TELEFUNKEN radar for safe

guidance from take-off to

landing

TELEFUNKEN

IFATCA JOURNAL OF AIR TRAFFIC CONTROL

THE CONTROLLER Frankfurt am Main, January 1963

Publisher: International Federation of Air Traffic Con­trollers' Associations, Cologne-Wahn Airport, Germany.

Elective Officers of IFATCA: L. N. Tekstra, President; Maurice Cerf, First Vice President; Roger Sodet,Second Vice President; Hons W. Thou, Secretary; Henning Throne, Treasurer; Wolter Endlich, Editor.

Editor: Wolter H. Endlich, 6471 Rommelhousen, Wil· helmstrosse 10, Phone 20821.

Production and Advertising Sales Office: W.Kromer&Co., 6 Frankfurt om Mein NO 14, Bornheimer Londwehr57o, Phone 44325, Postscheckkonto Frankfurt am Main 11727. Rote Cord Nr. l.

Printed by: W.Kromer&Co.,6 Frankfurt am Mein N014, Bornheimer Landwehr 570.

Subscription Rote: DM 8,- per annum (in Germany).

Contributors ore expressing their personal points of view end opinions, which must not necessarily coincide with those of the International Federation of Air Traffic Con· !rollers' Associations (IFATCA).

IFATCA does not assume responsibility for statements mode and opinions expressed, it does only accept re· sponsibility for publishing these contributions.

Contributions are welcome as are comments and criti· cism. No payment con be mode for manuscripts submit· led for publication in •The Controller•. The Editor re· serves the right to make any editorial changes in menu· scripts, which he believes will improve the material with­out altering the intended meaning.

Written permission by the Editor is necessary for re· printing any port of this Journal.

Advertisers in this Issue: The Decca Navigator Com· pony, Ltd. (Bock Cover). N. V. Hollandse Signoolappa­roten (36). Morconi's Wireless Telegraph Company, Ltd. (2, Inside Back Cover). Telefunken GmbH (Inside Cover).

Volume 2 · NO. 1

CONTENTS

Air Traffic Control Liablity in National and International Law Dr. Werner Guldimann

Civil Aviation Center to be set up in Beirut

Seventh National Meeting, Air Traffic Control Association, Las Vegas

Maurice Cerf

General Aviation, the Third Force

IFALPA Conference on All Weather Landing

Problems of Air Space for General Aviation Peter G. Masefleld

Air Traffic Control into the l 970's D. W. Watkins

IFATCA Annual Conference 1963

Stress and Performance in Air Traffic Control I<. G. Corkindale

3

4

5

6

6

7

12

19

20

NATO and the Committee nation

for European Airspace Co-ordi-23

Colonel K. Birksted

FAA/BFS Symposium on Air Traffic Control in Frankfurt 25

Greek and Japanese Air Traffic Control Associations founded, ATCO's in Central Africa to found an Association too 3l

Controller's Gossip 32

Aviation Writers meet with Avionics Industry 33

ICAO Meetings 1963 33

Resolution 34

Corporation Members 35

AIR TRAFFIC CONTROL

Television can present tabulated flight progress information instantane­ously wherever it is re­quired in an air traffic control centre.

TAKE A GOOD VIEW

APRON SURVEILLANCE

T elev ision prese nts an all­round view of the complete park in g area, eli mi nati ng the b lind spots and en­ablin g t he mars hall ing sup erv isor to see t he num­ber and d is pos1t1on of air­craft an yw here on t he apron .

DATA TRANSMISSION FOR AIR TRAFFIC CONTROL

PASSENGER HANDLING INFORMATION

ARRIVAL/DEPARTURE INFORMATION

FLIGHT SCHEDULE INFORMATION

FLIGHT MOVEMENT INFORMATION

WIND TUNNEL OBSERVATION

MET. BRIEFING

DOCUMENT TRANSMISSION

TRAINING

FLIGHT TESTING

RUNWAY OBSERVATION

APRON SURVEILLANCE

MARCONI TELEVISION FOR AVIATION

Closed Circuit Television Division

MARCONl 'S WIRELESS TELEGRAPH

COMPANY LIMITED

BASILDON, ESSEX, ENGLAND

RESEARCH Observation of after burn­ing in a gas turbin e engin e at a government resea rch station. This is t ypical of th e many resea rch appl ica­tions for whi ch telev is ion is bei ng used to-clay.

C2

Air Traffic Control Liability Dr. Werner Guldimann (Zurich)

in National and International Law

The renowned author of this article is Delegate of Switzerland to the Legal Committee of ICAO, Chairman of the latter's Sub­committee on Aerial Collisions, Chairman of the Federal Board of Aircraft Accident Investigations.

Most of our readers are already familiar with some of Dr. Guldimonn's numerous publications on aviation legislation, and the fallowing article will, undoubtedly, meet wide interest on account of both: Author and subiect.

I.

Wherever and whenever an accident of whatever kind happens, one of the questions which subsequently arise is the following: Will the damage remain where it was in­curred, or will it be apportioned, at least in terms of mo­ney, among the persons or organizations involved? In its essence, this is a question of law, and it may, by the way, serve to prove that lawyers are rather indispensable, if not always very popular members of any human com­munity.

As a matter of course, the question is of quite some interest in aircraft accidents as well, and in some of them it may be particularly interesting for air traffic control services and personnel: namely, where ATC was somehow involved in the sequence of events which finally lead to the accident. Unfortunately, such cases, if not very fre­quent, are not extremely rare either, and there is even some probability that their number will increase in the years to come, due to the increasing volumes of traffic and to the increasing percentage of controlled air traffic.

There is already a long series of collision cases in which liability claims were brought against air traffic con­trol. Let us mention but two well known examples from the United States of America:

On November lst, 1949, an EAL DC-4 and a mili­tary P-38 collided near Washington National Air­port. The 55 persons on board the airliner lost their lives. In the findings of the CAB it was stated that the control tower did not act with the requisite alert­ness and promptness in communicating to the air­liner the position of the P-38 in the critical traffic situation which confronted it. The United States Court of Appeals held that the failure of the control tower operators to keep both planes advised as to the activities of the other and their clearance of two planes to land on the same runway at the same time was negligence which contributed proximately to the collision, and that the United States was li­able for such negligence of its control tower per­sonnel. On June 30, 1956, a TWA Constellation and a UAL DC-7 collided over the Grand Canyon. Both aircraft were destroyed, there were no survivors among the 128 persons aboard. In a subsequent lawsuit against the United States of America it was claimed that the accident was caused by the negligence of air traffic control employees at Salt Lake City and Los Angeles in giving directions and failing to give warning to the two airliners. The action was dis­missed on formal grounds.

Aircraft collisions may be the most important group of ATC liability cases, but there are other groups as well. Just one example to prove the point: On July 12, 1949, a KLM Constellation crashed in bad weather near Santa Cruz Airport near Bombay, India. The Board of Inquiry considered that the following factors contributed towards the accident to a considerable extent: Air traffic control did not advise the pilot to delay the landing until the weather conditions had improved, or otherwise to divert to another aerodrome, and air traffic control designated a runway for the landing which necessitated the aircraft venturing low and over dangerous terrain. It is not known whether any liability claims were subsequently based upon these considerations, but one may be sure that in many places they at least served as a starting point for an ana­lysis of the legal situation.

II.

Speaking of the legal situation in cases like the ones mentioned before, one should first of all become aware of the very complex network of relations affected and created by such accidents. In cases of collisions, there are,

on one hand, the persons who have suffered damage: the aircraft owners, the aircraft operators, the crew members, the passengers, the freight owners, third parties on the surface etc.; on the other hand, there are the person.s whose activities have in some way contributed to the acci­dent: aircraft operators, crew members, ATC agencies and personnel.

More specifically, the following main questions want an answer, first on an abstract and general basis to be given by the national or international legislator, and se­condly, with reference to the facts of a given case, by judges and courts:

Who shall be the parties? Who shall be liable, wh? the defendant? The question is not as easy. as it might seem. Shall the bride of an unmarried pas­senger have the same right of action as the widow of a married one? Shall primary liability attach to the operator of the aircraft, or to its owner, or to its pilot? . Shall liability be based upon negligence, or shall. it attach to the mere performance of some activity such as the aircraft's operation or air traffic con­trol? If the basis is negligence, shall it be ~resum2ed, or shall the burden of proof be on the plaintiff. How shall liability be limited? Qualitatively: shall ·t d · d but to indirect 1 exten not only to direct amage, d I loss of reve-amage as well (such as, for examp e, nue of the aircraft operator in the time before[ a d d . I d)2Quant1tat1vey: estroye aircraft can be rep ace · 1.k shall liability be limited to definite amounts ( 1 e h d · th Warsaw Con-t e ones which may be foun in e b

. . h I I th mounts be esta -vention), and 1f so, how s a e a . , , fished, and shall there still be exceptional cases or

unlimited liability? 1 f Where sha 11 the action be brought (at the P ace 0

the accident at the domicile of defendant, ek.)? W"n · ' "•' .. ''me 1;m;t frirhrinaing the action? at sna11 oe me'" ,,, .... ·~· - · ~

3

Similar questions will arise with regard to recourse claims of persons who have been found liable for dama­ges in the first instance and subsequently try to get com­pensation from other liable persons.

It is therefore easy to see that these are most com­plicated problems, even if restricted to the domain of the law of one State only. Moreover, in a legislative per­spective there is not only one just and equitable answer to be given to each of the many questions which arise, but there is a wide spectrum of possible solutions. This creates still more problems with regard to cases of an international character.

Ill.

If there is no international convention to fall back upon in such cases, there always arises the first question a: to which national law will apply to the case. The que­stion may well be of decisive consequence, because natio­nal laws are different, and on the basis of the same fac­tual circumstances, a lawsuit might be successful in one country, whilst being quite hopeless in another one. Now, not even this apparently simple question can in many ~ases be answered with a satisfactory degree of safety: it may be the State over the territory of which the collision t~ok pla.ce, it may be the State of registry of one of the aircraft involved, it may be the State in which the aircraft fin~lly crash.ed, it r:iay be the State from the territory of which .an air traffic control unit issued a clearance or transm1th~d some critical information - and the answer may again depend on the place where the court is trying the question.

Thus, an internati~n~I convention can serve quite a usefu.I purpose even 1f 1t does nothing else but offer a definite .answer to the. question of the applicable Jaw _ so that interested parties may, with a sufficient d f

I. b'I' . f h egree o re 1a 1 1ty, 1n orm t emselves on the legal situation and take appr~pri~te n:ieasures .to protect themselves against the financial risks inherent in that situation.

IV.

Preparatory work for an international convention on liability for damages caused by aircraft collisions was taken up as early as 1930. After the second World War the Legal Committee of ICAO took over. Further develop~ ments then lead to a draft convention, established by a subcommittee in 1960 and 1961. Discussions of its details showed time and again that the subject matter is extra­ordinarily complex, even though the scope of the draft always remained restricted to liability of the operators of the aircraft involved, excluding third party damages. on the ground.

Due to the factual connection between many collision situations and air traffic control activities, and due to the growing importance of air traffic control in modern air navigation, it was recognized by more and more people that there were some legislative problems closely related to the project of a collisions convention. A proposal to take the bul! by the horns and to extend the scope of the draft convention to liability of air traffic control agencies was however rejected by the Legal Committee in 1960, nevertheless, the importance of the problem as such was recognized, and it wos at the same time decided to in­clude it as a separate subject in the work programme of the Committee. In 1962, the General Assembly of ICAO

4

took a decisive further step: Giving the subject priority immediately behind aerial collisions, it recommended that the Legal Committee should study it in a subcommittee prior to the next meeting of the full committee, probably to be held in 1964.

No one will expect this subcommittee to elaborate a detailed analysis of the whole problem of ATC liability in a session of a fortnight's duration, but it might at least do some useful preliminary work, so as to enable the full Legal Committee at its next meeting:

to survey the problems relating to the applicatio.n of the collisions convention in cases where ATC is involved, and to take appropriate decisions by adapting the text of the draft convention, to decide whether the work on ATC liability should be carried on with the final aim of an international

convention, b to take some tentative decisions in order to esta -lish guidelines for the direction of such further work (e. g., with regard to the scope of application, to principles and limitations of liability etc.).

v. . If one wanted to It is a long, long way to Tipperary. .

h I . I t. e work against put a possible time-table of t at eg1s a iv h · I d Jopments one the background of expected tee n1ca eve '

might state with a wide margin of safety that secondary . . b . Id 'd operational use surveillance radar will e 1n wor -w1 e

and that the first supersonic airliners will fly before. a co~~ vention on the liability of air traffic control agencies wi

be ready to be signed. h ·1 In the meantime, however, it might well be wort wi e

for the agencies and the personnel concerned to become conscious of the problems involved and to dedicate so~e time and thought as to how they should be resolved, in national as well as in international law. To adapt an old adage to jet age requirements: Law is too serious a mat­ter to leave it to lawyers!

Civil Aviation Centre to be set up in Beirut

The International Civil Aviation Organization is pa.rti­cipating with the Government of Lebanon in the setting up of a Civil Aviation Safety Centre in Beirut. The ~ajor portion of the money necessary for the project will. be supplied by the Lebanese Government, with the United Nations Special Fund for which JCAO is acting as exe­cuting agency, providlng the balance; Special Fund parti­cipation will continue for five years, after which it is ex­pected that the Government will carry on the project by itself. The Safety Centre will be open to nationals of other countries as well as those of Lebanon and the Govern­ments of eleven neighboring states have indicated their intention to utilize the training facilities to be provided.

The purpose of the Centre is to establish facilities for training airline personnel and government officials in the broad field of civil aviation safety. To maintain adequate safety standards, it is necessary both to give periodic refresher courses and training in the use of new equip­ment to pilots and other airline personnel and to have government services staffed with personnel qualified to deal with matters of licensing and control of civil avia­tion.

Seventh National Meeting,

Air Traffic Control Association,

Las Vegas

Everybody has heard of Las Vegas, the capital of gambling, quick weddings (for the next step, that is di­vorce, you have to go to Reno not very far away), lavish shows and sin. As for this last part I can say that the well known French austerity in general and mine in particular, were not shocked, I didn't see any. Las Vegas is located in a desert valley surrounded by barren ridges; the con­trast between this modern town mostly composed of huge hotels, motels and gambling halls, all ablaze at night with neon signs, and the desert which begins right at the end of the streets, is simply amazing. The background is really impressive.

Luxurious hotel Flamingo swarmed with more than one thousand controllers from all over the United States. The three days that the meeting lasted were packed with lec­tures, panels, exhibits, receptions and banquets which left very little time for sleeping. The ATCA is a master in the art of harmoniously combining business with pleasure and must be credited for the careful preparation of the meet­ing.

Most of the lectures and panels were of immediate interest to any controller, I cannot report on everything I saw yet I'd like to mention some of them.

"Improved Radar Presentation and Alpha Numerics" allowed us to hear the declarations of the representatives of several industries. Most of use radar, we know that in the near future our scopes will display data accom­panying the targets, scarce are the places where such systems are already in operation yet the industries are losing no time in trying to improve the displays. They will standardize them by using the same kind of symbols, the same colours for the same sort of information.

The controllers of the panel and some from the floor expressed their wishes: Radars with no blind speed, sco­pes displaying two video maps, one for IFR, the other for VFR conditions, scan converters giving bright pictures. A controller from Fairbanks (Alaska) wished that something was done about the influence of low temperatures on radar.

One point of concern for the industries is that con­trollers tend to ask too much of their radar, for instance they expect their scopes to display too much data which might distract their attention and clutter the picture. The solution industry offers is to have the data on several lines with the possibility of erasing those bearing a datum of lesser importance. These improvements, when made available, will certainly ease the workload of the con­trollers tend to ask too much of their radar, for instance

traffic. When ! sat down to hear a lecture on "Air Traffic Con-

trol Magic", I didn't in the least expect to witness the demonstration of magician tricks by a professionnal con­troller. This gentleman had a very effective way of deal­ing with things that bothered him: he made them dis­appear, quite simple as you can see. i wish I could do the

Maurice Cerf

same when I am on duty. No doubt such a gifted artist is very much in demand if he can handle the traffic with the maestria he displayed for his tricks.

Mr. Gerald M. Trusynski from National Aeronautics and Space Administration delivered an enlightening lec­ture on "Space Flight Control and Data Acquisition". It seems that control in space business is, in many ways, similar to Air Traffic Control with the difference, however, that NASA uses the most up to date equipment.

The main theme of the meeting was "Air Traffic Con­trol and National Defense" and, although it was not very apparent throughout the conference, there were some discussions in direct relation with this theme. I attended a panel about "Strategic Air Command and Tacticol Air Command Altitude Reservation Flights". An official from CARC (Central Altitude Reservation Committee), the only center specialized in handling air space reservations, dis­closed that 17,000 reservations were negociated in 1962 when 70% of military traffic was considered VFR on top

and so not subject to reservations.

One of the liveliest panel had "Project Beacon" as topic. To sum up the whole discussion I can say that con­trollers are opposed to it, though they admit its necessity, for different reasons: Insufficient radar coverage, the fact that most of the radars used nowadays are not meant to show targets flying at low altitudes, lack of aeronautical knowledge on the part of the majority of the private pilots. (The moderator of this panel, who represented the "Aircraft Owners and Pilots Association", was of the opi­ion that the members of his association would not readily agree to get such knowledge.) Another reason given by the controllers is the personnel shortage in the control towers. This, of course, did not solve the problem since every one is convinced that VFR flights must be controlled effectively.

During the three days of the meeting an exhibit was open with a display of some of the systems discussed at the panels. About fourteen of the major firms specializing in ATC equipment took part in it. I'd like to point out the advantage of such an exhibition where the participants can have the benefit of seeing the real thing, of using it and of discussing it with the specialists in attendance.

Two banquets gathered the whole of the particip~nts, the first one was presided by FAA Administrator Na1eeb Halaby who delivered what I deem a perfect speech on the part of such an important person. Indeed, Mr. Ha~a~.Y proved that he had a real and accurate knowledge 0 . is controllers' problems he did not try to sooth them with I d ' · h th o'nt not elud­au atory remarks, he went stra1g t to e P 1 ' ing any difficulty that might arise so that, when the speech

· • for thorn· was over, the controllers knew what was in siore "~ '· Understanding on the part of their administration, oppor­tunity for those who proved able to keep. up with the fast pace of Air Traffic Control techniques, l1m1ted futui·e for those who lagged too far behind. The FAA will reduce the

5

number of Air Traffic Control Centers from 29 to 21, this means that a number of controiiers will have to be trans­fered and that less supervisors will be necessary. Mr. Hala­by mentioned that the plan of retirement after twenty years of service has a fair chance to be brought to an issue.

When this first banquet was over, the head table, which was on the stage, was quickly removed to let room for a show featuring Brenda Lee, as I said before: pleasure (for those who like Brenda Lee) and business.

The Awards Banquet closed the meeting. I was honou­red with a seat at the head table, the Toast Master was Stuart G. Tipton, President of the Air Transport Associa­tion; an address was wittingly delivered by Mr. Grant Sawyer, Governor of the State of Nevada, who explained that, since no gambling, except for dog races, is illegal in the state of Nevada, the direct consequence is that there is no illegal gambling, a fact that very few states can boast of.

Mr. Walter S. Mac Connel was named Controller of the Year for emergency assistance to two turbojet aircraft. The Seattle, Washington Air Route Traffic Control Center was selected as "Facility of the Year".

Other awards and scrolls were presented to a number of c~ntr~ller~, facilities, and firms for their outstanding contribution 1n the development of Air Traffic Control. I was especially ~leased to see our friend Tirey Vickers, who _together with Joe Moraski, attended IFATCA's first meeting in Paris, honoured with a special award for "Out­standing and imaginative contribution to the science of Air Traffic Control".

I v:ould like to thank all those who have made my stay both interesting and. plea~ant, l have had the opportunity to meet and have d1scuss1on with the Officers and Coun­ci I ors of ATCA, I wish to mention the kind assistance I received from the Executive Director Edward H. Cocker­ham, the Director of Public Relations Donald J. Byers and Joseph J. Moraski whom you have all heard of. ·

During my short stay in Los Angeles I had the oppor­tunity of visiting the control tower and IFR room of the very modern airport, thanks to the kindness of the Acting Chief Ray Smith. I also visited the ACC which is a rather old one about to be relocated in modern premises in Palmdale, a village in the California desert about sixty miles East of Los Angeles.

On the way back to old Europe I overflew once again this bare state of Nevada at an altitude from which it was difficult to imagine that so much can be going on in a small city such as Las Vegas.

Genera~ Aviation - the Third Force

Announcing its claim to defend the legal rights of non­airl ine and non-military air space users, F.A.I. has estab­lished a special Bureau to concern itself with the protec­tion of General Aviation. The preliminary plan for the future work of the Bureau includes the following items:

6

l. To secure the most practical and equable Rules and Regulations for the use, by General Avia­tion, of the air space in all countries represen­ted in the F.A.1. and the l.C.A.O.

2. Freedom of passage between Countries and elimination of vexatious i-equirements of Police

and Customs.

3. Making available for General Aviation, aero­dromes placed in the most advantageous posi­tion in relation to Cities and towns.

4. Common forms of licences and other docu­ments required for pilots and others.

5. The assignment of VHF-frequencies for General

Aviation. 6. "Easy to handle" pilots' manuals. 7. Availability of Met reports for the private pilot

and the form in which these reports should be presented.

8. Help for Business and Private pilots in prepar­ing their journeys.

9. To study insurance problems and the possibi­lities of collective contracts.

10. Issue, through the National Aero Clubs, of a

regular information bulletin. 11. Constant co-ordinated action to obtain greater

freedom in the air.

N. B. It should be carefully noted that the F.A.I. . . h h th National Aero Bureau will function t roug e . d

Clubs with and through whom, individual pilots an

others wi 11 be required to dea I.

IFALPA Conference on All Weather Landing

. 0 17 1962 at Amster-Open1ng the conference on et. 1 h dam Hilton Hotel HRH Prince Bernhard of the Net er­lands pointed ou~ the background problem of all our endeavours to improve flight efficiency and safety: Th_e future role of man in our technical world, or more spec~ flcally, the function of the human pilot in the propose solutions of the all weather landing problem.

The 3-day symposium had been organized by iFALPA · d · · · I ·d of the deve-in or er to give participants a genera 1 ea . lopments in automatic und semi-automatic landing ~y­stems. Its purpose was not to formulate any special P 011.~Y or demands of IFALPA's but to provide an opportuni Y for the free exchange of thoughts and ideas.

Manufacturers' proposals cover a wide range - from improved ground installations to automatic airborne de­vices. The Standard Telephones and Cables Ltd. lectured on an improved ILS with more accurate glidepath and localizer guidance (a prototype of which has been opera-

) D.ff ent live for more than one year at Cologne-Bonn · 1 er types of windshield displays were introduced by the Ben­dix Corporatio(l and the Sperry Gyroscope Comp~ny, whose systems enable the pilot to read off the windshi.eld various information on flight attitude, runway centrel 1n.e, glidepath, airspeed control etc. A fully automatic 01r­borne device was advocated by Elliot Bros. whose "VC 10 ail weather system" is fed with data like wind component, weight etc., carrying out the landing all by itself and leaving the pilot just to monitor the approach.

The audience - including IFATCA President L. N. Tekstra and four members of the Dutch Technical Com­mittee - was strongly impressed by the fine lectures and the interesting films and slides. Everybody felt the con­ference to be a definite success. Discussions were ob­served to continue even on generous KLM Pilots Asso­ciation's cocktail party.

GZ

Peter G. Masefield Problems of Air Space for General Aviation M.A., F.R.Ae.S., Hon.F.lnst.Ae.S., M.lnst.T.

The following paper, as well as those on page 12 "Air Traffic Control into the 1970's", on page 21 "Stress ond Performance in Air Troffic Control", ond on page 24 "NATO and the Committee for European Airspace Coordination" have originally been presented at the Fourth Convention of the British Guild of Air Traffic Controll Officers in Bournemouth. They are reprinted with kind permission of the Editor of The Guild's Journal of ATC.

On behalf of all users ofairsp·ace,whetherprafessional pilots or amateur pilots - or, indeed, passengers - may I pay a most sincere tribute to that devoted body of men and women represented by The Guild of Air Traffic Con­trol Officers. All of us who fly owe a debt - not only of gratitude but also of well-being - to the skill, efficiency and dedication of members of The Guild. And, in my ex­perience, the never failing courtesy, tolerance and good humour of Air Traffic Control Officers throughout the United Kingdom is one of the most heartening aspects of modern Aviation. Indeed, it is not too much to say that those who use the air regard Controllers as their "guides, philosophers and friends" - albeit their conversational exchanges are, perforce, confined to "basic English" -somewhat unintelligible to non-flyers - and regulated to what would be regarded as the most brusque remarks in any other environment.

In Controlled Air Space, in particular, the guidance of Air Traffic Controllers is the essential link to the achieve­ment of that objective - the safe and unfettered move­ment of air traffic on its lawful occasions; although the term "safe and unfettered" is of course relative.

Now, there are almost as many ways of looking at the use and control of Air Space as there are users of the air. And the more one studies the subject the more one learns to have a sympathy and an understanding with all the varying views. The subject of Air Traffic Control is one of the most complex of a!! those concerned with Aviation (and that is saying something) and at the same time it is - inevitably - more imbued with emotion than most.

Certainly, in the present state of the art, at peak times some Air Traffic Control \ers are often over-worked. Cer­tainly many professional airline pilots, equipped with all the modern aids, and with more than 100 fare-paying passengers seated behind them, often feel, understand­ably, intolerant towards those who are flying in the same local air space without such aids.

Certainly, harassed Ministry officials, on whom respon­sibility for safety lies heavily, often must feel that concern to achieve as nearly as possible absolute safety ought to transcend the expeditious expansion of flying. Certainly too, the amateur flyer, leaping light-heartedly into his light aeroplane on a clear and cloudless day, often feels ~addeni.ngly "cribbe~, cabined, and confined" by regula­tions which prevent him - or often her - flying with go abandon directly from A to 8, or from engaging in aero~ batics at a safe and satisfatory height.

All these conflicting pressures and emotions have to be weighed, considered and catered for if we are t achieve that wide development of Aviation, and the us: of the air, to which we all look forward. And, certainly, I do not agree that the present state of affairs in control of Air Space is all for the best in the best of all possible Worlds. We do not have to be too conservative about these things - although, you know, o conservative is de-

fined as a statesman "who is enamoured of existing evils as compared with the liberal who wishes to replace them with others."

Be that as it may, we can, I believe, set down certain basic principles which should underlie all our efforts in control of Air Space - in particular to p~omote what has been termed "the safe, regular and expeditious flow of air traffic".

I suggest that the underlying principles are in fact as

follows:

First. The aim of Air Traffic Control should be to understand and to provide for - as counsellor and guide - the requirements of all users of the air. In doing this, the objectives of Air Traffic Control should be recognised as including not only the achievement of an acceptable standard of safety in the air but also the giving of the maximum of assistance to all flyers - thereby making

possible a steadily increasing use of the air by all sections

of Aviation.

Second. Safety is, inevitably, a matter of degree

and the aims of safety in the air must be kept i~ balanrn with those of the widest possible use of the air. An in­

discriminate use of Air Space, without any form of regu­lation, would result in an unacceptoble degree of risk -just as an intolerant insistence on restriction in an ~ndea­vour to eliminate all hazards would bring all traffic to a

standstill. Third. In order to ensure the fullest understanding

and co-operation from all categories of air users (aviators I · for being what they are) the reasons for all regu ations

Air Traffic Control should be made known, to ensure not only that they are necessary, but also that they are seen

to be necessary by a\ I those who are concerned. F o u rt h . General Aviation, thwughout the Worldf,

·11 · h · · t th air more a1rcra t w1 1n t e course of time bring 1n o e . . than all other sections of Aviation put together. This. 1fls 0

f . . d d ·11 inevitably, 1n u-act which cannot be rgnore an WI , .

d t ol of Air Space. ence many aspects of the use an con r . . Fifth. Except in zones of high traffic densityf, in

. . . .bTt th most important ac-cond1t1ons of adequate v1s1 1 1 y, e h. h d tor in the free and safe movement of all except igl -skpee t

. . f a satisfactory oo -ou aircraft is still the maintenance 0 d the

d . . . b th air crews concerne , on an visual nav1gat1on Y e d d VFR fl ing in old principle of see and be seen. In e.e ' t th: deve-VMC has been the most significant contributor . o .

h t th years and will continue lopment of flying throug ou e

to be so. . . 11 wel I to state laudable obiectives. It

Now 1t 1s a very d d . 't , ther matter to achieve results. In ee a con-1s qu1 e ano h · f · pa·tant f h b en described as "A got er1 ng o im i erence as e . , , h .. d

h . 1 can do nothing, bur 1oget e. can e-people w o, sing y, ,, cide that nothing can be done ·

I t I of Air Space, especially, we all know that n con ro . h. .

h mber of difficult problems in ac 1ev1ng any-t ere are a nu .. thing approaching an idea! environment, rn which every-

7

one can live together, safely and happily, in the air. And the problems are diverse. For instance, the fact that at present, for Air Traffic Control purposes, the air, as seen by most radar equipment, is flat and twodimensional means that we are, to a large extent, losing the benefits of the tremendous flexibility of aircraft operation in three dimensions. The widespread use of satisfactory height­indicating radar will be a major step forward in the effi­cient use of air space.

Quite a different, human, problem, is what one might term, the emotional preoccupation with the possibilities of air collision. This, understandable, psychological pheno­mena means that the potential dangers of air collision tend to be rated much higher than the statistics justify. Indeed, this has resulted in attempts to achieve absolute air safety from collisions - thereby introducing serious economic restrictions - which are out of step with accep­ted standards of safety in other directions, such as the standard of structure! integrity or the risk of three out of four engines failing at once.

The reasons for this preoccupation with the fancied hazards of collision are psychologically absorbing. They are, in fact, so powerful that it is even unpopular to query them.

The fact is, of course, that the professional airline pilot naturally wants to be relieved, totally, from all concern about the chances of collision with other aircraft. Part of this is because of the inadequacy of visual means of coi­lisio~ avoidance in modern fast aircraft with their high closing speeds, partly because of poor windscreen ar­rangements and partly because of the heavy demands of oth:r. en route and landing cockpit occupations of all varieties.

Be that as it may, the facts show that although a sub­stantial number of air misses are reported the numbers are declining and only a relatively few are near misses or potentially lethal. In fact, collision with high ground by transport aircraft has always been a far greater hazard than have been collisions with other aircraft. Now, please do not misinterpret what I am saying; I do not advocate complacency about air collisions, but I do suggest that the potential hazard is being magnified to a greater de­gree than is justified and out of proportion in comparison with other aspects of safety in the air.

All of this is by way of background to the main theme of "The Problems of Air Space for General Aviation". And the way the wind is blowing, from the West, can be seen by the latest FAA statistics from the United States on the number of civil aircraft registrations.

At 30th Apri I, 1962, they stood as follows:

Total Civil Aircraft on U.S. Register 117,560 (100 per cent.) Total General Aviation aircraft 114,029 ( 97 per cent.) Total Transport aircraft in airlines 2,170(1·8percent.) Total Government-owned civil aircraft 1,355 ( l ·2 per cent.)

In 1961 aircraft movement through the 256 FAA-opera­ted airports in the U.S.A. totalled 26,300,767. They were

divided up as follows:

Genera! Aviation Airlines Military

15,500,452 (59 per cent.) 6,842,198 (26 per cent.) 3,958,117 (15 per cent.)

In fact, General Aviation operations predominate at 99.c, oer cent. of all U.S. airports. And only at 35 airports do -a,irline operations outnumber General Aviation move­ments and then by only a small margin.

8

What has already happened in the United States is happening, more gradually, in other countries and is now well on the way in the U.K. This, then, presents the issue - that Air Space must be so regulated as to cope ade­quately - and without undue restrictions - with a pre­dominance of General Aviation movements - the pro­blem relieved somewhat by the fact that most General Aviation flying takes place in the lower levels of Air Space.

The problems are, however, complicated again by the fact that most General Aviation aircraft are flown by pilots of less experience than those professionally engaged in airline service. Further, few General Aviation aircraft are equipped with full radio and navigation aids because of their cost, their weight, and their complexity. More­over, General Aviation operations are likely to be of a random nature rather than flying over prescribed routes

at scheduled times. . So in order to get the whole business into perspective,

there 1are, I suggest, three further - and fundamental -points which have to be stated and taken into account ..

The first is that, in spite of the growth of flying, th~ air is not congested. It is, in fact, remarkable by its emptine~s - except at certain seasons and at times of the day 1.n the vicinity of a relatively few major airports. There is

. . f I and for the plenty of room in the air for everyone, so e y, . . h · · A · · h' h · certain in t e manifold expansion of v1at1on w 1c is

years ahead. h b Th d . b . h'I hy - is t at SU -e secon point - a as1c p 1 osop ' .

. 1· . . th' and some security 1ect to proper 1censing, a1rwor iness h considerations, everyone has the right to fly, to use1 t . e air space above us in which mankind has learned on Y in the present century. In the words of the old song: "The sky belongs to everyone." t

Third - and no less fundamental - we must accep in the air, as in every other means of transport, reaso.n­able standards of safety beyond which we should not a.im to go because of the restrictions and economic penalti~s which would be involved. This is just as much ~ basic democratic principle as Free Speech - it has certain dan­gers and disadvantages but the consequences of any other policy would mean a reglementation which could not be

· · the tolerated in any Free Society. So, absolute safety in air would mean an absolute ban on all flying - just as absolute safety on the road would mean an absolute ban on all motoring. What we have to define - and it is diffi­cult - is an acceptable standard of air safety towards Air Traffic Control, just as we have set up an acceptable standard of safety in airworthiness requirements.

So, may I suggest these three fundamental parameters as underlying principles which have to be recognised at the start of any discussion on the Use of Air Space. May I repeat:

1. The Empty Air - A reco~nition that the air is not congested - there is plenty of (00 m for everyone - and will be for many years to come.

2. The Right to Fly - for everyone, subject only to conforming with a minimum of procedures imposed on grounds of safety and security.

3. A recognition that we should define an acceptable standard of safety as something less than the absolute -though this has to be on an arbitrary basis.

That leads us, I think, to a brief examination of some of the facts behind this "three tier" philosophy which I am advocating.

At the start, then, the Empty Air.

There are, to-day, throughout the Western World, something like 140,000 active civil aircraft of one sort and another. Only some 6,000 of these are transport aero­planes. By far the majority come into the General Avia­tion category, that is, civil aeroplanes which are used for purposes other than those of scheduled, or unscheduled, air transport services. And it is interesting to note that in the United States, where there is a preponderance of General Aviation aircraft, some 4.0,000 are now actively used for business purposes and that most of these (30,000 of them) are single-engined four-seat types. As for their utilisation, in the United States, in 1961, whereas the air­lines flew some 4,000,000 aircraft hours General Aviation aircraft flew some 17,000,000 hours - a more than four­to-one ratio in the active use of the air.

In the United Kingdom the numbers are smaller but significant. There are, at present, some 1,600 aircraft on the British Civil Register of which 400 are in airline service and most of the other 1,200 come into the General Avia­tion category - which is growing fast.

A comparison of hours flown per annum in the U.K. shows that some 800,000 flying hours were performed by British airliners - mostly on journeys abroad - compared with some 180,000 hours flown by General Aviation air­craft - mostly inside the U.K. The current series of census of flying being conducted by the Ministry of Aviation at six-monthly intervals will offer much more valuable infor­mation on these points quite shortly. It is significant, how­ever, that in the Air Traffic census conducted over the U.K. in_ December, 1961, the peak traffic at any one time in all Air Space over the British. Isles amounted to a total of 151 aircraft of which only 25 were in Controlled Air Space. And, notably, most of the traffic was flying at less than 4,000 feet. These figures mean that there was only one aeroplane to every 20,000 cubic miles of Controlled Air Space - the equivalent of only some 25 cars on all the roads of Britain at the same time. The air is indeed empty.

Controllers will, of course, have in their minds the occasions on which they are hard-pressed, with an array of aeroplanes on and around a busy airport all waiting th .

eir turn to take-off or land. That temporary, manmade, congestion at a few, isolated points does not alter the fact ~hat the air, as a whole, is empty and that the problem is isolated to small areas of Controlled Air Space for short periods at a time.

Some other figures are interesting. If we analyse the total numbers of civil aircraft in a number of major coun­tries compared with their surface areas we find the follow­ing statistics:

United States one aircraft to every 28 square miles France one aircraft to every 53 square miles United Kingdom one aircraft to every 60 square miles Canada one aircraft to every 1,000 square miles Australia one aircraft to every 2,150 square miles

This comparison is not really quite fair, of course, be­c.ause it takes no account of cubic air space, only a rela­tively small proportion of the total aircraft are in the air at a~y one time and the different countries have widely varying amounts of uninhabited areas and different ratios of Controlled Air Space into which much of the traffic is packed. The fundamental point remains: the air is not congested as a whole.

This brings us back to the definition of an acceptable standard of safety and the problem of how to define it in such an intangible field as that of Air Traffic Control. What I think we can say is this. A system has to be achieved which will permit the maximum use of the air -what has been termed in a different context "the right of innocent air traffic" - while never knowingly "arranging" an accident.

What will happen, in fact, is that, because of a certain combination of circumstances, human and mechanical, there will, occasionally, be an accident. Somehow, we have to stack the odds so that these accidents will be "acceptably infrequent". That, stated coldly, means suffi­ciently rarely as not to arouse public disquiet.

If we take precedent as our guide we have to arrange things so that the "acceptably infrequent" occasions will not be more than about once in every 100 million occa­sions - just as a wing may fall off an aeroplane once in every 100 million hours.

Indeed, it would be unreasonable to aim for a higher standard because, figuratively speaking, the wings will have fallen off at that time anyway. At the present rate of flying in the United Kingdom this probably means an "acceptable risk" of about one air collision over the Uni­ted Kingdom every ten years.

Whatever the detailed figures may be this adds up to the fact that we should not pre-occupy ourselves with attempting an altogether higher standard otsafety against air collisions than we accept cheerfully in other spheres.

Unfortunately, as I have said, this is a subject in which emotion is liable to transcend reason, because an accept­able collision risk is difficult to measure and unwelcome to think about and because, in a civilised society, it is emotionally unpleasant to say that a particular standard of safety is "good enough". But that is what we accept as normal and unquestioned in everyday life. And certainly we accept that philosophy every time we take-off and land in a modern jet aeroplane.

Now, if we couple this approach with the undoubted fact that there is room for everyone in the air and with the democratic principle that there should be "freedom of innocent passage" in the skies, this leads us, I suggest, to a situation which would be judged acceptable in which all, adequately licensed, pilots are permitted to fly at large, subject only to the qualification that when entering Controlled Air Space they should be able to communicate satisfactorily with the Controlling Authority and either positively locate their own position while in Controlled Air Space, or be under positive surveillance on a radar screen. In other words, so long as the position, the head­ing, the speed and the height of any aircraft in Controlled Air Space is known and the Controlling Authority is in radio contact with the pilot then - up to a certain limit of traffic density - all reasonable safety requirements will have been met.

Such an approach faces up to one important point. It is this. Even in conditions of clear skies and unlimited visi­bility, aircraft should not enter Controlled Air Space with­out establishing radio contact and positive identification with the Controlling Authority and receiving clearance to proceed. I accept this as reasonable.

At the same time, however, such a principle places a responsibility upon the Authorities to ensure that Con­trolled Air Space is kept to a minimum. This is not being done at present, largely, I suggest, because of obsolete

9

ICAO performance standards and because of an un­realistic approach to safety in order to be comfortably "on the safe side".

This brings us really to the nub of the subject concern­ing the problems of air space for General Aviation. The requirement can be stated quite simply. It is "to be able to fly when and where desired, in all reasonable weather, without undue delay and without interfering with others and without being required to suffer an overwhelming penalty, in terms of cost, weight and complexity, by hav­ing to carry mandatory equipment".

This requirement has to be judged against the fact that General Aviation is growing to be the chief user of air­ports and of the lower regions of Air Space, that airline traffic requires "protected flight" and specific separations, that satisfactory standards for other than airline traffic must be achieved with the use of the minimum amount of airborne equipment and that a good deal of so-called "random traffic" will have to be fitted in.

Two different solutions are, clearly, appropriate to meet these needs and to ensure "the safe, regular and expeditious flow of air traffic" in conjunction with the steadily increasing aircraft in the General Aviation cate­gory in - may I say again - the relatively uncongested air. The two different solutions divide into those appro­priate to Controlled Air Space, and those appropriate for the rest.

I submit that - at least in the lower levels (up to, say, 20,000 feet) - uncontrolled Air Space should be free and unrestricted. Controlled Air Space should be kept to a minimum consistent with affording the required protected flight for air transport services, who also seek positive separation of each aircraft from every other.

Now, a very important point is this: it has been truly said that "Controlled Air Space is not in itself a require­ment, but it is a way of meeting a requirement for pro­tected flight for civil transport operation". Protection, in fact, for aircraft which are proceeding with passengers at high closing speeds and flying on instruments.

As we are all so well aware, Controlled Air Space does not always provide "an expeditious flow of Air Traffic". Canalisation can - and often does - breed delays. For the present, however, we have to accept Controlled Air Space as the only means of achieving the obje~t of pro­tected flight for transport aircraft. The really important issue is thus narrowed down to the need for a satisfactory arrangement for the coincidental use of Controlled Air Space by civil transport operations and by General Avia­tion aircraft.

In effect, this means a solution under two heads:

1. The establishment of a means whereby General Aviation aircraft, and gliders, can fly safely and expedi­tiously into, out of, and through, Controlled Air Space,

and 2. The freeing of as much as possible of the lower

levels of Control Zones - which are not normally used by civil transport aircraft.

On this second point, there is no doubt that many Control Zones are needlessly large. They are based, in fact on obsolete !CAO provisions under which transport airc~aft are allowed six nautical miles in which to gain, or lose, l ,000 feet - that is, 1,000 feet in 36,500 feet. In practice this results in Control Zones which extend 12 miles from each end of a runway of a major airport. Control Zones which are thus of the order of 26 miles long. Beyond

10

these confines aircraft are free to pass without hindrance so long as they do not exceed a height of 1,500 feet -thereby maintaining the 500 feet of separation below a 2,000 feet flight level. This is all, of course, well known to you but also, I believe, unduly restrictive and unduly extravagant in the use of free air space. It seems based on that hoary old criterion of "a York, with an elephant on board, full of fuel, taking-off down-wind with one en­gine out". And where two airports are relatively close together - such as Manchester and Liverpool - the result is an enormous barrier as in the case of the Manchester Control Zone.

I am not, of course, suggesting that the criteria are wrongly applied - just that the criteria are old-fashioned and unrealistic, redolent of "DC-3 thinking".

For modern traffic a distance of eight miles to 2,000 feet should be adequate, even in down-wind conditions. In other words, Control Zones should be kept to the mini­mum size necessary to offer protected flight to modern transport aeroplanes - not all transport aeroplanes.

That brings us now to the really fundamental point -the establishment of a means whereby General Aviation aircraft can fly safely and expeditiously into and out of, and through, Controlled Air Space.

Some most encouraging and co-operative discussions are going on between representatives of all air users, Air Traffic Control Officers and the U.K. Ministry of Aviation, on this subject at the present time. I believe that these discussions, in which General Aviation is fully represented, wil_I result in a new and realistic approach to this knotty point. In the meantime, as one of those concerned, may I state briefly my personal view.

It is this: Controlled Visual Flight regulations - to replace the present "Special V.F.R. clearances" through Controlled Air Space - can be so framed as to make possible the "safe, regular and expeditious flow of non­sched~l:d air traffic" in Controlled Air Space alongside the airlines operating under Permanent l.F.R. conditions. Furthermore, I believe that C.V.F. can be satisfactorily a~r.anged under meteorological conditions down to visi­bility of about one mile and cloud bases of about 800 feet - depending upon the local terrain and provided a few, simple, conditions can be fulfilled .

. Obvi~usly, the first requirement is that Controlled Visual Flight should remain visual _whatever the agreed minima may be. So the pilot concerned would have to satisfy himself that nowhere on the route through Con­trolled Air Space would conditions become worse than those agreed minima.

Second, the pilot would have to have a certain mini­mum degree of competence. At the same time we do not wish to impose a whole series of new and restrictive regu­lations such as a special C.V.F. rating would involve. I s~ggest th~ sort. of criteria which should be required of a pilot for flight 1n less than normal VMC Conditions (five miles visibility) through Controlled Air Space should be: a) Not less than 100 hours, and b) Radio competence.

. The 10~-hour r:iinimum flying time ought to ensure abi­lity to navigate visually sufficiently to maintain a required course through Controlled Air Space in visibilities of down to one mile. Radio competence is obviously neces­sary.

These qualifications should be sufficient. And the onus should, I suggest, be put on the pilot to ensure that he

possesses the minimum qualification before he applies for a Controlled Visual Flight clearance. I believe very strong­ly that a pilot should not be required to produce evidence of such competence before applying for a Clearance, be­cause such a course would negative many of the advan­tages to be gained in that such a clearance often would - and should - be sought and granted by radio a short while before entering Controlled Air Space. .

The minimum requirements could be adequately moni­tored by ex-post facto review on occasion. I am firmly against the complexity and paraphernalia of a special CVF Rating. The great thing is to have an agreed standard - and then to make its application as simple and as flexible as possible. Quite apart from the "policing" po­wers of the Ministry, the various responsible General Aviation bodies, such as the Royal Aero Club, the Associa­tion of British Aero Clubs and the Business Aircraft Users Association, have adequate means of enforcing discipline in matters of this sort. There are, of course, many business aeroplanes in the General Aviation category which are fully equipped with radio and navigation aids, which are normally flown by experienced professional pilots. These aircraft and crews present no special problems because they can meet all airline requirements. The problem revol­ves, therefore, around the standard required of the less experienced amateur with minimum equipment.

That is where we come back to the basis I have sug­gested - a pilot with not less than 100 hours, radio com­petence and, of course, the necessary radio frequencies. I do not consider that radio aids, other than a VHF trans­mitter-receiver, are necessary where visual navigation at low levels is to be used.

As soon as enough Omni-ranges are installed in the U.K. - as I hope they will be shortly - a single VOR receiver will be the cheapest and the most satisfactory additional aid for a light aeroplane. But Controlled Visual Flight should be perfectly satisfactory without it and no requirement ought to be brought in to insist on radio navi­gation aids for CVF operations.

The important thing is, obviously, to have the right frequencies. And in this connection the philosophy adopted in the U.S.A., in Europe, and by the R.A.F. -of a small number of common frequencies, on one of which contact can always be made with every airport has outstanding advantages. By all means let us have the 360-channel - and even the 540-channel - sets in as many aircraft as we can afford. But they are expensive and the maximum advance of flying requires that the cheapest possible sets, with around a dozen frequencies, should be available - and made useful - as widely as possible.

A year ago a sub-committee of the Civil Aircraft Con­trol Advisory Committee went into the matter of secondary frequencies aimed at the most comprehensive adoption with at least one at every airport in addition to those nor­mally used. The recommendation which came out was that six "secondary" channels should be adopted for use on a universal basis. These recommended frequencies are:

118·3 mc/s. 119-7 mc/s. 122·3 mc/s. 122·5 mc/s. 122·7 mc/s. 123·5 mc/s.

plus the international emergency frequency, 121 ·5 m/cs. T~ese particular frequencies have the advantage that

they include those most widely used in Europe and in the U.S.A. If the proposed plan is adopted then a light aero­plane pilot with only a seven-channel set would be able

to maintain communications with almost every airport he encountered. Furthermore, such an emergency stand-by set, with a minimum of seven channels, would be invalu­able for use in the more completely equipped aircraft. Certainly the adoption of such a plan would be a great step forward in safety. In the meantime the proposal to use a specially designated frequency - 118·5 m/cs. - for special VFR clearances through the London Zone is most welcome.

So there, I think, we have the basis of a reasonable solution which will meet the requirements of the steadily expanding field of General Aviation alongside air trans­port operations.

In essence it means freedom to fly without restriction outside Controlled Air Space. And it means freedom to fly visually into and through Controlled Air Space, subject to radio clearance and a positive check on position. In full VMC conditions I suggest that no specific separation is necessary between two aircraft when both are on Con­trolled Visual Flight. When there are conditions of less than five miles visibility a two-minute separation should be adequate if both aircraft are flying on similar headings at similar speeds. In opposite directions a five-mile lateral, or a 500-foot vertical, separation should be enough or, alternatively, a positive separation by flying on opposite sides of a natural feature such as a railway (if railways can be considered natural). Holding patterns, where neces­sary, should be arranged on a visual basis around certain natural points - a reservoir for instance.

The cost and complexity of VOR, ADF, or Decca -although pleasant to use - is not necessary and there is certainly no need for an Instrument Rating. There is, in fact, no need to make heavy weather out of something which can be kept visual, simple and safe.

We can, I believe, all feel encouraged by the steps which are already being taken towards this sort of solu­tion, which, when promulgated, will do a great deal to­wards removing any lingering cause for the bad name for excessive restriction ism which has grown up among foreign aviators about the U.K's. attitude towards General Avia­tion. It will help also to dispel the feeling in this country that everything is being made very difficult for the private pilot.

How these things appear to some of those in General Aviation abroad is well illustrated by an editorial in a leading American aviation magazine in October, 1962. This reads, and I quote:

"Even in CAVU weather British regulations require compliance with the following before using London Airport - which has a traffic density roughly equi­valent to that of Omaha, which ranks 79th among the 254 busiest United States airports.

The requirements are:

1. advance permission from the Airport Comman­dant;

2. a flight plan; 3. such flight restricted only to those operntng

within the U.K. (you cannot fly in from an a t~r­noon's business in Paris, 215 miles away, despite the fact that London Airport is one of the largest concentration of Customs facilities and person-

nel in the U.K.); 4. this privilege is available to private aircraft only

from 8 a.m. to 8 p.m. daily;

11

5. such flight cannot use Airways at all and come in through designated corridors;

6. two-way radio required, and

7. all pilots must have Instrument Rating."

And the fi no I remark is:

"Compared with previous British standards, this sort of thing, apparently, constitutes relaxation to the point of gay abandon, at least in the eyes of British bureaucrats."

l am afraid that our authorities have indeed built up a bad reputation for excessive regulations, and this repu­tation has certainly not helped our aviation business. I would like to say, however, that they are not really as black as some would have us believe. The real trouble has been the fact that General Aviation has not made its voice loudly enough heard in this country but I believe that there is a growing awareness of its needs to-day.

I trust, therefore, that in the days and years ahead, we can bring a really practical approach to the whole matter, recognise the growing extent of General Aviation opera­ted by responsible people, and ensure that all forms of aviation can develop safely and happily together, with a minimum of restriction and the maximum of assistance to promote "the safe, regular and expeditious flow of all air traffic, to and from all airports at all times."

May I conclude with a quotation from an old friend of so many of us - Ted Pike. He wrote, nearly three years ago, the following words:

"It seems to me completely unacceptable that present­day shortcomings in ATC capacity or practices should be allowed to retard the growth of any branch of Aviation. There is so much Air Space available that it is well within the ability of modern technology to satisfy all users and accomodate a tremendous expansion in air traffic. I con­tend that statements about limited Air Space availability, even in this small island, are only valid when related to the inadequate tools and the inefficient operating methods now employed. If private and business aviation is to ex­pand, as it certainly should, the ATC system must be able to accommodate their requirements by working with sim­ple and lightweight airborne hardware. It may be neces­sary to re-examine the parts that could be played by modern ground VHF equipment in order to avoid impos­ing too many equipment burdens on operators of light aircraft."

May I say in conclusion that I am certain that we have in the membership of The Guild both the imagination and the experience which will achieve success in a realm which is vital to the future of this country of ours and in World transport.

Air Traffic Control into the l 970's D. W. Watkins*

I realise all practising Controllers are very concerned about improvements to the present system and that the l 970's appear distant, and that - generally speaking -planners are looked upon as people who sit and dream up systems without too much regard for reality and the facts of life. So, before dealing with plans for the 1970's, I will give briefly the facts as regards the immediate fu­ture, and by that I mean the next 3-5 years.

First of all, more and better radar stations will be pro­vided, aimed at giving complete radar cover over the United Kingdom Airways System between 5,000-25,000 ft. Engineering work is proceeding as quickly as possible to provide these stations and the radio links to bring the radar information into the Air Traffic Control Centres. Associated with each of these Primary-radars will be full Secondary-radar foci lities.

Next, and almost as important, will be the introduction of the first machine to help the Controllers (if one ex­cludes the "ticker tape" at the Ministry of Aviation's Sou­thern Air Traffic Control Centre). This machine will take the form of a Flight Plan Processing System (FPPS), with electronic store, and this will take over the receipt and storage of Flight Plans and the printing and distribution of Flight Progress Strips throughout the Air Traffic Control Centres, so relieving Controllres from this soul-destroying task and making them more readily available to carry out

Ministry of Aviation; Royal Rador Establishment, Malvern.

12

the real task for which they are trained - controlling air­craft.

New Air Traffic Control Centres will be built in the London and Preston areas, so designed that they should be expandable to meet all our known and anticipated requirements for at least the next 20 years.

Work is proceeding on new and improved Communi­cations Systems. Closed Circuit Television and Electronic Tabular Displays will be used extensively, particularly for the display of information to the Radar Controllers. Many other improvements are also planned, including modifica­tions to the size and shape of Controlled Airspace in order to allow for twin track airways.

These immediate improvements are real and promised at the latest by 1966. In fact, 1966 should be a vintage year for Air Traffic Control.

Now, what of 1966 and into the 70's? It is the period when all the immediate improvements to which I have referred should be seen in their true light, as stepping stones into the System of the l 970's.

It is the period when civil and military Air Traffic Con­trol could be welded together into one National Air Traf­fic Control Service; when more machines could be intro­duced to assist the Controller, machines mainly concerned with Radar Data Processing in its broadest form, and the correlation of Radar Data Processing and Flight Plan Processing and the consequent availability of automatic

means of liaison between Controllers and between ATC Centres and Units, by the use of Data Transfer Systems.

The setting up of a Radar Data Processing System is a complicated task and, before enlarging upon the benefits which could be achieved from such a system, I would like to go, very briefly, through the various steps - both mechanical and organisational - which must be taken before data processing machines begin to function in any Air Traffic Control Centre. I also hope to show why I think that complete integration of civil and military Air Traffic Control and the Air Defence System is essential for efficiency and safety.

The Mechanics of an Integrated ATC System

In peace-time defence operations would seem to be very largely an Air Traffic Control problem, for exercising military aircraft require to be separated one from the other and from other non-military aircraft. It seems illogi­cal to allow a Defence Controller to move aircraft through airspace in which other aircraft are operating under a completely different and uncoordinated Control System. Separate Systems can only exist safely where they have their own allocated areas of airspace. Without segrega­tion there is always the possibility of any two aircraft coming into conflict; therefore close co-ordination bet­ween users is essential.

If this co-ordination can be carried further, a number of functions may be made common which would other­wise have to be repeated for each Controlling Authority. For example, only one radar deployment would be neces­sary if all Controllers had access to all radars and the extraction of radar tracks for data handling purposes would need to be done once only, with resultant econo­mies.

If an intensive study of these problems is made, one reaches the inescapable conclusion that a concept of inte­grated Air Traffic Control resulting in more efficient work­ing, considerable economies, and with extensive develop­ment possibilities, is the best way of tackling the future ATC problems. This has been taken as the basis of what is to follow.

The System proposed is very largely dependent on radar information. A number of military and civil radar are either already deployed or in an advanced state of planning. Taking a selection of these radars it is possible to provide complete cover down to 5,000 ft. over a large area of the United Kingdom and the airspace can be divided into a number of optimum performance areas for each radar. These I call Track Production Areas.

The lower limit of 5,000 ft. must be assumed for two main reasons: First, the provision of complete radar cover at the ......... 1- •• - 11·..__ • · · d

,:)t iuwer a1 1ruoes is extremely expensive an , se-cond, much of the problem below 5 OOO ft. is associated with Airfield Approach Procedures. Therefore, any system planned above 5,000 ft. must be carefully integrated with the Airfield Approach Systems and the associated radars.

A series of geographical boundaries now becomes apparent, boundaries which will have to be "remembe1·ed" by the machine in order to allow the automatic transfer of responsibility for Track Production from one radar to the next. In addition other organisational boundaries will be

required but it is obviously advantageous to restrict the total number of boundaries in use to a minimum.

The Air Ministry and Ministry of Aviation jointly deci­ded to establish two ATC Centres, one at West Drayton and one at Preston, these Centres being responsible for all Air Traffic Control within the United Kingdom. Thus the next boundary required is an organisational boundary between Northern and Southern Centres.

A further examination of the two Areas thus created shows that there are regions within each Area with parti­cular characteristics, such as predominantly military flying, or a region congested with Airways. Each Area presents difficu I ties in track identification so it therefore seems expedient to divide the U.K. into six Identification Regions, the boundaries being formed by the Track Production Area boundaries. These Regions are thus based on both radar cover and the grouping of various types of activity while still presenting a roughly equal division of work­load.

Let us now look a little further into the type of System being proposed. Activity figures have shown that over much of the land area of the United Kingdom high densi­ties of activity exist below 5,000 ft. Any System utilising data handling techniques and based on radar must be capable of reliable track production and experience indi­cates that reliable track production, at densities which would be encountered using a radar not discriminating in height over part of the U.K., would be extremely difficult without some further aid.

Secondary-radar in the form of Military IFF or the Civil SSR would aid tracking but a method of presenting the individual plots of aircraft flying above 20,000 ft. without confusion by plots derived from high densities of traffic at lower levels would ensure a higher standard of track production. Some of the radars contributing to the proposed Track Production Areas will have a stacked beam characteristic; this offers the possibility of displaying the raw radar picture in height layers. These radars can provide height layering above 20,000 ft. as far west as Liverpool and Bristol, the cut-off being purely due to the Earth's curvature but nevertheless covering most of the higher density activity areas.

The proposed radar deployment would allow the track­ing of all aircraft above 20,000 ft. within the U.K. FIR as far north as, approximately, 57c. To continue tracking beyond this latitude would not be economic in view of the number of radars that would be necessary and the relatively light aircraft activity.

It is now possible to define a central area of high activity which due to the tvoe of rndars in use will, nevertheless, allow the tracki~~ of all aircraft in the Upper Airspace. Within the Middle Airspace, i. e., 5,000-25,000ft., the same arguments do not apply and the radars pro­posed for this coverage will, in general, not be capable

f t'- __ .-craft flv-of height layering. Additionally, many 0 "" u" ·d· .. ,

b · ed with Secon cry-ing in this airspace may not e equipp h f radar or even R/T communications and it would, there ore, seem reasonable to offer Air Traffic Service in t is areta

b i t certain requ1remen s. only to those a i ;-craft a .e to mee . . rts. Thus an ATC System is possible consisting of three pa ·

· II aircraft First, an Upper Airspace System covering a

above 25,000 ft. in which certain rules would be manda-

tory;

13

Second, a Controlled Airspace System working very much as at present and,

Third, a Middle Airspace FIR Service available to all aircraft able to meet certain requirements.

Now as to the subject of track initiation and identifica­tion. In the system which I am proposing, an aircraft com­ing into the Control System or requiring a service in the FIR must be initiated as a radar track and be positively identified before any control can be exercised. For the purpose of initiation and identification aircraft can be divided into three categories:

1. Those entering the U.K. from outside;

2. Those airborne over the U.K. in the Middle Air­space FIR and requiring a service;

3. Those becoming airborne from an airfield with­in the U.K.

Dealing first with those aircraft incoming to the United Kingdom, there would need to be two forms of initiation. Over a large part of the U.K. FIR all tracks could be initiated as they appear on the radar, in order to ensure positive identification by the time they cross the FIR boundary. These areas are generally low density traffic areas in which all aircraft initiated will, normally, be entering the United Kingdom. In a smaller area to the South East, where our radars are necessarily looking at a large amount of Continental traffic that may not be in­tending to cross the FIR boundary, it would be necessary to initiate those aircraft on which information has been received from Europe, or those crossing the FIR boundary above 20,000 ft. Where initiation is undertaken as soon as the aircraft appears on the radar, this is a function of an Initiation Cell associated with the Track Production Organisation. Where initiation is selective, or only under­taken as the result of other information, this is the respon­sibility of the Identification Organisation, and, as already described, the Identification Organisation has been divi­ded into six Regions in order to obtain a reasonable

distribution of workload.

Identification could be accomplished by set proce­

dures:

First whern an aircraft is entering either the Airways or Upper Airspace, an ATC Estimate or Flight Plan should be available some time before the aircraft enters the U.K. This pre-notification would be followed up by an R/T call from the aircraft a few minutes before crossing the FIR boundary on a specific Regional Contact Frequency. In addition to this information, the Identification Cell would need access to Secondary-radar information and possibly a DF Triangulation System, working on the Contact Fre­

quency.

As soon as identification is complete, the track - now con·elated with the up-dated pion - would be released automatically into the Control System.

Second, in the case of an aircraft already airborne over the U.K. and requiring a service in the MAS/FIR, the aircraft would again contact the Identification Cell by R/T on the Regional Contact Frequency. Identification would then be carried out and the track would be initiated into the system by the Identification Controller.

Third, the;·e is the case of an aircraft getting airborne from an airfield within the U.K. The procedure here would no longer be the responsibility of an Identification Cell

14

and will be explained in some detail later. In short, such aircraft would be required to file a Flight Plan or pre­notification prior to departure. Immediately before depar­ture a liaison would be established between the airfield and a Terminal Controller in the Centre via a Zone Ope­rations Room, which would be responsible for departures and arrivals at a small number of airfields within a "clutch". By the use of a simple digital signalling system the airborne time, together with the time at two or more "gates" on the climb-out path, would be signalled to the Centre where the Terminal Controller's Assistant would initiate and identify the aircraft as soon as it entered the Notional Rodar Cover. The means of identification would be:

a) Signalled information between airfield and Centre;

b) Secondary-radar when available, and

c) R/T and direct liaison with the airfield.

Thus initiation could take place within the Extraction Group, within the Identification Cell or at the Terminal Control position. Identification, on the other hand, could only be accomplished either at the Identification Cell or at the Terminal Control position.

So far, I hove proposed a basic Radar Organisation and hove indicated the areas in which sufficient informa­tion could then be extracted to operate a "Control ~ystem", as against those Regions where, initially, only a Control Service" could be offered. I do not wish to go

too \ 0 r in:_o control procedures at this point but I feel we should follow the passage of on initiated and identified track a little further into the proposed System.

1 shall deal with this part of the problem in relation only to the Southern Area, which would be divided into two. Sub-areas, each Sub-area having two Identification Regions.

Look now at one of these Sub-areas which includes Identification Regions 1 a d 2 · t f Fl"ght . n ; on rece1p o 1 Pion or ore-notificat: 0 f · f · h U "t d . · ·· • n o on Oircra t entering t e n1 e Kingdom the Fl!ght Pion would be automatically routed, at 0 predetermined time before the aircraft's entry into the_ U.K., to an Allocation Controller and to the ldentifi­~~~ion ~ell. On receipt of this Flight Pion information the

llocation Controller would "allocate" the aircraft to one of t~e Controllers in his Sub-area. At this point the infor­~otion would not be displayed to the Radar Controller

ut. :V0 u!d be automatically routed to him as soon as positive 1dentifirofon h d k f .

• · ·- ' 1 a ta en place. In the case o air-craft taking off fro th U K . . . . . m e .. or requesting a service 1n the Middle Airspace, they would be routed to the Alloca­tion Controller who would then allocate to a Radar Con­troller.

~uch of this allocation to Radar Controllers could be carried out automatically but wh t 1 . . d . . ' a ever og1c 1s use 1n programming for this purpose th Id · ·t bi b . ere wou inev1 a y e coses which would hove to be ref "'d t All t. C 11 __ , . err_ o an .. oca.1on

ontro11er. The bulk of Radar Co t II Id f common "Control p " n ro ers cou orm a . ool and could be allocated to func-

tions, radars and frequencies as th ·t Th. e necess1 y arose. 1s allocation could be the responsibility of an overall Con­troller Allocator.

Next I will explain in a little more detail some of the basic techniques and facilities on which the proposed

r I'

Control System would depend. I shall only deal with the facilities which I believe could be available in the late l 960's. Further developments, to be explained later, can be foreseen from 1970 onwards.

Track extraction would be "aided manual", by which I mean that continuous manual monitoring would be under­taken on all tracks. The extraction team would consist basically of Initiators, Trackers, Supervisors, Height Ope­rators and one or two miscellaneous positions. Trackers would normally be allocated an average of five tracks each and they would check the positions of each track every 15 seconds. Under low density conditions there is no real difficulty in this task but as local densities in­crease the possibility of track confusion increases. It is known that Trackers do not always know when they are confused.

The Extraction System should be based on two princi­pal factors:

First, that the Tracker can get into difficulties without realising it and,

Second, that the Controller responsible for the aircraft concerned is probably in the best position to resolve the difficulty.Therefore, it is proposed that the machine should detect certain conditions relative to tracking and refer these conditions to the actual Controller responsible.When the extracted plot positions on any two tracks lie within a predetermined separation (say 3 nautical miles) then a "close track" signal could be displayed at the appropriate Controller's position. This would allow the Controller to monitor the Tracker's performance or, if he considered it necessary, to take over the tracking function himself until the two tracks had diverged.

It is also possible to couple Flight Plan track and radar track closely together from the moment that positive iden­tification takes place. It would then be possible to detect any situation which indicates that the radar track is deviat­ing from the track indicated on the Flight Plan.

Third, the machine could also detect any failure by the Tracker to associate a radar response with a track for a given period, due either to a radar fade or to faulty track­ing. Again this condition could be indicated to the Con­troller, who would take the necessary action.

There will certainly be some developments in the field of Secondary-radar and the proposed System would make the maximum possible use of information available from both military and civil Systems. It seems highly probable that telemetered height will be available on a number of c'.vil aircraft on SSR Mode C. The System would appre­ciate personal identity and height information on all air­craft. and also knowledge of the R/T frequency on which an aircraft is listening. Secondary-radar could be used to supply all this information.

Much of the use of Secondary-radar information is dependent upon the data rate at which it can be received. Manual decoding of large numbers of responses is slow and _expensive and an automatic interrogation system is re~uired so that, as soon as an aircraft position is ob­tained togeth_er with a velocity on which future positions may be predicted, the predicted position co-ordinates at the next sweep of the Secondary-radar aerial could be used to "gate" an active decoder. The result of this inter­rogation could then be held in the store from which the position co-ordinates were obtained. In this way it should be possible to obtain a check on identity, height and

operating frequencyeveryl5seconds on all suitablyequip­ped aircraft.

Radar height-finding is another technique which would materially aid the proposed system. With stacked beam radars it would be possible to do a large amount of auto­matic height-finding. As in the case of the Secondary-radar System the equipment would require track forecasting from the digital data handling system, together with digi­tised video from a multi-beam radar. Heights could be measured on all tracks in every sweep of the aerial and while these heights would be less accurate than teleme­tered heights they would be sufficiently accurate to enable immediate control decisions to be taken in the absence of telemetered information.

Earlier I referred to a link between airfields and Cen­tres for the initiation of aircraft taking-off within the U.K. Such a link has already been tried experimentally for ini­tiation, and used a simple 10 JPS dialling system trans­mitted over approximately 200 cycles of a voice telephone line. In most cases, telephone communication is required between "clutch airfields" and Centres and this simple signalling system is superimposed on these lines with resulting economies.

I now return to the techniques of data handling. One aspect of data handling which is of major importance to the Air Traffic System visualised is what has become known as Data Transfer.

Basically, by Data Transfer I mean the labelling of various items of information for the attention of certain individuals. I can illustrate this best with examples.

Consider the process which I have called the "Alloca­tion" of task to Controllers. This is accomplished in a Data Handling System by merely marking the store in which track information is held with a code appropriate to the Controller concerned. Allocation is simple and does not require the simultaneous attention of Allocator and receiving Controller. Further, it is relatively simple to in­ject conditions of allocation, e. g., not before a certain time, latitude, or particular function: Taking this a stage further, Data Transfer could be used so bring important information to the attention of Controllers instead of expecting them to recognise a particular situation, as is the case in an unaided manual system. Thus, Recovery or Approach Controllers could be informed automatically of the time and flight level of aircraft arriving at particular points. Also, the possibility of conflict between aircraft could be detected by the machine and referred to the Controller in time for him to assess and resolve the situa­tion instead of expecting him to recognise every such situation; a task which will surely become more and more impractical with increases in aircraft speeds and densities.

For some years to come, Controller loading must be based on the number of aircraft for which he can ensure safe separation virtually unaided in the recognition pffr~-

. . h Id b "bi t make more e i-blem. Ultimately 1t s ou e poss1 e 0 1 d cient use of the human Controller and base his_w~rkUo~. 1 on the amount of control required to be exercise · ~ _1

this time however any one Controller may often reqhun e ' .' ,, h " . aft ·1ust as muc as detailed information on ot er airer '

. . · the event of poten-he requires information on his own, in

. "t y Controller access tial conflict. Data Transfer perm1 s an . 1 . . . bi · th System by a relative Y to any information availa e in e

d d thus avoids the neces-simple push-button call own an . sity for interrupting other Controllers involved in equally important task. All these examples of Data Transfer cover

15

the bookkeeping and liaison side of Air Traffic Control. These facilities should be the first priority in any new system as they immediately ease the load on the Controller and are a necessary introduction to automated control procedures.

One more important function of data processing must be mentioned. It will be appreciated that a Track Extrac­tion System can keep in store a considerable amount of radar-derived information on each aircraft; a second and parallel storage system is needed to store all available information derived from Flight Plans or pre-notifications. Therefore, with radar tracking, it is possible continuously to up-date the Flight Plan and then use it for a number of additiona I purposes, including:

1. Assisting track production,

2. Assisting the detection of errors in tracking,

3. Determination of more accurate times of arrival at points en route, whether reporting points or recovery gates,

4. Track predictions made on the basis of intention held in the Flight Plan Store, rather than on past history which may have ! itt!e or no relation to future beha­

viour.

To do these additional things it is necessary to provide a means of detecting if the extracted and Flight Plan information do not agree. This is commonly known as detecting "Flight Plan deviation". It is also necessary to provide a means of correcting the Flight Plan to the ex­tracted information when required. This function is com­

monly known as "up-dating". The System should also be able to calculate from the

up-dated Flight Plan, the expected position of an aircraft at some time in the future, or alternatively, the time requi­red for that aircraft to reach a particular point in plan position. Th is function is ea I led "prediction", and forms the basis of conflict detection, which I deal with below.

The Upper Airspace System

Having introduced the different elements which, when combined make a complete Data Handling System, I shall now conc~ntrate on the Upper Airspace, which I believe can be controlled, by radar, on an Area Control Concept.

What exactly is meant by an Area Control Concept?

An aircraft under this system of control is free to fly from its starting point to its destination along a trajectory of the pilot's own choosing, at a speed to suit his own

requirement. Jt is obvious that such a System will bear very little

resemblance to the conventional Airways Procedural System which we all know so well, a System which has remained basically unchanged for the last twenty or more years and in which the Separation Standards em~loyed have a built-in allowance to cover System deficiencies but

still provide safety - even if the airspace is used un­

economically. When considering the Area Control Concept one must

forget all reference to the accepted Airways' methods of control and ask: '"vVhat me the main requirements for the operation of an Upper Airspace System, based on an

Area Contrnl Concept?" They are:

16

Flight Plan. First, and probably most important of all is knowledge of intention. We must know what an aircraft intends to do; so we must have a Flight Plan.

Radar Cover. Coupled with this we must know exactly where the aircraft is now; so we need complete radar cover.

Data Storage and Processing. Next we require to store and process the information, thus giving us the ability to predict where the aircraft will be at any future time.

Predictability Display System. Then, of course, we must be able to display the assembled information in a manner useful to the Controller.

Data Transfer. Controllers must be able to transfer any information, as and when necessary, to any other Con­troller in the System; so we need efficient Data Trans­fer facilities.

Controllers' Communications. Naturally, none of these things is of use without an adequate number of Con­trollers and efficient communications ground/air.

I have already described each of these individual parts of the System and we must now examine more closely the aircraft which are likely to be flying in the Upper Air­space.

First of all, the transport aircraft. This type will fly regular straight-line tracks between the major terminals in Europe. These routes will be flown regularly and I refer to them as "preferred routes". These aircraft will behave in a well ""gul •~cl cl" '· · ... b d .·· ... · - a .. , , pre 1ctan1e manner; they w111 e o-in.g their b:st to adhere to their Flight Planned track; they will be unlikely to climb or descend at excessive rates and we can expect from them the fullest co-operation in every respect.

. Then the military aircraft. Many people believe that this type of aircraft is not amenable to Air Traffic Control procedures. I do not agree and consider that within cer­

tain li~itat.ion.s the military aircraft is generally able to pre-notify its intention and this single factor is of great importance in the proposed System.

. The bomber aircraft on a navigation or bombing exer­cise should have a high degree of accuracy in navigation, and a general adherence to pre-notified intention, with th.e who!: operation being fairly well predictable, and with 0 . high degree of co-operation subject to certain operational limitations. For instance such an aircraft on a bombing run would not willingly' accept an ATC en­forced change of heading, except in a case of emergency.

The fighter aircraft is another category. These aircraft a~e capable of violent manreuvres and very high rates of climb and .des~ent and are subject to rapid changes of c.ourse and .height when carrying out practice intercep­tions. I consider this type of aircraft to be generally un­predictable on most types of exercise, but nevertheless, able to co-operate within certain operational limitations.

Yet another category is the military flying training air­craft; pilots can notify their intention to carry out a cer­tain type of exercise in a defined area, but as this type of aircraft is flown by relatively inxeperienced crews we cannot hope for strict adherence to intention.

We also have the research aircraft; here again pilots can notify their general intention but they may be carrying

out unpredictable operations for at least part of their flight.

These types of operation are fairly clear cut, but there are, of course, intermediate types of operation which can, nevertheless, be fairly easily defined.

It should be possible to categorise each type of opera­tion and allocate priority codes defining the acceptable amount of interference which ATC can impose on a flight, insofar as alterations of height and heading are con­cerned, in order to achieve safe separation.

I think we should now look closely at an example of a particular aircraft in the Upper Airspace, in communica­tion with a particular Radar Controller.

The Controller must know the full flight details of the aircraft, its route, its mission or destination, its required flight level, its priority, and its identification. All these items would be in the storage system, and could be called down on to the Controller's "read out panel" by the manipulation of a few simple keys. He could call out of store as much or as little of the information as he requires to control the aircraft. It is most probable that - in the first instance - he would be using marked "raw-radar"; this means that this particular aircraft would have a small mark superimposed on the "raw-radar" blip indicating that it is under his control. Any other aircraft he is con­trolling and any other aircraft being controlled in the System would also be marked in this way, but these marks would be suppressed unless the Controller made them visible by selection. The aircraft would be allowed to pro­ceed in accordance with its Flight Plan or notified inten­tion, the Controller only intervening should it be necessary to do so in order to maintain safe separation. To-day, safe separation is measured by the Controller's eye coup­led with an intelligent guess as to other aircraft's inten­tion. In the System proposed the intention of all aircraft would be known and forward prediction on track would be provided. These predictions could be displayed to the Controller on request, or a further computation could be carried out to indicate to the Controller when separation is likely to reduce below acceptable limits. Under such conditions the information on both aircraft would be automatically "called down" to the Controller, together with information on the priority attached to each flight. In order to resolve the conflict, the aircraft with the lower priority would be instructed temporarily to deviate from Flight Pian. Should the aircraft be in communication with different Controllers the two R/T frequencies could also be called down to each Controller, together with on­channel intercom so that confirmation of intended action could be agreed.

Now as to the relationship between the Aiiocaiion Controllers and their Upper Airspace and Middle Airspace Radar Controllers, and the way in which they must all be able to communicate with each other through the Data Transfer System.

The Flight Plan Store must hold all Flight Plans, whe­ther they be civil or military, destined for the Upper Air­space System, the Controlled Airspace System, or the Middle Airspace Service.

If an aircraft is coming into the United Kingdom from another ATC Authority the Identification Cel I must be the first contact - whatever the flight level. The flight level would decide whether the flight goes to an Upper or Middle Airspace Radar Controller, and the Allocation

Controller would 1n1ect the identity of the selected Con­troller into store thereby making the information avail­able to the Data Transfer System.

In the case of an aircraft departing from an airfield in the United Kingdom the aircraft may start its flight in the FIR or in Controlled Airspace but may eventually be enter­ing the Upper Airspace; during its flight it may also cross Area boundaries. In all cases the information on the flight must precede the passage of the aircraft.

The Data Transfer System must, therefore, be able to pass information quickly, accurately and unambiguously to the right person at the right time; so, in the case of this departing aircraft, the new active Flight Plan would be auto-routed in the first instance to the appropriate Allocation Controller responsible for the Sub-area con­taining the departure airfield and he would decide whe­ther to allocate the flight to a Middle Airspace Radar Controller or direct to an Upper Airspace Controller. The deciding factor would be the length of time during which the aircraft would be flying in the Middle Airspace. Ob­viously in the case of a high performance fighter aircraft it would be in the Upper Airspace System within three minutes from take-off and would be allocated straight to an Upper Airspace Radar Controller. The flight from the ground to the Upper Airspace would then become the responsibility of the Terminal Controller; his part in the scheme of things will be described later. The important thing to note here is that every aircraft bound for the Upper Airspace would be in the System and under con­trol at take-off.

We will now look at the aircraft which commences its flight in the Airways System, and eventually climbs into the Upper Airspace System.

The part of the flight which is on Airways is clean cut, the route automatically defining the allocation to a parti­cular Controller, and the aircraft being initiated into the System through the Outbound Radar Controller imme­diately after take-off.

At the appropriate time the information on the flight would be automatically passed through the Data Transfer System for allocation to an Upper Airspace Radar Con­troller.

At 20,000 ft., or thereabouts, again using the Data Transfer System, the flight would be transferred to the

Upper Airspace Radar Controller.

Each time a transfer of control takes place the receiv­ing Controller will be able to identify the airuaft imme­diately by use of the "Restrict Marks" facility whereby the aircraft being transferred will be suitably marked on the radar screen.

i think i have now covered ail aspects of liaison within the proposed Organisation, particularly as it would affect the Upper Airspace System, and you will observ~ that the telephone need rarely be used as a medium of intercom­munication between Controllers. The right information would go to the right Controller at the right time by means of the Data Transfer System. This - I feel - would be

a significant step in the right direction. . It is now necessary to consider the aircraft flying in the

U A. h' -h . · _ .. +o:~o thP I ln1tf'd Kinn-pper 1rspace w 1c 1s going uu 10 •~v ... - - · · · - - · ... "'

dam System. Up to now I have made no mention of Movement

PI · th u r Ai'rspace because I believe that the anners in e ppe . . . e ' S ,em doe< not require the11· services 1 n the propos a ys1 -

17

accepted Airways manner. However, there would be a requirement for a "non radar Controller" in each Area. This Controller would be responsible for ensuring that aircraft leaving the United Kingdom System are delivered to the neighbouring ATC Authority at a place, time and height acceptable to them. He wouid act as the link bet­ween the Radar Controllers and the neighbouring ATC Authorities and should probably be called the Upper Airspace Co-ordinator.

Climb-Out and Recovery Systems

The proposed Upper Airspace System could not ope­rate in isolation for it would be intimately connected with both the National ATC Organisation below it and the organisations of other ATC authorities which border it. I shall now pick out certain parts of the proposed Lower and Middle Airspace Organisations which would contri­bute to and support the Upper Airspace System.

The proposed ATC Organisation would operate from 5,000 ft. upwards; below this level is a heavily congested airspace which is largely the responsibility of Local Air­field Control. In the U.K. there are some 150 military and civil airfields capable of generating traffic bound for the Upper Airspace. This presents a tremendous co-ordination and communication problem. To reduce this problem, and at the same time to provide a service to transit aircraft operating below 5,000 ft., it is proposed to group t~gether all airfields which lie outside the Controlled Airspace System into a number of Airfield Zones. Three or four airfields would generally comprise one Zone. To co­ordinate the activity within a Zone, one airfield would be nominated as parent and would be equipped with suitable radar and operations room facilities. The operations room would be linked with the appropriate Centre by tele­printer and a simple digital/tele~~one '.11ess~ge :ystem, originating from airfields. To facilitate 1dentiflcat10~ .on entry into National Rooor co~er and t_o ~eparate arriving and departing traffic, each 01rf1eld w1th1n a Zone would be allocated permanent arrival and departure lanes. The Zone Radar cover over airfield approach and departure lanes would overlap into the National Radar cover.

The Zone Radar displays would have video maps show­ing the climb-out and recovery lanes along w~ibclh wo.uld hP marked 0 series of "gates" representing poss1 e points of entry into the National coverage.

In the Centres would be the Terminal Control positions, each being responsible for at least one Airfield. Zo_ne. Th Id provide the operational and commun1cat1on

ey wou 7 Th T · 1 "link" between the Centre and the ~one. e ermina. Controller and his Assistant would o~er~te from t:-Vo raw-

d d. lays each one showing their airfield arrival and ra or 1sp ,, ,, . d t lanes together with the gates representing epar ure · · 1

.,_, -n•··y ·1nto the National Radar cover s1m1 or to poss1u1e c; •• .

those provided on the Airfield Zone displays.

B means of the simple digital message system, the Fligh~ Plan Store in the Centre would be activated ta f_eed

t t t ·cally to the Terminal Controller the required ou , au oma 1 . , . . , , _ flight data. As the climbing 01rc~a_f'. reac.hed an entry " " ·t Id be identified and initiated into the radar gate 1 wou d t Th FI. ht Plan would be up-dated from the ra or

s ore. e 1g T k p d · · f t" d the track passed to the roe ro uct1on 1n orma ion an . . rll lJ G ta sk The identity of the M1d_.e or _pper roup as a new . . Airspace Controller previously allocated to the flight would be displayed to the Terminal Controller and after

18

radar initiation control of the aircraft would be trans­ferred automatically, by the use of the Data Transfer System, to the pre-allocated Controller together with the associated flight data. The aircraft would now be in the proposed System.

The procedure first outlined would apply to military and civil airfields located outside Controlled Airspaces. Major civil airports which are fed from, and feed into, the Airways System already operate a Terminal Organisation which regulates both outbound and incoming traffic and little could be achieved by changing it at this time.

Recovery from the Upper Airspace

Before leaving the MAS I want to mention briefly the recovery of aircraft from the UAS to destination airfields. The chief requirement is to ensure that when an aircraft which has been operating in the UAS penetrates the MAS it does so at a time and place which is acceptable to the MAS air situation. The System proposed, with intelligent use of the Data Transfer facility, would enable this to be done safely and expeditiously.

No ATC System can operate to the advantage of all airspace users without satisfying the requirements of both military and civil aircraft. Thus the accent in the proposed plan is on Integration from which, not only would we reap the benefit of certain overall economies but, more impor­tant still, we would obtain an organisational efficiency not attainable in any other manner.

It is true that, as far as control techniques are con­cerned, no revolutionary propose Is are made. The two essentials in the proposed System are radar coverage and data handling.The former provides the necessary accuracy of positional information and the latter relieves the Con­troller of much of his "bookkeeping" activity. In these pro­posals, many of the problems of liaison and co-ordination would be overcome through the operation of the central data strage and transfer facilities. The Controller's effi­ciency and work capacity would thereby be increased.

In this proposal for an Integrated System, the man/ machine relationship has been established with a system­foundation upon which future development could progress towards an era when the machine would assist in decision making.

Future Developments

It is obvious that once data has been stored it can be manipulated by the computers in 0 variety of ways. It is easy to visualise an increasing degree of sophistication; an increasing degree of automation in routine tasks; in fact, a continuously changing relationship between man and machine.

This changing relationship is the key to the future deve­lopment of such a system. It is technically possible to visualise a machine which carries most of the workload concerned with gathering data and the Controller using the machine to help in making control decisions. A great deal of emotion can be generated by this sort of proposal and it usually reaches its peak when considering the effectiveness of the man, relieved of most of the routine data gathering workload, dealing with control problems. It is claimed that he loses the "feel" of the situation and is not as effective as he might be. I am convinced that the various stages of computer aid should be introduced

when, and only when, the operator has acquired complete faith in the appropriate computer programme.

I have insufficient space in which to give a balanced survey on future developments. Instead, I would like to outline a few items which seem to be all-important.

Movement Planning

Computers can do a great deal to help Movement Planners. In particular, I believe that computers have much to offer in the fields of Flow Control and Terminal Area Sequencing since it is precisely in the problems with much data and simple rules that computers have the advantage over man.

Auto-Tracking

The problem of auto-tracking is one in which compu­ters can also offer a great deal. They allow us to consider the use of very sophisticated logic in maintaining tracks. In auto-tracking there are problems other than that of computer programming and time. Auto-tracking is not the immediate cure for ali the ills of manual tracking; it tends to break down under much the same conditions that cause manual tracking to falter. When tracks come close to­gether auto-tracking can make mistakes, though for nor­mal air traffic the mistakes are fewer than with manual operators. Under clutter conditions auto-tracking fails, if anything, more readily than does manual tracking, be­cause it is extremely difficult to reproduce in a computer the man's ability to "pattern recognise". On the other hand, auto-tracking has some very considerable advan­tages over manual tracking. It can use every paint and it tends not to make silly or careless gross errors. But more important still, it can take advantage of much more infor­mation than a man. In particular, a computer can assimilate data from more than one radar source, and easily take into account other pertinent data such as height, Flight Plans, Secondary-radar codes, etc. As far as this proposed System is concerned, the problem is eased by the use of height layering to reduce clutter. It is therefore believed that in an Air Traffic Control environment where tracks tend to be widely separate, clutter is minimised, and much extra data is available, auto-tracking has much to offer.

The Conflict Problem

The Conflict Problem is a good example of the way in which the proposed System could continuously evolve. The problem is to ensure that no violent avoiding action is necessary to establish some safe separation minima.

In the initial proposal the "present positions" of all the tracks in th~ system could be compared, say, once every aerial rotatron. A rectangular box, with sides aligned along the system co-ordinate, could be generated round each track, and compared with the box f

h rome~~ ot er track. If the box is large enough, this could act as a crude _conflict warning. The computer load is kept small by kee~rng the individual sum short and simple.

~uch more helpful would be the generation of points pro1ected, say, three minutes ahead along each track and comparrson of boxes placed about th · t Th . . ese porn s. ese predr_cted por~ts could be provided initially as a visual rnnfl:ct detection aid on the Controller's display. It is 0

srm~le matter to extend the conflict detection process to a srmple box about the predicted position.

Much discussion can centre on what is the minimum warning time required to guarantee that a Controller can decide how to divert the conflicting aircraft, communicate

with the aircraft, and have time for the actual diversion manceuvre. I think that three minutes is the minimum time for this. Obviously if this time can be increased, in gene­ral, that is a good thing, and for "well behaved" aircraft this time could probably be increased to, say, six minutes without increasing unduly the number of false alarms. There is a limit to the time ahead for which it is worth carrying out conflict avoidance, and this is set by the undesirability of unnecessarily diverting aircraft or caus­ing them to fly at uneconomic flight levels for too long. The introduction of a variable time would further compli­cate the programme.

Now, though the most probable future position of the aircraft is at the predicted point it may well not be there for a variety of reasons. It is possible to produce a surface which defines the volume within which the aircraft is most likely to lie, according to some degree of probability. This surface is not the rectangular box, but is a surface centred about the predicted track line as axis. It is desirable that this surface should be as small as possible in order to reduce the number of unnecessary conflict alarms. A civil aircraft on a straight run would have a very small con­flict surface, because of the small heading and speed errors expected with such aircraft. At the other end of the scale, a jet fighter will be able to occupy any point in a large sphere about its present position in the same time.

In between lie a set of crescent-like surfaces covering t~e degrees of freedom experienced by other classes of ?rrcraft. Of course, the dimension of height must come r~to th~ sum_. This is largely set by the uncertainty of the arrcraft s herght, from measurement and must be increa­sed if the aircraft is in a dive or cli:nb due to the uncer­tainty in the rate. The importance of k~owledge of inten­tion therefore cannot be over-emphasised. The better the knowledge of intention the smaller the conflict profile. The smaller the conflict profile the less frequent would be false conflict alarms, but the more significant would be those alarms that occur.

The above are ideas which I think could develop into an Air Traffic Control System for the 1970's. They must not be considered as the Official Policies of any Ministry, but it is my hope that Ministerial Policy may develop along the lines suggested.

IFATCA Annual Conference 1963

From April 29th till May 2nd JFATCA will hold its An­nual Conference in London, The Bonnington Hate':

Th - . h d I d for Aprrl 30th, e openrng ceremony rs sc e u e . 0900 hrs., with addresses by the Master of The Gurld of ' · T ff' K d b the Controller·, Arr ra rc Control Officers, U , an Y . . _ N . . UK A' v·ce-Marshal Srr atronal Air Traffic Servrces, , rr 1

Laurence Sinclair GC KCB CBE DSO RAF (Ret.). d . A number of business sessions will take place urrn~

~he conference and the Public Meeting, on May 1 st, wr be addressed by the United Kingdom Secretary ;fb St~~e for Air, the Rt. Hon. Hugh Fraser, MBE M.P., an y e President of IFATCA, Mr. L.N. Tekstra, Amsterdam.

May 2nd has been reserved for interest -visits in UK. A h d •ed tour of the Mar con r demon-mong ot ers a con ucr

. . . E fl' ht programme and demon-stratron srte rn ssex, a rg stration by the Decca Navigator Com.pony, Ltd'.,. and a conducted tour of the De Havillond arrcraft facrlrtres at

Hatfre!d have been arranged.

19

Stress and Performance in Air Traffic Control K. G. Corkindale*

In designing any modern man-machine system one of the earliest and most fundamental problems is that of specifying which tasks will be undertaken by men and which by machines. In order to make a rational decision one needs to know the relative merits of men and ma­chines.

Some eleven years ago a report was produced for the United States Air Navigation Development Board, entitled "Human Engineering for an Effective Air-Navigation and Traffic-Control System", in which the advantages of men compared with machines were listed as detection, percep­tion, judgment, induction, improvisation, and long-term memory. But the report also pointed out that not enough was known about the effect of overload and stress on human abilities.

Most Air Traffic Controllers would agree that theirs is a stressful occupation and it is the object of this paper to summarise what is known about the effects of stress on performance and to suggest possible implications for the design of Air Traffic Control Systems.

If one were to conduct a public opinion poll amongst Air Traffic Controllers as to why they think that their work is stressful one would get a variety of answers. Some would mention the responsibility involved and the pos­sible consequences of error. Others would deal with the nature of the task itself, in particular the quantity of infor­mation that has to be handled rapidly. Still others would dea I with the genera I conditions of work, such factors as noise, lighting, hours of work and so on. A different type of reply would mention the results of the work on the Controller, for example fatigue, and eyestrain.

These different possible replies highlight one of the maior difficulties in the study of the effects of stress; namely, although the word stress is widely used there is no exact agreement as to what the word means. This semantic problem occurred with the word fatigue which, up to a few years ago, was widely used to indicate chan­ges in a person's psychological or physiological state as a result of continued work [2, 3]. Because of the difficulty of finding an agreed definition the word has become un­popular in biological circles. Despite the problem of ex­act definition there is a need to have a word that refers to those conditions which are thought to have an adverse effect on people; hence the widespread use of the word stress.

The term stress in physics is used to refer to a force per unit area. When such a stress is applied to a physical body a corresponding strain is produced; the ratio of stress to strain is a characteristic constant of the body.

Most investigators engaged in work on biological stress in biology tend to think along these lines when they use the term sti-ess. In this paper the word stress will be used loosely as a short-hand form of abnormal or unpleasant environments which may adversely affect performance.

Since Air Traffic Control is an occupation which does not involve a great deal of physical exertion, the types of performance with which this paper will deal will be limi-

RA F. Institute of Aviation Medicine.

20

ted to those tasks where the muscular effort is small com­pared to the mental activity required. Typical of these tasks are ATC functions such as detection, tracking, moni­toring, problem solving, and decision taking.

in view of the wide range of situational factors that have been studied, it is not surprising that the methods of research that have been used have been drawn from all of the techniques available in psychology and physiology.

Studies have been conducted both in the field and in the laboratory. Although field studies are valuable for suggesting what the important variables are for optimum performance the general difficulties of adequate control of field studies make laboratory studies desirable so that the exact effect of particular variables can be studied in detail.

Classification of Stresses

In order to deal with various types of stressful situation it is convenient to use a classification of stresses based on one suggested by Harris, Mackie and Wilson [4].

The classification is based on the length of time that the stressful condition lasts. This gives two main cate­gories:

Short-term stress, where the condition lasts from a few minutes up to an hour or so, and

Long-term stress, where the condition lasts from an hour up to a period of months.

Short-term stresses can be sub-divided into four categories as follows:

Fa i I u re stress. In this situation the subject feels that he has failed, or is failing, at some task at which he wishes to put up a good performance.

D is tract i o n s tress . Conditions are studied which are thought to distract the subject from his primary task. Typical stimuli used have been sudden loud noises and flashing lights.

Physical discomfort stress. The stimuli in this category physically impinge on the subject. Conditions studied have included continuous noise excessive heat and humidity. '

S Peed and I o ad stress. In these studies the subject is required to work at a high speed. Both the number of signals requiring action and the number of channels in which the signals appear may be varied.

Of the long-term stress conditions two categories are of relevance to the ATC situation. These are:

Is o I at ion and con f i n em en t stress. It is difficult to differentiate between the effects of physica_I confinement and of being in a "percep­t~ally_ impoverished" environment. Most working situations that have one element present usually have some degree of the other.

Bio I_ o g i c a I stress. Under this heading one can list such conditions as dietetic deficiencies, Joss of sleep, and changes in the work-rest cycle (i. e., shift work).

Like most classification systems the one above is not a series of entirely separate areas but more a series of headings.

Failure Stress

Out of the number of studies in which the subjects were led to believe that their performance was inade­quate to attain the designed goal two, by Lazarus and his coworkers, may be selected as representative. In the first study the subjects (220 enlisted American Air Force per­sonnel) were given a standard tracking task used in per­sonnel selection programmes. The subjects were divided into five groups, four experimental and one control. The control group were tested under normal conditions where­as the four experimental groups were told that the results of this test would be a major determiner of their Air Force career. The distinction between the four groups was that they were given this information at different time during the tracking runs [5]. The results showed that the stress condition introduced early in the testing period produced a decrement in performance, whereas introduced later it improved performance. The stress produced greater varia­bility between subjects' performances than was found in the non-stress situation. Another study [6] using an intel­lectual task showed that the threat of failure gave, once again, a significant increase in inter-individual variability compared with the non-stress situation. The quality of per­formance suffered though an increase in rate of working compensated to some extent for an increase in errors.

These and similar studies indicate that there is in gene­ral some worsening of performance with failure stress but the most noticeable effect is the different effect it has on different subjects.

Distraction Stress

Since sudden loud noises are a feature of many work­ing situations this type of stimuli will be considered as typical of the effects of distraction.

An early experiment [7] required subjects to find a number of digits mixed in a jumble of letters, to ~dd the digits together, and to write down the answer. E_1ghteen such problems were given to each subject; during the middle six a klaxon horn was blown. The first problem after the horn started to blow took longer than those done in the initial quiet practice period. Somewhat sur­prising was the finding that another slowing occurred when the horn stopped after the twelfth problem.

This effect of a temporary decline in efficiency with a distracting stimulus has been found by various other in­vestigators. Usually the effect wears off quite rapidly if the stimulus continues.

The most recent explanation is that people are capable of only attending to one stimulus at a time and that any novel stimulus will gain attention even if only briefly [8].

Physical Discomfort

Although it has been said above that noise can act as a distraction with a measurable effect on performance, there is also evidence that continuous noise can produce an overall fall in efficiency. Tasks that require close and continuous attention, such as monitoring, seem particular­ly susceptible to the effects of noise (8]. It is as if in noisy conditions there are more frequent lapses of attention

with the result that a signal may be missed. In tasks that do not demand the same continuous attention there is no marked change in performance in noisy conditions com­pared with quiet conditions.

Another environmental factor which has been closely examined is the effect of heat. It has been shown (particu­larly by references 9 and 10) that performance at a large number of tasks deteriorates as the ambient temperature rises above 80°F. (effective temperature scale). Tasks stu­died have included tracking, monitoring, receiving morse code, and decision-taking. In line with most other studies was the marked variation shown by different subjects. Of particular interest was the finding that skilled operators showed a much smaller change in performance than their less-skilled colleagues when placed in the stressful in­vironment.

Speed and Load Stress

In many working situations an operator has to monitor and respond to information displayed to him via several channels simultaneously. Very often the rate at which the critical signals arrive is not under the control of the ope­rator; this situation is called paced performance. In un­paced tasks the subject is allowed to choose his own rate of working.

One characteristic of performance at tasks requiring a series of rapid responses is that at intervals the subject shows momentary hesitations or "mental blocking" dur­ing which time no response is made. In paced tasks these blocks will show up as errors since once the subject has failed to' respond he cannot catch up again as he can in an unpaced task where the signal remains until dealt with.

If the speed of a "paced task" that is the number of signals per unit time, is increased 1 then the usual finding is that although the rate of working increases the number of errors and omissions increases.

In the last few years another "task variable" affecting the rate of work has been studied. This second variable has been called load and defined as the number of sepa­rate streams of signals that occur independently of each other but require simultaneous consideration. A number of experiments have shown that at given rates of signal presentation increases in load result in large decrements in performance. Similarly, if load is held constant, then, increases in speed also adversely affect performance.

Confinement and Isolation

Of the possible long term stress conditions only two of immediate relevance to the ATC situation have been studied.

Although Controllers do not spend long periods of time on duty confined in the same sense as astronauts or prisoners are, it is of interest that confinement and isola­tion (i. e., being in a dull, non-stimulating environment) have been shown to produce decrements in performance. It would appear that it is possible to give a person too little to do just as it is possible to require too much.

The nearest approach to ATC condit'.o~s are the stu­dies of watch-keeping performance or v1gilanc_e tasks. In these the subject is required to attend to a d1spla_y and detect infrequent signals The results of many experiments [8] indicate that the number of signals detected falls_ off markedly in the first half-hour of a two.-hour watch period. Various ways of preventing this decline 1n performance

21

have been found. in general it may be said that anything that enlivens the situation, whether it be a higher signal rate or the presence of another person in the room, les­sens the decrement in performance.

Biological Factors

Under this heading we can consider the effect of loss of sleep and of changes in the work-rest cycle. The effects of loss of sleep of periods of up to 100 hours have been studied with demonstrating any great effect on a number of intellectual and perceptual tasks. However, recently, Dr. Wilkinson, at Cambridge, has shown that certain types of perceptual and psychomotor tasks are affected by even one night's ioss of sleep. The tasks he used were an un­paced serial reaction test lasting 25 minutes, a vigilance task, and pursuit meter tracking. The reason suggested by Wilkinson for the impairment at these three tasks is that in each case the subject is required to make continuous responses, any momentary inefficiency cannot be recove­red by a subsequent increase in performance. Once again tasks requiring close, continuous attention seem particu­larly susceptible to the effects of a stress.

Summary of Findings

The general conclusion that one can draw from the many and varied studies is that a number of conditions can adversely affect performance. It would seem that as the general conditions of work depart from the normal or usual then performance is likely to suffer. This seems ta be true whether the required rate of work is raised or lowered appreciably. A finding common to all studies is that differences in performance between the subjects is greatly increased by stress. It has been found that a high degree of skill prevents the performance being too badly affected. One line of research that is being pursued is the effect of age on the level of skill and on the effect of stress [11 ]. It has been found that tasks requiring the rapid handling of information or the use of immediate memory suffer a decline with age and that stressful con­

ditions amplify this effect. Although in real life stressful conditions seldom occur

singly, there has been relatively little research on the interactions between stresses. What little work there has been would seem to indicate that different stresses act often in slightly different ways and that at times the result is the sum of the separate stresses.

Discussion

In attempting to explain the reason for the changes in performance under stress it is possible to make use of two concepts suggested by Professor Hebb of Can?da ~12]. He has pointed out that any stimulus has two quite. diffe­rent effects. One he has col led the cue funchon: th 1s cha­racteristic guides behaviour in a suitable manner. The other effect he calls the arousal function, the effect of which is to keep the Centro I Nervous System toned-up, as it were and able to make use of the information (or cue functio~) given by the stimulus. The relationship b.etween these two functions is an inverted U-shaped d1str1bution. As ~he arousal function of a stimulus increases the cue fonction rises to a maximum and then falls off. At the e~tr~mes of the arnusal function {i. e., dozing and anxiety) the cue function is low. It follows that there is an optimum amount of arousal for the best performance for any given

22

subject. Deviations in either direction from the optimum will result in worsened performance.

Implication for ATC

The original problem was the choice between man and machine for various ATC functions. It can be seen that it is important to state in some detail what task is envisaged and what sort of operator is being considered as well as what stresses are likely to be present.

From what has been said earlier, it is clear that tasks requiring close, continuous attention are likely to be ad­versely affected by stressful working conditions. Since this is a characteristic of most monitoring tasks, which in addi­tion are often very low in their arousal function, the recommendation would be that as far as possible moni­toring should be undertaken by machines.

From the work on speed and load stress it follows that both the quantity of information and the number of sources (i. e., load) should be checked to ensure that the requirements do not outstrip human capabilities.

Many recommendations that fallow as a result of the study of performance are the same as those resulting from the study of comfort, e. g., adequate noise-protection, suit­able heating and ventilating conditions, and glarefree lighting.

Although much has been said on the individual diffe­rences between subjects little useful advise can be given on how to draw up a suitable personnel selection pro­gramme. It should be remembered, however, that a !though operators might perform much the same under norma I working conditions what one person will find a challenge to another might be a considerable stress.

Conclusion

From what has been said, it is hoped that the relevance of the study of performance under stress to the design of ATC Systems has been established. Possibly the biggest problem is how to ensure that the large, and everincreas­ing, body of knowledge is applied to make a worthwhile contribution to the human factor problems encountered in the design and operation of Air Traffic Control Systems.

References

l. Fitts'. P .. M. (ed.) 1951. Human Engineering for an Effective Air­Navigat1an and Traffic-Control System. Washington D.C. National Research Council Committee on Aviation Psychology.

2. Bartley, S. H., Chute, E., 1947. Fatigue and Impairment in Man. McGraw Hill, New York.

3. Floyd, W. F., Welford, A. T. (eds.) 1953. Symposium on Fatigue. H. K. Lewis & Co. London.

4. Harris, W., Mackie, R. R., Wilson, C. L., 1956. Performance under Stress. A review and critique of recent methods. Human Factors Res. Inc. Tech. Rep. VI.

5. Lazarus, R., Deese, J., 1951. The effects of psychological stress on psychomotor performance. Amer. Psycho! 6, 262-263.

6. Lazarus, R., Eriksen, C., 1952. Effects of failure stress upon skilled performance. J. Exp. Psycho!. 43 (2), 100-105.

7. Ford, A. 1929. Attention - automatization. Amer. J. Psycho!., 41, 1-32.

8. Broadbent, D. E., 1958. Perception and Communication. Pergamon Press, London.

9. Mackworth, N. H., 1950. Researches on the Measurement of Human Performance. M.R.C. Spee. Rep. Ser. No. 268, H.M.S.O., London.

10. Pepler, R. D., 1958. Warmth and Performance, an investigation in the tropics. Ergonomics 2, 63-88.

11. Welford, A. T., 1958. Ageing and Human Skill. Oxford University P1·ess, London.

12. Hebb, D. 0., 1955. Drives and the C.N.S. (Conceptual Ne1·vous System). Psycho!. Rev, 62, 243-254.

NATO and the Committee Colonel K. Birksted*

for European Airspace Co-ordination

Co-ordination of civil and military ATC in NATO, can, think, for the purposes of this Convention best be ex­

plained by retracing briefly why, how and when this sub­ject became a live issue within the NATO organisation; how it is handled; what has been and is being done about it.

In 1954 it had become apparent to the national autho­rities helped by ICAO and other agencies responsible for, or concerned with, the organisation and control of air­space and air traffic in NATO Europe:

That the programmed expansion of both civil and military aviation would lead to a situation in which it would be necessary to accomodate - simulta­neously - several hundred civil and military air­craft, climbing, cruising and descending at widely varying speeds and in all directions up to 60,000 ft. in the NATO European airspace. It was also apparent that this situation would intro­duce co-ordination problems which would be diffi­cult and time-consuming to deal with through bi­lateral negotiations between the many national, civil and military, and international authorities and agencies concerned. The civil agency, ICAO, has no responsibility for military aircraft.

Civil/military co-ordination problems had, of course, existed for many years and attempts had been made to resolve them, generally speaking, satisfoctorily eith~r ~t national levels, or through bilateral negotiations. This is, naturally, still true in respect of many, and indeed, the majority, of the existing problems.

A new foctor to be considered was, however, that the member States of NATO discharge some of their responsi­bilities and operations through the NATO organisati~n with the result that this organisation had become, and is, one of the major users of airspace. This is in particular so during large-s~ale exercises, and for airdefence in a large

part of NATO Europe. . Towards the end of 1954 a meeting was held in the

NATO Headquarters in Paris to consider the impl_ic~tions of this situation. The meeting was attended by civil and military representatives of the member States of NATO, the NATO military commands and members of other in­terested international agencies, notably ICAO.

!t was agreed:

a) that there was a requirement for better co-ordi­nation of civil and military use of the airspace and air traffic control;

b) and that experience had shown that co-ordina­tion between the many States and organisations involved could not be carried out effectively through bilateral negotiations only.

It was therefore recommended that a Committee with both civil and military representation from all NATO States and with active participation from the NATO mili­tary authorities, as well as from ICAO, IATA, and other

Technical Advisor to Committee for European Airspace Co-ordina­tion, North Atlantic Treaty Organisation.

international organisations as required, be established within the NATO organisation to consider measures for co-ordination of civil and military use of the airspace and control of air traffic in order to:

ensure all users, civil as well as military, safety from collision; and sufficient freedom of movement for achievement of their objectives, be these transport, training, or operational.

This recommendation was agreed by the NATO Coun­cil and early in 1955 it established a Committee for Euro­pean Airspace Co-ordination, commonly referred to as CEAC. The members are high-ranking civil and military representatives of the NATO States. ICAO and the NATO military authorities are represented, and IATA attends meetings when subjects of concern to this organisation are being studied. More recently, arrangements have also been made for EUROCONTROL to participate in the Committee's work, as appropriate.

Most of the Committee's work is accomplished through studies prepared by groups of experts made available for specific tasks and for a limited period by the States and other agencies concerned.

The Committee (CEAC) reports to the NATO Council. It has no executive authority, but its recommendations are in foct collective agreements or decisions made by the national or international authorities with executive autho­rity to implement these.

As soon as it had been set up, CEAC studied the pro­blem of co-ordinating civil and military use of the air­space during large-scale NATO and national air exercises, which, it was known, had caused severe disruption of civil operations over large areas. It defined a set of procedures to this end which have since, in the light of experience, been further refined to meet as nearly as possible the requirements of all the users of the airspace - that is to say safe, economic ond flexible conditions of operation for all.

Civil/military co-ordination in this specific field has gradually become a routine matter and can be briefly described as follows: National and NATO exercise plan­ners provide CEAC with an outline plan of programmed exercises affecting civil aviation and ATC; this is done well in advance of detailed planning (frequently up to a year before the exercise); ad hoe working groups with representatives from all the organisations concerned are then set up; these working groups meet as necessary (nor­mally once or twice) to formulate joint plans, which are subsequently issued by nations in Notices to Airmen de­scribing the exercise area and times, and the measui-es to be taken by exercise and non-exercise aircraft as well as by the control organisations. The objectives are, ago in, to ensure all users safety from collision and optimum free­dom of movement during the exercise.

Other Committee studies have dealt with abolition of or readjustment of restricted areas; adjustment of climb­out and descent paths; and amendment of airfield siting plans to avoid areas of high density.

Studies of problems in ce1·tain high density areas, not· ably in North Eastern France and Germany where up to

23

1,200 military sorties per day create temporary intense congestion, have led to the establishment of joint civil/ military Control Centres and joint use of radars for moni­toring of all traffic and suggestions for the resolution of conflicting traffic situations.

Procedures have been agreed for: a) crossing of Airways by military aircraft under

radar control, and for b) reporting and examination of near-miss inci­

dents . Rules for flight in bad weather more restrictive than

!CAO rules but more suitable for European conditions have been recommended by the Committee and adopted by users.

lnteri.m proce?ures for routing and control of the very substantial and increasing volume of low level traffic in th~ Channel area have been agreed and are being ap­plied. A long-term solution to this problem is now under study.

Navigational aid and associated frequency require­ments have been co-ordinated in one overall plan for the entire area.

Currently, joint problems associated with the introduc­tion of SSR are under study in an expert working group. This study is primarily concerned with measures to avoid interference between system; and with joint or compatible procedures, terminology and Mode/Code allocations.

Initially the problem of co-ordinating civil and military use of airspace and control of traffic was largely related to the lower airspace. However, as civil high performance jet transport aircraft were employed in increasing num­bers in the upper airspace, which for a long time had been used almost exclusively by military aircraft, the problems of co-ordination became more exacting.

It was recognised by all that the volume and speed of traffic precludes reliance on the principle of "see and be seen"; that a mere extension of lower airspace and ATC organisation and procedures to the upper airspace would be inadequate; and that a joint civil/military study of measures to cope with this problem wos needed. Accord­ingly, CEAC set up a Sub-Committee to study the upper airspace structure, the procedures and control organisa­tions required to serve this structure, and possible joint use of equipment with a view to introducing in due course a comprehensive solution satisfactory to all users and to make improvements progressively meanwhile.

The first phase of the Sub-Committee's studies has been to define some basic principles - or criteria - which on the one hand would be wide enough to accommodate the diverse requirements of the area as a whole, and on the other hand would contribute to bringing about the re­quired degree of alignment of plans throughout the area already in the early planning stages. These principles have now been agreed to by all the administrations res­ponsible for planning.

The substance of these principles can be summarised

as follows:

24

a) all airspace should be made available to all users in accordance with agreed joint proce­dures - as opposed to the policy of segregation of civil and military traffic applied in the lower

airspace; b) all traffic, military as well as civil, with certain

exceptions, should be subject to Air Traffic Con­

trol;

c) common or compatible regulations and proce­dures should be applied in the control systems;

d) and maximum joint use should be made of equipment and facilities to avoid unwarranted

duplication. (On this last point - data acquisition systems and the possibility of joint use of these obvious­

ly merits study.) To some, these principles may seem rath.er elem.entary

and obvious. To those who are well aquainted with the problems of providing control system~, regulations and procedures which will satisfy the requirements of ev~r~­thing from a puddle-jumper to a Mach 3 aeroplane, 1t 1s clear that they constitute a drastic change from the past and that it is going to take a considerable time and effort

to implement them. The second phase of the studies will be to ensure com-

patibility of national, EUROCONTROL and NATC? plan.s and procedures when these have been developed in suffi­cient detail. However, such factors as volume and type of traffic and national organisational arrangements v?ry considerably throughout the area and system require­ments will naturally differ accordingly. There is, neverthe­less, 0 requirement for a degree of technical compatibility of civil and military systems within the various control areas, as well as between these, in order to facilitate ex­change of data between units for co-ordination of ATC and far identification. Conversion between incompatible systems could be difficult and expensive where semi-auto­matic or automatic equipment is involved.

There is also an obvious need for standardisation, or as a minimum, compatibility of some civil and military procedures throughout the area - both in the air and on the ground - to facilitate an expeditious movement and co-ordinated control of traffic. A major difficulty here stems from the existence of so many different categories of traffic with different procedural requirements. A case in point is operational and general air traffic.

The two-phased method of study adopted has the following advantages:

a) planning will, throughout the area, be based on a common concept for the joint use of airspace and control of traffic;

b) it will be carried out by existing administrations and organisations with an intimate knowledge of conditions peculiar to their area of responsi­bility;

c) co-ordination of procedures and compatibility of systems will be studied only in such detail as necessary - but not as an end in itself;

d) and last but not least, there will be no duplica­tion of work which has already been, or can more appropriately be, undertaken by other organisations than CEAC.

In conclusion, I would like to state as a personal opinion, that perhaps the most important result of the CEAC activities has been to contribute to a common understanding of the many complex problems involved in accommodating - in the same airspace - both general and military air traffic with widely varying objectives and operational characteristics - and that this in turn will facilitate joint arrangements for optimum use of the air­space and effective control of traffic with maximum eco­nomy of effort to the advantage of oil users and control organisations.

FAA/BFS Symposium on Air Traffic Control

in Frankfurt

On December 12th, 1963, the European Research and Development Office of the U.S. Federal Aviation Agency, together with the Bundesanstalt Hir Flugsicherung (BFS -Federal Institute for Air Navigation Services) held a sym­posium on air traffic control in Frankfurt, Germany.

Purpose of the meeting was to inform the attendants on the present A. T. C. system in the USA, to give an out­look on future plans, and to discuss common problems.

Aside of the FAA, MOT, and BFS officials a number of civil and military aviation experts participated in the meeting: Dr.-lng. Kramar, Dr.-lng. Zetzmann, Col. Mieth, Dr. Karwarth, to mention just a few well known names.

Opening the meeting the President of the Bundesan­stalt Hir Flugsicherung, Dr.-lng. Heer, expressed his grati-

FAA Plans for Air Traffic Control

Air traffic control in the USA is, of course, exercised within designated control areas and control zones. FAA is responsible for the control of all IFR traffic, civil and military, in these areas, but authority has been delegated to military facilities to control terminal IFR traffic at cer­tain bases where military personnel meet prescribed FAA

standards of proficiency.

Airport control zones, which extend upward from the surface, are usually five miles in radius. There are also transition areas of about 15 miles radius, which extend upward from 700 feet above the surface where there is no control tower but where an instrument approach

procedure has been authorized, and from 1200 feet up­ward when designated to complement a contr~I ~one. T_he upper limit of a transition area normally co1nc1des with

the base of the overlying control area.

As to airways, there are three systems i~ the Un~ted States: the basic or low altitude network, the 1ntermed1ate altitude airway structure and the high altitude or jet route

structure.

The basic airway network is made up of 10 mile-wi~e airways, usually extending from 1200' above the terrain or 500' below the minimum instrument altitude, whichever is higher, to an altitude of 14,500' MSL. This network is designed to accommodate primarily short haul, low-level

operations.

Flights may be made under either Visual Flight Rules (VFR) or Instrument Flight Rules (IFR) conditions in the basic airway system, depending on weather and pil_ot preference. Air traffic control service is provided to air­craft operating in accordance with IFR, i. e. on instrument flight plans, on these airways, but no separation nor ad­visory service is given to VFR flights. Off the airways, no control service is given to either IFR or VFR flights, but all flights are required to observe certain cruising altitude rules designed to afford basic separation according to direction of flight.

tude to the FAA and made it a point of his adress that close international cooperation in air traffic control mat­ters is required if the tasks lying ahead shall be mastered.

Mr. Ralph F. Link, Chief of FAA's European R&D office presented a survey on the organisation of the Federal Avia­tion Agency and its R&D branch office in London. He then introduced some of the R&D staff personnel of FAA in Europe: Mr. Frank Cervenka, FAA Liaison Officer with BFS in Frankfurt, Mr. Lyle H. Ditzler from the London office, and Mr. Barkalow, also a member of the London office, and mainly dealing with automatic landing and secondary radar. They all contributed their share to the symposium, yet we are mainly basing our report on Mr. Ditzler's lecture, as we consider it to be the principal part of the briefing.

Lyle H. Ditzler

From 14,500' upward, all airspace above the conter­minous United States, other than within prohibited and resticted areas, is designated as control area. Within this area, which is known as the Continental Control Area, there exists between 14,500 feet and 24,000 feet the net­work called the intermediate route structure, made up of e_xpress routes, sixteen miles wide, designed to serve medium and long range operations. These routes are, of course, more direct than the low altitude airways.

From 24,000' upward there is the third network, the jet route structure, which is specifically designed to accom­modate long range operations.

Since the jet route structure exists wholly within con­trolled airspace (the Continental Control Area) these rou­tes have no defined width. They are merely lines drawn on the charts and named and numbered to assist pilots in flight planning and controllers in issuing clearances. The only limitation on route planning for those pilots not wishing to use the designated routes is that they must select navigation aids which are not more than 200 miles apart if they wil I fly between 14,500 feet and 24,000 feet, and 300 nautical miles apart if they will fly above 24,000'.

All three route networks are based primarily on VOR and YORTAC navigation aids which are spaced about 90 statute miles apart in the low altitude structure, 180 miles apart in the intermediate structure and 360 miles apart in the jet route structure. Some of these aids are used in one airway system only; others are used in two of the systems; and still others are common to all th1·ee networks.

Considerntion is now being given to reducing the three-layer system to two networks in order to ease the controller coordination problem and take r-ecognition of the changing altitude requi1·ements of present-day 011·­

craft. It is proposed that the intermediate altitude struc­ture be eliminated, the ceiling of the low-altitude airway system be moved up to 18000 feet and the floor- of the jet route structure be !ower-ed to this same altitude. At the

25

same time, the top of the jetroute structure would be placed at FL 450, above which aircraft would be given more freedom of operation in respect to random or area type operations utilizing a minimum number of designated ground navigation aids.

Within the Continental Control Area there are certain "positive controlled routes" and positive control areas, wherein all aircraft are required to file a flight plan and obtain an air traffic control clearance, regardless of wea­ther conditions. Except for these routes and areas, aircraft operating in the Continental Control Area may fly either YFR or IFR, depending on weather or pilot preference, but only IFR flights are separated from each other by air traf­fic control. However, YFR flights must be made with higher visibility and proximity-to-cloud minima than are per­mitted below 14,500 feet, and they must observe the rules governing altitude for direction of flight. Up to 24,000 feet, altimeters are set to station settings; above 24,000 feet they are set to 29.92 and cruising altitudes are stated as flight levels.

In order to appreciate our plan for making certain changes in this organization of the airspace, it is neces­sary to have some idea of the types and amount of air traffic.

Perhaps the most significant difference between Euro­pean and U.S. air traffic is the predominance of general aviation, that is, of private and executive aircraft, in the U.S. General aviation aircraft now number about 80,000, compared to on air carrier fleet of about 2,100 and a mili­tary fleet of about 22,000. In terms of total flying hours, the general aviation category accounts for almost 500/o, with the military making up about 36% and the airlines approximately 140/o of the remainder. However, in terms of instrument operations, general aviation is on the low end, accounting for only about 100/o of the total as con­trasted to 300/o for the military and 600/o for the ~irlines.

It is interesting to note how this traffic is distributed by altitude. On a typical day in the U.S., the bulk of all fly­ing will be operating between 2,000 feet and 8,000 feet, but the altitude distributions of the various user groups differ. The greatest density of air-carrier traffic is between 4,000 feet and 10,000 feet above terrain. The most-used general aviation altitudes ore from 2,000 feet and 7,000 feet above terrain. The military operates in three distinct altitude bonds, with a large number of helicopter flights below 3,000 feet and the remainder of activity concen­trated between 2,000 feet and 11,000 feet and above 24,000 feet. Taking IFR traffic only, there ore two distinct altitude groupings - the largest being between 2,000 feet and 14,000 feet, and the other between 18,000 feet and 36,000 feet.

The forecast traffic picture is one of greater concentra­tion in an altitude band extending from about 3,000 feet to 8,000 feet above terrain. This region has not only the greatest number of aircraft, the wides: range of ~pe~ds, the poorest visibilities and greatest mixture of c\1mb1ng, descending and straight and level flying, but also the greatest variety of airborne e~uipment. A pilot's ability to maintain "see and be seen separation is, of course, very difficult because of these factors.

At high altitudes, the traffic is less dense, but we have the problem of aircraft travelling at such high speeds that there is too little time for a pilot to detect another aircraft on a collision course and take the proper evasive action, even though the visibility may be excellent.

26

In our opinion, the best way to minize these factors is through positive control, and we have taken a number of steps to establish such an environment in the U.S. The first of these was taken in October 1958, when the first airline Boeing 707s began scheduled operation in the U.S. A_ll routes used by these (and subsequently DC8 and Conva1r 880) aircraft were designated as civil jet advisory routes, and every flight of a civil air carrier turbojet was fol!owed on radar by our controllers. Traffic advisories were issued and collision avoidance vectors provided whenever neces­sary. This service was started in recognition ~f the di.ffi­culty of pilots of high speed, high altitude flights being able "to see and be seen" in on environment where there was a mixture of YFR and IFR flight activity.

The service is only a partial step toward safety f~r military and civil aircraft flying at high altit~des, and it was recognized that a situation in which all aircraft were under control at all times, regardless of weather, _w_as necessary. Therefore, in October 1960, an area po~ihve

· h Ch' nd lnd1ano-control evaluation was begun 1n t e 1cago a . po/is Center Areas, comprising about 110,000 square miles, wherein all aircraft operating between 24,000 feet a;d FL 350 were required to be on an IFR flight pion and un. er

· II d "Operation control at all times. This evaluation, ea e ... 1 Pathfinder" was a success, although there was s.ome ihnih~

f th Ttary services t at it apprehension on the part o e m1 1 . might restrict their missions. Plans were laid for ex~adnsdi~n

· · being prov1 e in of the program and the service 1s now the Cleveland, Detroit and Oakland Center areas .a.s well as the Indianapolis and Chicago areas, with a c:iling. of FL 600 and a floor of 24,000 feet. The progrn'.11. 1s being expanded as rapidly as resources permit, and it is :xpec­ted that by September of next year (1963) al I OJ re raft operating between 24,000 feet an·d· FL 600 above the con­terminous U.S. will be under pos1t1ve control.

This program is only possible through the application of radar and the use of radar beacon decoders and radar bright display equipment. Airborne . equipment re~uire­ment-s are simply that the aircraft be instrument equipped and have a coded beacon transponder. YFR flights are prohibited. As indicated before, aircraft can operate a­long designated routes or fly on random courses as long as navigation aids no more than 300 nautical miles apart are selected to define the route of flight. The service is designed to allow for military operations such as test fly­ing, radar bomb scoring, training, in-flight refuelling, etc., and segregation of activities in special areas is avoided except for special missions such as air-to-air gunnery, which con be accommodated in no other way.

Although we instituted a positive control program first for the upper airspace, we hove been concerned also with collision hazards which exist around busy airports, where many different types of aircraft with a wide range of per­formance characteristics must operate in a very restricted amount of airspace. Therefore, in December of this year (1962), an evaluation was begun at Atlanta Airport, At­lanta, Ga., to determine the feasibility of providing posi­tive separation to oil aircraft within a terminal area. The area within which the service applies is roughly from the surface to 6,000 feet within 5 miles of the Atlanta Airport, and from 2,000 feet to 6,000 feet between 5 and 15 miles from the airport. The radio call-up area for inbound air­craft extends to approximately 25 miles from the airport, the whole area being divided equally into North and South sectors by a line running East and West through Atlanta.

A separate frequency is used for each of these sectors, and an aircraft remains on the appropriate frequency, either VHF or UHF, until it departs the area or is handed off to the tower controller about two miles from the run­way. An aircraft going through the area and not landing stays on this initial call-up frequency all the way unless heavy traffic necessitates switching to the other sector frequency, the object of course, being to eliminate re­

tuning for the pilot. Radar separation is given to every aircraft entering or

leaving the designated area, with VFR or IFR arrivals and departures being sequenced in many instances to make maximum use of the airport surface and the surrounding airspace. In order to ease the controller's radar identifica­tion of VFR flights, a number of geographical fixes which arn conspicuous landmarks, easy for the pilot to see and the controller to pinpoint on his display, have been set up.

It should be mentioned that the designated service area contains three other airports in addition to Atlanta, and that Atlanta Airport alone had over 215,000 opera­tions last year, 140,000 of which were IFR. No small job

is involved for the Atlanta controllers. To assist in the task, the Atlanta IFR Room and Tower

are equipped with radar bright display equipment of the scan conversion type. These displays, of which the IFR Room has three and the tower cab one, consist of 22 inch horizontal scopes, on which the widely known "shrimp boats" or target markers can be placed beside the radar blips for tracking each flight. No special airborne equip­ment is required other than two-way radio, which is man­datory for operation at any airport served by an FAA tower.

While the Atlanta service is termed an "evaluation", there is every expectation that the program will be suc­cessful and will be expanded to include other high acti­vity terminals. One of the things being evaluated at At­lanta is the requirement for aircraft operating in a ter­minal area positive control environment to be equipped with secondary surveillance radar, i. e., the radar trans­ponder or "beacon". However, with or without SSR, FAA

regards the program begun at Atlanta as a big ~tep fo~­ward in improving the safety and efficiency of air traffic

control within busy terminal areas.

Having described the present organization of the air­space in the U.S. and explained some of the air traffic control services being performed, I should like now to go on to the airspace environment proposed for the future.

Although FAA is taking large steps toward positive control, it is recognized that positive control cannot be applied in all airspace because of cost factors and the airborne equipment requirements that would be placed on aircraft owners. Therefore, we are planning to estab­lish positive control in portions of the airspace, and in other controlled airspace to provide other types of sepa­ration service to non-instrument rated pilots and non­instrument equipped aircraft in order to improve the safety and efficiency of these operations as well as IFR operations.

It is envisioned that enroute controlled airspace will be divided into positive control areas, control areas, air­ways and high activity airways. High activity ai1·ways will contain positive control and non-positive control ai1·way segments. Each specific airspace configuration will be de­signated according to criteria that will be based on traf­fic density and speed distributions.

The base of the upper positive control area overlying the conterminous United States will be on the order of 14,500 feet East of the Rocky Mountains and somewhat higher over them. Positive control airway segments and positive control terminal corridors will link this airspace to positive control terminal areas.

Above 24,000 feet only IFR operations will be permit­ted. In other positive control areas and airway segments, the system will provide for both IFR and Controlled Visual Rules (CVR) operation. In the remaining controlled air­space (control area and airways), another class of flight, Controlled Visual Flight Rules (CVFR), will be added to the existing IFR and YFR operation, enabling YFR pilots to receive traffic separation service in the enroute en­vironment.

Perhaps it would be well at this point to explain a significant difference between the present and proposed concepts of positive control. As I have explained, there are now routes and upper airspace areas in the U.S. with­in which YFR flight is prohibited. The system of the future on the other hand, incorporates the type of flight called CYR, which stands for "Controlled Visual Rules", which could be conducted by pilots not IFR rated or pilots fly­ing aircraft not IFR equipped. These aircraft would be provided separation from other CYR flights and from IFR flights, but the pilots would maintain the attitude of their aircraft visually rather than by reference to instru­ments.

You will note that the abbreviation "CVFR" is also used. The distinction between CVR and CYFR is simply that the former is used in connection with positive control airspace, while CVFR is associated with controlled air­space which is not positive control area. In either case, the term applies to flights being made visually with cer­tain visibility and proximity-to-cloud minima, under air traffic control jurisdiction and separated from each other and from IFR flights.

. The theory behind this organization of the airspace 1s somewhat as follows.

The positive control areas will of course eliminate ,, d ' ' see an be seen" separation at high altitudes and on

certain high density airways where high speeds or the volume of traffic would make dependence on the eyes and reaction time of the pilots to avoid collision a risky business. On high activity airways, however, provision is made for flight at the lower altitudes by the YFR pilot who cannot or does not desire to fly CVFR. "See and be seen" operation would be permitted here because the sp.eed limit and increased visibility and proximity-to-cloud min'.ma would improve the ability of pilots to see and avoid other aircraft. YFR airspace that is most of the air-

b [ ' ' space e1ow about 2,000 feet above terrain except around terminals.' would be reserved for YFR operations exclu­sively, with no I FR operations permitted.

Now, let us have a look at the proposed organization of the airspace around terminals.

Wherever a terminal positive control mea is designa­ted, the airspace structure between terminal entry points and the airport will contain stepped corridors of positive control airspace centered on the route structure previous­ly described. In the immediate vicinity of the principal ai1·port, positive control ai 1·space will be designated on an mea basis to a distance of 15 to 25 miles from the airport. At this distance the area type positive control airspace will end, giving way to the stepped co1·ridors.

27

Within about 5 miles of the airport, the positive control airspace will go down to the surface. Beyond, the base will be 700 feet above the surface, stepped upward at greater distances.

The 700 foot or higher base of the terminal positive control area will allow flights to be made to and from smaller airports in the vicinity without entering positive control airspace. To the extent possible, VFR airspace will be cut out of the 5 mile radius positive control zone sur­rounding the principal airport to allow uncontrolled ope­rations at smaller airports inside that radius.

At nonpositive control terminals with radar capability, an "airport traffic communications area" will be estab­lished within which radar control service will be furnished to all flights arriving and departing the airport served by the terminal radar facility, and to other flights requesting it. This will be IFR and CVFR service. Since not all traffic in the area will be controlled, pilots will be required to see and avoid other aircraft.

Aircraft operating in uncontrolled airspace would not be provided ATC separation service. Navigational guid­ance would be available in uncontrolled airspace only as a byproduct of the navigation system installed to serve controlled airspace.

On the low and medium activity airways, navigation and communications services would be available for all operations. Only controlled aircraft would be separated by ATC.

The highest grade of service will be provided by the designation of positive control airspace, in the form of areas and segments of high activity airways. Since only controlled aircraft are permitted to operate within these portions of airspace and since transponder equipment will be used, the ground-based air traffic control sub­system will offer the highest level of safety and service.

Perhaps it would be well to digress at this point to explain FAA plans for progressive implementation of SSR, or the ATC RBS (Air Traffic Control Radar Beacon System) as we call it.

The first phase of these plans is based on the employ­ment of 64 beacon codes, the second phase on the use of 4,096 codes.

In the first phase, we visualize an environment in which the airspace will be divided into a number of strata, such as from the surface to 6,000 feet, 6,000 feet to 15,000 feet, 15 OOO feet to 24,000 feet, etc. A group of beacon codes w~uld be assigned to each of these strata. Additionally, a code corresponding to each of these groups would be established for climb to or descent from the strata. Thus, while taxiing a pilot would set h'.s. trans~onder to the

1· b code appropriate to his cruising altitude stratum. ~1; reaching cruising altitude, he would be assigned a cruising altitude code for his a_ltitude stratum. When clea­red for descent he would be given a de.scent code appro­priate to the altitude stratum from which descent would

be made. There are several advantages to a s~heme such as this.

First, it achieves the objective of reducing th_e number of code changes a pilot must make on a long flight. Second, it enables the controller to display onl~ those responses from aircraft operating within the altitude strata over which he has jurisdiction.

The plan also aims at the use of the airbo1 rn~ i~ednti~­

cation feature as a primary aid to the contro ler 1n 1 ent1-

28

fying a particular aircraft or in accepting radar hand-

offs. . Code 77 will be reserved for use in emergency situa­

tions and other codes may be reserved for such things as radar failure and interceptor use.

The second phase of the ATCRBS plan provides for d · ft "d fty by means of reporting of altitude an a1rcra 1 en 1

the beacon, utilizing Mode 3/A for identity, Mode C !0 r altitude. The advantages of automatic altitude rep?rting

b · of course and the use of discrete aircraft are o v1ous, , identity codes will enable aircraft identification and radar hand off to be more easily automated. The ~eneral con­cept is intended to provide the controller with means of managing and reducing the data ~~ his. rad~r display t? that which pertain only to the pos1t1on'. 1den!1ty, and alti­tude of aircraft under his control or in which he has a

direct interest. It is intended that both phases of SSR implementat'.on

undergo extensive simulation and testing before be1~g placed in effect, but FAA is optimistic that the results will be good and that we shall, in the not-too-dist~nt futu~e, get away from the limitations of two-dimensional dis­play capability.

During the second part of my talk, I want to mov~ away from the airspace environment into the groun~ faci­lities and describe some of the air traffic control display and automatic data processing capabilities we hope to have in the future as a result of planning under the prin­ciples laid down in the report of the Project Beacon Task Force. Here again, it might be desirable to tell you some­thing about these elements as they are now used in our system, for they are the building blocks on which the future system is based.

As you know, our present system relies extensively on radar. Our long range radar installation program is now essentially complete, and we shall shortly have coverage from about 15,000 feet upward over the whole U.S. ex­cept for an area near the Canadian border in the north central states. In this area, we are planning to move into Air Defense Command SAGE direction centers in order to utilize the radar facilities of the USAF.

Data from the FAA and military joint-use long range radars are brought into our centers by means of micro­wave links, and displayed on the 22 inch scan conversion scopes mentioned earlier. These displays, which are the result of developments in the French television industry, have been eminently successful. The first of these equip­ments were purchased from the U.S. affiliate of Compa­gnie Generale de Telegraphie sans Fil (CSF) in 1957 and had improved definition and brightness compared to the old Navy VG, or Skiatron, horizontal repeater scope then in use. Recent bright display equipment is even better, having such features as two-second erase capability, off­centering, symbol generators and alpha-numeric capabi­lity. The big advantages of scan conversion are, of course, that the radar data, once converted to a television pre­sentation, can be seen in brightly lighted rooms, making the controller's job more pleasant and comfortable, and are capable of being portrayed with all the tricks avail­able to television. Our basic displays are horizontal, so that aircraft may be easily tracked using plastic markers, and so that a number of controllers can gather around the same presentation, thus easing the co-ordination problem. Using these displays, we have also found that the number of flight progress strips per aircraft can be greatly redu-

ced, with just enough used to indicate the flight plan (which cannot be contained completely on the small "shrimp boat") so that control may be continued by means of the tabular displays in the event radar fails.

This reference to tabular displays brings me to the subject of computers as they are used in our facilities today.

When FAA first started using digital computers in 1956, radar was not generally available to our centers nor as widely relied upon as it is today. Therefore, our efforts were directed mainly toward making the tabular displays as automatic as possible, in order to relieve controllers of the clerical task of preparing and updating flight pro­gress strips. By 1959, six of our centers in the northeast U.S. were equipped with standard, business-type electro­nic digital computers, which were used to prepare flight progress strips, complete with estimates over the various fixes along the route of flight. Additionally the six centers were connected by computer teletype circuits, so that transmission of flight plan and position information bet­ween the centers could be done automatically by the machines themselves.

Our experience to date with the use of these computer systems in operating facilities has been that they can pro­duce flight strips which are far more legible, free of cal­culation error and rapidly prepared than by human means, and we feel that they are worthwhile for these reasons at our largest centers where strip preparation workload is very great. However, we have found that, without the ability of the controller to update the flight plan information contained in the computer memory, the system is much restricted in usefulness.

When we first planned our computer installations, we considered that, to be truly efficient, the systems should be capable of accepting flight plans from airline an? military operations offices and process them automati­cally. Also, we wanted the controller to have the ability to update information in the computer, e. g., to insert changes of altitude, route etc., during the progress of a flight.

When we get these features, our automation pr~gra~ will become about as advanced as we feel is practical in

its present phase, that is, in the production of tabular dis­plays which utilize flight progress strips. We do not be­lieve in mechanizing the present flight progress boards.

So much for our current displays and automation equipment. In the final part of my talk, I should like to describe how these elements are expected to fit in to the future system as envisioned in the National Airspace Utili­zation System design, based on the principles set forth in the Project Beacon Task Force Report.

In June of this year the System Design Team of FAA completed the first edition of the long-range plan for a national airspace utilization system. Note that I say "first edition". Although it is considered that the fundamentals on which the design is based will remain essentially the same, in any field as dynamic as aviation a plan cannot be static but must be revised continually in the light of changing requirements and improved technology. There­fore, it is to be expected that the plan will grow and evolve with changing conditions, and you should bear in mind that what I shall describe is somewhat tentative, pending completion of our engineering model and the simulation and other evaluations which are contemplated.

It is planned that air traffic control displays consist of two basic types, plan view displays and tabular displays. First, let us examine the nature of the plan view displays.

The plan view display will be a bright flicker-free tele­vision type display, provided at each active control posi­tion to present a filtered plan view of all controlled traf­fic. The display will be capable of generating a combined picture from several radars, thus making it possible to use sector boundaries independent of radar locations. Data appearing on the display will consist of primary and secondary radar targets, or processed data from the com­puter, or a micture of radar and computer-generated data.

Since the problem of plan view displays is one of intro­ducing too much information onto the display, the con­troller will be provided with function keys to allow him to select the information he desires. However, certain in­formation relating to control actions that he must carry out to prevent a dangerous siuation from developing will be presented as a "forced" display. Forced displays in­clude outlines of severe weather, e. g., turbulence or icing; data on aircraft involved in the need to resolve a conflict or to hand-off, or adjust flight path; and symbols identi~ fying the position of the aircraft.

Selectable data include video maps, primary radar targets, route indicators, rectangles around each target representing separation criteria, and special information on such things as cloud levels.

In addition to these controls, the display console will be provided with function keys for beacon decoding, tracking, gate assignment, and updating the computer, together with a "joy stick" handoff and position reporting device.

Radar and the computer will work together to gene­rate the display, with primary and secondary radar data '.rom a number of separate radars being fed into a radar inputs processor, which derives the radar position, and the computer relating this position to the appropriate flight plan. Where radar track data are available, alpha­numeric information concerning identity, altitude, etc. will be presented adjacent to the actual radar track. When radar track data are not available, the aircraft position will be estimated by the computer from the flight plan and shown on the display, with the alpha-numeric data adjacent to it.

Flight plan updating, that is, keeping the flight plan information in the computer current with the actual status of a flight, will be done by the controller. He will insert changes of altitude, route, etc. in the computer by means of his function keys, in accordance with the control in­structions issued as a result of his own decisions or be­cause of a pilot request.

Tabular displays are expected to be of two types -one to be used at the active control consoles in conjunc­tion with the plan view display, the other to be used pri­marily for planning in respect to future traffic buildups, distribution of workload, long-range resolution of pos­sible traffic conflicts and center-to-center and center-to­terminal co-ordination, and what we have come to know as "flow control".

The first of these tabular displays is a "call-up" type of display, whereby the controller at the active display console may display the traffic presently in his sector and predicted traffic that will enter in the next five minutes either in altitude or time sequence, or in sequence of time of entry, at his option. His tabular display will provide

29

advance warning of incoming traffic, o picture of the present load, a method of quickly determining whether an altitude or route change is the best way of resolving a conflict, and a backup capability in case of loss of his plan view display. For those sectors where holding stacks are required, a holding stack posting board will be pro­vided, interlocked with the appropriate terminal area and arrival sequencing control consoles.

The tabular displays for planning will be of three types - one for the flow controller showing terminal traffic, sector traffic, flow control orders and diversion orders· another for the enroute planning controller containin~ data on future flights and traffic at major route intersec­tions, and a function keyboard for reroutes, altitude chan­ges and clearance issuance and a third for terminal area planning control, which will be done on a centralized basis for all airports within a multiple terminal area.

Near each of the planning tabular display consoles will be a "hard copy" printer, which will print out at periodic intervals such data as weather sequences, fore­casts, winds aloft reports and NOTAMS.

I have thrown quite a bit of technical information on displays at you rather fast, and perhaps it would help to put this information in perspective if I outlined briefly the operational concept within which they will function.

The system design contemplates that flight plans will be received by voice, teletypewriter or special data iink between facilities. Flight plans received by voice will be entered into the computer by an operator using a key­board entry device. Others will be fed directly into the computer.

All flight plans entering the computer will be broken down into route segments based on fixes, and estimates over these fixes will be calculated by the computer based on true air speeds, wind data and climb and descent pro­files. Based on this information, a position wiii be calcu­lated for all active flights and portrayed on the plan

view displays.

The extrapolated flight plan position will be correlated with the appropriate radar target either manually by the controller, or made available to the radar processor, which will automatically correlate the two targets by showing the proper format adjacent to the appropriate target. The use of beacon identit_y_ and al_titude informa­tion will, of course, greatly fac1l1tate this process and provide automatic track maintenance.

Actual control would be exercised by the two types of controllers - the planning controller, responsible over

0 large area for reducing potential traffic conflicts through organization of the flow of traffic, and the active con­troller, responsible in relatively small areas for spot reso­

lution of traffic conflicts. For both advance planning and active control, the

computer will be required to perform confli~t probes on each flight entering the system and on _each flight that h~s required an update action to .determine 1f a change 1n flight plan or clearance is required. In the later stages of

automation, it is planned that the computer assist con­trollers by recommending solutions for the problems 1t has detected. It is also contemplated that the computer be programmed to institute flow control on a center area

and later on a nationwide bas is.

~ince ;he system depends on extensive _radar cover­age, many control transfers will be accomplished using a

30

positive transfer of control action, with automatic radar handoff. The computer will be required to initiate a trans­fer of control by generating a hand-off symbol adjacent to the proper target on the displays of both controllers. The transferring controller will use a push button to indi­cate to the receiving controller through his tabular display that he has initiated the handoff. Also, the computer will display to the receiving controller the present flight plan position. A pushbutton action by the receiving controller will signify he has accepted control, and the alert signal

and symbol will be erased on both displays. The terminal area controller will have a tabular diplay

showing all proposed departures and arrivals. To assist him in his task, the computer will transmit information on incoming aircraft, including identification, type and esti­mated time of arrival at the runway threshold. The com­puter will sequence the order of take offs and landings, the estimated time of arrival for on aircraft being used by the computer to determine any delay which must be absorbed enroute or during descent.

When the aircraft approaches the terminal entry fix, and automatic handoff will be initiated to the sequence controller on his pion view display, and the computer will maintain automatic tracking on the target and indi­cate the time the flight is to leave the entry fix. As the flight proceeds on the descent path, the computer will monitor its progress relative to the planned arrival time, determine any deviations from the desired flight path, and indicate to the controller the required speed changes, resequencing, or track changes.

In very condensed form, that is the system of data acquisition, processing and display, based on radar and automation, that FAA is planning. You are probably won­dering how much it will cost and when we expect to hove it in operation.

At present I can't answer the first question accurately, but we do expect that the system can be implemented if we receive about the same annual budget for research, development, procurement and installation we are now getting.

As to "when", o schedule hos been set up to hove on engineering model of the basic system working at our evaluation center at Atlantic City by January 1964. There­after, six progressive implementation stages hove been established, starting in the first stage with modification of our present radar bright display equipment to generate information from several different radars on a single dis­play. The joystick video marker will also be installed at this stage. The next stage will provide digital readout of beacon code altitude and plan position co-ordinates for display generation. These first two stages, since they in­volve modification of existing or planned equipment, are expected to start by January l, 1964. Stage 3, which will give us alpha-numeric capability on our displays, is sche­duled to start in the middle of 1964. The three remaining stages, data processing and display inter-connection, radar tracking and the tabular displays, are to be ready for installation by the autumn of 1965.

It is not proposed that all of the features be installed at each location. For example, some facilities will require only improved display capability and no data processing capability. The implementation plan will take account of the fact that installation of a given element will depend partly on technical need and partly on the relative costs and benefits to be derived.

The discussion which arose after the lectures mainly concentrated on such subjects as Secondary Radar, IFR vs. CVR and CVFR, with particular emphasis on the point whether the U.S. will propose to ICAO at the RAC/OPS meeting to adopt a similar system, administration of ATC facilities in the U.S., human factors in ATC, integration of civil and military air traffic, with a particular view on the conditions in Europe.

Regierungsbaudirektor Glunz, Chief of ATC in the Ger­man Ministry of Transport, lectured on the latter subject and presented a survey on the present situation in regard to the EUROCONTROL Association. He mentioned that

"Rhein Control", the air traffic control center responsible for controlling upper airspace traffic in the central and southern part of the Federal Republic of Germany, will be one of the first facilities to be taken over by EUROCONTROL. Mr. Glunz then expressed his thanks to the FAA representatives for their cooperation and indi­cated that the exchange of ideas and experiences be­tween the U.S. and the German ATC administrations un­doubtedly has proved to be benefical to both parties.

Mr. and Mrs. Cervenka highlighted the day with a splendid reception, on behalf of FAA being host to the ATC experts who then, after all, diverted from the subject af Air Traffic Control.

Greek and Japanese ATCA's founded,

ATCO's in Central Africa to found and Association too

Nikolaos Ganos the President of the Air Traffic Controll ers Association

of Greece. '

Our hearty congratulations go to our Greek and Japa­nese fellow controllers who during late 1962 and early 1963 have succeeded in establishing officially their own air traffic controllers associations. The details are as fol­lows:

Air Traffic Controllers Association of Greece provisionally founded on October 16, 1961 fully legitimized on December 17, 1962 Administrative Council formed on January 17, 1963

President: Mr. Nikolaos Gonos

Address :

Air T roffic Controllers Association of Greece Aerodrome Control Tower Athinai Airport Ellinikon - Athinai Greece

Air Traffic Control Association Japan founded on May 20, 1962 ' President : Mr. Tan Hayashi

Address :

Air Traffic Control Association , Japan c/o Civil Aviation Bureau 1 - Otemachi, Chiyoda-ku Tokyo, Japan

Both associations have expressed th eir intention to join IFATCA at the earliest possible date and the subj ect will , undoubtedly, be given fa vourable attention at the IFATCA Annual Conference in London, which w ill take place from March 29th till May 2nd.

Meanwhile, the Secretar iat has had extensive corres­pondence with the Air Traffic Control A ssocia t ion of New Zealand, and with AECA and ACTAU, the nat ional asso­ciations of Argentina and U;·uguay. These associa tions are strongly interested in becoming IFATCA members, too, and it is hoped that they w ill be able to del egate observers to the London Conference.

We have also noted w ith grea t pl easure tha t th e A ir Traffic Control Officers of Central Africa are about to form a local associatio n. Th e ina ugu ra l meet in g w ill be held at the end of March, an d it is th e intent io n of the interim committee to apply fo r a ff i l iat ion to IFATCA . The association will be representi ng abou t 950/o o f the ATCO's in that area. Congratul at ions I

31

The following is an extract from Working Paper 101, 19/11/62, Corrigendum No. 2, 28/11 /62,

Limited European-Mediterranean COM (AFTN) M · 1962 eehng,

When required the following definitions may b d t I ("f d · e assu-

me . o ap~ y . I es1rable) in conjunction with WP/101 and its derivatives, only when necessary 1 th"

· I h · · · n is context opt10. na c o1ce is left to the administrat"1ons d A II . concerne .

t _o other times these definitions are obligatory and o~t1onal and should be used with discretion and random with equal care.

Definitions

It's in process: So wrapped up 1n red tape that the situa­tion is aimost hopeless.

A program: Any assignment that can't be completed by one phone call.

Expedite: To confound confusion with commotion.

Channels: The trail left by inter-office memos.

Coordinator: The guy who has a desk between two ex­pediters.

Expert: Any ordinary guy with a briefcase more than 50 miles from home. '

Informed source: The guy you just met.

Reliable source: The guy who told the guy you just met.

Unimpeachable source. The guy who started the rumor in the first place.

To activate: To make carbons and add more names to the memo.

To implement a program: Hire more people and expand the office.

Under consideration: We're looking in the files for it.

Meeting: A mass mulling by master-minds.

Conference: A place where a conversation rs substituted for labour and thought.

Panel: A conference of experts.

Here are some morn fine definitions which we picked up

recently:

Air traffic: A concentration of numerous aircraft over a given point, each demanding the same route and altitude and each having special prio1·ity.

32

ATC clearance: A verbal method of compelling a pilot to fly a route and altitude he otherwise would never have chosen.

ATC controller: An individual (subsidized by the railroads) and consecrated to the task of discouraging travel by air.

Airway: A route so designated by CAA that neither pilot nor ATC can find it on the charts.

Approach sequence: A means devised by ATC to make a pilot land last when he knows all along that he should be first.

Approach time: The time given the pilot to make him happy while attempts are made to figure out what to do with him.

Basic VFR mm1mums: Those weather conditions under which a chicken can clear a low fence while maintaining satisfactory forward visibility.

Center: Drafty, ii I-kept barn-like structure in which govern­ment pensioners congregate for doubious reasons.

Competent authority: Accredited individuals who have finished the third grade.

Control area: Air space in which only one center has authority to disrupt the flow of traffic.

Cruising altitude: Any altitude other than the altitude re­quested by the pilot, - or any altitude maintained by the pilot other than the altitude last approved by ATC!

Departure time: The time take-off is permitted by th tower after all other aircraft on the field have departed~ Flight plan: Any information filed by the pilot which com­munication can manage to lose or otherwise withhold from ATC!

Holding pattern: Laughable terms applied to the do fi ht . th d' f ·1· g g 1n progress over e ra 10 ac1 1ty serving a terminal air-port.

Reporting point: Is a location over wh;ch p'ilot · . . . . • s occas10-na lly v~rify their pos1t_1on during clear weather (Note: It 1s considered unsporting to report over s h · · . . . uc pos 1tions within five minutes of estimated time!).

Request for start-up clearance: Trigger for othe · t -1 d . r 1e p1 ots

to a v1se the tower that they have just started their en­gines and request IFR clearance now.

Separation: Procedure to prevent confliction f b · · .s rom e-coming known. Typical examples: Frequency Se ·

h fl . . . f paration, w en con 1cting mrcra t are being handled d'ff . on 1 erent frequencies; Pocket Separation when cont I t · f . . . . ' ro s rips o conflicting traffic are being preserved in the k t . . poc e. Know some more? Write to

Joe Chatterbox

Aviation Writers meet with Avionics Industry

In late December 1962 TELEFUNKEN, one of the lead­ing electronic firms in Germany, hat invited the editors of major German aviation publications to a symposium on air traffic control and air navigation equipment. It was intended as a platform for discussion of questions regard­ing present day and future R & D activities in the field of air- and space navigation.

Opening the meeting, Dr. Heinrich Bruckmann, Ma­naging Director of TELEFUNKEN's Equipment Division, reviewed the historical development of the electronics industry in Germany. In this context it was interesting to learn that during the last war 15 OOO airborne radar sets and about 6000 fire control radars of various types had been built in Germany, among them about 1500 of the well known "WOrzburg-Riese".

A number of papers were presented during the con­ference and discussed at length. Main topics covered: Future Equipment Design in Air- and Space Navigation, by Dr.-lng. Paul Kotowski, Managing Director, Research and Development HF and VHF equipment, Automatic Air­Ground-Air Data Link systems, by Johannes Emser, The PHI Airborne Navigation System, by Horst Brendes, Ra­dar Data Link System, by Dr.-lng. Jurgen Stelter.

Unfortunately, there was only little mention of TELE­FUNKEN's activities in the computer field. This firm has developed the TR4 general purpose computer which will also be utilized by the German ATC authorities.

Dr. Kotowski, in his address, described the bearing of technical developments on the economy, and we a~e quoting an extract thereof as we consider it to be valid not only for Germany but in every industrial state. "New developments result from unsatisfied requirements and new ideas. Yet, these by themselves do not justify the

ICAO Meetings 1963

Meeting

expense of a design programm. Taking into account pure­ly commercial considerations, expenditure is governed by the possible profit to be gained from new, improved equipment. Thus, the expenses for research and develop­ment appear to be excessively high, if one looks at air­and space navigation.

In the past, the number of R & D personnel was a small proportion of those employed by industry. Today there are, particularly in the United States, whole industries and divisions of large companies, mainly in the field of aero­space equipment which don't live from production but from research and development.

The main purpose of this industry is to continously develop new technology and new equipment.

It is, therefore, an attractive and worthwhile task to think about the future German aerospace equipment tech­nology, which, after the pause following the war begins to recover in the Federal Republic of Germany. When we shall investigate this area now, applying some specific examples, we will soon recognize why expenses for re­search and development regarding aviation and space electronics are justified, because of the bearing on the whole economy. This is true, regardless of military inte­rests, in the civil area too. From here electronics (techno­logy) will intrude into all branches of the economy as an essential part of automation."

It was a fortunate idea to provide the journalists with an opportunity to see some of the most recently designed equipment in operation, when a tour was conducted to the Long Range Radar (GRS 3) site, the Precision Ap­proach Radar (PAR 2), the Weather Radar, and the Area Control Center at Munich Riem airport.

EH

Dates Site

Legal Subcommittee on Resolution B of the Guadalajara Conference 18. 3. - 6. 4. Montreal

Facilitation Division, 6th Session

Special Communications Meeting preparatory of the lnternati.onal Telecommunication Union's Extraordinary Administrative Radio Conf.

Rules of the Air, Air Traffic Services/Operations Division

Fifth Meeting of the Meteorological Operational Telecommunications

Network (Europe) Panel

Legal Diplomatic Conference

Limited South East Asia Regional Air Navigation Meeting

Third Meeting of the Visual Aids Panel

Third Meeting of the Air Traffic Control Automation Panel

Meteorology/Operation

19. 3. - 6. 4.

16. 4. - 4. 5.

14. 5. - 12. 6.

17. 6. - 29. 6.

20. 8. - 16. 9.

7. 10. - 25. 10.

28. 10. - 16. 11.

28. 10. - 16. 11.

19.11. - 17.12.

Mexico City

Montreal

Montreal

Paris

Paris

In Region

Montreal

Montreal

Paris

(ICAO)

33

International Federation of Air Traffic Controllers Associations

WHEREAS,

WHEREAS,

WHEREAS,

WHEREAS,

THEREFORE,

NOTE:

Recommendation

the object of Air Traffic Control is to maintain a safe and orderly flow of Air Traffic; and

the Air Traffic Controller performs the ultimate executive function in the con­trol of such traffic; and

the Air Traffic Controller performs his exacting duty in close co-operation with pilots, which requires a high standard of practical knowled~e and under­s:anding of pilots' capabilities, flying characteristics of moder_n aircraf~,_oper~f ti~:mal pe~formance of airborne equipment, and the operating conditions mrcrews in-flight; and

· · h. hi f ·1· with it is 1g Y advisable for Air Traffic Controllers to become ami ia~ methods and problems of other ATC-units at home and in other countries by personal visits to such units.

the First Annual IFATCA Conference, held in recommends to all authorities reponsible for Services:

Paris on April 26-2?th 196?, the operation of Air Traffic

l. to p~ovide for familiarization flights in the cockpits of aircraft fo.r Air Traffic Controllers with combined facilities to visit adjacent and distant ATC-units;

2. a) to ~ncoura~e Air Traffic Controllers with flying experience to maintain their proficiency by offering special facilities, and .

b) to encoura~e Air Traffic Controllers without flying experience to gain such e.xperience by providing facilities for pilot-training to the level of t~e Private Pilot Licence, and practice to maintain the validity of such !1cence;

3. to explore the use of linktrainers for the familiarization of Air Traffic Con­trollers with specific in-flight problems.

"Fami!imization flights" (also known as "duty flights" or "route experience flights") are granted by national air car­riers on government request in accordance with IATA Traffic Resolution No. 200. It is strongly recommended that at least two such flights annually be granted to individual Air Traffic Controllers, and that one of these flights be a long-

distance one.

34

Corporation Members

of the International Federation

of Air T raffle Controllers' Associations

Cassar Radar and Electronics Limited,

Harlow, England

The Decca Navigator Company Limited,

London

Hazeltine Corporation, Little Neck, N. Y., USA

KLM Royal Dutch Airlines

The Hague, Netherlands

Marcon i's Wireless Telegraph Company, Ltd.

Radar Division

Chelmsford, Essex, England

N.V. Hollandse Signaalapparaten

Hengelo, Netherlands

Telefunken GmbH, Ulm/Donau, Germany

Texas Instruments Inc., Dallas 22, Texas, USA

The International Federation of Air Traffic Controllers' Associations would like to invite all corpora­tions, organizations, and institutions interested in and concerned with the maintenance and promo­tion of safety in air traffic to join their organization as Corporation Members.

Corporation Members support the aims of the Federation by means of an annua! subscription and by supplying the Federation with technical information. The Federation's international journal "The Con­troller" is offered as a platform for the discussion of technical and procedural developments in the

fleld of air traffic control.

For further information on Corporation Membership please contact Mr. H. W. Thau, Secretary, IFATCA,

Cologne-Wahn Airport, Germany.

35

N.V. HOLLANDSE SIGNAALAPPARATEN HENGELO • NETHERLANDS

36

MARCO NI'S 7,000Mc/s rod or doto link system

* designed to moke lnternotionol lnteuroted Air Ironic Control o reolity NOW

* Radar data links allow radar aerials to be sited remotely from control centres to take full advantage of ideal site conditions.

The U.K. airways system uses Marconi 7000 Mc/s radar data links.

MARCONI ~

l AIR TRAFFIC CONTROL SYSTEMS ,-:; ~-'-~,'-, ...,._ SURVEYED · PLANN ED · INSTA LLED · MAINTAINED

M A RCO Nl 'S W IRELESS TELEGR A PH CO MPANY LIMI TED CHE LMSFORD , ES SEX, ENGL A ND so

the data link navigation system

KEEPS THE SITUATION UNDER CONTROL "Ai r Traffic C ontr ollers are working at a level of sustained pressure

a nd t e n s ion u nequalled in aviation or any other profession ... "

Evidence submitted to the U.S. Senate Aviation Sub-committee on ATC