A switch available on the Collator enabIe·s an operator to route the standby page through the Collator to a video bus. This video bus is connected to the monitors as an alternate video signal.

When a normal communications path breaks down, the operator is able to select the standby page from the video bus. Additional fail-soft features include the use of an emergency page. The emergency page is supplied directly to the Collator and is maintained in a video memory of the Collator. During normal operating conditions, the CPU updates the emergency page. In the event that both CPU's fail, the emergency page is available within the Collator and the Collator operator can make the emergency page available to the video bus. When both CPU's fail the Collator operator can assume control of the emergency page and can manually update its content thereby maintaining the emergency page at a current status. Although there are two DAU's available, only one is used under normal conditions. The second DAU is provided as back up. The CPU te·sts the data received from a DAU and if it determines that the data is no longer good, the CPU will select the alternate DAU. Normal communications are maintained by a CPU using both Cluster Control Units. The data signals supplied back through the CCU are applied to both CPU's in parallel so as to maintain the same data in the memories of both CPU's. If the standby CPU determine·s that the master CPU is no longer available, the standby CPU assumes control of the system by sending out a CPU select command to the CCU's. The CPU select command causes the CCU's to be responsive only to the CPU that sent out the command.

System Features Consolidation The introduction of a computer allows the collection and storage in one data base, needed controller information which before now ha·s been presented by CCTV or viewgraph, clipboard

... by using a small computer the controller is given the power to produce whatever information he would like to see from the data base, simply by using his keypack selector.

Versatility Because the Operational Information Display employs a small but powerful computer, format changes and sector reconfiguration can be made with software program changes. Similarly, if a sector is reconstructed, the TV monitor used to display the information to the controller can be moved at will, restricted only by the constraints introduced by its influence on other systems.

Modularity Software programming for the system is done in a modular fashion. This allows a basic program to run a system for a stand-

alone terminal unit, or this same program by virtue of modular additions can also run a system for a large centre-terminal complex. The equipment itself will be modular. The various site configurations for OIDS are all different to a minor degree. However, the modular design technique allows totally interchangeable modules to be used in such a manner as to accommodate these changes.

Space Requirement Considering a 9-inch television monitor in the controller's con·sole replacing the functions of existing indicators, about a 7-1 space saving will result. The television output of the Operational Information Display System utilizes only a small solid state monitor in the console and requires one signal line. Total system interface for the sensors in the equipment area should require approximately the space at pre·sent occupied by a single RVR converter.

■

News from Corporate Members Cossor Major Supplier of Secondary Radar Cossor is a major international supplier of secondary radar and the lead firm in this field in the UK in collaboration with CAA and the Royal Radar Establishment. In 1979 the company was awarded contracts by CAA for 20 SSR interrogator systems using monopulse direction finding techniques. This represented the world's first order for monopulse SSR. The CAA systems will later be modified to full ADSEL operation. Flying trials of ADSEL are currently going on under airline operational conditions. Cessor anticipates that the increasing density of air traffic will lead to a steady demand for monopulse SSR which will in turn provide the lead-in to ADSEL. The only inhibiting factor will be the need for international agreement on standards.

Mexico City AFTN centre to be equipped with AEROPP switching system Philips' Telecommunicatie lndustrie has been awarded a contract by the Mexican Ministry of Communications and Transportation for installation of an AEROPP II message and data switching system at the AFTN centre in Mexico City. The order is valued at 5.4 million Dutch guilders. The AEROPP II system based on DS-714 81 hardware will equip the Centre, operated by the Civil Aviation Administration of Mexico, for fully automatic routing of AFTN, WMO and ATAIIATA traffic. The system is expected to be fully operational by the end of 1980 and replaces a semiautomatic Philips ES-2 electro-mechanical exchange commissioned in 1969, Initially the AEROPP II system will connect 250 lines (operating at up to 600 bauds) linking the Mexico City centre with national and international AFTN centres as well as with meteorological stations and airline offices throughout Mexico. Two medium-speed connections to the United States will follow w:th a direct line to Chicago carrying ATA IATA traffic, and one to the DS-714 MK II equipped U.S. Weather Message Switching Centre in Kansas City for transmission of meteorological data.

The ability of the AEROPP II system to handle the Centre's immediate switching requirements together with those anticipated over the next decade were largely responsible for its selection by Mexico·s telecommunication authorities.

The expected rapid growth in aeronautical message traffic between North and South America, and Mexico City's position as a key junction between the two areas, necessitated maximum flexibility in the Centre's switching equipment. The AEROPP II system will not only cover

the Centre's predicted traffic requirements for a minimum of ten years but also will enable the Centre to supplement its current functions with CIDIN operation, telex/data interface facilities and a range of other services if required.

Philips Costa Rica orders Electronic Teleprinters Radiografica Costarricense, S.A. (RACSA), the authority of Costa Rica responsible for telex communications, has awarded Philips Electronikindustrier AB (PEAB), the Swedish based division of Philips responsible for the manufacture and marketing of teleprinters, a contract for the supply of five-hundred PACT 200 electronic telex terminals. The order was won in a public tender against competition from leading international manufacturers of teleprinters and is valued at approximately 1.5 million US dollars.

Delivery is scheduled for completion by the end of 1980. The contract includes local training of RACSA personnel.

Nearly all of the units to be supplied are PACT 200 ESR automatic send receive terminals with solid-state memory in which messages can be prepared and edited with far greater facility than on paper tape. The memory can also store incoming messages automatically when an operator is preparing messages locally resulting in substantially higher terminal availability and fewer operator interruptions. Elimination of the paper-tape assembly, moreover, enhances the terminals reliability, lowers equipment costs and overcomes the noise problem associated with paper-tape punching. Modern features such as abbreviated dialling and horizontal tabulation are standard.

Selenia Other Selenia ATC Radars for Sweden The Swedish Board of Civil Aviation has recently ordered an ATCR-22 L-band Long Range Primary Surveillance Radar from Selenia of Italy. This radar is the fourth of the new class of adaptive radars that Selenia will deliver to the Swedish Civil Aviation Authorities. The two first are installed in Sundsvall and Jonkoping, the third delivered to be installed in Stockholm.

The new ordered ATCR-22 will be supplied in 1980, and will be installed at Alingsas near Gothenborg.

The sale of this ATCR-22 brings to total of the new 3rd generation adaptive ATC radar, sold for export, up to 35 dualchannel radar systems.

■ 47

TAIL PIECE Where does the money go?

Revealing Enlitled Household income and expenditure statistics, the ILO recently published a ·survey that covers the years from prerecession 1968 to inflation-ridden 1976.

It attempts to provide an answer to the question which puzzie·s economists and husbands alike - where does the money go?

As consumer patterns do not change overnight, the ILO data shed a revealing light not only on the 8-year period covered, but also on the present spending trends and, indeed, on those of the foreseeable future.

The survey shows that in developing countries households spend nearly all the money they receive (95 to 99 per cent) for consumption purposes, namely food, clothing and ·shelter, transport, education, medical care - items which are defined by the ILO as basic needs.

In developed countries, families spend money also for nonconsumption purposes, a major part of which is income tax and other direct taxes as well as private investments. For familie·s living in Australia, Canada, Finland, the Federal Republic of Germany, Israel and the US this outlay for non-consumption items amounts to about 13 to 18 per cent of total expenditures.

• In the USSR and other European socialist countries nonconsumption expenditure is about 14 to 23 per cent, a major part of which goes for services.

eating out accounts for 17 to 20 per cent of the food budget, and 10 to 15 per cent in socialist and northern European countries.

In all other countries, especially in Africa, Asia and Latin America people spend nothing or very little on restaurant meals.

Beverages About 18 per cent of food budgets in Great Britain is spent on alcoholic beverages. Australia and Greenland follow closely with about 16 per cent. In Ireland it is 12 to 15 per cent; Canada, 14 per cent; Czecho·s1ovakia, Papua, New Guinea and New Zealand, 11.5 to 12 per cent; Malawi and Sierra Leone (urban households) about 10 per cent; Denmark, Sweden and France, 8.8 to 9.5 per cent. The American family spends about 6 per cent of the food and drink budget on alcoholic beverages.

Transport and communications According to the ILO study, Americans spend more of their income on transport and communications, 23 per cent, than on food and drinks, 21 per cent. In Australia, Canada, Finland, Kuwait, New Zealand and Norway, transport and communication expenses are also high, about 17 to 20 per cent of the household budget.

Food budget

Housing

In Nepal and rural households in India, 50 to 60 per cent of the food budget is spent on bread and cereals, in Peru it's about 26 per cent, in Africa, about 20 to 30 per cent and for Americans and most Europeans, around 10 per cent.

Milk and dairy products account for 15 to 25 per cent of the food budget in India, topping that of the traditional "milk-dringing" Nordic countries where it is 14 to 16 per cent.

In Belgium, France, Italy and Spain about one-third of the food budget goes for meat and fish as against 26 to 30 per cent in many other European countries and 21 to 25 per cent spent

by Australians, Americans and New Zealanders.

Expenditures on shelter (rent, housing charges) are important item·s of consumption accounting for about 16 per cent in Asia, 15 to 20 per cent in North America and 12 to 20 per cent in Europe. In the USSR expenditures on shelter are less than 3 per cent; in other European socialist countries, about 5 to 9 per cent.

These are some of the highlights of this latest ILO inquiry into household expenditure. The data are given by social and occupational groups, size of households and geographical areas.

To facilitate comparative analysi's, the findings have been reclassified, as far as possible, in standardised form in line with international recommendations.

The ILO survey is especially valuable for income distribution studies, measurement of standards of living and the determination of poverty levels.

Thi's in turn may help national planners in formulating economic and social policies.

■

Eating out American·s and Canadians, however, spend about one-fourth of their food budget on meals taken outside the home, while in Switzerland, the Federal Republic of Germany and Australia,

48

The important thing about this service is the airline which flies it.

TORONTO CALGARY EDMONTON WINNIPEG VANCOUVER MONTREAL OTTAWA LOS ANGELES AMSTERDAM

ROME . MILAN MEXICO CITY LIMA NANDI ATHENS HONGKONG TOKYO HONOLULU SYDNEY I

For further details contact CP Air Reservations 62/65 TrafalgarSquare,London WC2N 5EB. 01-9305664.

£!!~!!B Canadian Pacific,CPAir. .. keeping the great name great.

OOS-80 Intelligent Display with the Selenia NOC 160 16-bit incorporated minicomputer

distributed intelligence - the system of the future The SATCAS 80 ATC System is based on the concept of distributed processing, using the Selenia developed NDC-160 mini-computer wherever intelligence is required. Radar data from the Selenia primary and secondary radars are extracted and processed by radar head processors.

Transmission is narrow band to radar data processors, which interface to flight-data processors and built-in display processors.

The benefits are better cost-efficiency.tighter program control and better man-machine interface.

INDUSTRIE ELETTRONICHE ASSOCIATE S.p.A.

CIVIL RADAR AND SYSTEMS DIVISION Via Tibunina Km 12.400, 00131 ROME, ITALY Telex 613690 SELROM I, Phone 06-43601

SELENIA IS EXPERIENCE IN AIR TRAFFIC CONTROL