IFATCA - The Controller - November 1976

D 21003 F

JOURNAL OF THE INTERNATIONAL FEDERATION OF Al R TRAFFIC CONTROLLERS ASSOCIATIONS

In this Issue:

International Aeradio College of Air Traffic Services The Lyo n 76 Medical- and Technical Panel Sessions

FRANKFURT AM MAIN

NOVEM BER 19 76

VOLUME 15

N0

4

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IFATCA

JOURNAL

OF

AIR

TRAFFIC CONTROL

THE CONTROllER Frankfurt am Main, November 1976

Volume 15 ¡No. 4

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

OHlcers of IFATCA: J-D. Monln, President, 0. H. J6nsson, Vice-President (Technical), H. H. Henschler, Vice-President (Professional), E. Bradshaw, VicePresident (Administration), T. H. Harrison, Executive Secretary, H. Wenger, Treasurer.

Editor: G. J. de Boer, P. 0. B. 8071, Edleen, Kempton Park, Tvl., 1625 South Africa, Telephone: 975-3521 Contributing Editor: V. 0. Hopkin (Human Factors) Managing Editor: Horst Guddat, Otto-Bussmann-StraBe 7, 0-6368 Bad Vllbel 2, (Federal Republic of Germany).

Telephone: (06193) 85299 Publishing Company, Production, Subscription Service and Advertising Sales Office: Verlag W. Kramer & Co., Bornhelmer Landwehr 57 a, 6 Frankfurt am Main 60, Phone 434325 and 492169, Frankfurter Bank, No. 3¡03333-9. Rate Card Nr. 6.

Printed by: W. Kramer & Co., Bornheimer Landwehr 57 a, 6 Frankfurt am Main 60 (Federal Republic of Germany).

CONTENTS

Subscription Rate: OM 6.- per annum for members of IFATCA; OM 10,- per annum for non-members (Postage will be charged extra).

The Controller's Legal Liability (Ill) .

6

I A L College of Air Traffic Services

10

Anticipation

14

Air Traffic Control in Sweden (Ill)

16

Report on Near Collision DC-10 I L-1011

20

International Law (XI)

23

The Lyon '76 Medical and Technical Panel Sessions and 15th Anniversary Reunion

27

Operational Control - A Unique Australian Concept

32

W~itt~n permission by the Editor is necessary for reprinting any part of this Journal.

The Air Traffic Controller's Problems associated with Ground Movement Control

35

Cartoons: Helmut Elsner.

News from Corporation Members

39

LAR II: Slgnaal's Versatile High Performance Radar

43

Comments on Air Traffic Control

46

Recent IFATCA Press Releases

47

Publications Review

47

Letters from Readers

48

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

IFATCA does not assume responsibility for statements made .a~~ opinions expressed, It does only accept respons1b1llty for publishing these contributions.

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 rlg.ht to make any editorial changes In n:ianu~cripts, which he believes will Improve the material w1t'1out altering the intended meaning.

Fotos: Archiv, Flughafen Frankfurt AG J. Fournier, Hollandse Signaalapparaten, IP Studio~ (IAL), Solartron, Stansaab, T. Wingstedt.

Advertisers In this Issue: Stansaab (inside cover), Holiday Inn Hotels (page 3), Hollandse Signaalapparaten (page 5), International Aeradio Ltd. (page 7), Ferranti Digital Systems (pages 24/25), CYATCA/IFATCA 77 (page 41), Selenia (inside back cover), Racal Thermionic (back cover).

From The Tower ...

--"--

--'--

----Let's Keep A Balanced View

There comes a time, in the life of all organisations, when its members sit back and review progress made. Undoubtedly our Federation, in the 15th year of its existence, is now going through such a period of self-examination, and the Executive Board has been aware for some time that - although many Member Associations are in agreement with the Federation's actions and policy - there are some Member Associations who question whether there should not be changes to the Constitution, in particular it is thought that industrial matters should receive greater attention. It has been suggested that a new International Federation of Air Traffic Controllers' Unions could possibly not only achieve a greater measure of success than IFATCA has in the pursuance of its aims, but could also be run more cheaply by "doing away with such paraphernalia as the Annual Conference". on the other side of the coin, however, there are beliefs that the Federation's successes in recent times in its support of actions by Member Associations have only been possible under the present Constitution, or that industrial action in these instances would not have obtained any better results. There is no doubt that there Is always room for improvement, but let us do this through reasoned evolution, not by hasty revolution, and then we can perhaps achieve the best for everyone. In this light, the Executive Board proposes to present a Working Paper at our next Annual Conference giving delegates the opportunity to decide the future course of the Federation.

During the past four years, under the leadership of Daniel Monin, we have been making real progress towards a more effective approach in respect of controllers' problems, and this more radical stance in supporting Member Associations in their actions has been welcomed by our membership. This type of progressive attitude was unheard of back in IFATCA's early days..in the sixties. And it is increasing. It can be said that IFATCA's Standing Committee IV and Committee 'C' at Annual Conference have virtually bE!°en'!the industrial branch of IFATCA for years. The International Labour Organisation has acknowledged IFATCA and is embracing us (i. e. controllers) in their considerations. This trend must be continued but certainly not to the detriment of the professional recognition the Federation has achieved.

The suggestion to form a world organisation of controllers' unions can generally be looked upon as symptomatic of organisations that are heavily labour-union oriented, where lip service is given now and again to professional and technical developments in the field of Air Traffic Control, but where the primary concern is workers' rights. However, to get anywhere in our unique profession, promotion of far wider goals are necessary if controllers really want to have a continued say in the constantly changing environment in which they perform their daily work. IFATCA, as presently constituted, provides this at all those international gatherings - such as ICAO meetings - where the present and the future of the controllers' profession is a topic of discussion, and decision.

One of the indispensable qualities of the controller's profession is common sense. As this Federation is a Federation of national Associations it is quite clear that its objectives can only be those which they have in common. As some national Associations are purely technical, whilst others nationally perform the dual function of technical association and trade union, it has been a principle until now that IFATCA shall not operate as a Federation of trade unions, but shall function as a professional organisation. However it is a practical impossibility to draw a clearly defined dividing line between the fields of activity of trade unions and a professional organisation like ours. The main obvious difference lies in their approach to certain issues that they are considering from different angles, in accordance with their distinctive constitutional principle. Certain aspects of trade union activity, generally ranked by union~ as of s.e~ondary i":'portance, are for IFATCA of prime interest, take for example professional trammg, recruitment, advancement of professional knowledge, etc.

2

IFATCA reserves the right to deal independently with all matters which have a direct bearing on its main constitutional principle of safety in air navigation. As such we consider for instance working conditions, by which we mean the environmental factors affecting personal efficiency, medical and technical aspects, pensionable age (early retirement). disputes, human factors, etc. But it would be of little use to study subjects and pass resolutions on them, when no reasonable chance exists for adoption. Therefore , a sound relationship between IFATCA and international and national aviation authorities is a condition for successful activity for our Federation. And so it is important to realise - and that is often forgotten by those whose idealism sees merit in trade union activity only - that by the very nature of the work, the representative organisation of IFATCA must preserve much closer ties with the various official administrations than would be the case with a union. IFATCA is composed of groups on whose members - chiefly civil servants - rests the onus of directly implementing central or local government policies; we cannot cipher this away. Nor can we cipher away that most of our Member Associations are prevented from operating as a trade union even if they wanted to.

That a world organisation of controllers¡ trade unions would operate more effectively and more cheaply at lower affiliation fees paid in by member organisations is a spurious viewpoint. Unless the inevitable accusation is to be avoided th at this type of argument tries to pull the wool over people's eyes, such contention will need to be supported with figures if it is to be believed by anyone who knows how IFATCA operates. All ou r costs are m inimal, and conference costs are self-supporting. We challenge anyone to prove that an international organisation like ours can be run more effectively more cheaply.

"What help is expected from an international trade union which cannot be obtained from IFATCA? Can anyone give a list of decisions which - in his opinion - IFATCA should have made in the past? What substitute can be suggested in the place of our Annual Conference which will bring us in more publicity and goodwill, or is it suggested th at our profession is so well known that we can do without?" Such questions must be answered convincingly by all Member Associations but more particularly by those who advocate a new world union of controllers.

Let us not destroy wantonly what we have built up. Change must be achieved by working within the organisation, not by pulling out. Let's at all times keep a balanced view.

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CONVEX '76 ..-...., OOOBll iaa & ~a.

Le B ourg et 1975 Farnborough 1976

IFATCA at the Farnborough Air Show, North Hall, Stand A. 15 " Display of magazines, pamphlets, and other printed material outlining the activities of the International Federation of Air Traffic Controllers' Associations , which is a non-profit, non-union and non-political body dedicated to realising the professional aspirations of its members and to the welfare of those who fly."

This is how the Federation's entry was listed in the official Trade Catalogue of Farnborough International '76, which was held from 5-12 September 1976. Space in the catalogue prevented a more detailed description of ou r aims and objectives, but these we re explained and elaborated upon by those who manned the Stand. Thanks to Larry Curry, Master of the British Guild (GATCO), who personally supervised all arrangements, and Guild Editor Lesley Austin , the enterprise - the first at Farnborough - can be considered as successful. GATCO used the occasion to promote thei r forthcoming Convention (Convex '76), and IFATCA put the emphasis on making known the extent of their international commitments. Lesley, and IFATCA's Editor - who represented the Federation - were on duty during the entire weel< of the Air Show.

It was during this week that the disastrous mid-air collision occurred over Yugoslavia, and an increased level of interest in ATC on the part of the public was clearly noticeable.

Although the media instantly blamed Yugoslav ATC in an intolerable way, the public at Farnborough reacted much more responsibly, and we dealt with quite a number of serious questions. Again it was proved that our public relations efforts - at times even considered unnecessary by those who should know better - should be maintained, not run down, and - if at all possible - stepped up.

Early Retirement Further to the comments in this column in our last issue, we have since received information from our Australian Member Association that official findings from statistical surveys conducted by their Department and Public Service Board have generally confirmed that invalidity retirement rates among air traffic controllers in Australia peak shortly after age 50. whereas for other selected occupational groups the invalidity retirement rates peak after age 60.

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The Controller's Legal Liability

by Andreas Avgoustls, LL. 8. (Lond.), Chairman IFATCA Standing Committee

VII

Part Ill In their efforts to implement the objectives of air safety, air traffic controllers have found themselves named as codefendants with their employers in civil suits for damages following aircraft accidents. The principles upon which controllers have been found to be responsible for negligence were fully discussed in the first two articles. In this final article, we shall look at Court precedents which have resulted from specific cases brought before the Courts in various countries, with a view to illustrate as far as this is practicable the extent of the controller's responsibility during the execution of his duties. The cases are classified under four different headings, namely: (1) Departure; (2) En Route; (3) Weather; and (4) Approach and Landing, depending on the phase of the flight in which the aircraft accident occurred.

Departure Most of the cases of aircraft accidents involving air traffic controllers which have occurred in the departure phase of the flight were caused as a result of wake turbulence, and these cases reveal the extent of the controller's obligation to warn his traffic regarding flight hazards. Such accidents were principally contributed to "negligence" in clearing lighter aircraft to take off behind heavier ones, where the lighter planes crashed because of the wing tip vortices created by the preceding larger aircraft. However, one or two cases have been reported where an accident occurred under different circumstances, such as the clearing of an aircraft for take off while the runway was not clear.

Let us first examine the latter instance. Last year, the High court of Australia delivered judgement in a case which involved an accident between a departing TAA 8 _727 and a landing CPA DC-8 (for details see page 30 of volume 15, no. 2 of "The Controller"). The Commonwealth f Australia as the employer of the air traffic controller lved was judged 40 % to blame, while 30 O/o liability was mvo h · f · attributed to each of the captains of t e .two a1rcra t mvold The controller has failed to check 1f the runway was vel ·r before allowing the 8-727 to take off, believing that chea ilot of the landing DC-8 had comp 1·1ed wit· h h'1s taxy!n: ~nstructions, i. e. to take the first turning to the right ft the execution of a 180-degree turn on the runway. ~u~r unfortunately, the pil~t of the landing DC-8 had interpreted the taxying instructions to mean that he could backk all the way down the runway after the 180-degree trac The pilot of the departing aircraft was found to be ~~~; liable because, in the words of t~e judge, he did not t abandon his take-off assuming that he could be attemp t ·0 b rne before meeting · · ft w h'1ch t he o th er a1rcra safely air o . · ng down the runway.

The pilot of the DC-8 was backt ra Ck 1 . . . . o~0 to blame for mterpretmg the taxymg m30 I • th 'th th was a so structions incorrectly and for not querym~ em w1 ~ The controller's larger proportion of respons1II contro er. mined mainly because o f h'1s f a1·1 ure t o enbility was deter

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sure by radio, as evidence showed that he could not do this by visual means from the Tower, that the runway was clear before issuing the take-off clearance to the departing B-727.

Some time ago, a case came before the Courts of Israel, where the High Court reversed the decision of the Lower Court in favour of the air traffic controller. Details of this case were not disclosed at the time because one of the aircraft involved was military. However, what happened was that the controller at Tel Aviv Tower was called after midnight by a TWA flight for taxy- and take-off clearance. The controller, believing that no other aircraft or vehicles were moving about at that hour, issued the requested clearance. Unfortunately, at that precise time a military aircraft - without obtaining permission - was towed to another part of the airport with its lights switched off. Fortunately, the collision which occurred on the middle of the runway was not disastrous.

The U.S. Courts have held, in accident cases attributed to wing-tip vortices, that in addition to their duty to alert pilots, controllers also have a duty to use reasonable discretion in allowing aircraft to take off when there is a possibility of the existence of wing-tip vortices. In Hartz v. U.S., a light aircraft was cleared for take-off behind a DC-7, and subsequently crashed as a result of wing-tip vortices. The controller had acted according to "the book"· by allowing the aircraft to take-off, and had warned the pilot of the possible existence of wing-tip vortices. The Court, although recognising the responsibility of the pilot in command for the safe conduct of his flight, nevertheless found the controller liable because he allowed the aircraft to take off and did not delay its departure. The Court took into consideration the controller's duties as outlined in the ATC Manuals, but also considered the pilot's lack of experience in operating from the· busy airport in question and compared that with the controller's skill who had at the time an excellent all-round view of the airport and of all aircraft movements. The judge said: "He was an experienced controller who knew or by exercise of reasonable care should have known that it was hazardous for a small plane to immediately follow the take-off of a DC-7."

In this case, the Court also found the controller liable because he had not used the correct phraseology. It held that the controller's use of the word "prop wash" to the pilot had not indicated the severity of the expected turbulence, and that the words "turbulence" or "wing-tip vortices" should have been mentioned. The judge said that before a pilot can be held legally responsible for the conduct of his flight, he must know - or adduce evidence to indicate that he had known all material facts for the safe conduct of that flight. In this particular instance, the controller had a strong duty to warn the pilot, but his subsequent warning was not considered to have been sufficiently clear.

In cases where the controller did not anticipate wing-tip vortices which nevertheless existed because of extraordinary conditions, he will most certainly not be held liable.

The bird selects its flight path, its speed, its height. Free to climb and descend as it pleases. Not so the aircraft pilot. He has to proceed in busy air lanes in a disciplined manner. For the safety of his aircraft and passengers he must have information enabling him to operate within accurate and precise limits.

From take-off to landing he has to rely on beacons, communications control systems and other navigational aids to

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In Leighterburger v. U.S., the Court of Appeal reversed the Lower Court's ruling and found that a twelve minute long duration of wing-tip vortices could not have been reasonably anticipated. This case involved a Cessna 310 on an instrument let-down behind a Boeing 707 which had executed a missed approach procedure. The Court of Appeal held that the controller need issue a warning only "if he foresees the possibility of turbulence being a hazard", but in this instance that possibility was improbable and unforeseeable.

In Furumizo v. U.S., the air traffic controller had given a proper warning to the pilot of the light aircraft before it departed after a heavier one. But the Court held that although the controller had acted according to "the book", he had not taken any further precautions. After the warning, he just watched while the aircraft took off in disregard of the warning. The controller, the Court held, has a duty to warn when it becomes evident to him that the pilot is about to encounter a hazard. Once the controller saw the little plane start its take-off run, he should have alerted the pilot to the hazard which he would encounter. The Court condemned the controller's non-intervention.

The long established view that the pilot is ultimately responsible for the safe conduct of his flight has lost ground and has had the effect of lessening pilot responsibility and increasing controller responsibility correspondingly.

En Route

are responsible for the safe conduct of the aircraft ¡ . ¡ The pilot is in command of his aircraft. He is directly responsible and has final authority for its operation. However, before the pilot is finally held liable for his aircraft, he must know those facts which are material to the operation of his plane." Controllers must therefore provide all the facts which they have at their disposal to the pilot.

Weather Aircraft accidents can occur as a result of the controller's failure to warn pilots of dangerous weather which could affect the safety of flight, and this failure may involve him in liability for negligence. In Ingham v. U.S., the controller was held liable under a provision in the ATC Manual saying that information should be given to pilots regarding changes in weather conditions when the controller believes it is necessary in the interests of safety. It was contested that the controller is not under a duty to warn the pilot for weather deteriorations if such deteriorations do not drop below the minima, and in this case the controller did not warn the pilot of a change in the visibility from one mile to three-quarters of a mile because, as the controller put it, three-quarters of a mile was still above the minima laid down for the approach aid in use. But the Court held that controller liable for negligence.

In Reidinger v. T.W.A., the Court held that the controller was not to blame for the crash of an aircraft which had been cleared to land during the approach, because the controller had informed the pilot of the prevailing weather conditions and also of the limited availability of navigation aids serving the runway in use. The Court held that under such circumstances it is the pilot's responsibility to land the aircraft safely and not the controller's. The Courts work on the understanding that the controller is not expected to fly the aircraft for the pilot. In Spaulding v. U.S., for example. the pilot who was rated to fly under VFR only found himself in IMC weather conditions and asked the controller for assistance. The controller told him to descend to a lower altitude, and the aircraft subsequently crashed. The controller was absolved from blame.

In Schutelus v. U.S .â&#x20AC;˘ it was held that the controller, having given sufficient warning to the pilots of two aircraft flying under VFR, was relieved of any responsibility, and the responsibility remained solely with the pilots of the aircraft involved to avoid collision, certainly outside the circuit area. The Schutelus case concerned two en-route light aircraft on head-on collision courses. But in Miller v.

U.S., the Court held that the controller was responsible for the mid-air collision which had occurred between two light aircraft operating VFR in his circuit at the time. One aircraft was climbing and turning downwind from the crosswind leg and the other was descending and entering the cirIn another case, Stork v. U.S., the controller cleared an cuit pattern. However, the Court also found contributory aircraft for take-off in nil visibility in violation of FAA regunegligence on the part of the pilot who was joining the lations. The Court held that the controller not only acted circuit. He ought to have known that there was a great in violation of the regulations, obviously, but was also in likelihood of confliction at the start of the downwind leg breach of the controller's duty to warn of a weather hazard. and that he was also responsible for the safe conduct of thus causing the accident, despite the fact that the pilot his flight since he operated under VFR. was well aware of the visibility factor. It is somewhat surIn Maryland v. U.S., the radar controller was held liable prising that the Stork case is not considered on parallel for a mid-air collision for failing to warn the pilot whose lines with the Spaulding case. The IFR pilot in the Stork aircraft he monitored at the time, about the presence of case was as aware of the weather as the VFR pilot in the another aircraft - unidentified - which had appeared on his Spaulding case, yet in the Stork case the control !er was screen. specifically blamed for not pointing out the weather factor It is generally accepted that the separation of aircraft to the pilot. It can therefore be said that the duty to warn from terrain is the responsibility of the pilot, even though pilots which the Courts have laid on the controller increahe flies under IFR. However, it is the duty of a controller ses the burden of responsibility placed upon him. Unlike to warn pilots should he foresee a possibility of insufficient the wake turbulence cases where the pilot is unaware of terrain clearance. On the other hand, the radar controller their existence, the occurrence of ground fog is a factor is definitely responsible for keeping aircraft clear of terwhere the pilot can obtain the information himself with rain if such aircraft are under his positive control. "his own eyes", but if the controller doesn't tell him, he (the controller) is still negligent. In the Stork case, the In Spaudling v. U.S. (for details see the following chapCourt also said that "the regulations in the ATC Manual do ter), the Court in summarising the controller's liability held: not make mere automata of the controllers. Their jobs re..... the standard of due care is concurrent, resting upon quire that they act in the interests of safety". both the airplane pilot and ground aviation personnel. Both

8

Approach and Landing In delivering judgment in the Wabush case, Justice Kerr of the Federal Court of Canada said: "Aviation safety requires the efforts of air traffic controllers and pilots. Their efforts complement each other. Also the public travelling by air have no alternative but to rely on the controllers and pilots for the safety of their flights." The Wabush case arose from a crash at Wabush Airfield. The approach controller cleared the pilot to carry out a let-down over a beacon; the beacon let-down procedure had been withdrawn the previous day and another procedure had been promulgated but over a different beacon. Apparently the pilot had carried out the new letdown procedure over the old beacon. Because the controller's clearance was not considered to be the direct cause of the accident, the Court held that the controller was not to blame.

In Hocherin v. U.S., the Court held the controller liable for the collision of two light aircraft because he had failed to give sufficient warning to the pilots involved. An aircraft on final approach was conflicting with a non-radio aircraft which was also approaching to land. The controller used light signals to warn the non-radio aircraft away, but unsuccessfully. The Court held that the pilot of the radio-equipped aircraft did not possess all the details of the situation and could not therefore avoid the collision.

The controller's failure to warn the radio equipped aircraft once the non-radio aircraft failed to respond to his light signals was decisive as to his responsibility. The Court parallelled this case with that of a traffic policeman controlling a road crossing. "If a traffic policeman signals a car to proceed through an intersection knowing that the driver cannot see an approaching vehicle which the officer knows has just passed through two other signals to stop. would it not be incumbent upon the traffic policeman to warn the driver of the other's presence? We think it should."

Conclusion From the examples given above, one may positively conclude that the standard of due care is concurrent on both pilots and controllers. Under the general flight regulations the pilot has the primary and ultimate responsibility for the safety of this aircraft regardless of the flight rules under which he elects to operate. However, with the increase of control restrictions and the resulting reliance of pilots on ground personnel, the Courts have held that adherence to this responsibility had resulted in an unrealistic assessment of responsibility in certain accidents. As a result the Courts have held that before this "pilot strict responsibility rule" is applied, the pilot must be found to have known all the material facts for the safety of his aircraft.

From this the controller's duty to warn is emphasised.

If the controller's warning is either insufficient or untimely then he has breached his duty of care and he is liable. For example, warnings beyond those prescribed by ATC Manuals must be given when the danger is immediate (Furumizo v. U.S.); when the danger is known to the controller only and not to the pilot (United Air Lines v. U.S.); when the controller is better qualified than the pilot to evaluate the situation (Hartz v. U.S.); or when the controller is able to gather more information than the pilot (Hochrein v. U.S.).

The air traffic controller's increased legal liability during the past few years has been the subject matter of studies conducted by IFATCA's Standing Committee VII

(Legal), and these studies have resulted in resolutions passed at IFATCA Annual Conferences. The Australian Association, as a result of such increased liability are seeking pay rises of up to 75 O/o to compensate for the great risks involved in the execution of their duty, IFATCA's 15th Annual Conference, held at Lyon, France, earlier this year, examined a Convention wherein States are asked to support, within ICAO, the air traffic controller against legal suits which may be filed against him. The Federation will, before long, approach ICAO on this issue.

What Do You Know About IFATCA? Simply answer the following questions and find out.

The next 16 questions should be answered by "true" or "false". Correct answers earn five points each.

1. The Greenwich meridian crosses three countries with IFATCA members.

2. The Equator crosses two countries with IFATCA members.

3. It is possible to fly from 140' West to 60' East and always be controlled by IFATCA members.

4. It is possible to fly from 80' North to 5' North and always be controlled by IFATCA members.

5. It is possible to fly from 75' South to 12' South and always be controlled by IFATCA members.

6. It is possible to fly from 110' East to 180' East and always be controlled by IFATCA members.

7. It is possible to fly from 90' West to 180' West and always be controlled by IFATCA members.

8. There are nine IFATCA members in Africa.

9. The IFATCA Annual Conference has been held three times outside Europe.

10. The IFATCA Annual Conference has been held on all five Continents.

11. The following have provided a Regional Liaison Officer or Regional Councillor for Africa: Germany, Malta, Ghana.

12. There are five members who control air traffic in Asia.

13. All the following have sent observers to Annual Conference: Ethiopia, U.S.S.R., Spain, Indonesia, Ecuador.

Japan.

14¡ Three consecutive Conferences were held in countries beginning with I. 15. Two consecutive Conferences were held outside Europe.

16. The 1979 Conference will be held in Scandinavia.

Answer the following 4 questions correctly and ear~ yourself five points for each country correctly named ~if you are required to name six, you can earn thirty points in all): 17. Six countries in Western Europe do not yet have Member Associations of IFATCA. Can you name them?

18. Which of the following are not Founder Members of the Federation: Iceland, Ireland, Italy, Israel, Sweden, Switzerland. t 19. Name the four Founder Members who have not ye hosted the Annual Conference. h 20. Two of the following have not yet had Officers on t e Executive Board: Belgium, Canada, Denmark, Fran~e, Germany, Greece, Iceland, Netherlands, R~odesia.

South Africa, Sweden, Switzerland, United Kingdom.

Name the two.

Answers on page 48

9

International Aeradio College Of Air Traffic Services The only Non-State ATC-School of its Type in the World This magazine would, of course, be doing less than Justice if it did not feature IAL's well-known College of Air Traffic Services in Its series on Air Traffic Control training and evaluation establishments around the world. To IFATCA members, International Aeradio is known as a Corporate Member of the Federation, but the company's world-wide reputation is not limited to air traffic controllers; in fact It is widely spread among other aviation officials as well as specialists for outside Industries.

Introduction International Aeradio Limited was founded in 1947 by a group of airlines to co-ordinate the development of technical services for aviation. An important technical service it has provided since that date is Air Traffic Control. Over the past twenty-seven years the company has expanded its activities and developed into a diversified international business, applying its technical capabilities not only to its original sphere of operations - aviation - but also to many other industries where specialised knowledge in the selection, installation, operation and management of communications systems is required.

For some three years, IAL operated its Air Traffic Control service without formal training for its controllers and without a licensing system, although a military/civil conversion course was provided at the end of 1947. This lack of formality was the general situation throughout the world.

When IAL introduced its own licencing system in 1951 it was several years ahead of the civil aviation authorities of many countries. At first, the IAL licensing system was introduced somewhat gently because it was appreciated that controllers at that time had received very little formal instruction. However, from that date all new controllers joining the company received formal instruction at the British Government's ATC School. Later the government's own training requirements increased to a point when it became more and more difficult to obtain places for IAL students on dates that fitted in with the company's requirements. A solution was needed to this problem.

own School Formed The only satisfactory solution was for IAL to start its own school. In the autumn of 1958 the IAL School of Air T ffic control was established on the company's headq~:rters at Southall, near London (Heathrow) Airport. It and still is the only non-State owned school of its type ~a~he world. It expanded rapidly and quickly earned an ~xcellent reputation for the quality of its training and the h'gh standard attained by its graduates.

1 Although the school was created basically for the purpose of training IAL staff, requests for places on the courreceived from overseas governments, town ses were soon . ¡ d others such as aircraft constructors operating councils an . . . . erodromes and private ind1v1duals. To date, their own a . .. almost 1800 students of 73 different nat1onallt1es have been ¡ d at th e school . Many of the non-IAL students have traine . ining contracts arranged with overtra Of It come as a resu seas governments and aviation administrations; some have

10

been sent under the auspices of the British Government Overseas Development Authority and ICAO fellowship grants. In addition, many aerodrome owners and operators have sent controllers to the College and there have now been a considerable number of private students who have undertaken courses on their own initiative and at their own expense.

In 1974, due to continued demand for an increase in its student capacity and an expansion of its curriculum. the school changed its name to the College of Air Traffic Services and moved from the IAL Headquarters to Oxford Airport at Kidlington, six miles north-west of the University City. The move was necessitated by the lack of space tor expansion at Southall. At Kidlington, the College operates in a unique aviation environment. The airport is the main base of the Oxford Air Training School, operated by CSE Aviation Limited who are the operators of Oxford Airport and Europe's largest general aviation organisation. The school trains pilots for many of the world's leading airlines. The new College was formally inaugurated on 22nd November 1974 by Lord Boyd-Carpenter, Chairman of the United Kingdom Civil Aviation Authority, who, in a brief ceremony at the entrance and watched by some 70 guests including members of the press, cut a ribbon stretched across the doorway and declared the College open.

The reason for the school's renaming as the IAL College of Air Traffic Services lies in the fact that, with the expanded and self-contained area now available on the College's new premises, training is now being offered in other aspects of aviation including aeronautical information services, ab initio training for Air Traffic Control and other associated subjects.

Many of the facilities provided by CSE Aviation for students training at their Oxford Air Training School are available to the students attending the IAL College. They are accommodated in comfortable, well-appointed study/bedrooms in the Langford Hall of Residence adjacent to the College buildings and have use of the various catering and recreational facilities on the airport. College students have the use of a common room, a television room, squash courts, billiards rooms, tennis courts and a football pitch.

In addition there are golf and boating facilities nearby. The city of Oxford is only six miles away and London is within easy reach by train or coach.

The floor area of the new premises is more than 6000 sq. ft. enabling lecture rooms, simulator rooms with their corresponding initiation rooms, instructors' common room. offices and a workshop for simulator maintenance all to be accommodated in the one complex. The total number of IAL staff at the College is 18 of whom 15 are tuitional staff

Part of one of the I ectu re rooms which are equipped with modern visual training aids.

so that four different courses of up to a maximum of ten students each can be conducted at any one time. The IAL staff are fully qualified air traffic controllers. All of them have had extensive experience with IAL both in the United Kingdom and at many of the airports operated by the company throughout the world.

The Courses Three standard courses in Air Traffi c Control are avail-

cedures. Following the course the student returns to his own FIR where he learns the local procedures before being validated by his superiors.

The Ab-lnitio Course The Ab-lnitio Course is designed for those students who wish to train as air traffic controllers but do not have an aviation background to enable them to cope with a standard Air Traffic Control course. The aim of t he course is

able at the College: 1. Aerodrome- and Approach Control; 2. Area Control (Airways) ; and 3. Surveillance Radar Control.

These courses follow the standards and recommend ed practices of ICAO. They all include theoretical training in the College's classrooms and practical training on procedural and radar simulators. In addition, there is a special ab-initio course. Special courses can be provided to meet customers' particular training requirements; a feature of the fl exibility of the College's sim ul ators is their abi lity to simulate the control pattern of any specific airport or locality, All the courses are approved by the National Air Traffic Services Department of the U.K. Civil Aviation Authority as satisfying their requirements for some of the experience needed before an ATC licence or rating for a spec ific type of control can be granted. The College is inspected regularly by th e Auth ority to ensure that the necessary high standard of instruction is maintained.

The College is eq uipped with four simu lators which provide practical as well as theoretical training . The ATC procedural trainer provides for the simultaneous syn thesis of two separate Aerod rome- and Approach Control units, and one Area Contro l Centre providing up to four controller positions (two exec utive controllers and two assistants) .

The survei llance radar simulator, comprising two radar displays, allows up to eight 'ai rcraft' to be represented on each display. The simulators whether radar or nonradar, are based on a hypothetical Flight Information Region. Within these areas normal ICAO procedures are practised in an idealised s ituation without any over-complicated local pro-

Practical w ork in Aerodrome Control.

11

Student Controllers at practical exercises on the Survei llance Radar Simulator.

to provide this background knowledge so that the students can progress to the standard co urses at the same level as expe rienced AT C assistants o r ai rcrew and so meet the req uirements of ICAO An nex 1. A reaso nable standard of educat ion is expected of entrants to th is cou rse, together with an aptitude for t he position of air t raffic control ler.

The course includes an i ntroducti on to aviation term inology and visits to airfields to observe operations and aircraft at close quarters. In addition each student has a few hours familiarisation flyi ng. Classroo m work includes an introduction to Navigation, Meteorology, Principles of Radio, and the general workings of jet and piston engined aircraft.

The duration of the course is twelve weeks. It is recommended that this is followed by a short pe riod of consolidation training at an airfield and then an Aerodrome- and Approach Control course.

The Aerodrome- and Approach Control Course The Aerodrome- and Approach Contro l course lasts for twelve weeks ; eleven weeks of actual train ing and one week for spec ial visits and examinat ions. In addition to A ir Traff ic Control, the subjects cove red provide the student with the necessary knowledge to become a proficient controller and obtai n an operating licence. IAL expects participants in the Aerodrome- and Approach Control course to have an aviation backgrou nd, as to attend this course without any knowledge of R/T procedure would be to put the students at a disadvantage.

The s ubj ects covered and the percentage of t raining time spe nt on each are as follows: Air Traffi c Control theory - 25 %; Air Navigation - 12 %; Meteorology - 10 O/o ; Telecommunications, radio and radar aids - 10 %; ICAO and air legislatio n - 3 %; Operation of aircraft and instrument approach procedures - 3 % ; Practical trainin g on ATC simulator - 37 % . Films on specialised aviation subjects are shown.

The s imulator training includes Aerodrome- and Appro ach Control and R/ T practice, techniques and speech record ing. During the course each student receives more than 20 hours individual tuition on the simulator. Th e course is designed to provide s ufficient grounding for a graduate to p lay a useful part in a contro l tower even during the im-

12

mediate post-course period when he is gaining the extra practical experience to become a fully l icen sed controller.

Area Control (Airways) Course The Area Control (Airways) course is designed t o enable a co ntrol ler to become of d irect value to an Air Traffic Cont rol Centre in the shortest poss ible time. The cou rse p rovides him with a basic knowledge of the theory and practical operation of Area Control and enables him to understand and apply quickly the special procedures in operat ion at the particular Centre where he is to work The course lasts for eight weeks during which the student. acquires the standard of knowledge, accuracy and judgement necessary for operation at a particular Centre.

During the first two weeks of the course there are lectures on airways regulations, procedures, equipment, etc.

Special local procedures will, at this stage, be confined to the routes under the control of the Centre chosen for practical train ing. Practical training on the Cent re simulator commences during the f irst week and is plan ned to ensure safe and correct operation with full appl icat ion of the appropriate procedures. Ini tially movements are limited to about seven an hour but this is progress ively increased as experience is gained. Diversions, emergency situations and failures in radio equipment are also simulated in the later stages of the course.

For t raining on the procedural simulator an Air Traffic Control Centre based on a mythical Flight 1°n formation Region has been devised.

Surveillance Radar Course The Surveillance Radar Course is designed to provide the controller with a sound knowledg e of the theory and practical operation of radar control, ei th er for Approach Control or Area Control functions. The course is of eight weeks duration.

Lectures on radar theory, equipmen t and operating procedures are given during the first part of the cou rse. Practi cal training is undertaken throughout the course and is directly related to the procedures taught during the lectures.

For practical training on t he course, a surveillance radar

Trainee Controllers In the Simulated Flight Information Centre.

simulator is used. It has two radar dis plays on which up to eight target aircraft can be represented o n each display.

The Aeronautical Information Service (A.LS.) Course This course is designed for those students wh o have some experience of an Aeronautical Information Service at aerodrome level, e. g. in a Bri efing Room or Flight Planning Office, and who now need to acquire a deeper knowledge of international A.l.S. organisation so that they can integrate their own country's informatio n organisati on at Government level into the intern ational system. An introduction to cartography and the vario us facets of the publication and up-dating of nation al Aeronauti cal Information Publications forms part of the course together with visits to various A .LS. Units in England.

The course lasts fo r ten weeks of which four weeks are spent in the College at Kidlington . The following six weeks are spent in th e Print ing and Flight Data Division at IAL's Head Offi ce at So uthall, where stu dents take an active part in the preparati o n of documents and ch arts for IAL's AERAD Flight Guide Service, together with a study of the processing of Aeronaut ica l Info rmation from all over the world.

Special Courses As an alte rnative to the Co ll ege's stand ard courses, students can be t rained realistically on the area in which they will be wo rki ng after training. Su ch a special course wo uld al so inc lude tuition in the appropriate natio nal ATC legislatio n. Fo r example, c ourses in United Kingdom leg islation covering the U.K. training area are provided for studen ts w ho are sitting for a Civil Aviati on Authority licence.

The courses normally last as lo ng as the appro priate standard course. However, th e course length can be altered depending upon the previous ATC experience of studen ts and the comp lexi ty of the ATC system on which they are to be trained. Th ese special co urses mean t hat the minimum ti me, and therefore expense, is required between s uccessfully completing the training co urse and becoming a validated c on trolle r working w ithout su pervis ion.

Because these courses are only suitable for students from th e particular area to be simulated, it is necessary for administrations to book all places on the c o urse. This varies from eight to ten students d epending on th e course.

The Co llege has provided these speci al courses fo r a number of civ il aviation auth orities inc luding those of Belg ium, Denmark, Iceland, Iran, J amaica, Jo rdan, Saudi Arabia, Switzerland and Yugoslavia when all local procedures and regional and lo cal agreem ents have been complied with.

The new Chai rm an of t he U.S. National T ransportation Safety Board has called fo r more and better paid controllers. Chairman Webster Todd said the FAA should get the funding fo r t his from the money it is now spending on a co llision avoidance system .

Controllers can provide better g uidance to pilots than black boxes w hich can be t urned off, said Todd in an interv iew with "Aviation Daily". Todd also said he wanted the NTSB to beco me mo re active in field and preventative activities rat her than only reacting after an accident has occ urred.

(PATCO Newsletter)

Litt le gir ls are made of sugar and spice and everything nice; little boys of s nips and snails and puppy-dog tails. But who knows what makes a good air traffic controller. Even former FAA Deputy Administrator Dave Thomas hired some losers du ring his career, he admitted recently. " In considering what makes a good controller, it seemed to me they should have all the attributes of a good chess player good long- and-short-term memory, the ability to plan and the understand ing that each move cha nges the sequence of events t hat follow." So acting on that theory. he went out and hired a State chess champion, who was otherwise qualified, expecting him to develop into a cracker-jack controller. But it didn't work out that way. Thomas said he had forgotten about the time element. A controller doesn't have time to ponder each move while a chess player can take all nig ht, he noted.

(FAA World)

13

Anticipation - Its Importance To The Air Traffic Controller And The Pilot

by Capt. E. C. Clark, Trans-Australia Airlines

craft rolls on and takes off without stopping. Naturally In civil aviation, the main function of the air traffic many factors affect the availability of a take-off clearance controller and the pilot is to safely and expeditiously and this is appreciated by the pilot who recognises that achieve the movement of aircraft from the point of depardelays at this point, although frustrating, are unavoidable. ture to its destination. In fulfilling this role, anticipation A study of accidents involving civil jet transports over plays a most important part, both in the cockpit and at the last ten years reveals that approximately twice as many the controller's station, be it in the control tower or in accidents occur in the landing phase compared to those the control centre. on take-off. Despite this evidence, most pilots regard a Although the purpose of this paper is to highlight the take-off rejected from or near the critical speed on a importance of anticipation in the operational area, it must balanced field as being the most critical manoeuvre they be emphasised that safety is unquestionably the most are likely to execute. For this reason the rejected take-off important consideration of those involved in aircraft control exercise is an important and repetitive part of a pilot's and operation. Safety must never be jeopardised to extraining in the simulator. In the event that a take-off is pedite traffic flow but correctly applied anticipation not rejected from or near the critical point during normal aironly achieves this but also improves operational safety. line operations, the crew will be fully employed in bringing In analysing ways in which anticipation can be used the aircraft to a stop and it is extremely unlikely that the to advantage in A TC, it is proposed to adopt the phase of pilots will be able to communicate with the tower controller flight method which is being used to an increasing degree at this time. While this emergency cannot be anticipated, in pilot training. The aircraft's progress will be traced from aircrew prepare for the possibility by a thorough pre takethe flight planning stage to its destination and the contrioff briefing. The tower controller, for his part, must be bution that can be made by controller and pilot examined alert for the first sign of an abnormal situation occurring in detail. during take-off and act promptly in redirecting traffic if this Soon after the flight plan is filed, various sections of action is warranted. the ATC system are notified of the impending aircraft movement. Such is the reliability of the modern jet transAn engine failure soon after becoming airborne poses port, it is approximately 90 O/o certain that the aircraft will the pilot with an emergency which will also involve the move off the blocks within 15 minutes of the estimated time controller. In VFR conditions the aircraft will probably of departure. To the controller at .major airports this means simply require a clearance to return and land. In some aircraft, on occasions, this clearance may be complicated that a request for an airways clearance from the pilot can be expected at or soon after the nominated time. This by a necessity to dump fuel prior to landing. In either event initial communication serves a twofold purpose. Firstly, it under VFR conditions the situation will normally be a relaalerts the controller to the fact that the aircraft will be tively simple exercise for both pilot and controller, providtaxying within approximately five minutes and updates ATC ing the malfunction is not compounded by fire. However. in anticipating the aircraft's imminent movement. Secondly, if an engine failure occurs soon after becoming airborne when the departure aerodrome Is closed to landings, both receipt of the airways clearance by the pilot enables him the pilot and the controller are faced with a much more to anticipate the departure track and set up the navigation critical situation, especially when it is necessary for the aids accordingly. aircraft to follow a special procedure for obstacle avoiAfter receiving a clearance to taxy it is normal for the dance. In this case prompt action may be necessary by pilot to adjust his taxy speed so that desir.ably the aircraft ·u roll at a constant rate from the terminal area to the the controller to redirect other traffic. Naturally, with an WI . d" t engine out, aircraft performance on climb and cruise is duty runway holding point. Where a I ong taxymg 1s ance .1s seriously degraded and normal fuel reserves are eroded. . ed the taxying wiJI normally be performed at a fast 1 mvo · ft ~1.·11 b e f ac1·1·1This means that the aircraft will require a clearance to its rate vand' the smooth movement of t he a1rcra destination without delay in order to avoid unnecessary d "f the surface movements controller ant1c1pates and tat e 1 • t · · wastage of already reduced fuel reserve. In this situation . clearances across other runways prior o receiving issues f" • f anticipation by the controller and prompt co-operation with est from the aircraft. A fringe bene 1t resu 1tmg rom a requ . t' · t · the pilot is vital to a safe operation. the controller's anticipation of the pt 1o s r~q~1remen s 1s During the manoeuvring, clean-up (i.e. retraction of gear. a reduction in the number of radio transm1ss1ons by one flaps and slats), and acceleration to enroute climb speed. ·11 11 b I third. anticipation by the pilot plays a most important part in All pre take-off cockpit checks w1 norma Y e comp esmooth aircraft handling and resultant passenger comfort. t d b the crew before the aircraft reaches the runway The configuration changes of gear, flap and slat retraction e .Y . t Consequently as the aircraft approaches the holding pom · . · t " d during initial climb cause large changes in the aircraft trim holding point, the tower controller can a~tic1pa ~ a . rea y and these are anticipated and compensated for as they for take-off" call from the pilot. In the i_deal s1tuat1on ~n occur. The stabiliser trim requirement also changes conimmediate clearance for take-off is received and the air-

14

tinuously during acceleration and this requirement is anticipated as the airspeed increases. During this period the usual role of the departures controller is that of a monitor to ensure that the aircraft adheres to its departure clearance.

Once established on the climb with the autopilot engaged, and after take-off checks are completed, the pilot function is mainly that of a monitor. Aircraft and engine performance, radio aids selection, and tracking are continually monitored but the cockpit workload is considerably lower than during take-off and initial climb. In the air one also gains the impression that a similar situation prevails in the ATC Centre. When the aircraft is transferred from the departures controller to the sector controller, the voice usually seems to be bright, relaxed, and noticeably free of tension.

On the cruise segment of the flight the workload on both pilot and controller is normally relatively low. In the cockpit, navigation of the aircraft, forward planning in the use of radio aids, regular checking of engine instruments, and monitoring of the weather radar are duties which are conducted in a routine manner. In-flight emergencies of a mechanical nature may cause the cockpit workload to increase well above normal, but fortunately these malfunctions are rare. However, a frequent cause of high workload enroute is weather. Extensive cloud and associated icing combined with thunderstorm activity on or adjacent to the aircraft's track cause a significant increase in pilot workload. On high density routes when diversions are vital to avoid enroute weather, such declarations by pilots can frequently be anticipated by the controller as a result of similar diversions by preceding aircraft. Immediate appreciation of the situation by the controller can ensure adequate separation with other traffic. It should be clearly understood by controllers that aircraft weather radar is provided to permit the pilot to avoid a thunderstorm area and not to penetrate it.

It is on the descent and approach phase of flight that the use of anticipation by the controller and the pilot is essential in achieving the optimum result. As the aircraft approaches its descent point, the pilot's request for a descent clearance can be anticipated by the controller.

Prompt granting of a clearance at this time, and subsequently when required during later stages of the descent, is of great assistance to the pilot. This type of anticipation and co-operation is ideal in that it enables the pilot to devote his maximum attention to aircraft operation at a time of increasing cockpit workload. Early advice by the controller of anticipated holding, speed variations or deviations from the planned track enable the pilot to make appropriate adjustments to the normal descent profile.

In the event that holding is required, the pilot will endeavour to hold at the aircraft's most economical holding flight level. In view of the current fuel situation there is a compelling responsibility to conserve fuel and both the controller and the pilot have a contribution to make towards improved fuel economy. Naturally, the accountants responsible for balancing the airline budgets are all in favour of this policy. Early advice of anticipated speed reductions permit the pilot to utilise the aircraft's flexibility to the maximum advantage. Pilot training in this area is directed towards achieving prompt and accurate compliance by the aircraft with all airspeed and heading instructions given by the controller in order to maintain maximum traffic flow.

At approximately 20 miles from touchdown, the aircraft commences deceleration from its normal descent speed by the extension of speed brakes, slats, flaps and landing gear. During this period of high work load, anticipation by the pilot of changing trim requirements ensures a smooth transition by the aircraft from the clean condition to the landing configuration. Once the aircraft is cleared to land, extreme alertness rather than anticipation is required of the tower controller. The controller must be prepared to redirect traffic in the event that the landing aircraft experiences an abnormal condition which prevents it either from landing or clearing the runway in the normal manner.

Once the landing is completed, surface control of the aircraft becomes routine.

In this paper, an attempt has been made to present the pilot's view of ways in which the air traffic controller can simultaneously expedite traffic flow and reduce the cockpit workload by anticipating the pilots' requirements. At times of high workload such as take-off, landing, mechanical failure or adverse weather, such anticipation by the controller makes a significant contribution to operational safety.

We in the airlines regard this type of presentation as a valuable means of communication between operational groups and also recognise that exchange of information should not be a one way street. In Australia, every ATC cadet completes a minimum of 40 sectors in our 8727, DC9 and F27 aircraft in order to gain operational experience in the pilots' environment. In addition, over the years, representatives from ATC have presented the controllers' view to groups of our supervisory pilots. Difficulties facing the controller and areas in which pilots can alleviate them are highlighted. Ultimately, this information is disseminated to the line pilot and a greater appreciation of each other's problems is developed. The benefits to the industry as a whole are obvious.

In the U.S., 41 cloud height indicator systems are being installed in the vicinity of airports for the measurement of cloud heights in feet by means of laser beams. The information will be displayed in easy-to-read numbers in control towers. Delivery of the units is scheduled to be completed by March 1977.

(ATCA Bulletin) In a recently concluded arbitration hearing in the U.S. on what category of personnel should be in charge of conducted tours through ATC units, the arbitrator ruled that this duty is not reasonably related to the job of the air traffic controller, except in special cases such as for a group of pilots or a special person such as a Congressman requesting a tour. Tours for groups such as boy scouts, school children and other non-aviation people should not be conducted by controllers. These types of groups can be shown the Air Traffic Control facility by management officials or staff, since the intimate knowledge of the air traffic controller is not required. It is hoped that this decision will be the precedent for all facilities throughout the country.

If asked, controllers should give tours to pilots and special groups investigating Air Traffic Control, such as a Congressional team. However, tours for the general public will be conducted by management or staff personnel assigned by management.

(PATCO News Bulletin)

15

Air Traffic Control in Sweden (Part Ill)

by Hakan Westermark

ATCAS I - A New Automated System for Stockholm's Air Traffic Control Centre Introduction The first system to become operational in the new Swedish Air Traffic Control Automated System, ATCAS I, is designed to provide positive control in the Stockholm Flight Information Region (FIR), the geographic region stretching from Ljusnan in the north to Vanern/Gotland in the south.

The system will serve not only the Stockholm Area and Terminal Control Centre at Arlanda, but also the Towers (ADC) at Arlanda (Stockholm's international airport), Bromma (Stockholm's domestic airport) and two military air bases, four air defence centres and Ostgota Kontrollcentral (0KC), a military Terminal Control Centre near Norrkoping.

The new system will provide air traffic controllers with comprehensive and continuously up-dated information on all traffic operating in the FIR. This information will be derived from various sources, including extracted radar data from remote and local stations and flight plan data received from Arlanda, Bromma and other civil and military control towers within the region. ATCAS I will accept radar data from five combined primary/secondary surveillance stations and bearing information from two VHF/UHF direction finding stations. Flight plans received via AFTN will be stored without manual intervention and flight data displayed automatically in tabular format on Electronic Data Displays (EDD's) and flight strips will also be printed at the appropriate control positions. The system will be capable of handling a considerable number of stored flight plans per day.

The operations room at Arlanda will comprise five ACC sectors, three TCC sectors, two sectors for combined Flight Information Services and military en-route coordination, two military sectors for TMA coordination and Approach Control. a Flight Data Section and a combined operational and technical supervisor console. Arlanda Tower (ADC) will be equipped with a Synthetic Dynamic Display (SOD) _ a PPI suitable for daylight viewing. Five data terminals and eight strip-printers are also used for data exchange with the ADC's and air defence centres mentioned above.

Preparation of the system specification was started in 1972 and the invitation to tender was circulated internationally in December 1973. After evaluation of tenders, a contract was signed with Stansaab Elektronik AB (IFATCA's Swedish Corporation Member) in October 1974. A contract tor the supply of remote radar plot extractors has also been awarded to Stansaab. System implementation provides for acceptance test on site to be comple.ted in mi~ 1977, and the system is to go into full operational use m 1978.

From the initial project concept, controllers have taken a very active part in the design and specifi~~tio~ of the system. A detailed operational project spec1f1cat1on ha~ been agreed in close cooperation between Stansaab engineers and Luftfartsverket controllers working together at Stansaab.

16

Radar Data Processing Co-mounted primary and secondary surveillance radar systems are installed at all five radar sites and are equipped with duplicated plot extractors for narrow band transmission of digitized radar data. Raw radar data are also transmitted over broadband link from two radar sites and used for terminal control purposes. Controllers at individual positions are able to choose between raw or synthetic display, or a mixture of both. They may select a picture derived from one radar station only, or a combined mosaic picture from three radars. The supervisor can readily reallocate any radar to specific sectors in the mosaic.

The display system also includes sweep compression facilities which enable raw radar information to be stored and displayed at four times normal speed, thus providing additional time for writing synthetic information such as symbols, labels and lists. For evaluation purposes, two ACC sectors will be equipped with SDD's for purely synthetic data presentation. The requirement for a mixed raw/synthetic display was imposed principally by the Air Force, since at present tactical aircraft do not carry ICAO compatible transponders. It is expected that, after an initial trial period, experience will show that the quality of primary tracking will enable complete transition to a full synthetic data environment. The extraction system at one of the area radar sites will also generate weather contour data which will be transmitted to the centre and made available for display at any working position on request.

The synthetic position symbols indicate the type of radar information received from the extractor; primary, secondary or combined, and also the type of transponder.

For the non-discrete (64-code) transponder, the position symbol also indicates whether or not the group code is selected at the working position. Thus, it is possible for the controller to base separation criteria as well as identification and label association methods on the type of position symbol displayed to him. . History plots, selectable between four and six, provide information on previous positions. The trail is smoothed to avoid track jitter caused by possible inaccuracy of the radar system.

A label is automatically associated with its respective position symbol provided the aircraft carries a 4096-code transponder. If not, the association is carried out by the controller using the pointer symbol and making a keyboard input. The manual association is facilitated by the use of lists presented to the controller on a separate EDD. Information is provided for flights expected to enter the sector from an adjacent FIR within the next fifteen minutes (Entry List) and those schedul~d to depart from an aerodrome in the sector within the same period (Departure List). After identification, association is easily carried out by using the pointer symbol and by reference to the list. When association has been made, a label containing data from the list and computer derived data on speed and level appears near the position symbol and is connected by a

ATCAS I at Stockholm-A rlanda airport is now In the f inal phase of installati on. Picture shows ACC Sectors in background, terminal control secto rs to the right and the combined technical/operational supervisor suite in the centre.

leader line. When a label appears, the relevant information is deleted from the list on the EDD. Complete label information includes: callsign Mode C level (or altitude, automatically converted with regard to QNH) c leared and requested level speed type of aircraft and destination (for Directors, who will not use strips) indication of c limb/ descent, coast status, garbling and a "no co rrelation status" used when handove r is attempted to a co ntro ller using another radar to wh ich the specific track is not corre lated.

A full label consists of three lines. The controller can select the amount of information that he wishes to be displ ayed in th e label in four steps, from callsig n only, up to full label. A mini-label which contains SSA code and Mode C level is d isplayed when decoding the reply from an ai rc raft not stored previously in the system. A mini- label is also used for non-controlled flights transmitting on a group code which has been selected at the working position and flying o n a level which is within the selected altitude filtering limits. Automatic repositioning of labels is used to avoid overlappin g. A label is displayed only to the controller who is responsible for the flight. By using a " quicklook" fun ction, ai rc raft labels of any other controll er or controllers can be displayed. A signatu re code near the position symbol denotes the controlling working pos iti on.

The position symbol automatically changes when SPI is received o r when the special codes for emergency, radio failure or hi-jacking are transmitted from an aircraft.

All aircraft in radar cover are tracked. Track initiation and correlation of replies received by different radars are fully automatic. This means that problems will not normally occ ur when a flight crosses a borderli ne between two radars or when handover is executed between two controllers using different- ra"dars. If, for some reason, there is no correlation, a warning will indicate the situation to the accepting controller, who can then select a different radar and avoid a coast status when accepting the hand-over.

To avoid the display of random plots, e. g. angels and permanent echoes not removed by the radar signal processing, a "soft-ware filter" is used. A new track is displayed only after the target has been detected th ree times, and the evaluation of the relative positions shows that the defined requirements with regard to speed, rate of turn and acceleration are met. The actual position, as well as the previous two, are displayed when the comp uter has fo und that the track is not false. It is possible to override the filter, for example, during military exercises when tactical airc raft are manoeuvring with extreme rate of turns, etc. For track ing of aircraft replying with discrete SSA code, compar isons are made with previous plots in order to suppress false SSR responses caused by reflection.

A coast status is displayed by a flashi ng " GT" in_ ~he label if a cont rolled fl ight is lost by the radar. The position symbol and associated label are then moved by dead reckoning for another four radar revolutions. If the target is not then retrieved _ possibly by trying another ra~ar informatio n on the flight is transferred to the Coast List on th e PPI and displayed there for ten minutes. Automati c or manual re-association from the coast List is carried out in the same way as for Entry or Departure Lists. Fli ghts

~;~q'" --.--~.1-~~~~~_._~___.~___.~~---.

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DISTRIBUTION I SWITCHING UNITS

.-------+----::7:'."."'=:-:-===-===:::':"'"--;:------, ------'-----~ ~___,1---+-~

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lost in specified areas around aerodromes are only displayed in the Coast List for a period of one minute, provided the flight is destined for that particular aerodrome according to its flight plan. A similar procedure is used for flights leaving Stockholm FIR. This reduces the amount of redundant information displayed in the Coast List.

The controller can allocate any flight to the Hold List when he considers it necessary, for example to avoid label garbling when aircraft are flying in a holding pattern. Coast and Hold Lists are displayed on the PPI and can be individually positioned at any convenient position on the display.

Most radar hand-overs will be fully automatic. This type of hand-over is initiated when the flight passes over a predefined hand-over line and meets the requirements for level and destination that are set up .for the line. For semiautomatic hand-over, the flight identity has to be indicated to the computer by use of the pointer symbol or by feeding in the cattsign and the identity of the receiving controller.

Hand-over is accepted by using the pointer symbol and a special acknowledge key.

Maps seventeen permanent maps are available in the system and can be used in any combination. For temporary information, such as danger and glider areas, there is a "library" n disc memory with a maximum of 150 elements. These 0 . d elements can easily be activated by the supe~1sor an combined into two special maps. When sele~tmg the appropriate temporary map toge~her ~ith the basic map, the co~t Iler receives an immediate view of any temporary act1ro affecting his area at the time. Numenca 路 I ~~ 路 f orma t路ion vity on heights is easily added to the. maps. In add1t1on to the 150 temporary maps stored on disc, extra areas of shortterm character may be defined to the computer by means of a console typewriter.

Man-Machine Communication Only a limited number of the available operational functions have been described in the above text. I~ total, t~e radar controller has more than 40 different functions at his disposal. Will there be time left for the control of aircraft?

18

Legend: CONSOLE OCR DISC EDD FPB KB LP MUCAS OCP PTP PTR RB SOD SMP STP TSO

Console Typewriter Data Cartridge Recorder Disc Storage Electronic Data Display Flight Progress Board Keyboard Line Printer .

Multi Computer Automatic Supervisor Operator's Control Panel Paper Tape Punch Paper Tape Reader Rolling ("Joy") Ball Synthetic Dynamic Display System Mimic Panel Strip Printer Time Shared Display

(2)

Number of units or connections

Most certainty. Most of the functions will not be used by the controller during a normal shift, as he is quite happy with the radar range, radar combination, the runway extension lines, maps, number of history plots, time-basis of the prediction line, and working positions for quick-look, already selected when he took over. Of the fifteen or so functions remaining, many are of the ON/OFF programmed function type. Great care has been taken to ensure that all functions are easy to use and operate and that the keyboard and display layout is logical and functional.

Flight Plan Data Processing ATCAS I is designed to process civil flight plans (FPL), stored flight plans (RPL), and military flight plans (PLN).

Through flight plans (TRU), used on Nordic basis only, are also processed. In addition, CHG, DLA and CNL messages and certain military variants are also taken care of.

Processing means that relevant data are sorted, stored and eventually distributed and presented to the sectors concerned in the form of printed flight progress strips and list information displayed on EDD.路 These data also form the basis for label association and presentation on the PPI. The AFTN is directly connected to ATCAS 1. and most flight plans will be received in this way. Flight plan data will be exchanged automatically with adjacent centres, including the military Air Traffic Control Centre at Norrkoping-Ostgota - which was supplied by Stansaab and was put into operation in October 1973 - and flight plans can also be keyed in from D- and A-positions within the Centre.

The complete processing procedure is shown in the accompanying chart. As can be seen from the chart, all flight plans received via AFTN with correct format (number of characters and sequence within a field, etc.) and with a route description which is recognised by the computer, are stored - and later displayed - without any manual intervention whatsoever. However, if the flight plan contains errors, undefined elements in the route description, or information in field 18, manual intervention for interpretation and possible action is needed. In these cases, the flight plan will be displayed on EDD to the operators in the Flight Data Section for validation. Format errors are indicated instantly to the operator when feeding in flight plans

Another modern digital display system, manufactured by Stansaab, has been installed at Gothenburg-Torslanda Airport.

from an on-line data terminal, thus relieving the FDS from some routine tasks. However, the FDS is always responsible for updating an inadequate or incorrect route description.

The correct or validated flight plan is stored as a passive flight plan, tog ether with its distribution data, derived by the system. Activation is divided into two phases. Phase One takes place at a specified time before scheduled departure, or, for arriving traffic, when the boundary estimate message is received and keyed in. When ATCAS II is operational, the boundary estimate message, currently exchanged via telephone, may be substituted by a computer-tocomputer ACTIVATE MESSAGE. The departing flight is displayed in the Departure List and corresponding flight strips are printed. Phase Twe 1s initiated when the departure time is keyed in, or, for arriving traffic, fifteen minutes before the flight is due over the entry point of the first sector. At Phase Two flight strips for all remaining points and secto rs are printed. Arriving flights are displayed in the Entry List of the first sector affected. The flight strips contain all relevant data from the flight plan and also ETO/ ETA computed by the system with prevailing winds taken into account. An SSR code is automatically allocated to the flight at time of activation or keyed in according to the EST message. The code is also displayed in the Departure and Entry Lists. The use and layout of the Departure Lists for clearance request and acknowledgement are expected to reduce to a minimum the need for voice coo rdination between the ADC's at Arlanda and Bromma and the TCC befo re take-off.

The Flight Data Section inputs stored flight plans. The RPL library on disc memory is automatically checked every third hour, and RPL's with a departure time w ithin the next fifteen hours are copied, and the copy is moved to a passive store. Activation procedure is the same as for a single FPL.

System Reconfiguration Traffic loads vary considerably during the day. ATCAS I has been designed to be flexible in order to meet requi-

red changes in staffing and sectorisation. This means, for example, that the duties of one sector can be transferred to another. The new combined sector will then receive both sectors' labels, flight strips, list presentations, rad ar hand-overs, pointer symbols, and inter-phone calls. T o facilitate system reconfiguration, four operationally feasible configuration levels for each ACC, TCC and FIS have been defined, and are selectable at the supervisor's console. In addition to these fixed levels, any combin ation between sectors or working positions may be used. Thu s, the duties of an unserviceable working position may be taken over by any other working position of the same type, and the strip printing of one printer is easily routed to another while, for instance, new paper is loaded.

Reliability and Computer System Reliability is an essential part of any ATC system. The reserve level in the event of computer failure must still ensure safe operations. ATCAS 1 has three main levels of redundancy.

In order t o provide maximum avail ability of service, the central computer comp lex will consist of a duplicated system with automatic fault detection and changeover.

Switchover to the standby complex is immediately and automatically executed if a fai lure is detected in the operational complex, and may be effected in less than one second without loss of data or interruption of operational serv ice. Switching, which is initiated by a separate " watchdog" unit, MUCAS, is therefore rapid and cannot be detected by the operators. Both complexes are continually updated in parallel, and the stand-by computers simply take over when the failing computer complex is c ut out. Hence, switching between the main computer complexes will not cause disturbance to the operational work. This is a tru ly fail-safe mode.

If a failure is detected in both complexes, the supervisor will switch to a third spare computer system, which may also be used off- line for software development. Certa in operational functions s uch as tracking, code-callsign correlation and flight pl an data handling are not avail able in

19

this fail-soft mode. However, special routines have been developed to handle the strip-printing of the RPL and the SSR-code assignment if this situation should occur. Should the spare computer system also fail, raw radar presentation is still provided. The display generation equipment for this method of presentation is in turn duplicated.

The following facts and figures provide a more concrete idea of the reliability of the system: One main computer complex fails, and the other takes over. No operational consequences ...

Once every 400 hours Both main computer complexes are unserviceable. The spare computer works . . .

Once every 20 OOO hours Both main computer complexes and the spare computer are unserviceable. Raw radar data are displayed ...

Once every 600 OOO hours A year has some 8700 hours.

As to the computer arrangement, each of the computer complexes consists of two Stansaab Censor 932 computers with a combined core storage of 152 K, 32 bits. One of the computers in each complex is primarily used for the pro-

cessing of radar data and the other for flight plan data and display processing.

The system will also record automatically certain data, such as the content of each flight plan, cancellation of flight plans, input of boundary estimate messages, radar hand-overs with the controllers involved, aircraft position and complete content of the label. To reduce the amount of data when evaluating a course of events, certain search criteria may be set up. Thus, all data concerning for example flights within a certain height layer in a certain airway and within a certain time interval, can be printed on a line-printer for subsequent analysis. The Spare Computer System will be used for these activities. Narrow-band radar data are also recorded and replayed using one of the ordinary narrow-band radar inputs to the system and any radar position in the centre.

Recorded data will also be used for statistical analysis and invoicing route charges, landing fees, etc.

ATCAS I is a 24-hours a day system. Technical maintenance will be carried out using stand-by computers and equipment during periods with low traffic density, and only stand-by redundancy will be affected.

Report Near-Collision DC-10/L-1011 Over Michigan, U.S.A. On November 26, 1975, an American Airlines DC-10 and a Trans World Airlines ¡L-1011 almost collided head-on at 35,000 feet near Carleton, Michigan. Both aircraft were operating In instrument meteorological conditions, within positive control airspace, and while under the control of the Cleveland Air Route Traffic Control Center. As a result of the evasive manoeuvre that had to be executed by the captain of the DC-10, 3 aircraft occupants were Injured seriously and 21 were Injured slightly. The cabin's interior was damaged extensively. None of the occupants of the L-1011 was injured.

ATC Handling of the Flight At the time of the near-collision AA 182 and TWA 37 were operating under the jurisdiction of the Wayne sector of the Cleveland Center, which is responsible for aircraft operating at or above FL 350. The radar beacon signals from both aircraft were being received by the national airspace system (NAS) Stage A Digitized (Narrow-band) Radar System and processed by the radar data processing equipment at the Cleveland Center which generated the data displayed on the radar controller's plan view display (PVD).

This display, for each aircraft, consisted of a symbol for the aircraft's position and an alpha-numeric data block that included the aircraft's identification or flight number and its assigned altitude. In the case of AA 182, which was climbing, the alpha-numeric data also included reported actual altitude, updated every 12 seconds.

The circumstances which led to the near-collision developed while the Wayne sector was being manned by two controllers: a radar controller and a manual controller. A third controller. who was assigned to the handoff position, was at lunch. consequently, the radar and handoff positions were combined and manned by the radar controller.

The radar controller is responsible primarily for radar control of traffic within his sector. He can display targets within the sector on the PVD while inhibiting the targets for traffic outside of his airspace. He communicates with the data processing computer through various devices at

20

his position to manage his PVD and to insert certain traffic control functions into the ~computer. He can initiate and accept a target's track as it moves into his sector; he can transfer a target's track to another sector, or point-out a target to another sector by forcing that target to be displayed on the other sector's PVD. The radar controller also can enter or change flight data stored in the computer such as a flight's assigned altitude or routing. The manual controller functions as a non-radar controller. He maintains current flight data on the flight progress strips, issues departure clearances, and coordinates as necessary with adjacent sectors and air traffic facilities. Although the manual controller also can make computer inputs at the manual console, the same inputs can sometimes be made more expeditiously at the radar console. Finally, the handoff controller, positioned next to the radar controller, assists the radar controller with his duties and coordinates with adjacent sectors and air traffic facilities.

The radar data processing equipment stores data in the computer in both received and processed forms. A radar log which contains these data was obtained from Cleveland Center for the time period during which this accident occurred. These data showed that the target for TWA 37 was first processed for display on the Wayne sector PVD at 1903:44.5. The display showed the target at its assigned FL 350 and tracking approximately 2900 true at a ground speed of 408 knots. The target was about 105 nm southeast of Carleton VORTAC on J-34. The Wayne radar con-

troller accepted the handoff of the target track from the adjoining sector at 1903:53.0. A full data block showed the progress of TWA 37 as it proceeded to Carleton VORTAC and then turned westbound onto J-584. At 1918:50, the Wayne radar controller entered the appropriate code through an alpha-numeric keyboard to initiate the transfer of TWA 37's track to the Chicago Center. At that time the target was about 6 nm east of Carleton and tracking 282° at 400 knots. A track accept message was received from Chicago at 1918:54. The target position symbol and data block continued to be generated for display on the Wayne sector PVD until 1928:54.

The target representing AA 182 was initially processed for the Wayne sector PVD at 1914:24. The data showed the aircraft to be about 100 nm west of Carleton, climbing through FL 262 to assigned FL 370. The aircraft was tracking approximately 092° at 465 knots. The Wayne radar controller accepted the target track from Chicago at 1914:40.5.

The target position symbol and a full data block were then generated for the Wayne sector. The periodic change in reported altitude showed that AA 182 was climbing about 1,000 feet per minute as it proceeded eastbound on J-584.

At 1921 :19.5, AA 182 was about 40 nm west of TWA 37 and reporting at FL 330. The two aircraft were on reciprocal courses and were closing at a speed of about 850 knots.

The radar controller stated that when he accepted the handoff of AA 182, he realized that there might be a traffic conflict between that flight and TWA 37. However, his previous experience that day had shown that several flights climbing eastbound out of Chicago to FL 370 had been levelling off a considerable distance west of where the incident occurred later. He thought that by keeping an eye on the situation he would be able to turn the aircraft in case the required separation criteria would not be met.

When asked if there were any operational factors that might have distracted him, he said that at about the time AA 182 reported at FL 280, Chicago Center called with a manual point-out and handoff of a Learjet. He accepted the handoff and for about 5 minutes thereafter he attempted to insert a change in the routing of .the Learjet into the computer.

According to the radar controller, the flight-planned route of the Learjet was not identical to its actual rout~, and Chicago Center failed to update the computer prior to handing it off to him.

The radar log showed that the Learjet had taken off from Chicago on an IFR flight plan to London, Canada. At 1917:55.5, the Wayne radar controller attempted to enter a change in the routing of the Learjet into the computer.

The computer rejected the routing change because the requested route involved a point to point, or direct, routing into airspace under the control of Toronto, Canada.

The radar controller said that, normally, the manual controller would have handled the computer inputs of the Learjet but he felt that the manual controller was busy. The radar controller considered his workload to be moderate at the time. According to the radar log, during the 10 minutes preceding the near-collision, there were 11 targets, including those for TWA 37 and AA 182, being processed for display in the Wayne sector. The controller indicated that, although TWA had been handed off to Chicago at 1918, the flight was under his control since it was still in his area of jurisdiction. He also stated that an aircraft is not turned over to another sector until it has been separated from known traffic. He recalled that he last saw TWA 37 southeast of Carleton, when he handed the aircraft off to Chicago. He did not remember when he last saw AA 182.

According to ATC records about 1922 the radar controller was relieved by the third controller who had returned from lunch. Hereafter, the relieving controller will be referred as radar controller No. 2.

Both controllers stated that during the briefing associated with the transfer of duties TWA 37, the Learjet and several other aircraft were mentioned but AA 182 was not.

FAA Handbook 7210.3C, Facility Management, stipulates that the relieving controller accept responsibility for the position only after assuring, to the extent possible, that the briefing is complete and that no unresolved questions concerning the operation of the position remain. The controller being relieved is responsible for the completeness and accuracy of the briefing.

Radar controller No. 2 made his first transmission at 1921 :59; he did not communicate with the Learjet and made no computer inputs for that aircraft. He considered his workload to be light to moderate. At 1922:52, he queried AA 182 about its altitude. The flight reported its altitude (FL 347) and its weather observations. As soon as this 7-second transmission was completed, radar controller No. 2 instructed AA 182 to descend immediately. When asked what drew his attention to the traffic conflict the controller said that he was just scanning the radar and noticed that AA 182's data block showed the aircraft to be at FL 345, and climbing to FL 370. TWA 37's data block showed that the flight was maintaining FL 350. The aircraft were at 12 o'clock to each other and about 3 to 4 miles apart.

When asked why he questioned the pilot of AA 182 about his altitude before he issued a descent clearance, the controller stated that his first reaction was one of disbelief. In addition, he stated that since there might be a lag in the readout on his data block compared to the aircraft's actual altitude, he considered the possibility that the flight might have been higher than shown on his data block. He used the term "immediate" because he did not think that a normal descent would be adequate to resolve the traffic conflict.

When he issued the clearance the aircraft were about a mile apart; he then saw the ta;gets merge and then separate.

The manual controller stated that during the period involved he was posting flight progress strips and entering flight plans into the computer. The flight progress strips of AA 182 and TWA 37 were posted in the proper bays. He considered his workload to be light to moderate.

When the radar controller received a handoff on the Learjet, he asked the manual controller if there was a flight strip for this aircraft in the Wayne sector. When it was discovered that there was none, the radar controller sent the manual controller to the sector through which the original flight plan would have taken the Learjet. The manual controller found the strip there and took it to the Wayne sector. According to the manual controller, he was not aware of the radar controller's problems with entering the Learjet's revised flight plan into the computer. He became aware of the near-collision when he heard the instruction for an immediate descent.

Other Information According to the captain of AA 182 , the flight was climbing eastbound on jet route 584 (J-5B4) and approaching or going through FL 350, when they were advised to descend immediately to FL 330. He started an immediate descent with the autopilot vertical speed control. Simultaneously, he and the other crew members sighted the lights of 21

another aircraft in the 12 o'clock position. He then applied forward pressure on the control wheel to avoid the aircraft.

He estimated that the vertical distance between the aircraft when they passed was 100 feet, and that 3 to 4 seconds elapsed from the moment he sighted the aircraft until it passed them. At the time of the near-collision, AA 182 was operating in instrument meteorological conditions (IMC), in and out of the cloud tops.

The NAS Stage A automated system was functioning as programmed while AA 182 and TWA 37 were operating in Cleveland Center airspace. There were three computer malfunctions on the day of the accident, two of which required the transfer to the older, standby equipment (broadband radar). The Cleveland Center log of facility operations showed that the malfunctions occurred at 0935, at 1835 and at 1955; the last two involved the transfer to broad-band radar and lasted 9 and 5 minutes respectively. The log did not contain an explanation of the malfunctions. The assistant chief in charge during the shift that the accident occurred stated that computer problems require the transfer to broad-band radar about once a shift.

Analysis A potential traffic conflict between AA 182 and TWA 37 was evident when AA 182 was handed off to Wayne sector of the Cleveland Center. Although the radar controller was aware of a potential conflict, he assumed that AA 182 would have climbed to FL 370 before passing TWA 37, which was cruising at FL 350. In addition, he assumed that, by keeping an eye on the situation, he ~ould. be able to t~k~ timely steps if the anticipated separation did not matenahze.

Both of these assumptions were not compatible with fe and positive air traffic control practices and procesa . f' . dures. By the time the radar controllers 1rst assumption invalidated, his second assumption, intended as a was h · · safeguard, did not work as planned because ot er act1~1ties distracted him. The fact that he consented to be relied from his position about 2 miRutes before the nearve . d .h collision proves that he had become preoccup1e wit ondary duties to the extent that he had failed to see :~c impending conflict that was clearly displayed on his ra~arscope by that time. The principle !esson in this near disaster is that intent to separate tr~fflc can ne~er be a substitute for positive action at the first opportunity to insure separation. . . of duties D ur ing the briefing associated with the transfer d'd . to radar controller No. 2, the first controller 1 not m~nt~on AA 182 undoubtedly because he was no longer thmkmg about ;he flight as an unresolved problem. Since radar Iler No. 2 had no reason to expect that the responcon t ro bi •t · f sibility he accepted included an acu.te. pro em, 1 1s orthat he noticed the problem within 50 seconds after tuna t e . · d" 1y . over the position.

However, this time 1scovery t a k mg h · f ·1 t does not exonerate both controllers from t. e1r a1 ure. o notice the conflict during the transfer of duties. :he briefing was incomplete because neither controller reviewed the actual situation as depicted on the PVD. R aders of this journal will recall that Jon R. Sharpe of the ;hicago ARTCC, was awarded at IFATCA's 1976 Conference the prize for the writer of the best article of the year (1975); the article appeared in the November 1975 edition of THE CONTROLLER entitled A~ EVA~UATION OF RADAR DATA PROCESSING. This technical article gave early warning of some of the dangers of ~ut~mation of. the ATC System now and in the future. The fmdmgs contained

22

in the analysis of this near-collision report are considerable and one can be criticised for "purposeful extraction" but the following points are significant following the Jon Sharpe article mentioned above: "The circumstances of this accident indicate that automation technology can lead to complacency when it takes the controller 'out of the loop' by reducing the need for his interaction with a flight crew and de-emphasizing the cooperative aspects of the air traffic control system. Had the radar controller been working with the broad-band radar, he would have been forced to take positive steps to insure separation as soon as AA 182 was handed off to him. Of the several steps he could have taken, we mention only two: (1) He could have stopped AA 182's climb at FL 330, or (2) he could have asked the flight to report at FL 31 O or 330. However, the automatic altitude readouts on the flight's alpha-numeric block induced him to rely solely on his own observation of the PVD data. He did not consider the possibility that he might become distracted or that the computer might fail, and thereby deprive him of his direct readout capability.

"Despite the advantages of narrow-band radar, the ATC system failed to provide the intended safeguards and endangered the lives of 306 persons. Advances in technology do not necessarily insure greater reliability and safety. The new conflict-alert system, now operational in all Centers. can serve its intended purpose only when it is not treated as a substitute for timely, positive separation measures which continue to protect air traffic even when the computer fails. .. Based on the high percentage of human failures in the ATC system, it is clear that, as long as the human element is part of the total system, an individual's level of competence, the quality of his performance and his understanding of his primary responsibilities must be given as much managerial attention as the equipment he operates."

Quo Vadis?

Probable Cause The National Transportation Safety Board concluded its report by determining that the probable cause of this nearcollision was the failure of the radar controller to apply prescribed separation criteria.when he first became aware of a potential traffic conflict, which necessitated an abrupt collision avoidance manoeuvre. He also allowed secondary duties to interfere with the timely detection of the impending traffic conflict when it was displayed clearly on his radarscope. Contributing to the accident was an incomplete sector briefing during the change of controller personnel about 1 minute before the accident.

Postscript Since the publication of this report, the NTSB has announced that it has reviewed several other recent ATC related accidents and incidents and the Board has determined that deficiencies in human performance were critical causal factors. The individual controller's susceptibility to error, despite sophisticated electronic equipment available to him, detracts from the overall benefits achievable through advanced automation in the National Airspace System. Common to these occurrences were the facts that all sector or control positions were staffed by experienced controllers, and the ATC facilities employed automated radar systems. These circumstances suggest that the so-

phistication of the ATC equipment does not obviate the system's dependency on a high level of human performance.

Equipment design innovations are intended to unburden the controller from ancillary tasks and to enhance his ability to fulfil his role as a vital functional element of the ATC system. However, the Board believes that controllers and FAA management must recognize that sophisticated electronic equipment is no substitute for constant vigilance, sound judgment, and proven control techniques. Accordingly, the FAA should undertake a program to identify those aspects of controller performance which are most likely to result in potentially critical control errors and then implement safeguards so that the system can tolerate a reasonable resi-

dual of error in human performance without jeopardizing safety.

In view of the above, the National Transportation Safety Board recommends that the Federal Aviation Administration: "Conduct a comprehensive study of the human failure aspects of Air Traffic Control System errors that have occurred since the introduction of terminal and en-route automation and take action to make the National Airspace System less vulnerable to the human failure element, either by changes in procedures, training, supervision, performance monitoring, and selection standards, or by providing increased redundancy in the man-machine relationship."

International Law (Part XI)

by E. McCluskey, IFATCA Standing Committee VII (Legal Matters)

International Institutions (4): Inter-governmental Maritime Consultative Organisation; International Telecommunications Union; World Meteorological Organisation IMCO was set up by a Convention signed in 1948. The Organisation was required to provide machinery for intergovernment co-operation in the field of regulations and practices relating to the technical side of shipping in international trade. It was also to encourage the general adoption of the highest standards in maritime efficiency and efficiency of navigation. Other¡ aims were the prevention of restrictive practices and advice to United Nations' agencies. The Organisation is important for us in that it is deeply concerned with problems of safety of life at sea and therefore can affect our work in the field of search and rescue.

It also concerns itself with buoyage, lights and marine beacons which are still much used in many parts of the world for aircraft navigation.

Membership of IMCO is open to all States. United Nations Members and States belonging to the United Nations Maritime Conference may become members by signing the Convention, whereas others must be elected by twothirds of the Members not including Associate Members.

These last are an exception to what we have been saying on international relations throughout these articles in that they are non-self-governing territories. Such territories may have large shipping interests just as they may have large aviation interests so here is our justification for recognition of Member Associations from non-self-governing territories.

The important organ in IMCO for us is the Maritime Safety Committee which has 14 members of which not less than eight are the largest ship-owning nations while the other six are nations with an interest in maritime safety because they supply large numbers of crews or passengers while some, as in ICAO, make up the geographical coverage of the globe. Close relationships are maintained with other

bodies which deal with transport and communications such as ICAO, which was the subject of our last article, the ITU and the WMO. ITU was set up to maintain and extend international cooperation for the improvement and proper use of telecommunications, to promote development of technical facilities and to encourage efficient operation. This objective is achieved mainly by allocation and registration of frequencies, adoption of measures for ensuring safety of life through co-operation of telecommunications services and formulation of recommendations.

The comprehensive functions of the ITU have been revised across the years by a series of Conventions. The first International Telegraph Convention was revised in 1875 at Saint Petersburg, in 1906 by the Brussels Convention, in 1912 by the London Convention, in 1927 by the Washington Radio Telegraph Convention, in 1932 in Madrid by the International Telecommunications Convention, revised at Atlantic City in 1947 and again at Buenos Aires in 1952. The use of satellites has brought subsequent revisions. As aviation, telecommunications is a fast developing field and a dynamic updating of the law is essential. The ITU lays down the general provisions on the rights of the public to use telecommunications services and priorities for safety of life. They equally supervise the rational use of frequencies and spectrum space, the establishment and operation of stations to avoid harmful interference, priorities for distress traffic, action against false or misleading distress or safety signals and irregular use of callsigns. Special arrangements on regulations had to be introduced to permit the USA to become a member as the USA, and to some extent Canada, does not accept governmental regulation of telegraph and telephone services or charges for radio services. The regulations of the ITU are supplemented by regional agreements such as the European Broadcasting Convention 1948, the European Broadcasting Agreement 1952, the North American Regional Broadcasting Agreement 1950, European Regional Convention for Maritime Mobile Radio Services 1948, North East Atlantic Loran Service 1949. etc.

23

Fenanti simulators put years on your student controllers

Our ATC training simulators give controllers the experience they need to do their job - before they start doing it.

This is due to the detailed and comprehensive realism of Ferranti digital simulator systems.

The trainee controller's radar displays are identical with those used operationally, and simulated RT and intercom are provided. With this equipment the trainee learns how to cope with aircraft identification, separation, sequencing, the allocation of levels, routing, stacking, and other problems.

Ferranti have studied air traffic control in depth and have an understanding of current and future needs as realistic as the simulators themselves. We know the economic importance of

handling heavy air traffic with minimum delays.

It's hardly surprising therefore that Ferranti ATC simulators have been chosen for the largest and smallest requirements and are currently in service or on order for London Heathrow, Amsterdam Schiphol, Rome Ciampino, Copenhagen Kastrup, Taiwan Taipei, Sydney Australia, and at the College of Air Traffic Control at Hum. And a Ferranti simulator is used at the .CAA ATC Evaluation Unit for their real time traffic control studies.

Ferranti Limited, Digital Systems Division, Western Road, Bracknell, Berkshire, RG121RA. Telephone: 0344 3232. Telex: 848117.

FERRANTI The real thing in simulation

The ITU has a plenipotentiary conference every five years, to revise the Convention if required. There are also administrative conferences. The day to day work is carried out by the Administrative Council, and International Consultative Committees in addition to the International Frequency Registration Board and the General Secretariat.

From our point of view the Frequency Registration Board is the most important. Before it was formed, frequencies notified to the ITU had to be registered. The Frequency Registration Board, faced with the intention of many States to use whichever frequency was deemed best by the State, arrived at the compromise of notification and registration. If a frequency is registered, it is subject to international protection if it conforms to all the regulations. If it does not conform, the frequency is notified only and the State makes use of the frequency at the risk of requiring to stop use if harmful interference results. If no interference results over a long period, the frequency may be finally registered.

Gradually the countries which accept the compromise are becoming larger in number. So when we receive complaints of interference we should not just be upset at having to repeat a message. Remember that the pilot who complains that your clearance was interrupted by someone's radar approach procedure may well also be interrupting reception for another pilot on a difficult final approach.

It may be that you are the one using the frequency which is simply notified, so report the matter and let it be sorted out through the proper international channels. The ITU has a similarity to IFATCA in that it has need of up-to-date information which it gets from private companies and manufacturers who participate in Administrative Conferences and International Consultative Committees, just as we now have an ever increasing participation of our Corporation Members in the work of Conferences and of Standing Committees of the Federation.

The WMO is an extremely powerful Organisation as far as aviation is concerned. This stems to some extent from the fact that Meteorology in many countries comes under military authorities and therefore is given much more weight than civil aviation. If there is a question of reducing transmissions from aircraft, there is a fair possibility that, if the WMO is represented at the Conference, air traffic position reports will be dropped rather than meteorological reports, especially in areas where there are few weather stations.

The meteorological services throughout the world have benefited from enormous budgets, which would have long ago provided adequate Air Traffic Control services, with varying results which have not always been crowned with success. Nevertheless there is a dire need, not only for aviation, for good meteorological service and the WMO is the World Organisation set up to facilitate improvement. Its functions are to facilitate co-operation by establishing a world-wide network of observing stations and meteorological centres; to promote rapid exchange of information; to standardise both observations and statistics; to encourage research and training.

The WMO now has access to satellite information which has yet to arrive in Air Traffic Control. The WMO operates through the World Meteorological Congress which meets at intervals not exceeding four years. It has also an Executive Committee, Regional Meteorological Associations, Technical Commission, Secretariat and Permanent Representatives of Member States. Congress determines policy.

Members must do their utmost to implement decisions of

26

Congress. The WMO decides on dates when changes become effective although it has never been given legal power to do so. Regional Associations are responsible for ensuring the execution of resolutions of Congress and of the Executive Committee in the regions. The Permanent Representatives are the Directors of the national meteorological services, whence the power of the Organisation.

Directors of Civil Aviation are seldom permanent representatives to ICAO. All specifications for meteorological services for air navigation must be agreed between the WMO and ICAO and promulgated by both.

This article has given a brief look at three of the Organisations responsible for technical services which are an essential back-up to Air Traffic Control. In the next article we must turn to another type of international Organisation which deals more with conditions for the personnel employed according to profession or trade: the International Labour Office (ILO).

For further study: Oppenhelm"s International Law, Lauterpacht, Longmans: pages 1014-1018 and 1023-1029. Final Act and related doc~ments of the United Nations Maritime Conference, United Nations Organisation. The International Telecommunications Union, Codding. Organisation M6t6orologlque lnternationale Publication 81.

League of Nations Handbook of International Organisations 1938â&#x20AC;˘ pages 139-143.

Last April, a new nationwide Aviation Safety Reporting Program to gather full information on circumstances or events jeopardizing flight safety went into operation in the U.S.A. All reports of actual or potential safety hazards observed by pilots, controllers or others should now be reported directly to the National Aeronautics and Space Administ~ation. NASA will not divulge the identities of anY p~rs?ns involved - with two exceptions: reports involving c~1mmal o~f~nses, in which case the Justice Department will be notified; and aircraft accident reports, which will be forwarded to the National Transportation Safety Board for investigation. . By ?roviding an opportunity for all persons concerned

w~th air safety to report potentially hazardous incidents without. fear of penalizing themselves or others it is hoped

~o ~btam a more accurate picture of the occurr~nce of such mc.1dents th.an. h~s been possible in the past, when no such

~a1ve~ of d1sc1plmary action or anonymity was possible. It 1s beh~ved that the actual number of serious near-accidents occurring throughout the nation is many times higher than the number currently reported. Statistical data received t~rough the new reporting system will help to focus attention on areas of potential hazard and to take steps to ~mpro~e the situation before anyon~ gets hurt. The program 1s particularly designed to identify situations in which safety is jeopardized or safety regulations broken without the knowledge or intent of the participant.

Persons involved in an incident should file a report to NAS~ ~it~in five d~ys. The program will not provide waiver of d1sc1plmary action for certain illegal actions such as reckless operation, gross negligence or willful misconduct, if the incidents are brought directly to the attention of FAA via other sources. For example, intentional buzzing coulci result in a complaint being filed with the local FAA District Office. In these circumstances the incident would be investigated by FAA and, If appropriate, enforcement action would be initiated.

(FAA General Aviation News)

The Lyon '76 Medical- and Technical Panel Sessions and 15th Anniversary Reunion The August 1976 issue of THE CONTROLLER contained a general report on the Federation's 15th Annual Conference which was held in Lyon, France, earlier this year. In this issue, we are publishi ng summaries of the proceedings at the Medical- and Technical Panel Sessions - compiled by David Hopkin and Walter Endlich respectively - and an outline of what happened at the reunion ceremony of former Officers of IFATCA.

The first Med ical Panel at an IFATCA Annual Conference was the realisation of an idea discussed within the Federation over past years. David Hopkin, second from the left, chaired this Panel of experts In Aviation Medicine.

The Medical Panel Session For the first time at an IFATCA Conference, a Medical Panel was convened to foster an exchange of views and knowledge between controllers and doctors. The Honorary President of the Panel was M. Mangenot, Head of the Supervising Com mittee for Air Traffic Control Medical Studies carried out in France. The Chai rm an was Mr. David Hopkin, Princ ipal Psych o log ist at the Royal Air Force Institute of A viatio n Medicine in the United Kingdom. The Members of the Panel were: Dr. Coby, Chief Doctor of the French Directorate for Civil Aviation; Dr. Nolland, Chief Doctor of the Northern Region for Civil Aviation in France; Dr. Chaix, a co ll eague of Or. Nolland, and Specialist in Cardi ology; Dr. Kalsbeek, Chief of the Laboratory for Ergonomic Psychology in the Netherlands; and Dr. Wagstaff, Senior Medical Advise r for the United Kingdom Civil Aviation Authority.

Following introductions by the President of IFATCA and

by M. Mangenot, the Chairman outlined the topics on which Members of the Panel would be willing to try to answer questions. These to pi cs included not only medical matters, but also matters whi ch could be designated as human factors, psychology and ergonomics. They covered the job of the air t raffic contro ller, hi s working conditions and attributes of the individual controller. Sources of stress and

the controll er's response to stress could also be discussed.

The intention of the Pane l was to convey information to representatives of Member Associations on the medical and associated problems relevant to the work of the air traffic controller.

Dr. Nolland then outlined a comprehensive programme of resea rch being conducted in France on manifestations of emoti ons and stress, and on defining the exterior measu rable signs of tiredness. Starting from a thorough know¡ ledge of the individual controller's medical history, numerous measures of the contro ller were taken , including oculometry, heart recordings, colour vision sensitivity, visceral activity and subjective assessments. The effects of emotions were assessed in abso lute terms as departures from standard levels, and in relative terms by comparing differences with time of day, and before and after work. The responses of the controller to stressful situat ions and to changing social relationships with his colleagues at work were also noted, and findings were related to workload in the form of traffic densities.

Dr. Nolland's paper raised several questions, as did a subsequent more spec ific paper presented by Or. Chaix. who was concerned with factors which according to recent research in France are relevant in predicting the propensity lo heart disease. Among factors known to increase this propensity were arterial hypertension, diabetes, high cholesterol, obesity, arterial illness, and, most importantly, tobacco smoking. The effects of smoking on the individual depended on how long he had been smoking . on whethe r

27

or not he inhaled and on how many cigarettes per day he smoked.

During the discussion, which started from points raised

by Or. Nolland or Or. Chaix and then turned to other issues, numerous topics were covered. Dr. Nolland explained that statistical sampling difficulties prevented the inclusion of women in his studies. In seeking to determine optimum working conditions and to assess job satisfaction, it was desirable to conduct studies comparing air traffic controllers with other professions, but permission to do so could sometimes not be obtained. Insofar as certain aspects of Air Traffic Control were claimed to be unique, any comparisons with other professions could therefore be only partial.

The effects of smoking on the well-being of non-smoking colleagues were discussed. It was explained that smoke would be inhaled by all who were in the room, and there would therefore be some detrimental effects, their seriousness being dependent on such factors as the provision of good ventilation within the workspace.

The implications of stress and of impaired cardiac function on career planning and retirement were mentioned, and there was discussion on why air traffic controllers were subjected to regular medical checks which could affect the retention of their licences. Smoking was discussed in relation to any beneficial and soothing effects it might have, but these were felt to be outweighed by its known hazards. In reply to a question about workload and decision making, it was pointed out that the gradual evolution of Air Traffic Control away from practical short term decision making and towards strategic pre-planned traffic flows would have the incidental effect of reducing the required urgency of many decisions. A possible approach to quantify this was to determine the number of decisions which had to be made by the controller each minute, and to relate this measure to man's innate capacity for decision making.

The complexity of the concept of stress became apparent as the numerous possible methods for assessing it were discussed. The effects of shift work on stress were mentioned. The citing of research findings provided evidence explaining why at the controller's annual medical examination his doctor may suggest that he should stop smoking, or reduce his weight, or consume less alcohol.

The desired recommended period for abstaining from all alcoholic drinks before going on duty was discussed. The topic of the use of drugs as an aid to stop smoking was mentioned, the advice being that if this was contemplated it should be done during a period of leave. The relevance of the personality of the controller to his response to stress was noted.

Inevitably, although the discussion was wide ranging, some relevant topics were not raised or pursued, but the opportunity to try and achieve greater understanding between controllers and their doctors was taken and was welcomed. The Chairman summarised the main points which had been made, and concluded by pointing out that controllers and doctors had the common aim of keeping the controller fit and able to work effectively and enjoyably, so that the high standards of safety and efficiency of Air Traffic Control would be maintained, and the known stresses to which the controller was subjected would not be unduly harmful to him. It was hoped that the Panel had succeeded in demonstrating that controllers and their doctors had these similar aims, and that the medical advice

28

given to controllers was not arbitrary but was based on established research findings and intended to promote their well-being and effectiveness.

The Technical Panel Session The Technical Panel Session was dedicated to the subject of "Strategic Air Traffic Control", with IFATCA corporation Members and ATC experts making up the Panel.

Honorary President of the Panel was M. Monnier, representing on this occasion the Director of French Air Navigation Services, M. Leveque. Mr. Arnold Field, former President of the Federation and the present Chairman of IFATCA's Standing Committee I (Technical), acted as Chairman and very ably managed to keep Panel members as well as speakers from the audience on the right track of this complicated subject.

In his opening address the Honorary President expres~ed the view that the stagnation of air traffic experienced m 1974/1975 was now over, and that in the medium term a growth ratio of 5 to 6 per cent could be expected. In order to cope with the demands of the next 15 years, it was necessary to solve most potential conflicts in advance, by strategic measures. Two important issues had to be considered in this context: the need to integrate the time factor when applying Strategic Control, for a more efficient use of the scarce airspace; the increasing sensitivity of the public in respect of aircraft noise, which was developing into an important constraint.

To a certain extent strategic measures had atreadY been and were currently applied. Organisation of the route netwo~k, flow orientation, flight level assignment schemes and flight plan scheduling were relevant examples. NeW features to be exploited comprised: the fourth dimension (time}; refined flight paths, including parallel routes the appli~ation of the "tunnel" concept, and "Route' Time Profiles" (RTP}; new technical systems for navigation and landing (e. g.

R-NAV, 3-0 and 4-D, Microwave Landing System); new mean~ of control (e. g, SSR, CAS, Data-Link).

In concluding, M. Monnier considered the subject of the :an~I very topi~al and w~lcomed the opportunity of disussmg these important items in the large international forum of the 15th IFATCA Conference.

Arnold Field then introduced the members of the Panel: J. R. Adderley Software Sciences Ltd. L. Deneufchatel S.T.N.A. (Technical Branch of the French Aviation Administration) Former Editor of THE CONTROLLER Ferranti Digital Systems Division Cessor Electronics Ltd. Editor of the Journal of Air Traffic Control, and H. Westermark Stansaab Elektronik A.B. and expl~ined the _envisaged proceedings. The first part of th~ Session consisted of brief presentations by Corporation Members and ATC experts; the second part was devoted to general discussion.

The introductory presentation by Walter Endlich aimed ~t g.athering everybody "on the same frequency" and establtsh1~g a fra~e. ~f reference for the ensuing discussions.

A suitable defm1t1on of Strategic Air Traffic Control, exampW. H. Endlich R. N. Harrison N. Ross T. K. Vickers

The Technical Panel under the expert chairmanship of Mr. Arnold Field, OBE, UK (center).

les of rudimentary and advanced systems in which ATC strategies were appl ied, assessment of demands on and capacity of the ATC system, and an outline of how demand and capacity can be matched were among the main topics of his talk.

Bob Adderley followed on with a subject paper which was well illustrated by OHP transparencies. Conclusions of this paper were that : T he requi red strategy for ATC is to accept responsibility for the traffic management as a whole, so that departure and arrival slots are correlated and so that if it is necessary for an ai rcraft to q ueue for its turn then this is, as far as is practicable done on paper or in the compute r and before the aircraft leaves the ground, and then refined by such techniques as linear holding.

Obviously there are numerous commercial or company requirements such as peak hour passenger demands to be taken into account, and general aviation must also be catered for. But however many difficulties may arise, it is still technologically possible and economically more sensible to " manage" them beforehand, rather than let the aircraft concerned waste fuel and unnecessarily overload the ATC system.

Many controllers know little or nothing about Air Traffic Control in the Soviet Union. The presentation by Hakan Westermark on the Soviel/Stansaab approach to Strategic Ai r Traffic Control therefore gathered much interest. An order for automated ATC systems in the USSR was placed with Stansaab in September 1975. The project which is called TERCAS (Terminal and En-Route Automated System) in fact includes four operational centres, an advanced system training simulator and a programming centre , as well as radars, plot extractors, communications and buildings. The param ou nt features of this system we re outlined in the Stansaab presentation.

More on the technical side was the description of the French Air Ground Data Link System (AGDLS) given by L. Deneufchatel. By reference to many interesting OHP transparencies, the speaker reported about the first experimental results that had been achieved with AGDLS, its potential for navigational purposes and for the exchange of coded messages, and the order of accuracy that could be expected from such a system.

Nigel Ross from Cossor Electronics Ltd . gave a supplementary presentation on ai r/ground data links, with particular reference to the ADSEL system. The compatibility of ADSEL with existing systems was emphasised. Improved navigation capability, versatility of suitably coded messages, and reduction of R/T load were considered to be among the main features for making air/ ground data link systems important tools for the efficient application of Strategic Control.

R. N. " Bobbie" Harrison of Ferranti rem inded the audience that suitable tools for ATC were not only required for high-density areas such as Western Europe or the United States, but also fo r regions with lower traffic. Less sophisticated (and less expensive) systems wou ld be adequate for such envi ronments, and the Computer Assisted Radar Display System (CARDS) had been designed by Ferranti with this aim in mind. CARDS can process primary and secondary radar data and display it in conjunction with raw primary radar. Inputs are accepted in any s tandard format and - by selection - from any one of a number of sources.

Discussion As can be expected in view of t he subject chosen, a wide field was covered in the second part of the session .

In this brief resume only a few areas can be mentioned. which appeared to be of special interest duri ng the discussions: Scheduled airlines have certain reservations against balancing ATC capacity and demands, as they fear that this may result in restrictions. Commenting on this point, various parties - from the audience and from the Panel - explained that already the strategic measures currently applied (e. g. f light plan scheduling. flow orientation , etc.) have well contributed to using the (scarce) airspace more efficiently.

When looking at certain systems which are already in operational use sin ce a couple of years. for instance the Eu rocon trol MADAP system at Maastricht UAC. it becomes readi ly apparent that efficient tools are available. Flight plan processing, reliable mu lti-radar tracking, automati c correlation of flight plan and radar data. automatic update of flight plan data by radar information without any ¡¡induced load " on the controller. suit29

able display of labelled radar data, all these are important features for increasing ATC system capacity and reducing controllers' workload. The technology and know-how are there. Could the implementation of relevant systems in high density areas please be expedited.

Strategic measures affect wide areas. Flow Control arrangements for North Africa, for example, cause repercussions right up to the Scandinavian countries. The application of Strategic Control should, hence, be on a European (or regional) rather than a national basis. In this context the need for a central European Flow Control facility was emphasised.

The Technical Panel Session was well attended, and the very active participation of the audience highlighted the importance of the subject.

15th Anniversary of IFATCA After the official closure of the Lyon Conference, President Monin announced that a special anniversary ceremony to commemorate IFATCA's 15th birthday would follow.

The Executive Board had invited the former Officers of the Federation who had made IFATCA into what it is today, to attend the 1976 Conference, and Mr. Monin proceeded to introduce them to the meeting: "Sitting at the head table are Bernard RUthy, one of the first people who conceived the idea of a European Federation, later altered to embrace the whole world; Walter Endlich, the first Editor of the Federation; Roger Sadet who was IFATCA's Vice-President at its very beginning; Arnold Field, our Federation's third President; Maurice Cerf, the second President; Geoffrey Monk, the first Executive Secretary; and "Bobbie" Harrison, who has represented the Corporate Members over such a long period. Unfortunately Mr. Tekstra, the first President, is seriously ill and could not be with us today, but we have sent "Tek" the following telegram: The Executive Board and Assembly of the 15th IFATCA Conference in Lyon send sincere good wishes for a speedy recovery."

The first speaker was Walter Endlich who briefly sketched the way in which IFATCA was formed in 1961, with preparatory work going back to 1959. Since then the Federation's growth had been breathtaking, due to a considerable extent to the first IFATCA President Tekstra or "Tek" as he is called because of his high sense of motivation, energy and other great capacities such as a considerable talent in soliciting the support of and to choose his collaborators. The good old days were to an extent easy: no red tape, no terms of reference, no Manual, no statements of policy, which all made tor very quick decisions, quite different from what happens today if you look at what is going on in the Standing Committees and sub-committees and compare this how quickly big executive decisions were taken at that time. Mr. Endlich said he wanted to make one plea: don't get involved in too much red tape in the deliberations; stick to the subject matter, don't get lost in formalism so that 30 or 40 per cent of the time is wasted in endless discussions.

President Monin thanked the speaker and mentioned that, with the exception of Geoffrey Monk, Walter Endlich was the only Officer who had worked under all tour presidents of the Federation.

Next came Bernard Ruthy who said that he would leave the speaking to more eloquent men and would show a number of slides taken during past IFATCA Conferences he had attended (in fact, he had attended them all except IFATCA 30

'73). The slides showed the first Annual Conference in Paris in 1962, attended by 25 to 30 people (what a difference from today), with "young" Maurice Cerf prominent and "young" Daniel Monin, of whom no one took much notice at that time. The slides took us from the Second Annual Conference in London to the Third one in Brussels, the Fourth in Vienna, and so on to the 1975 Melbourne Convention. Many former local and IFATCA personalities could be seen on the slides, at times to the obvious delight of the audience, and Bernard's commentary was listened to with appreciation. Bernard concluded by saying that he hoped that 1976 Conference participants would now have an impression of the atmosphere which prevailed at earlier occasions; one thing he had always liked about IFATCA was the big family spirit and he hoped that with the steadily growing membership this would remain. One of IFATCA's best achievements was the valuable personal contacts established between so many individual persons.

Maurice Cerf was the next speaker to take us back over the years, and he delighted his listeners with a most amusing and witty record of his experiences in the service of IFATCA, eventually leading to the presidency. It all began for him in 1959 in Frankfurt "as a rather obscure member of the French Association attending the historical Preparatory Meeting at the request of the French President. I was a bit surprised by this kind offer but thought it would be more comfortable eating a Frankfurter than watching a radar scope in Paris. In Frankfurt it did not take me long to discover that I was expected to act as an interpreter. It did not take me long either to find out that it was an impossible task. By the time I had translated a point for consideration, the meeting had already voted and proceeded to the next business. This being so I took upon myself to express my views as being those of the group and in this way found myself elected as the Vice-President of the new Federation; this you may consider is a questionable way of selecting the first Officers, but let me hasten to add that mine was a special case, as the others clearly had all the abilities required. They were in fact such wonderful persons that by just following their example, I managed to play my part."

Maurice had his audience in laughter throughout, but, ending on a serious note, said that his ten years as an ¡ IFATCA Officer had been the most rewarding of his life.

Arnold Field said he would not endeavour to follow Maurice Cerf in his excellent humour. It was a privilege to be associated with IFATCA. He was not a retiring sort of person as we must have noticed and for that reason was still engaged in IFATCA duties today, which he hoped to continue as the Chairman of Standing Committee I. Arnold somewhat regretted the passing of the days when he was ~lso the Chairman of Conference Committee "B"; today it is necessary to have propositions and amendments to propositions, but in his time it was the right approach to say to Committee "B": this is the proposal which you need to pass, is it not, and before they had any chance to say anything whatsoever, the motion was passed and recorded in that manner. It wasn't quite like that, of course, but, none-the-less, things have in actual fact changed. Arnold ended by saying that it had been a great pleasure for him to associate again with so many of his colleagues.

Mr. Geoffrey Monk then captured the audience. After the last speakers he had had to throw away that sheaf of witticism with humourous reminiscences that he had compiled. He felt like a prima donna or a ballerina - though the resemblance was imaginary - who keeps on making

During a special anniversary ceremony President J .-D. Monin, third fr om the left, welcomed former officers of the Federation, who not only knew a l ot of interesting details about the earl y days of IFATCA, but also deserve our respect for their input into the Federation.

repeated last appearances, and if it was up to him, would somehow try to get to next year's Cyprus Conference too.

There is an English saying : what a man proposes God disposes. "Although I am getting on a little in years, I have no intention of filing a flig ht plan at the moment because the estimated time of departure is a bit uncertain, but even more uncertain is the destination." It had always seemed surprising to him, having consistently taken an interest in the wives of the Board of Officers in the nicest possible way, that the wives managed to put up with IFATCA, but then it seemed they were warned when they married that they were also partly marrying IFATCA. It pleased him to see the Federatio n approaching the SO-members mark in such a short time. In an international context, many problems can only be solved by time, and it applies in fact to quite a number of IFATCA problems.

The last speaker was "Bobbie" Harrison, the doyen of the Corporate Members, who mentioned that this so rt of speech on behalf of the Corporate Members on many occasions in the past used to be made by the late Bob Shipley, and he congratulated Bern ard Ruthy on prod uc ing only one slide of Bob standing on his head; it's a thing whicl' he has not been ab le to emu late but the technique to be developed is not to stand on your head and drink from a glass but ju st to stand up with a large number of glasses and d rink on your head, but - again- he did not intend to go in for that. Bobbie cong ratulated IFATCA on another successful Confe rence, a Conference at which the Corpo¡ rate Mem bers were delighted to see their numbers substantially increased. He was sure that the new members wi ll wish to maintain the tradition of friendly relations between their companies within IFATCA whatever rivalries there may be outside. Thanks were due to the French Assoc iation espec ially for putting a room at the disposal of the Corporate Members which they found very useful, and to the charming gi rls from Air France who performed hostessduties during the Conference.

Mr. Monin c losed the proceedings by saying that he wished to see everybody in Cyprus next year.

Postscript Thi s conc ludes the seco nd and last chapter of our report on the Lyon Conference, but it would perhaps be appropriate to end by reprod uc ing the words spoken by the

Portuguese delegate o n the occasion of his Association's acceptance as an IFATCA member. These words reflect as never before the Federation's message of solidarity and hope to controllers wherever they may be and in whatever circumstances they are.

Quoted from the official Conference Report : " The representative of the Air Traffic Controllers' Association of Portu gal apologised for any nervo usness possibly apparent, but said this was the first time Portuguese controllers were amongst colleagues outside their own country.

They were very happy to join IFATCA at last. The representative went on : During the long dark night in Portugal when mail was lost, when to receive communications from abroad was difficult, when certain people wanted to know everything we did, when we could not organise no r attend professional meetings like this one, we were ext remely grateful to receive excellent help from , among others, Belg ian, French, Swiss, Argentine colleag ues, and to receive copies of the IFATCA journal and IFATCA technical information.

We shall now try to respond to the trust you showed in us, and we promise to do our best to work harder and harder in order to avoid that ¡solidarity does not become an empty word ."

The three surviving crew members of an East German charter aircraft that crashed at Leipzig in September 1975. killing 26 persons, have been sentenced to prison for negligence, according to AON, the official East German news agency. The agency said the pilot was sentenced to five years, the co-p ilot and navigator to three years each and a ground radar controller to four years.

(AP)

Perhaps there's not complete agreement on what makes a good air traffic controller, but everybody seems to think they have very interesting jobs - including the controllers themselves. The results of a recent survey published in U.S. News & World Report indicate that controllers have one of the least boring jobs around. Only doctors and college professors were shown to have a lower "boredom factor" for their occupations. But surprisingly, the survey found the job of contro ll ers at small airports has a slightly lower boredom factor than that of controllers at large ai rports.

(FAA World)

31

Operational Control: A Unique Australian Concept

by F. J. Swadling, Chief Operational Control, Australian Department of Transport.

Australia is probably unique in its concept of including within its Air Traffic Control structure an Operational Control section. It was born as a result of a disaster of a DC2 aircraft in 1939 which flew into mountains east of Melbourne during very poor weather conditions. The subsequent court of Inquiry recommended that certain operational decisions should be undertaken by ground personnel and these recommendations have been reaffirmed by other Courts of Inquiry which have investigated subsequent accidents. Operational Control is not necessarily a career structure entirely within its own section although it has grades progressing from 1 t~ 5 wh~ch basically are th~ same as in the traffic separating sections. At the top position of Senior Operations Controller we look for an experienced Air Traffic Controller who has a good knowledge of the Australian Air Navigation Regulations, the Aeronautical Information Publications, the Air Navigation Orders and has demonstrated a high degree of ability to make operational judgements. He should also be well versed in meteorology to the point where he can understand the basic weather patterns affecting his area of responsibility.

This officer is one whose background has included some experience in the traffic separation functions. The association of the Operational Control unit with other units or agencies will be explained.

Operational Control is the exercise of authority over the initiation, continuation, diversion and termination of flight. This authority is exercised by the operator, the pilot in command and Air Traffic Control, and imposes responsibility for ensuring that flight operations are conducted in accordance with any rule, regulation or conditions prescribed or specified for the flight or service.

The provision of Operational Control by Air Traffic Control is the responsibility of Operational Control Centres and is provided in all controlled airspace including control reas temporary control areas and control zones, except~ng ~ilitary. It is confined to the following categories and classifications: 1. Regular Public Transport.

2 . Charter flights with a maximum take-off weight in excess of 5700 kg.

3. IFR. 4. Other categories when requested by a pilot of a suitably equipped aircraft.

Irrespective of the area in which an aircraft is operating, Operational control service will be provided by Air Traffic Control to: 1. An aircraft which is experiencing difficulties and which requests assistance; and .

2. An aircraft which the Operational Control Centre has reason to believe, on meteorological or other advice, is not aware of all the operational factors affecting the flight.

In respect of International Operators, Air Traffic Control provides a full Operational Control service to approximately one third of the operators, an inflight Operational Con-

32

trol service to another third and the Company Despatcher provides a full Operational Control service to the remaining third.

Australia is divided into nine Operational Control areas with Operational Control Centres at Melbourne, Launceston, Sydney, Brisbane, Townsville, Adelaide, Darwin, Perth and Port Hedland Airports. These are located at the airports of Australian centres of population which are all situated on the seaboard and are separated by a distance betw1een 500 and 1000 miles. To cover the most sparsely populated areas within central Australia, but nevertheless containing a relatively high proportion of aviation activity, a subsidiary Operational Control unit has been established at Alice Springs which is geographically in the centre of Australia. There is also an Operational Control Centre at Port Moresby covering Papua New Guinea.

Each Operational Control Centre is co-located with the Area Control Centre serving the Flight Information Region and each Operational Control Area is coincident with the controlled airspace managed by the associated Area Control Centre. The land mass of each Operational Control Area ranges from 200,000 square miles to 700,000 square miles. Each Operational Control Centre is connected to the Regional Forecasting Centre by intercommunication links and they are not necessarily co-sited. However, the aerodrome weather office which supplies meteorological briefing, six hourly terminal forecasts and two hourly trends on routine aerodrome weather reports, is located immediately adjacent to the Operational Control unit and both share the same briefing counter. The Operational Control Centre is connected by intercommunication channels to all operating airline companies at the airport, all Airways Operations Units within the FIR, all adjacent Operational Control Centres, all emergency services connected with Aerodrome Emergencies and Search and Rescue operations.

There are four distinct areas of operation at the larger Centres and a daytime shift consists of four controllers.

Their nomenclature and duties are as follows: Operations Flight Data: Responsible for attending the telephones and teleprinter and compiling Operations Control flight progress strips on all flights under Operational Control, both inbound and outbound, for use by other Operatio'lal controllers.

Operations Departure Controller: This officer provides the pre-flight briefing facility for all aircraft departing from or transiting through the airport and under Operational Control. He compiles Pre-Flight Information Bulletins, Frequency Change Plans where required, AIS material such as radio navigation and terminal charts and issues these as required to each flight. He is responsible for updating the briefing of pilots who have trunk planned through the airport. Trunk planning is in common usage and involves a pilot flight planning for his day's activities, through Operational Control Centres and being updated with AIS material at each centre. The pilot is responsible for reporting to the Operational Control Centre either personally or by

telephone before his departure. The Operations Departure Controller is responsible for ensuring that the flight has been planned in accordance with Regulations i. e., sufficient fuel, correct flight level, sufficient navigation aids, correct radio frequencies, etc. He in fact signs flight plans and imposes his terms of Operational approval. For example, if the flight plan was from A to B to C and B required 60 minutes holding, the plan could be endorsed "subject to" X "minutes of fuel endurance ex B". He holds Operational requirements for all airports which are served from his Flight Information Region including his own. Operational requirements are conditions put on a particular airport by the Senior Operations Controller in respect of additional fuel for either holding or alternate requirements. This officer is also responsible for NOTAM origination, cancellation and weekly check within his FIR and Sydney is responsible for the Australian NOF. Operations Flight Controller: This officer is responsible for liaison with the operating companies. He passes all ETAs, delays, cancellations and amendments concerning aircraft operating within the FIR. He is responsible for passing all inflight information to aircraft within his area of responsibility. This includes SIGMETS, amended terminal forecasts, amended enroute weather, NOTAMS concerning Navigation Aids, Gunnery and changes in airspace requirements. He is also responsible, after a flight has been cleared by the Operations Departure Controller (Briefer), to ensure that a pilot meets the statutory requirements at all stages of a flight. If it becomes apparent that the requirements cannot be met, he will divert or terminate the flight. This is normally done in consultation with the Company concerned in order to ensure that the optimum alternative course of action is taken. However, it is this officer's responsibility to ensure that the flight proceeds in a safe manner.

Senior Operations Controller: This officer maintains close liaison with the local Meteorological Office and the Regional Forecasting Centre. He is responsible for ensuring that Operational requirements in respect of fuel requirements are issued If necessary for controlled aerodromes within his area of responsibility in respect of aerodrome forecasts either issued by the Regional or Airport forecasting office. These requirements are transmitted to adjacent Operational Control Centres and his own section for action.

The Australian Aeronautical Information Publication, Instrument Approach and Landing Charts denote three minima: landing by reference to precision approach aids, landing reference to a circling minima and an alternate minima.

The alternate minima is a cloud base of 500 feet and a visibility of 2 kilometers better than the landing circling minima. At selected airports certain aircraft may carry an alternate based on the precision approach minimum plus the 500 feet and 2 kilometers. The Senior Operations Controller may, in the interests of safety, require that an alternate aerodrome or holding fuel should be carried even though the meteorological forecast does not indicate the need.

Some Operational Control functions are delegated to the traffic separating controller. The Aerodrome Controller has the authority to close the airport when there is subminima cloud base or visibility. That is, when the weather elements for either landing or take-off are reduced below the published minima, the airport is closed to landing and/ or take-off. The Aerodrome Controller who continually and directly observes the local atmospheric conditions, evaluates pilot reports and utilises all available information, then

makes the Operational judgement for all aircraft. Departing aircraft are held on the ground and arriving aircraft are held above the lowest holding altitude until the weather improves to at least above the authorised minima or they are diverted to another aerodrome on the authority of the Senior Operations Controller.

When the Approach/Departure and/or Aerodrome Controller cannot devise clearances to avoid known severe turbulence within 10 miles of an airport, the airspace within that distance will be closed to operations. Known severe turbulence in this context means knowledge based on current forecasts, including SIGMET and advices from Terminal Area Severe Thunderstorm services, inflight reports, airborne radar, ground observations including visual and radar observations made by meteorological officers or air traffic controllers.

Note: The Terminal Area Severe Thunderstorm service enables observations of thunderstorms by meteorological radar to be expressed by a forecaster in terms of expected areas of severe turbulence. Advices are disseminated to nominated Air Traffic Control positions by means of closed circuit television and the displayed picture comprises an area or areas within sixty miles of the aerodrome made up of: a) An area where severe turbulence is considered to be probable at the time of issue; and b) An additional area to embrace the probable movement and development during the validity of the advice; c) An arrow and figures indicating respectively the expected direction and speed of movement of each area; d) The estimated upper and lower limits of severe turbulence in hundreds of feet; and e) The date and validity times of the advice.

Advices are prepared at intervals not greater than ten minutes and are valid for a period of ten minutes from time of issue. The initiation of this service will be as a result of discussion and agreement between the Senior Operations Controller and the Regional Forecasting Centre.

This very briefly outlines the function of Operational Control which by definition, is the control of the initiation. continuation, diversion and termination of flight.

The Senior Operations Controller is responsible for the supervision of operations within the FIR and, depending on the aviation activity, staff is reduced accordingly and some functions concentrated to permit them to be accommodated by a lesser number of controllers. In addition to these functions, the Senior Operations Controller is a rated SAR Mission Co-ordinator. Once an emergency phase has been declared by an Airways Operations Controller, or on information received from other sources concerning an aircraft in distress, the Senior Operations Controller has the responsibility for the conduct of the action required.

Prior to 1958 the Royal Australian Air Force was responsible for Search and Rescue actions. Air Traffic Control was responsible for notifying the Air Force of SAR phases.

Since that time the action has been conducted by Air Traffic Controllers with assistance from the Air Force for specialised searches. One very significant feature of the change was the sharp reduction in costs to the Department.

The Search and Rescue areas basically coincide with the FIRs, but are rationalised to conform with State boundaries, i. e. Victoria, New South Wales, Queensland, Tasmania, South Australia, Western Australia and Northern Territory because many of the facilities brought into service are controlled by the State. Each Operational Control Centre is equipped with a Rescue Co-ordination Centre

33

which is located adjacent to the room wherein the Operational Control functions are conducted. The Rescue Coordination Centres are of a standard design and are equipped with plotting tables, maps and charts, large and small scale of the area, plotting instruments, tides and currents charts, intercommunication with other Airways Operations Units, Airline Companies, Police, emergency services, etc., telephones with recorder capabilities, suitable tables for the SAR Mission Co-ordinator, his assistants and recorders. There is a facility index which details disposition of suitable search aircraft and their operating characteristics and details of all facilities, equipment and organisations likely to be of use in a search. Details of communication with these other facilities are included.

Items shown within the SAR facilities index include details of lighthouses, authorised landing areas, disposition of fuel, forestry watch towers in remote areas and many others.

Search and Rescue is generally on a self-help basis insofar as search aircraft are concerned as aircraft are not specifically maintained for that purpose, but are requisitioned as required. The Department of Transport possesses a few aircraft, but as their prime function is that of navigation aid testing, their activity is planned well ahead and _ therefore - they cannot be guaranteed to be available at any particular time. Civil aircraft are called upon in the following order: (a) Departmental aircraft; (b) Private aircraft; (c) Spare commercial aircraft; (d) Commercial aircraft under charter; (e) Scheduled commercial aircraft; (f) Foreign commercial aircraft. Military aircraft are called upon when no suitable civil aircraft are available without causing disruption to scheduled air services.

In the advent of a search, the Senior Operations Controller hands over his Operational Control duties to the Operations Flight Controller, calls on relief staff and assumes the role of SAR Mission Co-ordinator. He is then responsible tor the overall co-ordination of land, sea and air search in respect of a civil aircraft and is responsible for the arrangement of search aircraft. His detailed studies are as follows: a) obtaining all data of the emergency; b) deciding what action is necessary to relieve the emergency situation; c) alerting, despatching and co-ordinating the activities of all SAR facilities necessary for the operation; d) supervision of all action taken by Airways Operations Units; e) co-ordination of operations with adjacent RCCs when necessary; f) arranging for briefing and interrogation of all SAR units; g) calling for and evaluating reports from all sources; h) arranging for supply dropping to sustain the survivors when required; i) keeping all concerned notified of the state of operation; j) continuing to co-ordinate the operation until such time as the survivors are rescued or the SAR effort is terminated.

In respect of searches for other than aircraft, and if an air search is requested, he is responsible for the co-ordination of that air search.

This provides the scope of the Search and Rescue effort and practice search actions are conducted on a regular basis to ensure all concerned are completely competent to carry out their duties.

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In addition to local Search and Rescue practice actions, Australia has conducted several International Search and Rescue exercises. The reasons for them are similar to the need tor local exercises, but working with other countries provides the opportunity to become aware of their SAR capability, procedures, facilities and - probably more importantly - the chance to liaise directly with them and benefit from others' points of view. We have conducted exercises in respect of simulated flights between Australia and New Zealand which involved both countries; between Perth and Mauritius which involved Australia, Mauritius, Indonesia, Singapore and South Africa; between Sydney and Tokyo which involved Australia, Papua New Guinea, Hawaii and Guam, and between Perth and Bombay. The Department's Search and Rescue Section conducts SAR Mission Co-ordinator courses for Australian personnel and almost every year an International course is conducted.

A recent typical International course included personnel from Ghana, Indonesia, Iran, Korea, Papua New Guinea, Singapore, Sudan, Thailand and the East African community. Each Rescue Co-ordination Centre holds its own SAR stores which include inflatable liferafts, food and water containers, signalling equipment, medical stores and delivery containers, including heliboxes.

The Senior Operations Controller also has the responsibility for classifying bomb reports in respect of aircraft.

On the information available he decides if a warning is either "specific" or "general". If it is specific it falls under the distress phase of search and rescue, but if it is general he passes the information to a committee comprised of members of the Department, the Airline concerned and the Australian Federation of Air Pilots. They decide whether to treat the warning as a hoax or to increase security arrangements.

It is quite significant that in the past twenty years no aircraft under Operational Control within Australia has suffered a mishap due to operating below authorised minima or contrary to Regulations. Operational Control has imposed operating requirements above those indicated by the Meteorological authorities as circumstances have demanded and the central point of issuance of operational information has proved to be a most efficient means of ensuring aircraft are completely and quickly acquainted with pertinent information. Operational Control also obtains upper winds from the MET Section at regular periods and computes from graphical representation time intervals between selected points for several types of aircraft. Frequently, standard flight plans are submitted and they may be condensed to: FLIGHT NO. (RMB) ROUTE AND STANDARD PLAN NO, (B2MS) FLIGHT LEVEL (310) ENDURANCE (215)

Operational Control is the contact point between the Department and the aviation industry and, to some extent the public. The Senior Operations Controller requires t~ have a good working knowledge of the technical side of the Department in order to fulfil the role of public relations.

The Things That Happen ...

An aircraft was waiting to take off from runway 28R at ... (cens?red) when another aircraft was towed across the runway m front of it. The Tower did not see this hap e P n and the following conversation ensued: Controller: AL123 you are cleared for take-off.

AL 123: Roger. Would you like me to go round it, over it or under it?

The Air Traffic Controller's Problems Associated With Ground Movement Control *

The Ground Movement Control Unit at Frankfurt Airport, Gcirm any, where ai rcraft taxying i n from and o ut to the runways are handled by the Aerodrome Authority. Areas of jurisd iction are precisely divided between ATC and the Airport Company's GMC.

Introduction The purpose of Ground Movement Control (GMC) , very simply, is to faci li tate the movements of aircraft from the Parking Areas to the Holding Point serving the Departure Runway (s) and from the Arrival Runway (s) to the Parking Areas, and also to control any other movements on the Manoeuvring Area. The complexity of the task varies proportionally with several factors which are mentioned in this paper.

To ease the operation of GMC, aerodromes are normally divided into two areas - The Apron and The Manoeuvring Area. Th ese are defined by ICAO thus: Apron A defined area, on a land aerodrome, intended to accomodate ai rc raft for purposes of load ing or unloading passenge rs or cargo , refuelling , parking or maintenance. â&#x20AC;˘ This paper was presented by the IFATCA delegation to the 15th Congress of the International Civil Airports Association, held in Brussels in September 1975, and was prepared by IFATCA's Standing Comm ittee I.

Manoeuvring Area Th at part of an aerod rome to be used fo r the take-off and landing of aircraft, and for the movement of aircraft associated with take-off and landing, excluding aprons.

Background In theory these two ICA O definitions precisely apportion the usage of aerodrome surfaces, and at some aerodromes this may well be so. However, at many aerodromes such is not the case as t he need for Parking Areas continually increases whilst the land available for extension is often found on ly within the confines of the present aerodro me bo undary. This is very mu ch the case at Heathrow, for examp le. where (because of t he central location of the Terminal Buildings) the provision of additional Par king Areas has now almost filled the space between the two main runw ays , so this parti cular su rface could well be classified as Ap ron .

However, since it is also used for the movement of aircraft . it could equally well be c lassified as Manoeuvring A rea which would lead to co nfusion ove r the GM C rules to be observed.

35

At some aerodromes that fortunately divide into the two precise areas, GMC - from the ATC point of view - presents few problems as the movement of aircraft off the Manoeuvring Area is handled by some other agency - say the Aerodrome Authority. They would do this by using "Follow Me" vehicles following precise direct routes from the runway exit points (or other designated handover points) and from the Apron to the Holding Point.

However, since most aerodromes do not lend themselves to such a straight-forward organisation, this paper will elaborate on the problems encountered where there is no precise dividing line between the Apron and the Manoeuvring Area and a full GMC Service is provided by ATC.

The GMC Task GMC at a busy aerodrome is perhaps one of the most complex types of service provided by ATC, often yielding the most job satisfaction to the controller. During a busy session there are few hard and fast rules that can be applied all the time, and very little is predictable. The GMC controller requires to: 1. have a completely flexible choice of taxy routeings; 2. have an extremely detailed knowledge of the aerodrome; 3. have the ability to think quickly and to give clear and concise instructions; 4. keep R/T loading to a minimum so as to permit sufficient time for other essential tasks (e. g. liaison and planning); s. continuously monitor the traffic under his control, which is particularly difficult where the Control Position is located centrally and taxy routes surround it.

Bearing these points in mind, there are six problem areas to be dealt with in this paper, which beset the controller in his general method of operation, viz R/T Communications, Taxy Systems, Holding Areas, Work in Progress, Parking Areas, Operations at Night and in Bad Visibility.

The Problems R/T Communications 1. Phraseology - There is very little laid down in the way of standard R/T phraseology for GMC except for such obvious things as "Cleared to taxy", "Hold position", etc. It would clearly not be practicable to formulate phraseology for every eventuality that could occur, nor would it be desirable because of the reduction in flexibility that such an innovation would bring. The use of one common language (English) for R/T communications does lead to complications in GMC phraseology. Each language has its own idiomatic terms for certain obstacles and manoeuvres and when these are translated the meaning may well not be the same. For example, at Heathrow the term 'cul-de-sac' which is used very often was not understood by a crew from Scandinavia even though it is regularly used by ATC and the British Airports Authority to describe the location of many Parking Areas.

2. Standard of R/T Transmissions and R/T Technique There are several problems with R/T that needlessly add to the GMC controller's difficulties: a) faulty equipment in aircraft which causes breakthrough on adjacent R/T channels; b) faulty or badly installed equipment in vehicles; c) apparent lack of training in R/T technique of ground crews; 36

d) repeated transmissions caused by replies not being received due to screening of antennae; e) simultaneous transmissions caused by failure to 'listen out' before transmitting or by inability of the one transmitting to hear the other due to screening

by Terminal Buildings (particularly so at aerodromes with large Apron Areas).

Taken in conjunction these faults could well increase the GMC R/T loading by 20 O/o - not much, you may think, but it erodes valuable time that should have been used for liaison.

Taxy System Most aerodromes were designed and built in the days before the introduction of wide-bodied jets. Perhaps the fact that so much of the original taxyway system is useable by the latest aircraft is a tribute to the foresight of the designers of 20 years or so past. However, certain areas of most aerodromes are restricted for use by such aircraft which tends to upset the flow pattern organised by th~ GMC controller and therefore increases his workload. It is good to see that work is in hand to eradicate these deficiencies, but it must be emphasised that even though ATC has managed to cope so far, they cannot be expected to do so for much longer without the necessary improvements being made.

Holding Areas Generally, the increase in air traffic has not been matched by a corresponding increase in the size of Holding Areas - which poses a difficult problem to ATC. To reduce the overall delays to air traffic, it is essential that GMC be capable of marshalling aircraft at the Holding Point into the optimum Departure Sequence. This procedure necessitates a large area of taxyway close to the end of the Departure Runway - which, regretfully, is not present at many aerodromes. The introduction of wide-bodied jets has exacerbated the problem since even more spacing is required to enable them to pass each other without risk of collision.

\York in Progress This, a necessary evil at all aerodromes, is an activity which never ceases. It always adds to the complexity of the GMC task since route flexibility is reduced and thus diminishes the amount of traffic that can be satisfactorily handled. The main problems associated with Work in Progress are: 1. Marking of Temporary Routes - These markings may be located either on or at the edge of the taxyway. Due to th~ nature ~f most of this work on the aerodrome, there 1s a requirement for standard Day and Night m k. f . ar mgs o obstruction boards, cones and tights. From the Flight-deck (and the Tower, for that matter) this formidable array often appears to be very confusing N t . . 0 so Iong ago. one A mencan pilot was heard on HIT to politely enquire whether he was really at an aerodrom Skittle Alley. R/T loading is increased by the e ~r a .. . requirement fo.r add1t1onal instructions, but the problem can be alleviated to some extent by the use of aircraft marshalling staff.

2. Works Contractors' Equipment _ Problems caused by 路 d by the presence . . of equipment can be m路1n路1m1se segregating 1t from the rest of the Manoeuvring A B d 路 l"ttl h rea. Y oing so, very I e c ance will exist of non Airfield-

trained personnel creating hazards to aircraft (and themselves). One of the better ways of controlling this is to arrange special access roads to and from the Work area. If these need to cross over taxyways, they should do so via controlled crossings operated by trained aerodrome personnel. Occasionally the need arises to move heavy equipment around the Manoeuvring Area, in which event it must always be escorted by trained aerodrome personnel. One very important factor that has to be borne in mind by all Works Contractors is Jet Blast. This can be extremely dangerous to the unwary and several people have been killed or seriously injured because they were not aware of its danger.

Great care must be taken therefore when siting equipment and choosing taxy routes so as to minimise the effect of Jet Blast on the Works personnel.

3. Work Permits - Work Permits must state very clearly the Runway(s) in use and a thorough briefing must be given to the Contractors involved. Major Works will normally be carried within an enclosed area so there will be little likelihood of a vehicle or person straying onto the Manoeuvring Area. However, not all Aerodrome Works fall into this category - there are many small jobs, such as painting taxy lines, grass-cutting and small repairs to concrete/tarmac. The Contractors who carry out these jobs must also be well briefed for, apart from the hazard they may cause to aircraft, they must be told to keep clear of restricted areas such as ILS compounds.

4. Emergency Repairs - These, although entirely unpredictable, always appear to arise at the busy traffic times.

Since they can cause long delays and create confusing taxiway routeing s, they must be attended to as soon as possibl e. Unfortunately speedy repairs are not always possible as it may be found that the Repair Gang are "temporarily out of contact with Base." If the repai rs could be done at once, the compounding of problems to the GMC controller wou ld be minimised. There is, clearly, a time limit beyond which, if the area in need of repair is not attended to it paradoxically becomes less of a problem to the GMC controller si nce (from the practical point of view) it achieves the same status as a permanent Work Area. Particularly onerous peaks in GMC workload are created by the need to carry out emergency repairs, caused by: a) the immedi ate requirement for a rapid rearrangement of the traffic flow as soon as a part of the taxiway or runway becomes unserviceable ; b) a consequential requirement (if the delay becomes too great) to move aircraft from the Holding Point of th e affected runway to another runway for departure.

In the event of emergency repairs, close liaison with the authority controlling the Repair Gang is essential.

Parking Areas As menti oned earlier, a Parking A rea may be either a c learly defined area in which few problems arise for ATC, or a comp lex mix of Manoeuvring Area and Apron. In the latter s ituation it is extremely difficult (if not impossible) to control all the service vehi cles operating therein. So that some semblance of order and priority may exist, special reg ul ations are needed to permit the harmonious operations of all concerned. The fundamental principle must be that all vehi c les NOT under control of ATC must give way to

A Follow-Me car, in contact with the Airport's Jumbo Jet to a pre-determined parking position .

GMC,

l eads a

aircraft at all times. Special areas around aircraft stands and a system of roadways can be designated in which NON-controlled vehicles must confine their operations. The provision of such regulations and their rigid enforcement eradicates the problems otherwise created for ATC. Specific ATC problems in regard to the Parking Areas are: 1. Methods of Parking Aircraft - A ircraft parking is ach ieved by use of either self-manoeuvring or nose-in stands.

The first present no problem to ATC as aircraft may taxy onto and away from the stand with no external assistance. The latter c reate problems to ATC in the case of departing aircraft since more time is taken for the aircraft to be pulled-back and then disconnected from the tug before they are ready to taxy. Nose-in stands are located so that they have direct access to taxyways, or in cul-de-sacs. Either location entails some delay in moving off from the stand and great care must be taken by the GMC controller befo re autho rising a Push- back. Where aircraft require to carry out a Pushback manoeuvre into a taxiway delays are unavoidable if there is a stream of movements along that taxiway.

However, such delays could be obviated by the provision of additional taxiways to provide a by-pass routeing.

Similar delays arising in cul-de-sacs mig ht possibly be reduced by a better arrangement of the parked aircraft having due reg ard for the times they will depart. Inevitably it occurs that three or fou r aircraft in neighbouring stands will all call at the same t ime for Pus h-back when nothing else is moving on the aerod rome.

2. Repositioning of Aircraft - Due to the limited number of stands available at most aerod romes, there is a requirement to keep stand-occupancy time as short as possible. Pursuit of this objective consequentially incu rs several additional movements (usually at bu sy ti mes)

37

Aircraft under tow are normally slow and rather cumbersome, whereas aircraft that are taxying for repositioning fit in neatly with the normal traffic flow. Sometimes an aircraft will be prepared for service and leave the Maintenance Area before its allocated stand is vacant. This creates a parking problem on the Manoeuvring Area and should not be permitted.

3. Absorption of Delays "Off-Stand" - Since the number of stands is limited, when ATC en route delays are affecting outbound flights, it is in the best interests of the Aerodrome Authority to permit aircraft to start-up and taxy to the Holding Point to absorb the en route delay there. Although excellent in theory, in practice this does not work at all well. Whilst on its stand an aircraft presents no problem to the GMC controller, but as soon as it commences to taxy it is one more movement to monitor. Most aerodromes have insufficient space and taxiways available for this procedure and to attempt it with the limited facilities presently available increases ATC workload by an almost unacceptable degree. ATC have enough problems at the moment in holding aircraft for which stands are not yet available.

4. Method of Stand Allocation - Stand allocation is usually the responsibility of the Aerodrome Authority or the Operators. The method by which this information is passed to ATC must be clear and concise and preferably by visual rather than voice communication. However there must also be ready and rapidvoice communication between ATC and the person allocating stands in case of queries. The method of allocation must be based on the time aircraft actually leave their stands NOT their scheduled departure times. If the latter are used, problems are created for ATC when inbound aircraft are allocated stands which are still occupied.

2.

3.

4.

5.

e.

of a routine nature be delegated to an assistant, if possible.

The possibility of reducing GMC workload by sectorisation without an undesirable increase in the liaison task should be studied.

R/T equipment and operating standards must be of the highest order.

ATC staff must liaise closely with the Aerodrome Authority in regard to Planned Maintenance and future planning of taxy routes etc. to thus ensure a smooth and uncomplicated flow of traffic on the ground at all times.

Airline Scheduling might well be rearranged to remove peaks in traffic which create problems in stand occupancy.

Finally, it is fair to say that the two prime attributes of a good GMC controller are: a) a lot of patience, and b) a sense of humour.

Controller responsibility is the cornerstone of the present ATC system .. E~c~ day on the job, the controller must make numerous md1v1dual personal decisions. Most other civil servants rarely make managerial decisions to th degree of importance of the controller even at a low Ieve~ facility.

We all know the life or death nature of our busin ess.

This must ta ke prece dence over all lesser considerations _ s~ch as traf_fic. ~ounts, fuel cost~ and noise factors. The vital role of ind1v1dual controller discretion is well ace t d not only by legislators, but by all those who fly. e;he understand full well its implications to their continued w:ri being.

Limitations of GMC at Night and in Bad Visibility The courts too have recognised its inviolate nature.

In at least one case when a wake turbulence hazard It is very fortunate that the periods of peak traffic fall occurred, a controller has been blamed for the ·1n "d during the daytime, for GMC is defin~tely a service based . . c1 ent, although he maintained legal separations and foll on the visual perception of both controllers and pilots. GMC . d . ff owed orders. Th e JU ge,. m e ect, said that the controller was controller workload can be eased by instructing one taxythe one charged with the safety of that plane. He must go ing aircraft to follow another, thereby requiring routebeyond orders and regulations if need be, should h" ing instructions to be issued once only. By night, in the .

I . d t . d" is profess1ona JU gmen m 1cate a safety hazard existed.

Parking Areas (thanks to the floodlighting) the same techThe employer appears eager to blind himself t nique is normally possible even though the traffic flow is ·t· h H 1· i o such rea l 11es, owever. e 1ves n the philosophy of decades much less than in daytime. Since more caution is needed ago that management can do no wrong. On the other hand at night, the monitoring function occupies much more of he also refuses to accept any legal consequenc ' the GMC controller's time. The use of Red Stop-bars, and . th es. He h m e event of a difference in profe · expects t at Green Centre-line taxiway lighting (with a facility to switch b t ss1onal · · opinion e ween a controller and his supervisor th routes at intersections) is most helpful although it does troller shall comply with the instructions of h"is s' e ~onhave limitations if the traffic rate leaps, since it is difficult . uperv1sor to switch the routes quickly enough. In fog conditions, the ~nd. t~e su~trv1sor :h~ll a~sume responsibility for his own Green Centre-line Lighting used in conjunction with AeroP.c1s1~ns. a. con ro ~r is relieved from his position of operation by his supervisor because of alleged drome Surveillance Radar is very effective, providing that unacceptthe traffic rate is low. This is because a different method able perf~rmance ~f duty, the controller, if he requests shall be given a written explanation of the rea f ' of control must be employed in such conditions, necessitat. . . son or such Id action by his supervisor within 24 hours FAA ing careful study of the radar display and extra liaison in . . wou have 1t that controllers cannot have a difference of f . addition to the normal tasks. The number of taxiways . . . . pro ess1ona1 available for use may have to be curtailed to avoid areas opm1on from their supervisors. If they do they . d" t k" b ' are msubof poor radar coverage caused by the screening effect of or ma e,. ma mg trou le, destroying the whole stru cture and fabric of managerial rights. any local buildings.

Conclusions 1. GMC controllers need to be flexible in the planning and provision of their service. It is highly desirable that tasks

But controllers are not robots. They must k . . . ma e mdepen den t d ec1s1ons on the job. This ·in no way violates managerial prerogatives. In fact, that deci·si·on making power is the only way the system can work.

(PATCO Newsletter)

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News From Corporation Members

Ferranti Limited The U.K. Defence Ministry has awarded a contract to Ferranti's Digital Systems Division to supply the Aeroplane and Armament Experimental Establishment (A&AEE) at Boscombe Down with a computer assisted radar display system (CARD) for processing and displaying SSA and remote primary radar data. The total cost of the system will not exceed £ 350,000.

The Ferranti CARD system will process SSR data derived from the Civil Aviation Authority radars at Ventnor (Isle of Wight) and after co-ordinate conversion will display it at A&AEE in conjunction with primary radar data from any one of the three local radars. It is also designed to handle both primary and secondary remote radar information from Burrington, Heathrow and other sites if required.

The Defence Ministry's decision to take CAA data stems from the need to avoid over-interrogation, and a decision to limit the number of SSA interrogator equipments which can be approved. There is an economic advantage in that no new radar equipment is required. Additionally the use of both primary and secondary radar from Burrington could extend the effective area of A&AEE control during trials.

The use of SSA data will provide A&AEE controllers with height and identity information from all transponder-equipped aircraft. Controllers will be able to provide vertical separation between their aircraft and other traffic instead of (as now) being limited to lateral separation standards.

This will allow better use of airspace and greatly simplify airway crossings. At present, trials aircraft have to be routed around other traffic and some trials are aborted because it is not possible to arrange a straight run.

The ability of CARDS to handle both local and remote radar data allows the system to cover a range of applications. Typical applications envisaged are: (1) SSR labelling of civil and military Approach Control radars where there is no local SSA data source; (2) Extension of radar control of civil air traffic using data from military radars; (3) Processing and display of data in new radar systems, or from new radars added to existing systems. Although not called for in the A&AEE system, the CARDS program can provide tracking, ground speed readout and coasting facilities, digital maps and recording of radar data.

The A&AEE CARD system accepts primary and secondary radar data in FAA format. Identical processing is carried out in two computer channels, each having its own core store. Common access is provided to a disc which holds test and operating programs. The computers used are Ferranti FM 1600D. The system includes nine Ferranti FRO 1641 displays with the capability of driving additional displays, up to a maximum of sixteen. This is a new display developed from the MD 88 and has both a raw radar and a graphics capability. Data displayed includes a minitab positioned on the tube at the discretion of individual controllers. All alphanumeric data is written in intertrace time, but the high deflection speed necessary for this is achieved with a deflection power consumption of only 300 watts.

A rolling ball and keyboard are provided at each display console to allow the controller to select the data required.

Input from the keyboard and rolling ball to the computer, and output from the computer to the displays is by means of the Ferranti S3 (Serial Signalling System). This uses only a twisted pair in each direction. S3 was designed to simplify cabling in naval ships, and this is its first application in Air Traffic Control.

Outputs from the two computer channels are identical.

They are fed to the displays over separate S3 links. Selection of the computer channel is by switching at each control console. Each computer program includes a full range of test functions, and a malfunction in either channel is indicated to controllers by the flashing of data on that channel and illumination of a channel malfunction warning light.

Individual keyboard and rolling ball entries are input to both computer channels, and when the alternative computer channel is selected the display data is completely re-written within one eighth of a second. The system includes hardware at each console to monitor the S3 links so that any interruption is signalled at a display console in the same way as a computer channel malfunction.

The order includes the provision of digital encoders at the three Boscombe Down primary radar heads.

International Air Carrier Association IACA's Director General, Mr. F. A. Pfiffner, has announced that the Association has accepted Cimber Air, the independent Danish charter airline, as an active member.

Headquartered in S0nderborg, Denmark, Cimber Air operates both passenger and cargo charters, many of which are for industrial organisations. In addition the company has been involved in ferrying aircraft, aerial photography and mail flights and scheduled passenger flights in areas as varied as Northern Norway and Saudi Arabia.

On August 2, 1975, Cimber Air celebrated its 25th anniversary and is now operating 4 Nord 262s, 2 VFW 614s, 1 Mystere 20 and additional small twins.

International Aeradio Limited An increase of more than 50 % in the combined turnover of the parent company, its subsidiaries and associated companies to£ 35 m (£ 22 m in 1974) has lifted IAL turnover and profits to another record level in 1975. The rise in turnover was complemented by a 65 % increase in pre-tax trading profit (after charging all interest) of £ 2.1 m as against£ 1.3 m in 1974. These results were achieved mainly outside of the U. K. by expanding contracts and increased trading throughout the 61 countries where 90.3 % of the Group's total revenue was earned.

In addition, intensive marketing achieved exports from the U.K. of electronic systems of £ 15 m (£ 9.2 m in 1974).

Significant sales of computerbased vehicle command and control systems were recorded in the U.S.A. and Canada.

Projects, contracts and orders already realised enable the Group to feel that 1976 will show another substantial increase in turnover and profits.

IAL's Middle East involvement was once more illustrated when Saudi Arabia's Director of the Technical and Com-

munications Department in the Directorate of Meteorology announced recently that IAL has been awarded a five-year contract to develop manpower and technical systems in the fields of electronics, radar and communications engineering for the Kingdom's meteorological service. A maintenance and technical operations service is also included. A significant part of the contract would involve the training of over 250 Saudi employees in the U.K. During the next five years, IAL will supply the Directorate with the necessary technicians and engineers to operate and maintain the meteorological equipment. These technical staff will gradually be replaced by qualified Saudi personnel as they return from the completion of their studies in the U.K. IAL's U.K. based training activities are complemented by many similar training schemes centred overseas. One of these centres has received a boost with the opening of the Bahrain Civil Aviation Directorate's new training unit. The unit, which was officially opened by Bahrain's Minister of Development and Industry, will be run by IAL on behalf of the Bahrain C.A.D. In a speech made at the opening, the Assistant Under-Secretary for Aviation Affairs stressed the important part the new unit will play in providing the State's future specialists in Air Traffic Control, Meteorology and Electronics.

Philips Telecommunications The Civil Aviation Organization of Egypt have concluded a contract with Philips Telecommunications for an AFTN link between Cairo and Luxor, involving an ISB circuit with one telephone and one teleprinter channel. The 2 million Guilder contract covers the supply and installation of four 5 kW channelised ISB transmitters, ISB receivers with AFC circuits and all the accessories such as aerials, coaxial cables and teleprinters. Deliveries will be effected in the course of 1977.

Plessey Company Limited Bahrain's Civil Aviation Directorate has ordered a Plessey AR-5 primary radar and a Series 200 secondary surveillance radar. Of particular significance is the Directorate's lead with regard to the second item, as this will be the first automatic SSR to be ordered for ATC anywhere in the Arabian Gulf. It will automatically display on the ATC radar screens the identity and height of all civil and military transponder-equipped aircraft within range. Emergency codes such as 'HiJack'. 'RT Fail' and 'SOS' will appear as flashing indications to instantly alert the controllers to the aircraft in difficulty. A Plessey AR-1 has been operating at the airport since 1966 but the AR-5 will detect aircraft at much greater range and altitude.

The Swedish Board of Civil Aviation has ordered five PLAN 17/18 Instrument Landing Systems from Plessey Navaids. Two will be installed at Landvatter International Airport, under construction near Gothenburg, and one each will go to Norrkoping-, Ronneby- and Angelholm Airports.

Plessey Navaids has also received a £ 200,000 contract to provide instrument-approach equipment at Plaisance Airport, Mauritius. The equipment comprises a PLAN 17/18 Cat 2 ILS, two marker beacons, an NOB and a DME. For terrain reasons the ILS glideslope is being set at 3 112°; the DME is co-located with the glideslope, and the NOB marks a 2,250 ft mountain in the approach area.

New customers for Plessey Navaid's PLAN 50 Doppler VOR beacon are the Civil Aviation Administrations of

40

Mexico, Thailand and Sharjah (one of the United Arab Emirates}. A key factor is the ease and economy with which Doppler VOR can be installed at sites with rough or wooden terrain, relative to conventional VOR - whose radiation pattern would suffer unacceptable distortion, giving inaccurate bearing information. Sharjah is a particular case of the Plessey Plan 50's cost effectiveness, because the new international airport there is surrounded by an area of migratory sand dunes. With conventional VOA, not only would high initial expense have been incurred in preparing the site, but due to drifting sand a continuing site clearance and flight calibration programme would have been necessary.

Racal Electronics Group Racal-Amplivox Communications Astrolite headsets have been selected for aircrew on all British Airways' concordes.

The headsets - specially modified to meet the specific requirements of this supersonic airliner - were all delivered ahead of schedule in time for the introduction of the London/Washington se~i~e. British Airways say that they are impressed by the eff1c1ency of the Astrolite earphones which give the clear communication needed in all conditions. In addition, the ear cushions do a great deal to cut out all the background noises experienced by aircrew.

The "Six-ninety Series" of Racal Communications Control Station boxes dominated the Stand of one of the Racal companies at the recent Farnborough Air Show. The custom designed CCS units are used to centralize the control of all communications systems on board an aircraft. They are found in many of the advanced aircraft in use with the R.A.F. and civilian fleets and with the U.S. Marine Corps "Harrier". Also on show at Farnborough was the type 2 1 A 200 Series headset tester. It provides clearly defined measurement relating to a wide range of audio ancillaries such as headsets, handsets, microphones, oxygen masks and communications helmets. Simple to operate, the tester can be used by non-technical personnel and covers continuit sensitivity, distortion, phase and cross talk test function~'.

Sofreavia IFATCA members . ..will be interested in knowing a l'ttl 1 e more about the act1v1t1es of this new Corporation Me b . . t t d' m er.

S of reav1a carries ou s u 1es, anywhere in the wo Id f ground aeronautical installations, brings these stu: ' to .. h . t II . . ies o fru1t1on, puts t e ms a at1ons mto service and actually runs rt them. The company collaborates with the Paris A' .

1rpo . d b.

A ut honty, an rings mto play the experience of F h d renc .

• te eh mca 1 services an the assistance of the large b k which take part in the work. Completely independent ~nin~ dustry, research bureaux and of suppliers of eq · t u1pmen , . . h Sof reav1a acts m t e most objective way and seeks th . · t f b . e most eff 1c1en ormu 1ae est suited to the interests of its customers.

0

Thanks. . to the 1• t s ·m . . assistance of the finest spec·1a1s French c1v1l av1at1on, _Sofreavia gives the customer the double advantage of being up to date with technique ( t _ 0 mation of Air Traffic Control, radar data P s a~ . . d" rocessmg, prec1s1on Ian mg, meteorological forecasts etc ) d f · I technicians with w·ide ' an· h avmg at h"1s d"1sposa e·xpenence . ba~ed on a long period of practical application in all sta es of improvements. g

°

~he company can undertake economic and technical studies, whether general or specialised, equipment and in-

16th Annual Conference International Federation of Air Traffic Controllers Associations

NICOSIA. CYPRUS

NICOSIA 25th-30th April 1977 General Information Location The Nicosia International Conference Centre. (near Hilton Hotel).

Official language English Registration fees (per person).

Participants C ÂŁ 15.Accompanying persons C ÂŁ 10.These fees cover: Participation in the Professional Sessions Receptions, local Transportation, Lun ches, Coffee-Breaks, Social Events, Ladies programme.

Whole-day Tour including lunch, kindly offered by Cyprus Tourism Organization.

Ladies' Programme In addition to the general social activities in which the accompanying ladies will participate, a diversified program will be arranged for them during session time.

Secretariat: 16th Annual IFATCA Conference CYATCA, Civil Aviation Nicosia - Cyprus " Rock of Romios" legendary birthplace of Aphrodite, the Goddess of Beauty and Love, in Paphos d istrict, along the road to Limassol.

Provisional Time Table Sunday

April 24, 1977 Arrival of Participants Registration Press Conference Monday April 25, 1977 Registration Official Opening Working Sessions Social Event Tuesday April 26, 1977 Working Sessions Social Event Wednesday Apri l 27, 1977 Working Sessions Evening at Leisure Thursday April 28, 1977 Working Sessions Social Event April 29, 1977 Friday Technical Presentation Final Sessions Banquet April 30, 1977 Saturday Whole-day Excursion Tour

Paphos harbour and medieval castle .

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stallation projects, planning and installation of equipment 380 ILS systems have been delivered to date by Thomsonwith reception checks. Through its subsidiary, SofreaviaCSF ~nd its U.S. licensee Texas Instruments. Deliveries Service, the company provides technical assistance for the have included units for Pyong Yang (North Korea), Zurich, use of equipment, loans of personnel, servicing and mainAmm~n and .Aqaba (Jordan), Stockholm/Bromma, and the tenance, and funding for personnel training. Among the 18th m a series of units delivered to Yugoslavia. services which have been supplied in the last few years are the following: Ulmer Aeronautique Air transport plans and aeronautical systems in Algeria, . T~is new Corporation Member has been engaged in Argentine, Colombia, Morocco, Mexico, Tunisia, Yemen, aviation for a very long time. Nearly thirty years have and in France itself. ~ass~d sine~ the company started to manufacture runway Studies on the evolution of traffic and the aeronautical hghtmg equipment. Progressively during the years the services required: Andorra, Cameroons, Spain, a Francocompany has studied and added other achievements ~o •t German airport, Iceland, Reunion, 30 aerodromes in f · IS range o 7qu1pment which now permits it to offer lights in France; economic studies for French air routes; studies following three categories: the on tourist forecasts in Corsica and France's Mediter(a) Recessed lights; (b) Semi-recessed lights· and ( ) ranean area; study of regional air transport customers Elevated lights. ' c in France.

The ~L rec~ssed tights are the latest achievement of Studies and technical achievements: Brazil (12 aeroUlmer Aeronaut1que and this equipment is now installed at dromes), Laos, Colombia, Gabon (pilot school), Haiti many aerodromes.

(5 aerodromes), Libya (air bases), Tunisia (3 aeroThe U':- lights can be plugged in and the connections dromes), Zaire, Djibouti (airport terminal), Egypt and are watertight. They are conceived in such a way as to be Cuba (radar cover, en-route equipment), Algeria (weather able to take out and replace the optical system with ease. telecommunications centre), Abu Dhabi (air base); These lights exist in different types: Personnel training for Algeria, Spain, Libya, Syria, Zaire, Approach lights and missions to many countries.

Threshold lights

Stansaab Elektronik AB The West German authority for Defence Techniques and Procurement has placed a contract of 23 million Swedish Crowns for delivery of a radar simulator. The simulator will be used to improve the education efficiency of Approach Controllers and Precision Approach Controllers of the German Air Force. Through the simulator, the trainees will be given the practical and theoretical knowledge required to be licensed as fully responsible controllers after necessary practice at military units. Furthermore, the simulator will be utilized for refreshment training of previously licenced controllers.

The simulator is divided in three school groups each able to operate independently and simultaneously of the others. The three groups can also be combined for larger exercises. Each exercise is based upon pre-prepared and stored data describing the tracks to be simulated. The exercises of each school group can be started and stopped individually. It is also possible to reverse and replay any part of an executed exercise. Also several other methods to aid the teacher to evaluate the results of an exercise is included. Besides the trainee positions the delivery comprises two teacher positions and several "pilot" positions.

The simulator is based on Stansaab's Censor 900 computer system and comprises among others a computer Censor 932, a number of displays type PPI 850 and type Alfaskop 3500, and necessary communication equipment. Three types of radar stations will be simulated, i.e. ASR, SSR and PAR. It will be possible to select for display either raw or synthetic information or a combination of both. The system will be taken into operational use in 1978.

Thomson-CSF The company has confirmed a new series of orders for its instrument landing systems. Included are installation of a second ILS at Singapore, two at Vienna-Schwechat (bringing that airport's total to four), one each at Linz (Austria) and Bali (Indonesia), and two at Cape Town. Over 42

Runway centre line lights, lights delineating curved paths and active runways.

Since the original plan for the lights, studies have been made of the manufacture of common parts for the diff h erent . f'f . t ypes th us s1mp 1ymg t e problems of maintenance of the components. In the range of recessed, semi-recessed and elevated lights, Ulmer Aeronautlque can meet an d 't s pro d ucts a II owing · Y or · er w1'th 1 the equipping of all cate · rt All 1· h gones o f a1rpo s.

19 ts come up to ICAO standards and are checked and tested constantly to allow for stilt more im rovements in endurance and performance. p The Ulmer Aeronautique company is a dynam·ic . concern responding to all the needs and the essential te h · requirements in the field of runway lighting and ·in c dni~at . . .

• so omg g1_ves its users the equipment which conforms to the· wishes. ir

FAA's 20 Air Route Traffic Control Centres hav · d w1'th a " con ff'1ct alert system" to hel e now b een equ1ppe d . . t . p ra ar t II con ro ers to ~n t 1c1pa e potential mid-air collisions of aircraft under their control. A computerised system •t . mon1 ors the fltght paths of tr~cked a~rcraft. If it appears they will pass closer than required horizontal and vertical se t· · · d para ion minimums, ata tags on the radar scope start t 0 bi' k · aIe rt .mg contra II ers to a possible conflict. The syst m. • . . b em 1s use d m airspace a ave 18,OOO feet where all aircraft are under ATC control and all have encoding equipm t Other expansion of the capabilities of the A~;s 11 1 system are planned, such as: A metering and sp~cing program that will assure the even flow and spacing of aircraft in approach and d _ parture sequences. e .d.

Automation of control messages to pilots prov1 ing • d .treet•tons resu 1ting from the conflict pred· t' . .

1c ton and metering and spacing functions.

Flight data handling improvements includi·n th . .

• g e processing and electronic display of flight data to re lace the present system of flight strips.

P

LAR II: Signaal's New Versatile High-Performance Radar

MAINTEN ANCE SWITC H

ANTENNA

TRANSMITIER

RECEIVER

WAVEGUIOE DRIER ANO C OOLING CABINET

REMOTE CONTROL UNIT

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I I II L ___ _ ___ ____ ______ ___ J

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LAA II Long Range Air Surveillance Radar

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E - R a d - ud-ata-lod-iopla yoy-olem- - - '

Hollandse Signaalapparaten B.V., IFATCA's Netherlands Corporation Member of SARP fame (SARP : Signaal's Automatic Radar Processing System at Schiphol Airport, Amsterdam, described in THE CONTROLLER of May, 1975) has produced a new, exciting triple purpose radar which is being marketed under the name of LAA II. The LAR 11 is an L- band long-range enroute surveil lance radar which incorporates a number of advanced technical features, and which also has the capacity to handle medium- and shortrange tasks in the terminal area in addition to its airways control function. It is Signaal's latest addition to its range of civil and military primary radars. The company believes that modern conditions demand that today's equipment should meet the requirements of both terminal area and airways air traffic control, with optimum suppression of ground and rain clutter, and a very high standard of reliability.

In order to meet these needs, equipment should have high power output for long-range performance, coupled with high definition and a suitable minimum range for terminal area work - and a modular design directed towards the reliability requirement. Operational applications of the LAR 11 therefore include: (1) long-range surveillance of air traffic, (2) medium-range surveillance for terminal area contro l, and (3) short-range approach vectoring. LAR II is, of course, fully prepared for integration of secondary surveillance radar (SSR), and for that purpose is fitted with mechanical and electrical facilities for SSR integration.

LAR II operates in the L-band between 1,250 and 1,350 MHz, has a max imum range of more than 200 nautical miles (333 km) and a height of 120,000 feet is claimed , with a minimum range of approxi mately 1,000 m (3,300 ft) and a resolution of 1,7 ° in azimuth and 90 m (300 ft) in range. Signaal's new installation comprises the fo llowing units: an antenna, either provided or not provided with a se parate or a main-reflector-integrated antenna for SSA ; a transmitte r, which also contains the receiver r. f. head, and the power switches fo r the antenna drive motor; a waveguide drier and cooling cabinet which supplies dry air to the wavegu ide system and demineralised cooling wate r to the transmitter travell ing wave tube (TWT) and a few waveguide components ; a receive r, consisting of the IF stages and the video processing circuits; th is cabinet also contains t he frequency control unit which supplies the control signal for the transm itter, the various local oscillator s ignal s and the necessary trigger pulses ; a maintenance switch permitting the antenna drive and the transmitter high voltage to be interrupted. for instance during maintenance of the antenna ; a remote control unit.

The radar data output of LAR II can be supplied to the users both via a coax cable and through video link. It is also possible to extract v ideo first, after which data transmission by narrow band li nk is possible.

43

tube is used) is considered to be at least ten times that of a magnetron ; in practice several individu al units are claimed to have clocked up more than 20,000 hours' life each. Although a TWT provides a high mean power output, the peak power is relatively low - eliminating the need for a pressurised waveguide system containing spec ial gas.

Pulse Compression System

Th e electronic equipment is of solid-state design, incorporating many integrated c ircuits. The transmitter control signal and all the necessary auxi li ary frequencies and trigger pu lses are derived from one and the same crystal , thus realis ing an exceptional system stabi lity. The crystal-controll ed coherent transmitter produces a peak power of 180 kW and a m ean power of 4.1 kW, giving a duty cyc le o f 2.3 %. The receiver is a double supe rheterotyne with a low-noise transi sto r amplifier as r.f. p re-amplifier. The noise figure is 3.5 dB. Th e first intermediate frequ ency is 270 MHz, the secon d 30 MHz. There are two separate channels: a semi-loga rithmic channel w ith pulse c o mpression for the lo ng pulse and a logarith mic chan nel w ith PLO fo r t he 1- microsec pulse.

Both chan nels are provided with MTI fac ilit ies.

Parabolic Antenna Th e r adar beam is transmitted from a new horn-fed pa rabo lic antenn a w hich has a st a inless steel reflecto r for m inim um c o rrosion ensuring that maintenance even under t he wo rst atmosph eri c conditions is minimal.

Beamwi dth (-3 dB) is 1.7 ° in the ho rizontal p la ne and 4.5 ° cosec 2 t o 35 ° in t he vertical pla ne. The powe r gain is 31.6 dB. near- in si d e-l obe level is -25 d B. Two rotatio nal s peeds are provided as stand a rd : six and twe lve rev/m in, and five and ten rev/ min, as requ ired by the custo me r.

Travelling Wave Tube The radar b eam is created by a trave lling wave tube (TWT) device, w hich is c laimed to o ffer many advantages ove r the more conventio nal magnetro n powe r sources inc lud in g g reate r life. TWT provides a h igh mean output powe r for lo ng -range operation and a high d etect ion p rob ability, and is co ns ide red to have also adva ntages over a magnetro n radar w here t he provision of movi ng target indicatio n (MTI ) fo r c lutter suppress io n is concern ed, so g iving bette r anti-clutte r performa nce. A ccording to Sig naa l. the MT I effect is limited on ly by exte rn al influences such as antenna rotation and c lutter mot ion, and not by system instabi lit ies T he re liability of a TWT (a Raytheon 44

The low peak power, however, necessitates the use of a long transmitter pulse, which would lead to poor definition and deterioration of shortrange characteristics. To counteract this, Signaal has applied pulse-compression techniques with the object of compressing the long transmitter pu lse to a pulse an order smaller than that realised by a comparable magnetron. Additionally, a separate short pulse is generated immediately after the main transmitter pulse, and detected by a separate receiver and processing c ircuits, with the object of improving performance at s hort range.

The transmitter pulse therefore consists of two parts, and by employing two different pulse lengths w it hin the overall transmission, the new radar allows targets at both long and short range to be satisfactorily detected. So, first a long pulse for the long-range case, a pulse of 34- or 68microsec duration (according to the operational requirement) is used. By advanced pu lse-compression techniques this is reduced to 0.6 microsec on reception, wh ich enables a much lower- powered beam to be employed w hi le retaining excellent long-distance capabilities. For s hortrange detection a short pulse of one-microsec duration is transmitted directly after the first at a frequency 7 MHz fro m it. It is received and processed separately in the receiver and serves to improve the minimum rang e of the radar. In this way, the total pulse length is 35-mic rosec at a p. r. f. of 660 Hz, or 70-microsec, at a p. r. f. of 330 Hz: The combination of the two gives a perform ance where targets of airliner size can be d istin guished and c lea rly displayed from 1/ 2 n. m. to over 200 n. m. fro m the radar head.

For the purpose of pu lse compression, the radiated signal (transmitter pulse) is provided with a linear frequency modulation of wh ich the reciprocal value is equal to the co mpressed pulse length required .

It is also poss ible to introduce phase cod in g instead of frequency coding, but Signaal preferred the latter method because of a number of important advantages, namely: a hig h comp ression factor can be realised more r eadily; lowe r s ide lobe levels are poss ible by "weighting ", that is, special shaping of the frequency curve of the c ompression filter ; the effect of doppl er frequency shift is negligible, while in the case of phase coding this shift wi ll res ult in a rapid ly decreasing compression factor; the design of the circuits is relatively simple; it is possible to in corporate an effective anti-c apturing provision.

The Capturing Effect When for instance an aircraft makes an overland flight, the relatively weak airc raft echoes and the strong c l utter wi ll co incide partly or c ompletely. Due to the un avo id able limiter operation in the receiver, th e strong echo w ill almost co mpletely disp lace the weak echo, thus c ons ider ably reduci ng the signal-to-clutter ratio. But any c apturing effect,

i. e the elimination of weak pu lses by stronger ones in the event of overlap, is effectively dealt with by the specially developed three-channel pulse compression system. The hardware used has to meet rigid standards as regards phase and amplitude equality, frequency characteristics, etc.

For this reason the p . c. circuit consists of surface accoustic wave delay lines and filters, since this is the only way to realise these standards. The SAW devices have been developed by a specialist firm in this field: MESL of Edinburgh, Scotlan d.

Solartron Video Map The display system incorporates the Solartron videomap, which is coupled into the processing system (like Signaal, Solartron are Corpo ration Members of IFATCA).

The unit consists of the outline definition of the surrounding a irways, coastline and other aeronautical information carried on a magnetic tape cartridge. Each cartridge contains two map displays, and feeds the picture-generating computer. The controller can thus choose which map disp lay he wants and at a big centre there may be several such video-map units providing a wide choice of maps.

Additionally, on the dark-room display the scale of the picture can be changed, from 256 n. m. down to 2 n. m. across the screen, and from 160 n. m. to 20 n. m. on the daylight display. The map presentation has therefore to be synchronised with the di splay of radar information at all times.

Clutter Suppression The performance of the system is also favourably affected by the fo llowing anti-clutter measures: a polarisation unit which is co ntinuously adjustable between linear and circular polarisation, permits optimum suppressio n of ra in c lutter, and results in an improvement of approximately 12 dB in the signa l-to-rain c lutter ratio ; STC is not only used in the IF channels but also in the low-noise transistor amplifier (LNTA) at the input of t he receiver ; opt ionally, a dual beam arrangement can be provided.

By means of the passive hig h beam an improvement in signal to ground clutter ratio of 10 to 15 dB can be obtained for targets at an elevation of 3 ° to 4 °; for MTI , use is made of a digital double canceller with 8 bits. It has a cancellation ratio of 42 dB, and produces a n MTI imp rovement of approximately 35 dB with an overall system stability exceeding 50 dB. The first blind speed is more than Mach 5 due to p. r. f. staggering ; a video co rrelato r, also of the digital type, suppresses isolated clu tter residues and noise pulses so th at a black-white radar picture is obtained.

Off-Centre Display As w ith most synthetic displays, the display can be offcentred, so that the centre of the screen is the geographic location (rather than the radar head) of most interest to th e controller. This is achieved by separate thumbwheels driving in north-south and east-west directions, rather than the more usual rolling-ball. These thumbwheels can also drive a vector line, which is used to measure the bearing and distance between any two points on the radar screen - typi cally an aircraft and geographic feature such as the runway thresho ld or a reporting point. A sta ndard key-

board is used to communicate with the computer, in conjunction with the light pen which is used partic ularly for transposing data about the screen.

Primary Video Extractor The primary video extractor has the followi ng features: moving window detector (window size, 15 hits); digital quantize r with double thresho ld ; range in crement, 0,76- microsec.; amp I. quant., 8 bits; sampling rate, 2 per increment ; adaptive plot criterion for constant false plot rate ; clutter w indow 15 x 17 cells.

Extreme Environmental Conditions LAR 11 can withstand extreme environmental co nditions. Temperature limits for the antenn a are -50 to +55 ° C, for indoor equipment o to + 55 ° C. Relative humidity - up to 95 D/o at 40 ° C. The antenna can operate with wind speeds of up to 140 km/hour and will survive wind speeds of up to 180 km/ hour without sustai ning damage.

Mains Power Requirements 380 V 50 Hz 3-phase - approx. 45 kVA : anti-condensation heating: 220 V 50 Hz 1-phase GdB approx. 1 kVA.

Mr. Pierre Cochereau, who organises the organ services at Notre Dame Cathedral in Paris, said he is perp lexed by the call of the New York leg is latu re for a ban on Concorde landin gs because of excessive noise.

Mr. Cochereau said the noise developed by Concorde on takeoff was 108 decibels. while the Notre Dame organ put out 11 4 dec ibels. He said that for the recita ls given each Sunday or holiday, he often invited American or(Sapa-AP) ganists.

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Comments On Air Traffic Control From Far And Wide

H. Trautwein, Director, DOsseldorf Airport, on the need for priorities for certain aircraft: .

The "first come, first served" rule is no lon~er suitable for major airports. In the interest of optimum a1rs~ace u~e and the handling of commercial aircraft, certain traffic must receive priority. .

Such priority should as a rule be given to commerc~al rather than general-aviation traffic. Within commercial aviation the coordination of flight plans and use of flow control 'means that no special priorities are ~e~~ed as between commercial flights. The question of pnonties between on-schedule and delayed flights needs further study.

Slow-flying aircraft are a problem for Air Traffic Con~rol, and minimum speeds should be laid down in terminal areas. 1 call on airports and their associations t? press governments to give priority to commercial traffic.. and for ICAO to provide the necessary basis in international law for such a philosophy.

There is no question in my mind that controllers should be getting double the pay they are getting now.

PATCO President J. F. Leyden: U.S. controllers expect a great deal from the new Classification Report which will be issued shortly by the Civil Service Commission. After being underpaid and underclassified for so long, controllers anticipate new standards which better reflect the complexity and intensity of the work, and the high degree of responsibilities. Controller patience has worn thin at being locked in a totally inappropriate salary system, and controllers are well aware of the great and unfair disparity in pay compared to airline pilots.

David R. Israel, Former Director, Office of Systems Engineering Management, FAA, expressing a cautious view on the impact of automation in the area of productivity: There is no question that as we proceed up the automation ladder, we should reduce controller workload, but the real question is, however, whether and when that reduced workload can be converted to increased traffic handling capacity and hence higher productivity. Those things which we do feel sure of today include that through automation we can reduce the size of the control team and the overhead staff, and that we can increase the flexibility of sectorization from peak to minimum traffic periods.

However, whether we can increase the amount of traffic that existing sectors will handle is more difficult to judge, since it probably bears directly upon system reliability and backup and the less quantitative aspects of the experience and confidence of the controllers.

Edward w. Stimpson, President, General Aviation Man.ufacturers Association (USA), on the need of more easily obtainable weather information for pilots: The "cleaning up" of the controllers' radar scopes by the elimination of weather returns has increased thunderstorm and severe weather hazards for pilots flying und.er instrument flight rules, especially if they do not have airborne weather radar. We realize efforts are made to pl~ce some weather outlines on the controllers' scopes by using information from en-route radars, but this system seems to be ineffective from the users' point of view. . .

Attempting to use a single radar fo~ both Air. Traffic Control and weather purposes raises serious questions .. It In short, in the area of productivity, I tend to be very be wiser to have a network of weather radars (which conservative in my estimates and predictions. While 1 am relatively inexpensive and needed by the sure that automation offers great potential for improveWeather Service in any event) and provide controllers ~1th ments in productivity, I believe that this will be a very longterm project. weather information from those radars rather than continue existing efforts to make one radar try to serve non-comJohn Stackhouse, writing in the "Financial Review" patible functions.

(Australia), under the heading "Parallel scheduling slammed Some comments made at the 1976 San Diego Annual by air traffic controllers": convention of the Professional Air Traffic Controllers OrgaThat old bugbear of air travellers, parallel airline schenisation (USA): dules, has come in for a roasting at the IFATCA Conference FAA Administrator J. L. Mclucas: The Agency will take in Melbourne. A report prepared for the technical sessions on 500 additional controllers during the year 1976. Air traffic slammed clustering of flights at peak hours, parallel schewill continue to increase and we must staff up to meet the dules and provision of too many seats as the main causes increases. IFR traffic will go up by four per cent in 1977, of the expensive and fuel wasting delays in the air transfrom 25 to 26 million movements. The Agency is requesting port system. The report goes on to point up two types $ 2.4 billion from Congress. of "clustering": U.S. Senator J. V. Tunney: I come out strongly for higher The normal peak-hour syndrome - the peaking of arripay for controllers and improved working conditions. You vals and departures at preferred times; should get more money for the job you do, and I want to A clustering within these hours - arrivals in 15-minute be of help in any way I can. The vast disparity of salaries segments of an hour can vary from 33 per cent to between pilots and controllers is unfair. It is clearly impos27 per cent and 7 per cent in succeeding quarter-hour sible to have the present high safety level without you. periods.

Controllers have a "punishing job, great stress, and "It would appear that as long as schedules are dictated tremendous pressures. You also have a shorter life expecprimarily by marketing actions based on presumed custotancy than the average citizen. mer demand, peak-hour delays Will continue unless peak Airline Captain Brian Power-Waters, author of the book hour quotas are established by some authoritative body," "Safety Last": the report said, citing international experience. Clustering

::Y

46

Natio~al

is often created or compounded by parallel scheduling of five or more airlines over the same routes at the same time.

In Australia, parallel scheduling results in routine delays in the norm. On September 6 1974 at Melbourne Airport there were 275 movements and 142 delays which could be attributable to scheduling for a total of 7 hours 17.5 minutes delays. While placing a portion of blame for delays on over-scheduling, one must not lose sight of certain constraints imposed on airlines which often mitigate against a spread schedule. Curfews in particular tend to concentrate traffic. International flights must operate through "windows" to meet curfews in differing time zones throughout the world. Parallel scheduling and/or over-scheduling creates routine delays which are often blamed on the air traffic system.

Peak hour scheduling and clustering are basically the result of individual airline marketing actions. These predicate that customers wish to travel at certain times of the day and at no other. One wonders in the absence of a detailed survey whether the airlines dictate the time at which passengers travel or vice-versa. It may well be true that where a seating over-capacity exists, the schedule must meet the demand of the passenger. When a seating over-demand exists, the reverse is true. In accepting that the main delays are beyond the control of the aircraft operators, controllers are not convinced that enough efforts have been made to reduce delays by re-scheduling.

The report also complained that airlines schedule flights into airports on the basis of visual flight rule operations.

When the weather deteriorates and instrument approaches are necessary, the slower rate of handling causes delays which bank up in the system. The report says that IFR capacity is only 60-80 per cent of VFR capacity.

Recent Press Releases originated by the Executive Board of IFATCA: . Airlines badly hit by strikes in Canada Great many Airlines have been badly hit by strike of Canadian Controllers. Aircraft from Europe to USA and Canada were delayed and detoured, and some cancelled when faced with the fact that Canadian Controllers had closed up the almost 3,000 mile long boundary from north to south. Aircraft destined for United States Airports were detoured as much as thousand miles burning up expensive aviation fuel. The International Federation of Air Traffic Controllers Associations is aware that a tense situation is building up amongst the controllers of Canada due to the proposed implementation of bilingualism. The Executive Board of IFATCA are of the opinion that such a plan to implement bilingualism in an already existing environment would highly jeopardise safety in Air Traffic Control and air navigation. The situation is further aggravated by the Court proceedings against controllers and pilots, and more difficulties are foreseen if the Canadian Government does not withdraw their proposal.

IFATCA recommends a return to the status quo and calls for urgent consultations between the Canadian Government, ICAO, IATA, IFALPA, IFATCA and CATCA, to help produce a solution to this difficulty as it is becoming a world problem.

RELEASE - PRESS RELEASE - PRESS RELEASE On the tragic mid-air collision near Zagreb ••• The International Federation of Air Traffic Controllers Associations deplores and condemns the unrestrained and illconsidered articles and opinions published worldwide in certain newspapers and other media, regarding alleged controller actions which resulted in the Zagreb mid-air collision on 1O September 1976.

In a civilized society no man should be judged guilty until so proven and the effect of these articles has been to mislead public opinion Into acceptance of controller guilt before the facts are known.

This Federation therefore challenges the media to prove the validity of the evidence used to support their statements to date.

RELEASE - PRESS RELEASE - PRESS RELEASE .•. and on the situation in Spain: The public travelling to Spain should be made aware of the real reasons behind the delays experienced in their flights of recent weeks. The facts are that the Spanish controllers have, after many years, finally decided that something must be done to ensure safety in aviation. It is essential that equipment assisting the human controller should match the advance in the improved performance in aircraft.

Instead, therefore, of complaining about these delays passengers should be thankful that their safety is considered to be of the utmost importance by those who know best the dangers inherent in an unsafe air traffic control system.

The media have distorted the situation into an industrial dispute which is so commonplace these days but this only disguises the failure of the Spanish aviation authorities to provide the necessary equipment and working conditions for controllers to keep up with the ever increased burden created by today's .air traffic.

Any reasonable and thinking pilot flying into Spain today will surely support the controllers' claim for a safer system of air traffic control.

Publications Review The ICAO Annual Report, 1975 published by the International Civil Aviation Organisation, Montreal, P.O .. Canada.

In this comprehensive Report, which was published last May, ICAO as usual gives prominence to the latest developments in Air Traffic Control and associated Services. The report says that efforts to improve the overall air traffic management system continued on a broad front but at a relatively modest pace. The trend continued towards an overall systems approach aimed at correlating the various elements which make up the air traffic management system.

The need to extend ATC service to routes or portions of airspace so far limited to flight information service or air traffic

47

advisory service continued to be emphasized. The rate of progress, however, was slow and the introduction of SST aircraft into commercial service gave added emphasis to this question. In high traffic density areas, continuing attention was given to ways and means of ensuring better utilization of the airspace and providing for greater air traffic handling capacity. There was growing recognition of the need to develop internationally agreed minimum navigation performance specifications as a basis for reduction of current separation minima in specified portions of the airspace. Work on the formulation of basic principles in this respect was initiated.

Studies of the practicability of reducing lateral separation in the North Atlantic organized track system were nearing completion. Studies relating to the spacing required between parallel tracks in ATS route structures based on VOR or VOR/DME led to the development of draft guidance material, and the feasibility of reducing vertical separation above FL 290 was further examined. Reduction of longitudinal separation between aircraft equipped with Inertial navigation systems or Doppler was implemented on certain routes. The potentials of area navigation techniques continued to be explored and exploited, as did the use of ground-based monitoring systems in ensuring adequate separation between aircraft.

Measures to regulate the air traffic flow along heavily travelled air routes or to limit the number of flights into particularly congested aerodromes continued to be applied and refined, in order to eliminate or reduce excessive delays while in flight. Work continued on the development of detailed forecasts of expected traffic along main traffic itineraries and on advance planning of the air traffic flow based on such forecasts. The need for central flow control facilities or, as a minimum, flow control cells in the major ATC Centres working in close co-ordination with each other was further accentuated. The application of primary and secondary surveillance radar continued to expand, and the development and refinement of methods for the utilization of SSR codes was given increased attention, with the objective of keeping the number of code changes by aircraft to a minimum. In the U.S., a plan which would permit aircraft to use a single, discrete code from take-off to landing was due to be implemented.

In the U.S. also, a ten-year programme to automate all 20 air route traffic control Centres was completed. The final phase introduced automated processing of SSA-derived data and direct read-out of aircraft identification, level and other flight data on the controllers' radar scopes. A system to provide a Minimum Safe Altitude Warning in ATS units equipped with Automated Radar Terminal Systems (ARTS) was due for installation before the end of 1976.

Aeronautical telecommunications growth in 1975 continued to follow the reduced rate of growth that occurred in 1974 and, except for specific problem areas, there were few examples of telecommunications deficiencies arising from ATC congestion. The "Aerosat Programme" has been progressing more slowly than had been anticipated. It seems unlikely that the test and evaluation satellites Will be in orbit before the early 1980s.

Radar Enhancement of Small Aircraft in the Air Traffic Control System published by the Federal Aviation Administration, obtainable from the National Technical Information Center Springfield, Va., U.S.A. price $ 4.50.

A careful study of 271 mid-air accidents in general aviation over an 8-year period has indicated that the radar transponder is the b~st available means of preventing such accidents in a radar environment.

The investigation was instigated following recommendations by the U.S. National Transportation Safety Board that radar detection of small aircraft could be improved with the use of low-cost reflectors and other devices to increase the radar return and also eli~inate the danger of "tangential effect" (loss of radar return when flying at a certain angle to the transmitter). The FAA study covered both "passive" and "active" enhancement devices and concluded that to be effective. passive devices would have to be too large for Practical purposes. Active enhancers that amplify the radar signal before sending it back have a number of unresolved technical problems, such as antenna placement and potential interference with g;ound radars, and would offer no substantial saving over the cost 0 a transponder (minimum cost 8 600). d The report recommends that FAA continue to focus research and ev~lopment efforts on improving the design of the ground radar equipment to increase its ability to detect small aircraft.

GdB

48

Letters from Readers Dear Sir, I have read the May 1976 edition of THE CONTROLLER with great interest, especially the article on "The Provision and Use of Information on Air Traffic Control Displays," The Federal Administration for Air Navigation Services in Germany has set up a project team for the planning and specification of a 'German Air Traffic Control System for the 1980's' in co-operation with 'Computer Sciences International Deutschland' (CSID) as consultants.

Your magazine, and especially articles like the above mentioned, belong to our mandatory reading material.

Reading them has resulted in some fruitful and heated discussions. We must thank you for the input that you provide in publishing them, as well as their originators.

- F. W. Fischer, HQ BFS I Project TARK.

Dear Sir, I hereby acknowledge with thanks receipt of the 1975 Annual Writing Award for the best article published in "The Controller". For over eight years I have known and appreciated this journal - the only regular publication devoted to Air Traffic Control issues and developments - and it is a real honer to be both a contributor and also an honored one.

The Award had to follow me around the country awhile, for I was recently transferred to the Alaska Center as a controller. From Anchorage it is possible to get to many places in the world with ease, and I hope to attend an IFATCA Conference soon.

- Jon R. Sharpe, Alaska Center, Anchorage, USA.

Answers to IFATCA quiz on page 9: 1. True (5 points), 2. False (5 points), 3. True (5 points), 4. True (5 points), 5. True (5 points), 6. True (5 points), 7. False (5 points), 8. False (5 points), 9. True (5 points), 10. False (5 points), 11. True (5 points}, 12. True (5 points - do not overlook Turkey), 13. False (5 points - Ecuador has never sent observers), 14. True (5 points), 15.

True (five points), 16. False (5 points), 17. Andorra, Liechtenstein, Monaco, San Marino, Spain, the Vatican (5 points each), 18. Italy, Israel, Sweden (5 points each), 19. Denmark, Finland, Luxembourg, Norway (5 points each), and 20. Greece, South Africa (5 points each).

Some of the more difficult answers: 1. U. K., France, Ghana: 2.

None; 3. Canada to Iran; 4. Norway-Sudan; 5. Australia: 6. AustraliaNew Zealand; 8. only eight.

Total points possible is 155. How did you do? If you earned 155 points, you are either a Board Member or have attended all the Conferences (or you are a likely candidate for the Board). If you obtained more than 120 points, you know your Federation and obviously should be on the delegation to the next Conference. 80 - 120: You have a fair knowledge of the Federation. Under 80: Either you are not a member or you are not getting access to IFATCA information. Contact your Association so that you may receive the Federation's publications such as Newsletters and Circulars and do read the Conference Reports which IFATCA publishes. And take out a personal subscription to "The Controller" which you - as a Federation member can receive in your own letter-box at a ridiculously low rate.

(E. McCluskey)

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