IFATCA The Controller - July 1962 by IFATCA

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TELEFUNKEN radar for safe guidance from take-off to landing

TELEFUNKEN

Satco

Efficient transport means prosperity

Satco comprises the ground equipment to predict, coordinate, check and display the movements of air traffic en route and in terminal areas. It provides an extremely rapid method of calculating flight paths, for assessing potential conflicts and for coordination between Area Control Centres. Special features are included for military I civil coordination and for the control of jetpowered traffic. The system has been ordered by The Netherlands Government and the first phase is in operational use.

N .V. HOLLANDSE SIGNAALAPPARATEN - HENGELO - NETH ERL AN DS

NEW NAME, NEW SIGNATURE

G//f/7/an Corporal/on Los Angeles, California

... mark the continuing forward progress of the most experienced name in radar In its Golden Anniversary year, the company founded in 1912 as Gilfillan Brothers changes its name to the Gilfillan Corporation. Under the new name and "forward G" signature, the same progressive management will continue to maintain policies and capabilities that have established Gilfillan's worldwide position as prime contractor of complete radar systems to the military services and civil agencies of the United States and 40 nations around the world.

IFATCA JOURNAL OF AIR TRAFFIC CONTROL

THE CONTROLLER Volume 1 â&#x20AC;˘ No. 3

Frankfurt am Main, July 1962

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 Sade!, Second Vice President; Hans W. Thau, Secretary; Henning Throne, Treasurer; Walter Endlich, Editor. Editor: Walter H. Endlich, 6 Frankfurt am Main 1, Raimundstrasse 147, Phone 20821 or 521710. Production and Advertising Sales Office: W.Kramer &Co., 6 Frankfurt am Main NO 14, Bornheimer Landwehr57a, Phone 44325, Postscheckkonto Frankfurt am Main 11727. Rate Card Nr. 1. Printed by: W.Kramer&Co.,6 Frankfurt am Main N014, Bornheimer Landwehr 57a. Subscription Rate: OM 8,- per annum (in Germany). Contributors are expressing their personal points of view and opinions, which must not necessarily coincide with those of the International Federation of Air Traffic Controllers' Associations (IFATCA). IFATCA does not assume responsibility for statements made and opinions expressed, it does only accept responsibility for publishing these contributions. Contributions are welcome os ore comments and criticism. No payment can be made for manuscripts submitted for publication in "The Controller". The Editor reserves the right to make any editorial changes in manuscripts, which he believes will improve the material without altering the intended meaning. Written permission by the Editor is necessary for reprinting any part of this Journal.

Advertisers in this Issue: The Decca Navigator Campany, Ltd. (Inside Back caver). General Precision, Inc. (43). Gilfillan Corporation (2). Marconi's Wireless Telegraph Company (Back cover). Hollandse Signaalapparaten N.V. (1). Telefunken GmbH (Inside front cover). Helmut Wuttke (39). Picture Credit: The Decca Navigator Company, Ltd. (20, 21, 22, 23, 24, 25, 26). Helmut Elsner (40, 41). Technische Universitot Berlin (12, 13, 14, 15, 16, 17, 27, 28, 30, 31, 32, 32, 33).

CONTENTS

IFATCA Annual Conference 1962 Walter Endlich

Seventh National Convention and Exhibition of the U.S. Air Traffic Control Association 11 Several Results of Researches on the Problem of FlightSequence in the Terminal Area of Airports Dr.-lng. Hansjurgen Frhr. von Villiez

Fourth Convention of the British Guild of Air Traffic Control Officers in Bournemouth

Corporation Members of IFATCA

HARCO, A Hyperbolic Area Coverage Navigation System for Air Traffic Control W. E. J. Groves

Some Remarks concerning the Possibilities of Calibrating the Subscale of an Altimeter in Terms of Altitude Prof. Dr.-lng. E. Roessger and Dr. G. Raenike

Annual Dinner of the British Guild of Air Traffic Control 35 Officers The Projects and Developments of EUROCONTROL R. M. Soward Controller's Gossip, "The Name of the Game" Letters to the Editor Draft Recommendation

42 44

IFATCA Annual Conference 1962

From April 25th to 27th, 1962, the International Federation of Air Traffic Controllers' Associations held its First Annual Conference in Paris. Being host to IFATCA and its guests, the French Association Professionnelle de la Circulation Aerienne had excellently prepared the Paris Conference, with kind cooperation of the Aeroport de Paris and the Electronics Industry. Wednesday, 25th, was scheduled for an internal meeting of the Elective Officers, during which they took care of organizational and business matters and prepared for the official part of the Conference. The administrative part of the Conference took place on Thursday, 26th, and on Friday, 27th, a demonstration of the Air Traffic Control Facilities at Orly Airport, the CAUTRA automatic ATC system, and lectures on recent technical and procedural developments were scheduled. Quite an extensive program had to be squeezed into these three days. Wednesday seemed rather short for the Elective Officers to discuss all matters that had to be taken care of prior to the administrative session, however they did very well, thanks to the perfect timetable planned by the APCA and the excellent facilities of the Aeroport de Paris. Most of the IFATCA Directors arrived during Wednesday, and in the evening there was ample opportunity to meet with old and make new friends in the bar of the Terrass Hotel, where the Marconi Company had invited for an informal "get together". A most pleasant surprise for the editor: The first person he met in the hotel lounge was U.S. ATCA President Joe Moraski and with him ATCA Councilor Tirey Vickers, who had come all the way from Washington to attend the Conference. (Needless to say, and off the record, that old friends meeting in a town like Paris will not go to bed early.)

Observers delegated by non-affiliated associations, and from countries where an association has not yet been established Mr. Joseph Moraski Mr. Tirey Vickers Mr. B. Hailu Mr. Vasco de Serra Reis Mr. Saturnine Garcia

Observers delegated by the aviation industry Mr.J. Adam Mr. W. E. J. Groves Mr. G. King Mr. J. J. Thomas Mr. G. N. S. Taylor

Observers delegated by International Aviation Organizations Mr. J. Orr Mr. P. Berger M. R. M. Soward Captain C. C. Jackson

Mr. V. R. Pitcher

RAC/SAR Section, ICAO Paris Regional Office, ICAO Operations Divisions Officer, EUROCONTROL Association Executive Secretary, Internationa I Federation of Air Line Pilots Associations Chairman, International Airline Navigators Council

The Decca-Navigator Company, Ltd., England The Decca-Navigator Company, Ltd., England The Decca-Navigator Company, Ltd., England Hollandse Signaalapparaten N.V., Netherlands Marconi's Wireless Company, Ltd., England

Other observers Captain R. Gannon Captain E. S. Willey Mr. Jaques Meline

Administrative Session The following is an abstract of the Conference Report, kindly prepared and edited by the Conference Secretary, Mr. Hank Meijers, Amsterdam. The report mainly deals with the meeting of directors and observers, held on Thursday in the perfectly equipped conference rooms of the Aeroport de Paris Building, Boulevard Raspail, for this occasion kindly placed at the disposal of IFATCA by the authorities of the Aeroport de Paris. A great number of distinguished guests, delegated by international and national organizations, non-affiliate organizations, the press, and the aviation industry attended the Conference:

President, USA Air Traffic Control Association Council or, USA Air Traffic Control Association Air Traffic Control Officer, Ethiopia Air Traffic Control Officer, Portugal Air Traffic Control Officer, Spain

Mr. J. Dabry Mr. A. Lunella Mr. P. S. Flanagan

United States Air Force British Overseas Airways Corp. Air France, lnternat. Organizations Divisions President APNA Civil Aviation Administration, Finland Department of Transport, Ireland

Members of the pres.s Mr. P. Ramage Mr. Fevrier Mr. Riche Mr. Tiller Mr. Chaki Mr. Donot Mr. Simon

Call to Order and Roll-Call of Directors The Secretary of IFATCA, Mr. H. W. Thau of Germany, called upon the Directors of the 13 affiliated associations to determine whether all associations were duly represented. With the exception of the Air Traffic Control Association of Israel all were present. Transportation difficulties had prevented this association to send official delegates.

Opening of the Conference

The President of IFATCA, Mr. L. N. Tekstra of the Netherlands, then welcomed the delegates of the 12 represented associations, and extended a special welcome to the invited observers. He said that the interest shown by aviation authorities and organizations proved to be an incentive for the achievement of the aims of IFAT CA, and he was convinced that their attendance and helpful advice would be of great benefit for the federation. The President emphasized that only six months had elapsed since the Inaugural Meeting, and that the available time to prepare the conference had been too short. He suggested to regard the First Annual Meeting as a continuation of the Inaugural Meeting, where some questions were left open. Correspondence and Applications for Membership

The Secretary read out a letter from Iraq and a telegram from Cyprus, both wishing the conference all success in the deliberations, and expressing their disappointment for not being able to participate due to lack of transport. He said in this respect that the prohibitive costs of travelling long distances had prevented many fellow-controllers from countries all over the world from attending the conference. On January Sth 1962 a letter of application for membership from the Air Traffic Control Association of Israel had been sent around for approval of the Directors. The association was admitted with unanimous votes by postal ballot. Further applications were received from the British Guild of Air Traffic Control Officers and the Swedish Air Traffic Control Association. Both associations were duly represented at the conference, and admitted by unanimous votes of the Directors. In his welcome-address to the newly affiliated associations the President with regret noted the absence of the Association of Israel as the idea of an international federation of air traffic controllers associations was first propagated by its chairman, Mr. Jacob Wachtel. The President said that the affiliation of the British Guild should be considered as a milestone in the history of the federation. The British Guild, although not a founder member, had played an active part in forming the federation, and it can assist the federation with its valuable experience. Welcoming the Swedish Association, the President stated that the formation of IFATCA had been an incentive for the Swedish controllers to found a national association, and congratulated the Swedish delegates on their activities. Two applications for Corporation Membership, from Marconi's Wireless Telegraph Campany, Ltd., Radar Division, England, and from Hollandse Signaalapparaten N.V., Netherlands, were also approved by unanimous votes of the Directors. Report of the Treasurer

The Treasurer of IFATCA, Mr. H. Throne of Denmark, stated that the Elective Officers had decided to close the first annual budget of the federation on 31 st of December 1962, and that therefore an official report of the Auditor was left out as item on the agenda. He gave some general

comments on the IFATCA accounts and on the present financial situation. His proposals, to leave the annual subscription unchanged and to give the Secretary a small annual allowance as an acknowledgment for the considerable workload of the secretariat, were both accepted by all Directors. Agreement was also reached that a special committee for financial affairs be established under the chairmanship of the Treasurer to provide the Elective Officers with advice relating to matters of financial nature, which were brought forward during the discussions and may arise in the future. One of the duties of the committee will be the consideration of a basis for a sliding-scale of annual subscriptions for large associations. The discussions showed that the financial consistency of membership is of present interest for the Air Traffic Control Association in the USA. Mr. J. Moraski, President of the Association, said in this respect that his association with approximately 8000 members is exploring ways and means to attain the necessary funds in order to be able to join IFATCA. Another matter referred to the Committee for further investigation, was the question how far the assistance of the Federation should be extended to applicants with undue financial hardships, which may prevent them from becoming member of the federation. Valuable advice in both questions was rendered by Captain Jackson of IFALPA and Mr. Pitcher of IANC. Finally, the meeting decided with unanimous votes to grant a deduction of the annual subscription to applicants, whose affiliation is effected by postal ballot after the annual conference but before the end of the budget year of the federation. In these cases the annual subscribtion will be fixed relative to the remaining quarters of the financial year, for which the applicant will be a member of the federation. No deduction will be granted to applicants admitted at annual conferences. Miscellaneous

Under this item of the agenda the decision on place and date of the next annual conference was brought forward for discussion by the Secretary. The British Guild of Air Traffic Control Officers was invited to organize the next conference at or in the neighbourhood of London. The Immediate Past Master, Mr. A. Field, accepted the invitation on behalf of the British Guild. The precise date of the conference (each year to be held in March or April) shall be confirmed to the Elective Officers within six months. Other subjects discussed under this item concerned mainly the Journal of IFATCA "The Controller". The Editor was advised to insert a column "Letters to the Editor" giving readers the opportunity to express themselves on various aspects of ATC without writing a full article. One of the observers raised the point of inclusion of national inlays in the Journal. A particular article in the German inlay "Der Flugleiter", which was attached to the first issue of "The Controller", appeared to have caused some apprehension with regard to the technical professional objects of IFATCA. The Editor pointed out tha~ the German inlay was included in all copies of the first issue due to technical reasons only to speed up its appearance. This practice will not be continued in future, except for the national distribution of "The Controller" for economic reasons, or on request. The discussion which followed this point made it clear, that utmost care should be taken to

differentiate between statements of opinion and newsitems in the columns of "The Controller". Certain newsitems, i. e. these related to trade-union affairs, may have a detrimental effect on the public image of IFATCA, when inserted in "The Controller", even though the impressum includes a statement that IFATCA does not assume responsibility for statements made and opinions expressed. The conference agreed that a possible false impression in this respect should be prevented by a most cautious policy of the Publications Committee. A further point of discussion was the request from certain individual controllers to be accepted as individual members of the Federation. According to the constitution individual membership is only possible through membership of an affiliated national association. In view of the fact that in certain countries no associations exists (sometimes due to legislative difficulties), the conference agreed to foster contacts in such countries with an individual controller, who will act as official contact between the group of Air Traffic Controllers in that particular country and the federation, until such time that an association may be established.

Afternoon Session, April 26th, 1962 Jn welcoming the delegates on behalf of the "Ministre des Travaux Pub I ics et des Transports", Mr. Aker, Directeur Adjoint Navigation Aerienne, noted the signif:cance of the aims of the federation. He said he was pleased that I FAT CA had chosen Paris as the site for its conference, and that he was hoping that the discussions would come up to its expectations. In reply to the address of Mr. Akar, the President expressed the sincere appreciation of the Elective Officers and the Directors for the co-operation met by various French authorities in organizing the conference, in particular the assistance rendered by the authorities of the "Aero port de Paris". The afternoon meeting was opened by an official address of the President, as most of the invited guests participated in the afternoon.

Opening Address Dinstinguished guests, officers and directors of IFATCA, Only half a year after the Inaugural Meeting of the federation in Amsterdam, we are already holding our First Annual Conference. The first financial year of the federation will be closed on the 3lst of December this year, and therefore this is a somewhat abnormal annual meeting, because there is not a complete year to report upon. Nevertheless we have all been looking forward to this conference. We have indeed started this federation with little more than a lot of enthusiasm and a prominent lack of experience, and therefore six months of experience is quite something to look back u~on. Having. supervised the activities of the Officers 1n this short period, I must say that their enthusiasm has more than compensated their Jack of experience. The interest from outside the federation and the co-operation offered by authorities and industries has stimulated our activity. Our entry into the world of international aviation has been applauded by longestablished organizations. This has given us the feeling of being a welcome new-comer. At the same time it has

made us realise that there has been a need for international co-operation of Air Traffic Controllers for a long time, and that we will have to make up for lost time. This appears to be a good excuse for organizing this conference at such short notice. Our problems in this stage are merely of an internal organizational nature, and can be divided under two main headings: Membership and Management. As for membership, we have set ourself the task of becoming a real worldwide international federation. Internationalism is a must in our profession, even though this may not yet be recognized by every ATC-association. It is not mere coincidence that this federation has been formed by the professional associations in Europe. National boundaries divide our part of the world in numerous airspaces; the responsibility for Air Traffic Services is in the hands of many national governments. Although ICAO Regional Meetings have gone a long way towards standardization of general ATC-procedures, there is still a great deal of difference in operational practices, for instance use of radar and co-ordination of civil and military traffic. Lack of standardization in these everyday-practices is much more prominent here than on the American-continent or in Australia. This does not mean, however, that these continents can do without international co-operation of controllers. Aviation itself has done away with distances on earth. Pilots take off in Europe and land in America after a few hours only, and they certainly notice a distinct difference in general control practices. The need for international co-operation has become greater with the introduction of jet-aircraft, and will become even greater with the introduction of automation in ATC and the appearance of the supersonic airliner in the next decade. Twelve European associations have founded this federation. It is with great pleasure that we can now already announce an extension of our membership. This morning we have welcomed three new member-associations: the ATCA of Israel, the U.K. Guild of Air Traffic Control Officers and the newly formed Swedish ATCA. If numbers are at all important: the actual individual membership is now well over 2000 controllers. This number has possibilities of improvement in two ways: more Air Traffic Controllers per association, and more member-associations of I FAT CA. The percentage of controllers organized in the memberorganizations can still go up in many countries. Thereby I think in the first place of our present host-association here in France. I hope that this conference will be an incentive for the French controllers to join in mass the "Association Professionne\le de la Circulation Aerienne", which has given proof of its viability by the excellent preparation of this conference. However, not only numbers are important. The Israel ATCA is the first member-association outside Europe. May I take this opportunity to make a fervent appeal to all existing associations in the world, and to those controllers who have not yet formed a national association, to try and join us in our sincere attempt to further safety and efficiency in Air Navigation, by promotion of the Air Traffic Control Profession. Our American and Canadian fellow-controllers, for instance, have a world of experience to offer. May we call on their generosity to offer this experience to their fellowcontrollers in a sincere effort to widen the scope of their activity. The Air Traffic Control Association of the United States proclaims itself "dedicated to progress in the

science of Air Traffic Control". If we can agree that the science of Air Traffic Control is anything but a national affair, then there is reason to believe that we will be able to come to an agreement in order ta be able to spread this science all over the world. I purposely use the word "generosity" in this respect, because I believe that the principle reason for membership of IFATCA should be an express desire to moke a contribution to our joint effort to promote the profession. I will repeat again, that the federation should not be approached with the question: "What can IFATCA do for us?" In my opinion the right approach is the question: "What can we do for IFATCA?" We sincerely hope that in the near future controllers from all over the world will realise that only a combined effort can give the profession a voice internationally. Only by using all available practical professional knowledge and manpower can we hope to build up a sufficiently strong organization, which is capable of taking up and holding its place in the international world of aviation. We will welcome any proposal which may facilitate the affiliation to our federation of interested associations from anywhere in the world, provided that the object of its affilitation is in the first place to offer co-operation to the benefit of the profess ion. The second problem we are faced with is closely related to what I have just mentioned. Efficient management of an international federation is hardly a job for spare time. Nevertheless, all activities of the federation have had to be done in spare time of Officers and Members of Standing Committees. Although we do not see a solution for this in the very near future, it is apparent that we will have to think of an efficiently organized executive body in the form of a permanent secretariat. This will only be possible when a certain minimum of yearly financial income is guaranteed. The financial side is a problem for every voluntary organization, especially for those with more or less idealistic objects. There is a certain maximum to voluntary contributions which cannot be surpassed. I dare not say whether we have reached this maximum as yet, we started with a rather moderate subscription, although for some national associations this already means a heavy burden. One sure way to augment the annual income is the extension of membership; this also has the advantage, that the burden is more evenly spread. If every professional association contributes towards the expenses, which are also made in their interest, we will be able to set up shop more permanently. We will have to face the fact however, that the professional controllers will hardly be able to support their federation exclusively from own funds. This is the reason for the appeal we have made to the aviation industry to support the aims of the federation by means of an annual subscription and by supplying the federation with technical information. We have offered our Journal "The Controller" to be used as a platform for the discussion of technical and procedural developments in the field of Air Traffic Control. We trust that this co-operation of the industry will contribute to the achievement of our objects. Some companies have answered very promptly to our request, and on behalf of the Officers and Directors of the federation I should like to thank them here and now for their spontaneous reaction. We do hope that many others may join them in the near future.

The organization of this conference has been in the able hands of our First Vice-President Mr. Maurice Cerf. In co-operation with national and local authorities, and with the industry, he has succeeded in offering a very promising program. It is evident that without the help of the aviation authorities he would have had a practically hopeless task. Therefore, I wish to thank the authorities of the ~'Ministere des Travaux Publics et des Transports" and of the "Aeroport de Paris" for their kind and efficient help in organizing this conference, and for their hospitality in this nice building to-day, and at the airport to-morrow. We are also very endebted to the industries, who have offered the social functions during the conference. No doubt these functions will serve as excellent places for discussion, and for the exchange of views on topical subjects. To-morrow the whole day will be devoted to technical professional subjects. We would like to thank the lecturers for the work they have had in preparing their lectures. We hope to be able to publish their scripts in "The Controller", to give them a greater audience than can be provided here. Gentlemen, the attendance of observers from internationa I organizations, the very active co-operation of national aviation authorities and industries, combined with the keen interest of the representatives of the national organizations, gives this conference all the assets for becoming a success. May it later be recalled as a milestone in the development of our "International Federation of Air Traffic Controllers' Associations". I thank you.

Reports of the Elective Officers

The Elective Officers gave a review of their activities by reading their reports. The SECRET ARY, Mr. H. W. Thau of Germany, stated in his report, that as was to be expected the first six months of the federation had almost entirely been devoted to building-up an effective administration, to the establishment of the Standing Committees, to wide-spread international publication of the aims and objectives, and to the preparation of the First Annual Meeting. Establishing the primary and secondary account of the Federation took considerable time due to the required formalities. Parallel to the composition of the report of the Constitutional Conference at Amsterdam, all last minute amendments and alterations to the Convention, Constitution and By-Laws had to be co-ordinated between the Elective Officers to arrive at the ultimately agreed text for these documents, including the provision for acceptance of Corporation Members for which approval was ob1ained by a "Draft Release". These documents, including the first issue of "The Control Ier", and where appropriate a printed letter of invitation for Corporation Membership, were sent to high-ranking officials of international organizations to all ICAO Council Members, to the national Europea~ and United States Air Traffic Services _Admi~i足 strations and relevant Ministries, as well as to ma1or aviation and electronic industries and to the main Air Line Companies throughout the world. Two European electronic firms had applied for Corporation Membership so far. The decision of others is still pending since the informa1ion material on this subject had been mailed only three weeks before the conference.

The Secretary noted that the most promising and pleasing results of the past half year were, however, the applications for membership by the national associations of Israel, United Kingdom and Sweden. Several letters from Air Traffic Controllers of various countries were received, announcing the pending foundation of national Air Traffic Control Associations and their intention to join IFATCA as soon as possible. Unfortunately, he said, most of these countries could not be represented due to the prohibitive costs of travelling long distances. He emphasized the need for transportation facilities, and solicited national governments to give particular consideration to this problem by making use of the provisions of IATA Traffic Resolution No. 200. For the next year of business, the Secretary suggested to intensify the work of the Standing Committees, and to improve the contacts and correspondence with other international organizations. Finally, the Secretary recommended the meeting to endeavour by all means to employ as soon as possible a full-time paid Executive Secretary, as the management of an international organization as IFATCA is already at this stage beyond the scope of an honorary secretary's spare time. The preparation of the First Annual Conference was committed to the care of the First Vice-President, Mr. M. Cerf of France, and the French Association. An official report of this activities was therefore not submitted, mainly, as he put it, because of "the facts not being of any interest". The President thanked Mr. Cerf and his members on behalf of the delegates and the officers for the excellent and skilful manner in which the conference was organized. The Second Vice-President, Mr. R. Sadet of Belgium, being in charge of the supervision and co-ordination of the activities of the Standing Committees, reported that the five established Committees had reached different stages of development. The main objective of these Committees is to investigate, study and initiate action on matters of particular interest to the federation. Obviously, the activities had to be developed administratively and organizationally in order to meet the requirements. The first few months after their establishment had therefore mainly been devoted to these matters. Spectacular results at the present stage were out of question, he said, though some technical work had been put forth by some committees. The Standing Committee of Publications produced for instance the first issue of the IFATCA Journal "The Controller", the Standing Committee for Professional Problems collected a considerable amount of valuable information on different subjects regarding the environmental facets of working conditions in the Air Traffic Control profession, and finally the Standing Committee for Co-operation with Pi lo1s framed its first draft recommendation and resolution under this particular heading for this conference. Mr. Sadet stated that the experience gained in relation to the co-operation of the member associations concerned had proved a promising team-spirit to the achievement of a large and ambitious programme in the future. The subjects brought forward by the Editor, Mr. W. Endlich of Germany, were merely of a technical nature. Considerable attention was given in his report to problems associated with the cover page, the impressum, the deadline of the first issue of "The Controller", the question of national inlays, etc. Mr. Endlich emphasized the fact that

the whole venture is still a sparetime operation, and not backed up by a commercial organization with a number of experienced personnel. With regard to the editorial policy for the coming issues, the Editor recommended to run a series of articles under the heading "ATC in IFATCA Member States". In order to facilitate comparison, it was proposed to specify certain areas which should be observed in these articles. The following subjects were proposed by the Editor for consideration: Civil/military coordination, with particular emphasis on the procedures for Operational Flights in the upper airspace; radar procedures; coordination between Area- and Approach Control; controlled VFR flights; control of General Aviation aircraft; control of IFR helicopter traffic; positive control environment; Air Traffic Control on small airfields; automation in Air Traffic Control; special examples of lateral separation (e. g. dual airways); runway visual range measuring and data processing; investigation of special occurences; particularities of national aviation legislation, which differ from the international regulations; status of ATC personnel. Reporting any national ATC activity was also recommended, while the intention was announced to publish papers and articles on altimeter problems, traffic flow analysis, secondary radar, helicopter IFR flying, and the Human Factor in ATC. The Editor concluded his report with an incitement for contributions to the Journal, and said in this respect "Don't restrict your activity to just reading the Journal. Your comments and suggestions essentially contribute to making your Journal into what we want it to become: The voice of the professional Air Troffic Controller!" Reports of Standing Committees

The Standing Committee for Professional Problems in Air Traffic Control, (Chairman: Mr. 0. Schubert of Austria) submitted an interim report. The committee gave help and advice to fellow controllers in Iraq, which may finally lead to the foundation of a national association. A circular, concerning the organization of the Air Traffic Control Unif路s in the affiliated countries and their objectives, had been issued. A questionnaire had been forwarded to all member associations, with the purpose to collect data associated with the organization of the Aeronautical Services, the recruiting requirements for ATC-staff, the basic and special training of Air Traffic Controllers and Controller-students, and licensing. The Committee intends to study the collected data carefully, and will prepare a summary for final distribution as information material to all member associations. Further circulars will follow requesting information related to the environmental factors of working-conditions in general, duty-hours i. e. on radar units or low/high density ATC-units, and legal responsibility of the individual controller, to enable the committee to study operational facets of these subjects. After careful study and evaluation of the material collected, the committee will prepare working papers and frame proposals for consideration at the next annual conference. The committee's report was accepted by all Directors, 1-hough it was generally recognized that some activities of the committee may cause misinterpretations in regard to the purely technical character of the federation. It was therefore decided by the meeting, that the committee shall undertake no action or disseminate data outside the fede . ration without prior consent of the Elective Officers.

The Standing Committee for Publications and Public Relations, (Chairman: Mr. W. Endlich of Germany), issued no official report, as most of its activities had been mentioned in the reports of the Secretary and the Editor. The activities of the Standing Committee for Co-operation with Pilots, (Chairman: Mr. R. Sadet of Belgium), had led to issuing a circular to examine the extent of cooperation between pilots and air traffic controllers in the affiliated countries. The circular was divided into four parts. Part I and II intended to find out if problems of common interest were studied jointly by the initiative of the associations concerned, or by the initiative of Government Authorities; whereas Part Ill and IV made an investigation on efforts made by Air Traffic Controllers to become familiar with operating conditions of the pilot. The replies on the circular indicated that, in general, no permanent contacts between national Controllers' and Pilots' Associations had been established. A first attempt had succesfully been made in Belgium. The committee's report strongly recommended to establish regular contacts, and to organize meetings between representatives of the two professions. 路 Joint courses for Controllers and Pilots are nowhere organized, except in rare cases reported by Norway. Such courses, given for example when new procedures are being implemented, would encourage mutual understanding. The investigation of the committee showed also the necessity for Controllers and Pilots to form working groups for examination of common problems involving Air Safety. With regard to facilities for pilot training for Air Traffic Controllers, the report stated that only four of the twelve countries offered such facilities. The situation in relation to familiarization flights is far better, although Norway reported not to have any flights at all. In other countries too many restrictions limit the benefit of these flights. All member associations emphasized the need for longdistance flights. Lengthy consideration was given to the committees' draft recommendation in respect to the provisions for the implementation of familiarization flights, and the need for facilities for pilot training. It was generally recognized that the exacting duty of an Air Traffic Controller required a high standard of practical knowledge and understanding of Pilots' capabilities, flying characteristics of modern aircraft, operational performance of airborne equipment, and the in-flight operating procedures of aircrews, and that it is highly advisable for Air Traffic Controllers to become familiar with methods and problems of other ATC-units at home and in other countries by personal visits to such units. In order to gain and maintain such knowledge and proficiency the draft recommendation proposed to all authorities responsible for the operation of Air Traffic Services to provide for familiarization flights in the cockpits of aircraft for Air Traffic Controllers with combined facilities to visit adjacent and distant ATC-units; to encourage Controllers with flying experience to maintain their proficiency by offering special facilities, and to encourage Controllers without flying experience to gain such experience by providing facilities for pilot training to the level of the Private Pilot Licence, and practice to maintain the validity of such licence; to explore the use of linktrainers for the familiarization of Air Traffic Controllers with specific in-flight problems.

After a lively and interesting exchange of views, and having discussed the matter in all its aspects, the meeting decided that the final text of the recommendation should be drafted by the Elective Officers, as not every Director was in entire agreement with the wording of the actual proposal. The meeting adopted the following resolution, which was also prepared by the above-mentioned committee.

Resolution Whereas, Pilots and Air Traffic Controllers perform duties which have a common aspect with regard to safe and efficient air navigation; and Whereas, the lst Annual Conference, Paris 25-27 April 1962, believes that, at present, insufficient professional relationship exists between most of the Associations representing these professions; and Whereas, these contacts can foster direct co-operation with a view to studying mutual problems regarding Air Navigation Safety through the medium of working groups; Now therefore, it is agreed that this co-operation be made effective; Therefore, the IFATCA Paris Conference resolves that all Member Associations endeavour to establish the necessary official relationship with the Air Line Pilots Associations in their respective countries. Captain C. C. Jackson, Executive Secretary of the International Federation of Airline Pilots Associations, admitted that official relationship between national associations of controllers and pilots was almost non-existent at the present time, and he stated to consider this situation as an "unnatural state of affairs". He launched the idea to convene a technical meeting in Europe within the next year on a joint basis, sponsored by IFATCA and IFALPA, where a single topic of current interest could be discussed by a group of controllers and pilots from an operational and air traffic control point of view. He said that by organizing such a meeting the elements for a worthwhile discussion could be obtained, and that it would improve at the same time the relationship between the two groups.

Composition of Standing Committees At its Constitutional Conference the federation resolved to establish seven Standing Committees, five of which were allotted to different national associations. Due to the fact, however, that at that stage a number of associations were not in a position to establish a Standing Committee on a national basis the composition of the Standing Committee forTechnical Problems and the Standing Committee Coordination and Relation between Military and Civil Air Traffic Control was postponed to a later date. At the present meeting the British Guild accepted the invitation to take over both Standing Committees. The delegates of the United Kingdom stated that their Guild was already closely involved in studying the latter p~o颅 blem in co-operation with the British Guild of Air Line Pilots and Navigators. It was noted by Mr. J. O~r, the observer of JCAO that his organization is also vitally concerned with pr;blems associated with the joint use of ai.rspace by state and civil aircraft, and that the matter will be brought forward to the 14th Assembly of ICAO to be held in Rome this year. 9

Mr. J. Moraski, President of the Air Traffic Control Association in the USA, suggested to the meeting to consider the establishment of a Standing Committee of Awards, for recognition of significant contributions to Air Safety, outstanding duties, or efficiency in the field of Air Traffic Control. The meeting charged the association of Iceland to collect available information on the given subject from the associations in the United States and the United Kingdom, to study all aspects and to present the information as basic material to the Elective Officers for further consideration.

Nomination and Election of Officers

Federation policy

Adjournment

Most of the professional aspects of the federations' policy were covered by the previous items of the agenda. Mainly matters associated with the administrative policy were discussed under this heading. There was agreement on the desirability to review the present text of Corporation Membership in the federations' By-Laws, and to add to the relevant article the rights and dues of this membership. Authority was given to the Elective Officers to accept Corporation Members immediately after application.

Mr. A. Field, Director of the U.K. Guild, moved for the adjournment of the meeting. This motion was unanimously adopted. In terminating the meeting, the President stated that the deliberations had provided sufficient ideas and working material to pave the federations' way to a healthy and successful organization. In conclusion, he thanked all participants for their contributions to the success of the meeting, in particular Mr. Maurice Cerf and the French Association for the tremendous work of organizing the conference. He lhen declared the conference closed.

Co-operation with appropriate Associations

The Elective Officers maintained excellent relations with the International Federation of Airline Pilots Associations. The Treasurer, Mr. H. Throne, represented the federation at the XVl!th Annual Conference of IFALPA, which was held earlier this year in Stockholm. A lengthy discussion came up when the question of establishing more permanent contacts with other international organizations, in particular with ICAO, was brought forward by the President and the Secretary. The question of seeking recognition by the International Civil Aviation Organization was treated circumstantially, as the professional activities of the federation lie almost entirely within the scope of the activities of !CAO, and whereas one of the reasons for the foundation of IFAT CA was to secure the presence of practising Air Traffic Controllers at !CAO-meetings. It was noted that recognition of other private international organizations is based on defined provisions, which were set forth by the First Assembly of ICAO. There was entire agreement on the policy recommended by the Elective Officers, to await further wo1路ld-wide expansion of IFATCA before making a formal request for recognition. It was also envisaged that official recognition by ICAO would increase the workload of the federation considerably, and that an efficient management of the federation by an executive body should be established first in order to meet the requirements. To limit the consequences of awaiting a wider-concept and an executive body, the meeting recommended that the Officers would file an incidental request for official representation of IFATCA in the capacity of observer at !CAO-meetings of particular interest. Such request could perhaps be judged by ICAO on its own merits. The next meeting of the RAC/OPS Division of ICAO, to be held mid next year, could be one of these occasions. In this respect it was suggested to convene the earlier mentioned joint meeting with IFALPA in preparation of the divisional !CAO meeting. Official policy of the federation on some agenda items con then be defined at the next Annual Conference of IFATCA, which wiil be held p1路ior to the ICAO meeting.

Owing to the absence of an agreed procedure on rotation, retirement, nomination and election of Officers, and the early stage of development of the federation, the Officers stated their willingness to stay on for the coming federation year. A proposition from the floor that the Elective Officers would remain in office until the next Annual Conference was unanimously accepted by the Directors. The Officers will draft an election-procedure for consideration by the Directors.

* CAUTRA System and Technical Lectures

Friday was devoted to lectures and demonstrations. Mr. Jaques Villiers, Chief Engineer of the French Air Traffic Control Experimental Unit (CENA, Centre d'Experimentotion de la Navigation Aerienne) gave a very interesting and instructive introduction to the CAUTRA System of automatic Air Traffic Control, which is working with two general purpose IBM 650 computers. A detailed report on the CAUTRA system is scheduled for one of the next issues of The Controller. This was followed by a tour through the Centre Controle Regionale Nord (Northern Air Route Traffic Control Centre), where the efficient anti-glare lighting system, the one-strip-per-sector-method, the curved control board for easier strip handling, many closed line television circuits for data transfer, and swivelmounted radar scopes attracted much attention. In the afternoon, the following interesting lectures were held: The HARCO System,

by Mr. W. E. J. Groves, The Decca Navigator Company. HARCO stands for Hyperbolic ARea COverage. The system has been developed from the Decca navigation system in Collaboration of the firms Decca, CSF, and Telefunken. It has been tailored to meet the EUROCONTROL specifications and is presently being evaluated by EUROCONTROL. EUROCONTROL, Planning and Development,

by Mr. R. M. Soward, Operations Divisions Officer. EUROCONTROL will become the supranational controlling agency of traffic in the Upper Airspace of Centro! Europe. Belgium, England, France, Luxembourg, the Netherlands, and Western Germany for this purpose are pooling

their efforts to establish three Upper Area Control Centers. Specifications for an appropriate navigation system in accordance with the EUROCONTROL area concept have already been worked out and proposed to the industry by the EUROCONTROL Planning Office in Paris. Long Range Radar,

by Mr. G. N. S. Taylor, Marconi's Wireless Telegraph Company, Ltd. A more uniform specification of radar parameters is desirable for the design of long range radar equipment. Mr. Taylor referred to the quite variable terms used by administrations to specify the requirements for the ATC radars they intend to establish at Air Traffic Control Centers and Approach Control Offices, and explained how the different parameters and their interelation affect the radar performance. Two high-speed movies of radar displays effectively supplemented Mr. Taylor's lecture. Air Traffic Control Radars,

by Mr. Lucien Gerardin, Compagnie Franc;:aise Thomson Houston. Mr Gerardin lectured on such techniques as Airborne Target Indication (A.T.I., an effective system for eliminating ground targets), automatic extraction of radar data, circular polarization, staggered pulse repetition frequencies for eliminating blind speed, and other methods of improving radar performance, which are applied by CFTH. In order to give the presented papers a greeter audience, it is intended to reprint them in The Controller. Some of them are olready included in this issue. Social Events

Although the Conference schedule was very tight, problems could be discussed at leisure too. The Aeroport de Paris Authorities, Marconi's Wireless Telegraph Company, Compagnie Franc;:aise Thomson Houston, and the Compagnie Generale de Telegraphie Sans Fil had established a most hospitable environment, sponsoring a luncheon at Orly Airport, and receptions at the Terrass Hotel and the Hotel Lutetia. CSF had invited to a reception at their beautifully located research plant Corbeville. During the tour of Orly Airport, there was already occasion to inspect the CSF picture transformer type 442, which had been demonstrated by Mr. Troud. Friday evening, at Corbeville, highly advanced EHF equipment was on display (opposite to the cocktail bar), and ATCA's President Joe Moraski found, much to his surprise and pleasure, a huge reproduction of the Industry Award he had signed to years ago when it was presented to CSF's American affiliate Intercontinental Electronics for bringing the bright display into the control rooms, thanks to the "Frenchicon". Al I these activities offered welcome opportunities to meet with high ranking aviation officials. Just relying on his memory, the editor remembers the following distinguished guests who have honoured IFATCA through their presence at these occasions: Miss Colslater Mr. Boursicot Mr. Cot Mr. Moroni

Civil Air Attache, American Embassy President du Conseii d'Administration de l'Aeroport de Paris Directeur General, Aeroport de Paris Secretaire General a !'Aviation Civile

Mr. Beurdeley Mr. Florissone Mr. Akar Mr. Aucouturier Mr. Allard Mr. Lecerf Mr. Lecurieux Mr. Boquet Mr. Latron Mr. Pailhas Mr. Bulin Mr. Giret Mr. Couhe Mr. Benard

Directeur D.T.E.A. Aeroport de Paris Directeur D.T.E.A. Aeroport de Paris Directeur Adjoint Navigation Aerienne Chef de Department Aeroport de Paris Commandant, Aeroport Orly Adjoint au Commandant Aeroport Orly Adjoin! au Commandant Aeroport Orly Commandant Aeroport Le Bourget Commandant en Second, Aeroport Le Bourget Commandant B.C.T. C.C.R. Nord Orly Directeur EUROCONTROL Administrateur en Chef, Direction Generole Aeroport de Paris President d'Honneur du Conseil d'Administration, Aeroport de Paris lngenieur General Region Nord

Mr. Peter Ramage, Mr. Fevrier, Mr. Riche, Mr. Tiller, Mr. Chaki, Mr. Donot, and Mr. Simon represented the press at the IFATCA Conference. Their interest in the federation, and their timely reporting, are much appreciated. Summarizing, it can be stated that the First Annual Conference was a great step forward, despite of the fact that Officers and Directors were confronted with an unfamiliar task, and despite of the fact that all activities had to be taken care of in spare time. Enthusiasm, and the excellent cooperation offered by the industry and by the national and international aviation organizations and authorities have made possible the full success of the conference. Last but not least, our highest appreciation to Maurice Cerf and the APCA, who have so excellently prepared the Conference and made guests and members feel at home in beautiful Paris. Walter Endlich

Seventh National Convention and Exhibition of the U.S. Air Traffic Control Association The American Air Traffic Control Association will hold its seventh ATC Convention and Exhibition on October 1, 2, and 3 in the fabulous Flamingo Hotel, Las Vegas, Nevada. Aside from the administrative session there will be interesting lectures on Air Traffic Control and a huge display of modern ATC equipment. Many social activities are provided, and awards will be given by the ATCA to a member or members of the industry making a significant contribution to air traffic safety through the development of equipment, research studies and other contributions, to the controller of the year, and to the facility of the year. Reservation Requests should be mailed to: Reservations Committee ATCA Inc. P.O. Box 45784 Los Angeles California, USA 11

Several Results of Researches on the Problem of Flight-Sequence in the Terminal Area of Airports*

Dr.-lng. Hansjiirgen Frhr. von Villiez**

(An analysis of oir traffic in the terminal area by means of PPl-photographs, strips and air-ground communications)

The research on operating problems of air traffic control becomes more and more important. With the presented results we like to support the solution of problems in terminal areas. The principal difficulties on board and at the ground for manoeuvres and traffic control in the terminal area are well known here. What can we expect from a traffic analysis as we have done? This question is to be answered as well from the standpoint of traffic control as from piloting and it leads to statements which are useful for the beginning of automatisation of air traffic control, just now. Above all, we may expect particulars how air traffic actually operates in the considered air space. The stress lays on "actually" because it is sufficiently known that all fixed procedures can only represent a fundamental scheme, from which certain deviations cannot be avoided. In instances of vectoring by radar these deviations even are significant and necessary to obtain maximum traffic flow. Here, it is necessary to determine the maximum variation as to quantity. As the manoeuvres of aircraft in a terminal area extend to nearly a 11 altitudes, increased attention has to be paid to aircraft operating under visual flight rules (VFR). Later on we will see on a picture that these manoeuvres represent a considerable portion of the whole traffic, provided, of course, that the weather conditions are adequate. From the standpoint of traffic control it is very important to know which accuracy of navigation actually can be reached in practice, whereby finally important criteria for the flyability of procedures can be stated. Hereby, it is not sufficient to know the technically possible but the actually existing data in an air space with high traffic density and all its resulting conditions. It is obvious that such an analysis necessitates a large number of observations which we made under most striking weather and traffic conditions during many days. From the standpoint of traffic control a critical consideration of the information sources available for the controller will be profitable. If we start with the regular flights the most important data are already known by means of strips before the aircraft enters the airspace in question. In general, only the given time estimates and the altitude indications are corrected. Both informations are given by the pilot - except the actual time of departure - and therefore, they cannot be checked independently by the controller, respectively very conditionally as far as radar allows the observation of the aircraft in its actual time overhead any reporting point. It is necessary to change these conditions immediately in regions of high traffic density because continuous altitude information is not available yet, and discrete values have to be demanded by radio telephony and are even then uncontrollable Therefore, only lateral separation is Papc1路 presented at ihe Three-Nations-Convention, Dusseldorf 1962. Chief Engineer at the Institute far Pilotage and Air Traffic, Technical Un!vcrsity Berlin, Directo1: Pi'ofessor Dr -Ing. E Roessger

possible which requires radar control in order to obtain maximum traffic flow, if we do not consider the rigid conventional controlling method. The decisions of the controller essentially depend on the quality of the radar scope that means, in particular, on the reliability and the accuracy of indication. The success of the decisions, built up on this only independent information, again is dependent on the speed and accuracy the pilots follow the given orders. Here, too, objective statements can be made. Before starting to speak in particular about the results, you may like to have some information about the manner we got this material. In several periods we took photographs of the radar scope of the terminal area Frankfurt for which - according to the special task - we used a miniature camera or a 16 mm film. Moreover, all radio-telephony frequencies were recorded and, finally, we had the strips of the Tower, Approach, and the Area Control Frankfurt at disposal. That was not more or less material than the controller uses. The observed periods lasted 2 1 /i to 3 hours and had approximately been fixed before by means of the timetable of the "Rhein-Main-Flughafen" in order to obtain a maximum of flight manoeuvres. In the daily "rushing hours" certain deviations had been caused by the military air traffic in the Frankfurt area which could not be considered before. But, nevertheless, I think to have observed periods which represent the present traffic density in the terminal area Frankfurt. For those of you not familiar with the local situation of the terminal area Frankfurt, the video-map of the ASR 3 1n the 30 NM-range is given in picture 1.

Fig. 1.

Video map ASR 3 Frankfurt 30 NM range.

Fig . 4.

Fig . 2.

Approaches Frankfurt and Wiesbaden , 26 . 7. 1960 , 1054-1327 GMT .

Rodar screen ASR 3 Frankfurt ; Range 30 NM, 26 . 7. 1960, 12h 15' 40" GMT .

The way we took the photographs can be seen from the following pictures : No. 2 is typical for pictures taken all 20 seconds in a period of 2 1 /i hours, each of them exposed during one revolution of the antenna. The photograph No. 3 is taken of a series of pictures each of which had been exposed for about 5 minutes on the average. In order to avoid overexposures by electronic map signs and range marks, they had been switched off at each ex posure olways after the first revolution of the antenna. Concerning the 16 mm photographs I must say that they were exposed one by one, each for a revolution of the antenna . These pictures had mainly been taken in order to get as many photographs as possible for the evaluation, fixing each revolution of th e antenna . It produces quite a good impression of the manoeuvres if we show the pictures by quickmotion . Because of the inevitable

switching time of the camera shutter a small sector of each picture necessarily must be under-exposed . We had put this sector nearly into the "10 o 'clock-position" of the radar scope in order not to lose essential parts of the pictures. The few targets in this sector can sufficiently be perceived for the evaluation by the afterglow of the radar screen . The fluctuation of this sector can be explained by releasing of the camera by hand. All together, we had 3656 separate pictures at disposal by this 16 mm film . In this film three sections can be di stingui shed . The first one shows the so-called "west-traffic ", that means, acti v e runway is 25 R, for about l h 4 min. The second section is very short ond shows only a holding procedure at the METRO-beacon . Finally, the third section presents the ob servations of l h 16 min with so-coiled " east-traffic ", tha t means active runway 07 L.

.·

. ·'V

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Fig . 3.

Ro da r scree n AS R 3 Fran kfur t; Ra nge 30 NM , 27. 1. 1961, lOh 11 ' 50 " - lOh 16' 50" GMT .

Fig . 5.

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De part u re; Fran kfurt and Wiesbaden , 26 . 7. 1960, 1054- 1327 GMT .

Fig. 6.

Overflights Frankfurt, 26. 7. 1960, 1054-1327 GMT.

Before all I. like to stress a very remarkable situation in the holding pattern at METRO-beacon: there can be seen how 3 targets finally run into one non-soluble luminous point on the radar screen, that means, that their safety only depends on the vertical separation which cannot be directly checked by the control !er_ Later on, I sha 11 take up this point again. First, the flight paths had been registered by means of the photographs, strips and the radio-telephony tapes, see picture No. 4, 5 and 6. In order to get a better view and for an easier evaluation they have been represented separated into approaching flights, departures and overflights. Besides that, in order to get a general impression of an observed period, we have additionally made a coloured diagram of the manoeuvres of January 27th, 1961 (0956-1304 GMT) according to picture No. 7. In addition to these pictures we used a lot of registrations directly taken at the radar screen for the evaluation. What are these pictures showing? The critical consideration of plotted flight paths leads without further expense to the question of space-requirements for ~everal flight-procedures. Firstly we have to pay attention to the movements of jet aircraft. We cannot conclude too much from the low number of the observations

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shown but in the view of safety it is very important to consider the individual movement. Thus, in the high level approach (Fig. 8) it is striking not to find the starting point overhead the Charlie beacon but up to 7 NM abeam. In spite of the fact that the error in position-finding overhead the VOR at flight level 200 is less or equal to 1 NM the velocity and manoeuverability should be responsible for the displacement. All but the aircraft which are approaching Charlie (CHA) via the Modau beacon (MOD) ore forced to carry out considerable course corrections which are started normally after passing the beacon. Here we will find the reason that it is impossible to follow the desired outbound-track from Charlie (between 030° and 055°) and by following this fact even the "gate" at the begin of the penetration turn will be missed. Besides that it is to be seen that the aircraft Kl 843 overshoots the defined border at a distance of 18 NM from Charlie without any direction for stretching the flight path. The pilot is forced to use elapsed time instead of distance information because an immediate distance measurement is impossible without the so-called Distance Measuring Equipment (DME). Disregarding the well-known workload in the cockpit during an approach procedure, this may be the most important source of error. Fortunately, there has not arisen a dangerous situation because the airspace in question is not yet used for other procedures. Nevertheless we will meet other aircraft in that area and the situation becomes critical if radar contact with the approaching aircraft is lost. As we know this must not oniy be caused by radar-failure but will also happen by quite a lot of other reasons. Next, we will deal with the holding procedures. The main interesi also lays on space requirement if possible depending on type of aircraft, altitude, and the meteorological conditions. There is no doubt about the fact that the performed flight paths in a holding procedure depend mainly on the pilot's attention and accuracy, and additionally on meteorological conditions and aircraft-performances. Although the ASR 3 is not intended for observations of aircraft at flight level 200 we succeeded in registrating the "holding pattern" of a Boeing 707. We present in Figs. 9, 10 and 11 a selection of holding procedures being observed under most different conditions. Beside the

Fig. 9.

Flugbahn

~ 58,

Holding precedures at Charlie and Wiesbaden Range.

required area the flown pattern must be in accordance with the procedure prescribed. Look at the pictures and you will see what happened. The holding pattern of LH500 is the most accurate one. It has to be considered that the holding procedures sometimes cannot be completed because the expected approach time (EAT) is given before. As to the departures the consideration of space requirement leads us again to the flight paths of iet aircraft. If there is no significant course deviation after the take-off the difference to the flight path of piston-engined aircraft will only be in vertical direction. Therefore, the pictures give no indication. The space requirement for iet aircraft increases in case of a considerable course deviation after take-off. Radius of turn of 3-4 NM could be observed, versus an average radius of 1 NM (see Fig. 12). Another problem, very important in the view of automation of air traffic control, is the loss of radar-echos. Especially in case of jet-departures we noted quite a lot of missing radar-echos. The assumption for such an observation was the registration of each revolution of the antenna. This requirement could be achieved by means of the film·camera. The result concerning the approaches and departures was an average rate of loss of 5,7%, in special cases a rate of 28% could be stated. As for the distribution the maximum number of missing echos in sequence is of great interest. Very often we couid find values of 10-12, but in individual cases such of 20 and 47. If we consider the overflights additionally we have to reexamine the vertical coverage of the radar. It paints targets up to an altitude of 15 OOO ft as well as at 10 OOO ft, normally the upper limit of the area to be observed. _On the other hand the elevation of the vertical characteristic of the antenna with 22° does not seem to be rea I istic. If we use this value we will meet a rate of missing rndarechos of at least 18,6%. The angle of the vertical charac· teristic of the antenna goes down to 12' in orde1· to get figures for the missing rate comparable with the values given by the approaches and departures. This is the result 15

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of the evaluation of about 3656 single pictures of the radar-screen, that is to say a number of 53 flight-paths completely observed with at least 16971 echoes which should have been seen. This number gives us a sufficient background for the given results. The critical consideration of the overflights raises two

Fig. 11.

,,,I

1. What size has the vertical characteristic of the antenna and, by that, the vertical coverage of the radar actually? 2. What is the accuracy of track-guidance within reach?

Holding procedures, Metro.

questions:

The first question I have already mentioned while discussing the missing rate of radar-echoes. The evaluation of all observed overflights - as far as they fly the "RheinMain-Range" - results in a mean value of r1 = 8,7° for the vertica I characteristic of the antenna. With regard to the value of rt = 22° given by the manufacturer, the difference is quite notable. With respect to that we have to notice that only certain directions within the 360'' are covered by the observed overflights. Therefore, we should not generalize the result. Moreover, the reflection of the observed aircraft is an important factor depending on the configuration of the aircraft and on the position of the aircraft with regard to the antenna. We shall not be able to dispose of these data. Therefore, the influence of these parnmeters has to be estimated by a large number of observations. Even if this large number should not be 1·eached the accordance given by our measurements is still Furthermore, the results derived mainly from 1·ernarkable. those directions being in use primarily. As for the accuracy of track-guidance there is hardly to be found any publication covering the whole problem. Mostly, just the navigational systems and their physical chmocteristics me discussed. In view of pilotage as well as in view of ti-affic control these considerations are very

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Fig. 12.

Departure-route 1, Frankfurt, 26. 7. 1960.

important but in no case sufficient. Here we are just interested in the degree of accuracy to be reached in practice, for instance in flying a navigational aid or a certain procedure. In this concern the human factor - and by that the flight technical error - is very important. Furthermore, we have to mention the meteorological influence and the flight mechanical behaviour of aircraft. Excluding the systematic errors of the navigaitional aids in question, these are parameters without the possibility of being determined directly; even the flight mechanical behaviour can be measured conditionally. Besides some theoretical considerations the experimental method to get useful data is the radar observation. Therefore, we have evaluated the material with respect to the accuracy of track-guidance and we will get the error coming up from all influences mentioned above. The overflights are most suitable for this purpose. The special problem is to find fixes with only one navigational aid, otherwise it would be necessary to ask the pilots for the used aid {if there are more than one) after they passed the reporting point. Under these circumstances, in the terminal area of Frankfurt we only can use the aids

Nierstein (NST), Konig (KNG) and Nauheim (NAH) without the inbound-track Wiesbaden {WBD) - Nauheim. But, this restriction gives a too limited number of usable data. Therefore, we have to check at all nondirectional beacons (NDB) in the Frankfurt area. Following this method we got 139 values, fig. 13 shows the result. It responds very well to a "Gauf3-distribution", the width of tracking being 4,6 NM at 95% of probability. The results which were presented here can only be seen as partial results, and our researches on the problem of flight sequence in the terminal area will be continued. %

left

+--.--+

right

Course Deviation

Fig. 13.

NDB track guidance.

Fourth Convention of the British Guild of Air Traffic Control Officers to be held in Bournemouth The British Guild of Air Traffic Control Officers will hold its Fourth Convention on October 9th, 1Oth and l lth, 1962 in the Town Hall, Bournemouth. A very interesting program has been scheduled, the highlights of which ere listed below, for those who are interested to attend.

October 9th: 11.30 The Mayor of Bournemouth opens the 1962 Convention. Opening Address by the Master of the Guild. 12.00 Lunch adjournment. 12.30 The Master, Guild Officers, Wardens and certain Guests take Lunch with the Mayor. 14.30 "Problems of Airspace for General Aviation", Peter G. Masefield, MA., FRAeS, MinstT, Hon. FIAS. 16.30 "Air Traffic Control and Executive Flying", Group Captain Douglas Bader, CBE, DSO and Bar, DFC and Bar. Managing Director, Shell Aircraft Ltd. 20.30 Dance and Buffet given by the Mayor and Corporation of Bournemouth.

October 1Oth: 09.30 The Guild Paper: "The Personal Equation in Air Traffic Control." 11.00 "Telecommunications Field Engineering in ATC", W. P. Nichol, Ministry of Aviation, Gatwick. 12.00 Launch adjournment. 14.00 "Stress and Performance in Air Traffic Control", K. G. G. Corkindale, BSc., Dip. Psych., Royal Air Force Institute of Aviation Medicine, Farnborough. 15.30 "Collision Avoidance by Radar Control", E. S. Calvert, CBE, ARScl, BSc., Sen. Principal Scientific Officer, RAE.

20.15 Cocktails: Delegates, Guests and their Ladies "get together" at the Suncliff Hotel.

October l lth: 11.00 "HARCO - a proposed radio navigation system for EUROCONTROL and its relationship to ATC requirements", J. Adam, The Decca Navigator Company, Ltd. 12.30 Lunch. 14.30 "Any Questions". Chairman: Captain H. L. Lee, BOAC. Panel: Mrs. D. St. Johnston, Automation; E.W. Pike, Automation; Capt. A. P. W. Cane, BOAC Supersonic Development; Max Settelen, Radio and Radar; P. G. Masefield, G/Capt. Bader, Executive and Private Flying; E. S. Calvert, Electrical Engineering; Dr. B. J. O'Kane, Radio/Radar: Representing Electronic Engineering Association. 16.15 Termination.

Further information may be obtained from: The Clerk of the Guild Guild of Air Traffic Control Officers 14, South Street Park Lane London W.l

....

Corporation Members

of the International Federation of Air Traffic Controllers' Associations

Texas Instruments Inc., Da Ilas 22, Texas, USA

Marconi's Wireless Telegraph Company, Ltd. Radar Division Chelmsford, Essex, England

KLM Royal Dutch Airlines The Hague, Netherlands

N.V. Hollandse Signaalapparaten HengGlo; Netherlands

The Jnternatianai 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 annual subscription and by supplying the Federation with technical information. The Federation's international journal "The Controlle1路" is offered as a platform for the discussion of technical and procedural developments in the field of air traffic control. For fudher information on Corporation Membership please contact Mr. H. W. Thau, Secretary, IFATCA, Cologne-Wahn Airport, Germany.

W. E. J. Groves*

HAR CO A Hyperbolic Area Coverage Navigation System for Air Traffic Control For some years now it has been my firm conviction that the needs of Air Traffic Control place more exacting demands upon a navigation system then do the needs of pure navigation. No one would deny that the existing short range navigation aids enable one aircraft to fly from A to B without difficulty. The trouble arises when a number of aircraft wish to fly from A to B at more or less the same time, and it is the Air Traffic Control Ier upon whom the task fal Is to m路ake up the deficiency in the current navigation system. The overall ATC system comprises two important elements, one the airspace structure and route system, the other the ground organisation controlling aircraft within this route structure. The former depends for its efficiency upon the navigation system, the latter upon data acquisition and, above all, display to the controller. It is vital that improvements in both these elements should take place simultaneously, for the neglect of either will impair the ATC System efficiency as a whole. Fortunately, and certainly not before time, these facts are gaining ever wider recognition in international circles. It is within this theme that I should like to describe, briefly the development of the HARCO Navigation System.

History and Origin of HARCO Before examining the HARCO System itself, it is important to appreciate the background against which it has developed, and at this stage I should like to make two points quite clear. Firstly the EUROCONTROL Association proposes to evaluate the HARCO System to test its ability to meet the stipulated operational specification, but this does not imply that EUROCONTROL has accepted HARCO for ultimate operational utilisation. Secondly, although the HARCO proposal has been submitted specifically to EUROCONTROL to meet its stated requirements, HARCO has a universal application and will, I believe, become essential wherever the density of air traffic or the restriction of airspace creates an ATC problem. Turning briefly to the origins of the HARCO proposal which is, of course, a result of years of development experience of the Decca Navigator System, the proposal itself was a result of the EUROCONTROL Operational Specification for a Radio Navigation System for Air Traffic Control. This Specification was issued by EUROCONTROL in April 1961 to the radio electronic industries of the participating countries. Having considered that the existing standard navaids would not meet the requirements for positive Air Traffic Control in the upper airspace, EUROCONTROL's next logical step was to draw up an operational specification for a navigation system which would meet these needs and to test the feasibility of producing an operational system by seeking comments from the industries concerned. Three specific points were called for: firstly the practicability of meeting the specification with an operational system by 1965; secondly, the date by which ~Decca Navigator Company, Ltd.

any proposed system could be evaluated and, thirdly, the general principles and technical description of the system proposed. Upon receipt of this specification, three European companies, CSF of France, Decca Navigator of U.K. and Telefunken of Western Germany, who have long been associated in the field of radio electronic techniques, decided to pool their relevant development resources to produce a joint proposal to the EUROCONTROL Association for a radio navigation system to meet the Operational Specification. This proposal was submitted in early June, 1961 under the derivative name of HARCO, signifying Hyperbolic Area Coverage.

The EUROCONTROL Operational Specification It is pertinent at this stage to look briefly at the EUROCONTROL Specification itself. In general terms it was considered that a new or improved navigation aid would be required for the upper airspace before 1975 (the protection date of the ICAO standard VOR/DME). Furthermore, after 1975 the navigation system used in the upper airspace should also be employed for the lower airspace. Therefore the requirements for low altitude navigation have been included in the specification where we find particular mention of the need for accurate navigation for all traffic in terminal areas including helicopters and light aircraft. The detailed requirements can be summarised as follows: a) Ai-ea coverage to serve any desired route system, to facilitate changes without costly redeployment of ground stations and to provide the highest coverage/cost ratio. b) High diversity of use amongst all categories of aircraft to meet ATC requirements, with vertical coverage from ground level to 80 OOO ft. to serve all users from helicopters to pure jets. c) High accuracy, especially for terminal area navigation; here the requirement specifically calls for 卤2 NM operational tracking accuracy 卤1 'h NM position fixing accuracy d) Simplicity of interpretation and use of airborne equipment coupled with high system reliability. e) Pictoria I presentation in the cockpit for accurate adherence to ATC procedures. f) Integration with automatic techniques into the ATC system by automatic data link without loss of basic navigation accuracy. g) Compatability with long range navigation systems. Although much condensed in form, these items cover the basic essentials of the EUROCONTROL Operational Specification.

Significance of Navaid Requirement I should like to draw you1路 attention here to a continuity which can be traced running through a number of reports and statements on navigation systems. First the Curtis 19

s DON/

Ailrs

REG~

~ ~ ~

,, ,,

, /

/ /

,, /

~ ~

;..

;.,

.(?4'

Fig . l Omnitrac Chart

D/T I

....~

Londo n -

Par i s

Report of 1957, with its reference to hyperbolic systems, then the Jet Operations Requirement Panel Report (JORP) recommended the adoption of an accurate area coverage navigational aid with pictorial presentation. IFALPA have continuously advocated area coverage with p ictorial presentation for the pilot. Now the same trend is apparent running through the EUROCONTROL Specification . In the recently published Project Beacon Report w e find references to the adequacy of rho-theta systems " so long as the traffic does not get too heavy" and, further, after quoting examples of lateral displacement due to bearing errors of VOR, the comment appears "Thus small lateral separations permitting closely spaced airways are hard to achieve with rho-theta systems ." This is a clear indication of the limitations of such systems . On analysing these various reports and documents we can see that the primary reason for any enhanced speci fication for navigation systems stems from Air Traffic Control, rather than purely navigational problems.

The HARCO Proposal Using the techniques and development experience of the Decca Navigator System, HARCO, like Decca, is a low frequency (50- 150 kc/ s) hyperbolic phase comparison system . In the simplest terms, the aircraft's position as derived from the airborne receiver is processed by a computer and Flight Log combination which automatically records the track of the aircraft by means of continuous position plots derived from a serie s of position fi xes. So far as ground stations are concerned each HARCO Chain , as with Decca , consists of a Master and three Slave stations . A chain deployment plan has been submitted to EUROCONTROL to cover the airspace concerned to an accuracy of Âą 0.25 NM by day and Âą1 .5 NM by night. Exi sting Decca transmitting stations, whi ch already provide coverage over 62% of the EUROCONTROL area, would be utilised in the configuration envisaged in the interest of economy. Each chain covers an area of about 100 OOO square mil e s and this cov erage is , of course, unbroken from ground level to any altitude. The complete coverage to the accuracy specifi ed will require the addition of the equivalent of only five new chains (see fig . 4). The low freq uency propagation is unaffected by physical obstacles (as distinct from VHF transmissions) so that HARCO is suited to low flying helicopters and pure jet a ircraft alike . One of th e main improvem e nts in the ground stations is the employment of synchronous crystal clock techniques whereby the trigger signals upon which the airborne equipment depends for the resolution of ambiguities w ill occur at the same instant of fime for all chains, thus a v oiding any readju stment of receivers when entering a new chain. Tw o main types of airborne receivers are included in the propo sal , both fully tran sistorised and designed for a re liability of 1000 hours m ean time between failures . Type A is inte nded for aircraft w ith speeds in excess of 4000 kts; Ty p e B, of re duced size and weight, for slower and light aircr a ft. Th e proposal includes various pictorial presentation d ev ices ranging from simpl e unsophi sticated displays for small a ircraft to t h e O mn it ra c, a lightw eight d igita l airborn e com p uter w hich con ve rts hy perbolic co-ordinates

Fig . 2.

Omnitrac computer .

into cartesian form for the display on conformal charts in conjunction with an automatic self-setting Flight Log. Omnitrac I (see fig . 2), the first development model, was built to prove the principle of hyperbolic to cartesian co-ordinate conversion. Housed in a 1 ATR package, it uses a drum store and entirely off the shelf components, the small size and weight being achieved not by elaborate electronic techniques but by the logical design of the computer itself. In addition to co-ordinate conversion, the Omnitrac calculates range and bearing to any desired point within the coverage of the system, regardless of whether there is any beacon at the point or whether the des i red point is shown on the Flight Log chart. This is achieved by solving the triangle formed by the aircraft 's position , the cartesian co-ordinate origin and the desired point. Co-ordinate conversion calculation takes 0.5 sec . and rho -theta calculation 0.1 sec . so that every 0.6 sec. a new pos ition in cartesian co-ordinates and a new rhotheta is available. The full accuracy of the basic HARCO positional information is preserved in the calculations; thus range can be presented to 0.25 NM and bearing to 0.1 degree. A further advantage is that the range and bearing suffers from no line of sight limitations . As an illustration, an aircraft on the apron at Le Bourget selected the 10 NM locator beacon at Gatwick as the desired point. Omnitrac gave range and bearing whilst still on the ground and continued to supply up dated rho-theta throughout the subsequent flight to Gatwick. The flexibility offered to ATC in the choice of routes and reporting points must be immediately apparent. Development of Omnitrac II is now proceeding, using core storage and designed for half the size of the prototype . In addition to co-ordinate conversion and rhotheta calculation , Omnitrac II will accept inputs from doppler or air data as well as the basic HARCO position information, for the provi sion of an integ ra ted display output. It will also provide the digital output in a form suitable for the automatic transmission of position information to an ATC computer by digital data link. In combination w ith Omnitrac, th e ne w Mark 3 self setting Flight Log provides the pilot with undistorted pictorial presentation literally at the pu sh of a button (see fig . 3) . On selecting the required ch ar t by pu sh button , lhe display sets itself up automatically to indicate the correct position of the ai rcraft by means of a sty lus which inks

Fig . 3.

from behind the plastic chart (see fig. 1). This automatic position setting is achieved by the comparison of information read from digital tracks on the side of the Flight Log charts by photoelectric sensors in the display head, with the digitised output of the receiver. The operation of servo drives for both X and Y co-ordinates is based upon this comparison of digitised information, such that any discrepancy between stylus position and the receiver output forms an error signal which corrects the position of the stylus to conform with the position of the aircraft. With the Mark 3 Flight Log in conjunction with Omnitrac, the pilot merely has to switch on the system, select the appropriate chart by push button and the stylus is automatically set to its correct position in he pattern. Thereafter it records the track of the aircraft on the undistorted chart, further chart changes being made at the pilot's convenience by button selection . No loss of basic accuracy is involved in the Omnitrac and the self positioning facility avoids manual setting errors.

Development Potential of HARCO Any navigation system proposed to meet the needs of Air Traffic Control, particularly in high density areas, must obviously have a considerable development potential to cater for the changing demands of modern aviation . Among the techniques being actively pursued are the further reduction in size and weight of receivers and display sy stems. Auto pilot coupling is foreseen either from the digital output from Omnitrac or through the medium of optical sensors on the Flight Log feeding deviation from required track as corrective input to the autopilot, thus enabling curved as well as straight tracks to be Aown. This has an important application in busy terminal areas both for helicopters and for conventional aircraft where departure tracks are required to avoid built up areas . Development of a dual data link is proceeding by means of which the digitised position , height and identity would be automatically transmitted to the ground upon interrogation, with ground computed data and instruction s being transmitted back to the aircraft. In addition the way is open for the integration of accurate position information with height to provide three dimensional navigation information fed into the auto pilot for accurate adherence to the correct slant track .

Omn itrac self setting fligh t lag

The Operational Application of HARCO Although primarily a navigation system, the Harco proposal recognises the importance of navigation in the overall ATC System as reAected in the EUROCONTROL specification . The efficiency of any ATC system depends largely upon the organisation of the route structure and the separation standards used between aircraft on those routes . In this context, accurate nav igation plays an important role in Air Traffic Control. As currently practised , the ATC system employs airways defined by point source aids. By their very nature they tend to confine aircraft to a single track along the airway and to concentrate traffic over focal points at route intersections. The controller 's ability to separate aircraft is limited to the vertical allocation of Aight levels or time spacing between aircraft at the some level. As the operating altitudes of the major ity of a ircraft increase, there is a greater requ irement for prolonged climbs and descents. Thus vertical separation along airways is limited to aircraft at cruising altitude and time separation is so cumbersome in application as to be of little value where aircraft are climbing and descending . Yet the essential element of lateral separation, i. e. the allocation of separate track s for climb/ descent or passing, is lacking on poin t source defined airways . This vital need has to be fulfilled by radar controllers to whom the task frequently falls of providing lateral separation during altitude changes. To achieve this the radar controller is forced to vector aircraft to establish the five miles spacing . Thus his capacity to deal with conAictions dur ing climb/ descent ond at intersections is limited by the workload imposed by navigation. In summary, present methods of Air Traffic Control involve the limitations of th e procedural system with controllers verifying safe separation by an exacting mental proc ess using Aight progres s strips, supplemented by radar control working in a rigid medium in direct opposition to the lateral Ae x ib i lity required by the radar controller . For the future , Air Traff ic Cont rol has a clearly defined requirement of the na vigatio n aid. It needs a route structure, fl ex ibl e in its orientation , unhindered by poin t so urce concentrations . It requ ires area coverage to permi t chan ges to routes , reporting points and holding area s without costly and time consuming changes in ground facilities. In addition it needs a reduction in hori zo ntal separation standard to make ma xi mum use of the ava ilabl e airspace

COVERAG E

PROPOSED

RADIO

NAVIGATION

SYSTEM

FOR

EURO

CONTROL

•·

.,·

~·

~AL£ -

Fig. 4

~• . ooo.oor..

- ~ --- ......

SECTION

OF OMNITRAC CHART

LONDON

AMSTE:RDAM

'-.

"'-,_____ '""'

, -"'c-. ,

.?"t=. ,_ .

::.1"( •.;.

----~ \j __

__ .

Fig . 5

and it requires the ability to define discrete departure and arrival paths with twin or multiple en route flight paths so that the radar controller is relieved of the need to provide lateral separation by vectoring (see fig. 5). This will enable him to concentrate on the main task of sequencing the flow of traffic and monitoring safe separation, with lateral separation "built into" the route system. It is the aim of the HARCO proposal to provide these essential improvements in the airspace element of the ATC System without which the efficiency of the ground elements, however sophisticated, is bound to be impaired. There is, however, a further development allied to the HARCO proposal in the form of the air-ground-air data link, by means of which the two environments, air and ground, of the overa II ATC system con be integrated (see fig. 6).

:~r.:...---. DATA LINK

Fig. 6.

Elements of the Future ATC System_

The digital output of HARCO is presented in a _f~rm suitable for the outomotic transmission of aircraft posrtron, height and identity to the ATC computer or Central Doto Processor. Interrogation of the aircraft, at a s~anning ra.te of about ten aircraft per second per channel, rs automotrc, and the sequence can be varied at will by the controller. The way is thus open for the development of a two way system in which airborne position and height is transmitted to the ATC computer which compares this data with required position and height according to the ATC clearance issued for the flight and automatically re-transmits to the aircraft the required height and position and corrective action to attain. Furthermore, the airborne derived position and height information may be fed into the ATC computer and compared with radar derived information, for the continuous updating of visual dynamic displays for the controller. For this purpose it is vita! that the accuracy of the navigation information shall be of the some order as the radar derived data. Air Traffic Control in the future will require a careful synthesis of the best techniques availa~le. In the flexi_ble choice of route structures and reductron of seporatron standards, a precise area coverage aid with pictori?I presentation ploys a dominant role. Through the medrum of the data link, oilied with radar, the two aids, airborne and ground, form complementary and mutually checking bases on which to built on ATC System.

Conclusion Jn conclusion I should like to revert to the opening paragraphs of this paper, so that, having examined th_e HARCO proposal, we may confirm its significance for Arr Traffic Control. I can stress this in no better way than by reference to eminent opinions on the subject of navigation and Air Traffic Control. In the report of an exchange of views on automation in ATC during the Limited EUM Meeting in January, 1961, we find these comments: "Automation should not therefore be regarded as the only means for improving the air traffic situation but rather as one of a number of measures which, token as a whole, will eventually improve present techniques and procedures ... any progress in automation should b_e closely related to progress mode in other fields of air navigation, such as air navigation aids systems, and that a sound balance should be maintained between improvements mode to ground services and those mode on the airborne side." Mr. D. Thomas, Director of the Bureau of Air Traffic Management, FAA mode a number of eminently ap~ro足 priote comments in a paper to the Institute of Novigotr?n. I quote " ... the requirements placed on the navigotron element by the Air Troffic Control System are far more exacting than those required for purely navigational purposes"; and further: "The amount of airspace required by ATC to protect aircraft from collision hazards in the v:rticol and lateral dimensions is dependent upon the quolrty of position information available to the pilot, not the Air Traffic Controller. This statement assumes that the navigational responsibility will remain in the aircraft and not be taken over by ground personnel." In support of this Mr. Thomas outlines the operational requirement for Navigation: "Provide aircraft crews with 0 means of navigation which allow them to follow any route, preselected or not, without visual reference to the earth's surface, and

without assistance from Air Traffic Control personnel." I believe I need soy no more to justify my contention not only that the navigation aid is a vital element of the ATC system, but also that it is the ATC requirement which dictates the terms of the specification for improved navigation. But to preserve a sound balance of opinion let us note the pilot reaction. The International Federation of Airline Pilots Associations, an organisation from whom I know you have received much support and assistance, recommended that: "IFALPA request ICAO to take such steps as are necessary to arrange on early evaluation of the latest version of that navigation system which uses hyperbolic area coverage principles with distortion free pictorial presentation (HARCO) with a view to establishing its suitability for use in high density air traffic areas and to help solve the increasing air traffic control problem within such areas. This request should indicate that the Federation would wish to ploy on active part in such on evaluation." I trust I hove also justified my contention that HARCO can provide this essential airborne element of on effective ATC System to meet modern requirements for safe and efficient traffic flow.

Some Remarks Concerning the Possibilities

E. Roessger / G. Raenika

of Calibrating the Subscale of an Altimeter in Terms of Altitud~ (Report of the Institute for Pilotage and Air Traffic at the Technical University of Berlin, Director: Professor Dr.-lng. E. Roessger)

Summary: The system used at present of long distance flights on flight levels and of take-off as well as landing by QNH altitudes is explained. Moreover, the usual method of indicating the amount of vertical displacement of the calibration curve of a barometric altimeter in the altitude-pressure-chart by pressure values is described. Then it is shown that there exists also another simple way of indicating the amount of the vertical shift of the calibration curve by values of altitude. Finally, some methods as well as indicators and slide-rules for ascertaining of special subscale values which are analogous to the QNH well known in aviation are stated.

1. The current method of calibrating the subscale of a barometric altimeter in terms of pressure units Momentarily, during long distance flights, the altimeter subscale is set to 1013.250 mb, thus the altimeter is calibrated to ICAO Standard Atmosphere, and indicates the flight level of the aircraft (an altimeter reading of 500 ft pressure altitude corresponds to fl 5). Aircraft flying at the same isobaric levels register - aside from the instrumental errors - the same altimeter readings. This guarantees a sure vertical separation of aircraft made possible by a system of flight levels, beginning with zero flight level corresponding to 1013.250 mb [3]. During take-off and landing, the altimeter should register, as far as possible, utmost reliable and direct readings for the ground or terrain clearance. Generally, during take-off the altimeter of the aircraft is set to QNH. On reaching the transition altitude, the pilot adjusts the subscale to 1013.250 mb. The setting of QNH (Fig. 1) results in a vertical shift of the ICAO Standard Atmosphere curve by the value H,: H, = QNE - H,., = H" (QFE) - He1. (1) After vertical shifting, the calibration and atmospheric H I

ONE

\\ \ \

QFE

fig l.

The altimeter, set with QNH, indicates - apart from the meteorological factor - a measure of the clearance above msi ').The new curve - the QNH calibration curve - obtained by vertical shifting, intersects the axis H = O at the pressure QNH. The method of obtaining the QNH value from the QFE value is explained in [l] and [2]. There exist aneroid instruments to be installed at the airport that indicate the QNH settings directly [4], [7], [15], thus making redundant any calculations or tables. The subscale adjustment is carried out during take-off and landing at different altitudes. Before descent, at a prescribed reading of the 1013.250 mb adjusted altimeter, i. e. on reaching a prescribed flight level, the subscale is adjusted to the rndioed QNH value. This prescribed flight level is defined as the transition level. After climb-out, on the contrary, on reaching a fixed QNH altitude - indicated on the QNH adjusted altimeter - the subscale is adjusted to 1013.250 mb. This particular altitude is defined as the transition altitude 2 ).

There are valid the following definitions:

1. Flight levels. Levels of constant barometric pressure values, based on the 1013.250 mb isobar. 2. Transition altitude. The altitude at which or below the vertical position of an aircraft in the neighbourhood of an airport is controlled by altitudes. 3. Transition level. The lowest flight level above the transition altitude, set at the disposal of an aircraft by Air Traffic Control. 4. Transition layer. The air space between the transition altitude and the transition level. The transition altitudes have fixed values, independent of the meteorological conditions. Since May lst, 1961, the German airports have a transition altitude fixed at 4000 ft with the exception of Berlin-Tempelhof and Berlin-Tegel airports. The inte1路val between the trnnsition altitude and the transition level, i. e. the depth (thickness) of the trnnsition

\ \

curves intersect at H0 1, which signifies that the meteorological error vanishes in the airport elevation.

'"" ""' H.

QNH

Occasionally, this factor is called "tempernture co,路rection factor". Rut this factor depends not only on the air tempetature but olso on the atmospheric pressure [13), and therefore in this paper it is called

The transition altitude is co,路rectly de~ned as 0 geometrical altitude over msl, crnd not as an indicated QNH altitude. But in the daily practice of Air Traffic Control th~ geometrical altitude is set ap路 proximately equal to the indicated QNH altitude. Consequently. an aircraft is said to have passed 0 certain tiansition altitude when the reading of the QNH adiusted altimeter equals the numerical value of the transition altitude.

"meteorological factor".

OFF

1013. 250 mb

QNH calibration curve in o cold low pressure zone. ICAO Standard Atmosphere QNH calibration curve - - - Actual atmosphere (cold low pressure zone)

ONH-alfitudes flight levels

ff 20

(QNH=1007,3 mb)

----- ---

l- --

__ . - - - - - - - - - - -

2000(1

----------------L--H_j_r=S0m=l64ft

------------------

---~-----1600{/

H1 =50m=l64 ft

----~~~----1---1

f/16J1

,--

----------

--------

---1200 ft

---------------J__Hy0m=l6Ht

ff 12 -

ir- - - - - - - -

--- ---------------

--r- ---- __ 1

-426fl

f/ B

Ho=l30m=426ft

Fig. 2.

!_____

' li,1=BOm

ONE=130m

-- - L _____ ------ ----- -

The system of flight levels and QNH altitudes in a low pressure zone Flight levels (subscale setting 1013.250 mb or 0 m = 0 ft)

layer, is usually 1000 ft3). The transition level, depending on meteorological conditions, must be altered from time to time. The following can be noted with regard to the assumed airport elevation and meteorological conditions of Fig. 2: The transition levels fl 20 or fl 25 correspond to a transition altitude of 800ft and this is derived as follows.An altimeter adjusted with QNH = 1007.3 mb - aside from the meteorological factor - in the altitude of 800 ft indicates 800 ft, while an altimeter adjusted to 1013.250 mb in the same isobaric level of 978,4 mb indicates (800 + 164) ft = 964 ft, which corresponds to flight level 9.64. By the addition of the minimal depth of the transition layer (1000 ft) to this value the flight level reading 19.64 is obtainedâ&#x20AC;˘). Flight levels in the lower controlled air space are stacked at 1000 ft intervals. One differentiates the system of the even-numbered flight levels, fl 10, fl 20, fl 30, etc., and of the odd-numbered flight levels, fl 5, fl 15, fl 25, etc. 5 ). When one deals with even-numbered flight levels, then in the example of Fig. 2 fl 20 is the lowest possible transi') '')

aooft

H1 =50m=164 ff

Due to the above mentioned reasons, Berlin, with a minimal transition layer of 500 ft is once more an exception. Contrary to this argument, one can rightly state that the readingdifference of 1000 ft, indicated by the barometric altimeter, does not necessarily indicate a difference of true altitude of 1000 ft. This orgument is only true in a hypothetical otmosphere in that all parameters are identicol to the ICAO Stondord Atmosphere. On cold days, the indicoted by the altimeter 1OOO ft altitude difference is less than true 1000 It, ond vice versa on o warm doy. The relation between the true geometricol spacing between two flight levels and the meteorological parameters are referred to here. One avoids the daily checking by specifying the indicated altitude difference instead of the difference of true geometrical altitude. Even-numbered flight levels correspond, therefore, lo the pressure altitudes of 1000 ft, 2000 ft, 3000 ft, etc., ond the odd-numbered flight levels to the pressure altitudes of 500 ft, 1500 ft, 2500 ft, etc.

QNH altitudes {subscale setting QNH = 1007.3 mb or -H, = -50 m = red 50 m)

tion level, just as fl 25 is obviously the lowest possible transition level in the system of odd-numbered flight levels. The general formula for the determination of the lowest possible transition level in ft in the case of a minimal transition layer of 1000 ft depth is given by: Transition altitude

+ (QNE -

Hei)

1000 ft.

The result of the above formula must be rounded to the next highest value (in ft), both, in the even- or odd-numbered system of flight levels respectively. If the minimal thickness of the transition layer is 1000 ft, then, depending on the meteorological conditions and on the system of flight levels used (even-numbered or oddnumbered) the transition layer depth may vary between 1000 ft and 1999 ft. By a minimal thickness of 500 ft, the vertical expansion of the transition layer (i. e. the depth) varies between 500 ft and 1499 ft. Below is a curious example of data such as obtained in extreme high pressure regions. Given: He1 = 80 m = 262 ft, Transition altitude = 2500 ft, QFE = 1050 mb, QNE = -989 ft. Thus: 2500 ft +- (-989 ft -

262 ft)

1000 ft = 2249 ft.

Rounded to the lowest odd-numbered flight level gives fl 25. Thus the numerical value of the lowest possible transition level in extreme high pressure regions may be equal to or even smaller than the numerical value of the transition altitude.

Frequently, presuming the availability of air space, the transition level is so fixed, that it does not approach the transition altitude closer than 1000 ft in the case of the minimum occuring ground pressure QFE 111 ;u. This method eliminates the continous determination of the transition level. With the aid of ICAO Standard Atmosphere Tables the value Hn{QFEmin) = QNEmax is obtained, and with the difference QNEmax -

He!

the expression Transition altitude

(QNEmax -

He1)

+ 1000 ft

is derived in ft and rounded to the next highest odd- or even-numbered flight level. Imputing that, with He1 = 262 ft, the minimal ground pressure is QFErnin = 950 mb, then 2500 ft

(1773 ft -

262 ft)

1OOO ft

5011 ft.

One obtains, after rounding up, for the transition level in the system of the odd-numbered flight levels the level fl 55, which is valid for a transition altitude of 2500 ft and an elevation of 262 ft, for all meteorological conditions, especially for low pressure regions. In the system of the even-numbered flight levels this transition level that is valid for all meteorological conditions would be fl 60. The general usefulness of this transition level is payed - especially for high pressure regions - by very huge transition layers. In the above example, the transition layer in the high pressure region with QFE = 1050 mb stretches between the pressure altitudes 1249 ft and 5500 ft or 6000 ft, i. e. has a depth of 4251 ft or 4751 ft instead of the prescribed at least 1OOO ft.

1.1. Discussion of the current method in aviation of vertical stacking on basis of numerical data The following example relating to Fig. 2 will make matters clear6).

Hc1 = 80 m, QFE = 997.7 mb, QNE = 130 m, QNH = 1007.3 mb, H, = 50 m. The dotted lines (in Fig. 2) correspond to the system of QNH altitudes with a subscale setting of QNH = 1007.3 mb. By changing the subscale to 1013.250 mb, the QNH altitudes trace the flight levels - denoted by the continous curves. The flight level system lies 50 m below the system of the QNH altitudes'). For the purposes of take-off and landing, it is general current practice in aviation to express the adoption of the altimeter's calibration curve to actual atmospheric data by this pressure value in which the adjusted calibration curve intersects the abscissa axis of the altitude-pressure diagram. These pressure values may be QNH, QFE, or QFF respectively. ~values are taken from [5], QNH, corresponding ta [l], [2], is 7)

derived from QFE and H,.,. For an aircraft flying in pressure altitude H,, = 130 m, the actual clearance above msi is only (130-50) m = 80 m.

2. Methodical and instrumental advantage in calibrating the subscale to altitude values It has a Iready been mentioned [6], [11], [16], [17], [18] that there are other methods besides of indicating the vertical shifting of the calibration curve by pressure values. A glance at Fig. 2 is enough to realise that the amount of vertical shift can be characterized by an altitude as: -H, = -(QNE-H 0 I) = -(130-80) m = -50 m. By t路urning the adjusting knob of a modern sensitive altimeter the calibrating curve is moved parallel to the altitude axis (i. e. vertically) in the altitude-pressure-diagram. The adjusting gea; must make it possible to adjust the altimeter needle independent of the diaphragm movements - i. e. independent of instrumental readings. Only, with the linearity of the altitude scale, all points of the calibration curve can be shifted by the same !'1H (in m or ft), corresponding to an adjusting knob rotation of angle a. A subscale is coupled to the adjusting knob, to characterize the position of the latter. Fundamentally, the vertical shifting can be carried out in two different ways:

1. The adjusting knob, coupled with the subscale, operates with a free wheeling mechanism on the altimeter needle. This mechanism registers rotation in one direction only, i. e. the adjusting knob can be used to adjust the altimeter needle. The altimeter deflections, however - caused by volume changes of the diaphragm - are however not registered on the adjusting knob and subscale. In other words, though subscale adjustment can be used to deflect altimeter needle, deflections of the latter hove no inAuence on the subscale setting. 2. The aneroid barometer mechanism is housed in an inner casing, which can be rotated by a knob in the outer casing. This arrangement serves the same purpose as the free wheeling mechanism. By turning the adjusting knob, the inner casing rotates with the diaphragm and the needle, i. e., turning the knob has an effect on the altimeter readings. On the other hand, deflection of the aneroid membrane results only in an altimeter needle deflection without any change in subscale reading. The altimeter dial is engraved on the outer casing lid, while the pressure scale (the subscale), is fixed on the inner casing lid. A window on the outer casing lid enables one to read the pressure scale (i. e. subscale) on the inner casing. This (non-digital kind of) subscale with pressure readings is engraved or pressed on a circular disc with logarithmic spacing. It is advantageous to have full circumference for a nondigital subscale, so that the reading accuracy is not impaired by engraving a big reading range on a short subsca !e. !t is current oractice to have a pressure range of about 930 mb to i040 mb with a reading accuracy of approximate 卤0.5 mb for non-digital subscales. There are modern altimeters having a counter as a subscale. This counter or digital subscaie is coupled with the altimeter by a logarithmic distorting mechanism (logarithmic gear). Digital subscales have a greater reading accuracy with some little g1路eater reading range. The scale range and reading accuracy is limited not by the counter, but by the logarithmic gear which furthermore considerably increases manufacturing costs. 29

The present relative positioning of main and subscales, i. e. of main altitude scale and pressure subscale results in the altimeter indicating a reading of 0 m, when the out1er ressure reading set on the subsca e. pressure equa Is the P . I路 t F' 3a illustrates such a subscale of an aircraft a time er (~;~-digital subscale, calibrated to pressure values). Actual! the non-digital subscale extends - as already. me~颅 tio~ed - over the whole scale circumference. For s1mplif1cation of drawing in Fig. 3a the scale extends over a

altimeter after a vertical shift of the calibration curve relative to the ICAO Standard Atmosphere is carried out by turning the adjusting knob: When the calibration curve lies by the altitude H beneath the ICAO Standard Atmosphere in the altitudepressure-diagram then the pressure reading, corresponding to the altitude + H (plus H) from the ICAO Standard Atmosphere is to be read off the subscale. When the calibration curve lies by the altitude H above the !CAO Standard Atmosphere in the altitude-pressure diagram then the pressure reading, corresponding to the altitude - H (minus H) from the ICAO Standard Atmosphere is to be read off the subscale.

smaller angular range. . . nt The following rule is valid for obtaining the amou and correct sign of the subscale pressure value of a current

On the other hand, without any difficulty it is possible to characterize the amount and sign of the vertical shift of the calibration curve with respect to the ICAO Standard Atmosphere not by pressure values but directly by that altitude value which equals the amount of vertical shift in the altitude-pressure-diagram. The following analogous rule for obtaining the amount and correct sign of the subscale altitude value is valid: When the calibration curve lies by the altitude H beneath the !CAO Standard Atmosphere in the altitudepressure-diagram then the altitude reading -H (minus H) is to be read off the subscale. When the calibration curve lies by the altitude H above the !CAO Standard Atmosphere in the altitude-pressurediagram then the altitude reading + H (plus H) is to be read off the subscale.

. I bscale calibrated in pressure units (mb). Fig. 3a. Convent1ona su

Fig. 3b. Subscale calibrated in altitude units. . f F. 3a are car路 Altitude units analogous to pressure u;1ts ob t '~~graved with responding to ICAO Standard Atmosp ere, u opposite signs.

ea ..

D.,.,,.,

Fig. 3c.

Subscale with altitude units (similar to Fi_g. 3b) with the signs distinguished by the colour green for positive and red for nega路 tive values respectively.

One observes that in Fig. 3a, 3b, and 3c the reading O m, corresponding to 1013.250 mb pressure, is not situated in the center of the scale. The reason for this is the present practice of taking-off and landing to both QNH and QFE settings. Because of small QFE readings at high aerodrome elevation, one is compelled to expand the subscale for small pressure values, at the cost of reading accuracy. As the positive or negative signs conveyed by HF or VHF radio telegraphy or telephony could, under circumstances, be either mixed up or lost, it is advantageous to substitute positive and negative signs by green or red colours, respectively 8 ). This type of subscale is illustrated in Fig. 3c. Should the aircraft altimeter have the (Fig. 1 illustrated) QNH calibration curve, then the subscale setting (as already mentioned before) is no longer the QNH pressure value, but the altitude -H 1 (red H1 ), i. e. in the low pressure zone of Fig. 1 the subscale records a negative (red) altitude reading. The use of positive and negative signs is also avoided by adding a positive altitude reading to all readings on the subscale, which numerically is at least equal to the amount of the maximum negative altitude reading occuring on the subscale. The subscale illustrated in Fig. 4 originally had a range from -1000 ft to + 1000 ft9). By adding the constant altitude 1000 ft to all readings, the subscale now stretches from 0 ft to 2000 ft thus eliminating the sign for the readings. ")

In everyday life red numbers signify negative values, too. The blue/ yellow colour combination does not come in question, as it is used for the Instrument Landing System (ILS). There is no special reason for the subscale being symmetrical about O ft (corresponding ta 1013.250 mb).

The altitude -H, (red H,), as illustrated in Fig. 1, has a clear significance far the pilot, but this cannot be said of the QNH pressure reading. The altimeter of an aircraft on a long distance flight (calibrated to !(AO Standard Atmosphere with subscale setting 1013.250 mb) indicates (see Figs. 1 and 2) - in comparison to an altimeter calibrated to QNH - the isobars with a value H, more than the latter. On the other hand, the reading of the QNH calibrated altimeter is a nearly accurate measure far the geometrical altitude above ms!. In other words, the indicated reading of 2000 m by an iCAO Standard Atmosphere calibrated altimeter corresponds to an actual indicated QNH-altitude of (2000 - H,) m. The pilot during a long distance flight needs only to obtain his QNH corresponding altitude reading -H, radioed to him from the airport he flies over, to register lhe actual clearance above msi which he momentarily has. In Fig. 2, to the pilot is radioed the altimeter setting -50 m (red 50 m) instead of QNH = 1007.3 mb. This "altimeter setting" -50 m (red 50 m) signifies to him that the flight levels lie 50 m below the QNH altitudes. The pilot thus has 50 m clearance above ms! less than the flight levels signify' 0 ). The fallowing are the advantages of a subscale calibrated to altitude readings:

1. Linearity of the subscale resulting in a simplified construction of the altimeter and eliminating the complicated and expensive logarithmic distorting mechanism of digital subscale altimeters calibrated in pressure values. Consequently, it is not difficult to get a subscale, having a range from +9999 m to -9999 m which could be read off with an accuracy of ±0,5 m (corresponding to ±0.05 mb). Using this type of altimeter, it is possible, independent of the aiport elevation and meteorological conditions to land and to take-off by the QFE (altimeter needle indicates airport elevation as 0 m) and QNH methods (altimeter needle indicates airport elevation as He1 11 ). Such an altimeter (with digital subscale and al :1 ratio linear translation gearing) could possibly lead to a renaissance of the QFE method, as the disadvantage of ma [functioning at highly situated airports is obviated. The calibration of a non-digital subscale in altitude readings has neither advantages nor disadvantages in reading range and reading accuracy becaus~ ~he scale circumference is 360° in either case. As the d1g1tal subscaie altimeter is a newcomer on the market, and as most of the present altimeters have non-digital subscales, the apparent (from the viewpoint of the instrument designer) advantages in the method of calibrating the subscale to altitude values has not invoked particular interest, up to now.To carry out the above mentioned method with a non-digital subscalde altimeter, it is oniy necessary to change the subscale, the whole other construction is not to be altered. 2. The subscaie reading analogous to QNH render a clearer interpretation by the pilot. in example Fig. 2, the value -50 m (red 50 m) signifies a system of flight levels that lie 50 m below the system of QNH altitudes. ,l!._s the QNH altitude approximately equals the altitude above mean sea level, a iong distance flight with a subscale setting O m corresponds to a QNH altitude of ~the airport illustrated in Fig. 2 a QNH altitude of only (2000")

164) ft= 1836 ft corresponds to an aircraft assigned to flight level 20. The QFE method is also known as "zero method".

50 m less than that indicated by the altimeter. The essential disadvantage of the pilot having no proper knowledge of his actual clearance above ms! while flying in flight levels is in this manner ruled out. The pilot must only add the subscale value to the flight level reading (pressure altitude) to get his actual QNH altitude. In the example of Fig. 2 he gets QNH altitude = pressure altitude minus 164 ft. With a subscaie setting 0 m in a long distance flight the pilot attains a knowledge of his QNH altitude as well as of the tendencies of the change of the same in a greater area. It is only necessary to obtain the QNH analogous readings - H, (minus H,). When the readings are increasingly negative, the logical conclusion is that the flight levels are stacked further and further below the QNH altitudes, i. e. the aircraft approaches a low pressure region, and extra caution is called for, as the clearance above rnsl diminishes. !n this case, permission to seek a higher flight level should be obtained from Air Traffic Control. Consequently, the old pilotage axiom of flying into a iow pressure region is dangerous is a logical and obvious conclusion. The phrase "altimeter setting -50 m (red SO m)" in example Fig. 2 signifies to the Air Traffic Control personnel, that aircraft flying the flight level system approach the QNH altitude contro!!ed aircraft and the ground by SO m. On the other hand "altimeter setting +SO m (green SO m)" signifies that flight levels withdraw from the system of the QNH altitudes and the ground by SO m. This kind of altimeter settings render the Air Traffic Controller a vivid picture of the relative vertical position of aircraft in the airspace controlled by him. Aside from subscaie setting Qt'~H, the already known QFE setting is being applied. As mentioned above, the Q-Code QFE indicates the actual atmospheric pressure at airport elevation. The altimeter indicates airport elevation as 0 m by setting the QFE pressure value on the subscale. The pressure value QFE corresponds to altitude value QNE as defined by !CAO Standard Atmosphere. In order to !and at an airport analogous QFE and with altimeter subscale calibrated to altitude values according to the above mentioned specification it is obviously necessary to set the altitude value -QNE (minus QNE) on the subscale. This subscale setting - QNE indicates the amount of the vertical displacement between the system of flight levels and the system of QFE altitudes. The pilot must only add the value -QNE, i. e. the value of the QFE analogous subscale setting, to the flight level reading (pressure altitude) to get his actual QFE altitude. The latter is a measure for his terrain clearance, i. e. his clearance above HcI· Further, the Q-Code QFF defines actual atmospheric pressure at mean sea level. A barometric altimeter will indicate mean sea level as O m, when its subsca!e is set to QFF pressure value. In order to land at an airport according QFF with a subscale calibrated to altitude values the subscale must obviously be set to -Hp(QFF) (minus H11(QFF)) altitude reading. The QFF method (for reasons explained in [13]) 1s not being used anymore. See Table l for a comparitive summary. 31

3. Methods of calculation, indicators and slide-rules to determine the subscale setting analogous to QNH The subscale setting analogous to QNH can be determined easily with the help of an !CAO Standard Atmosphere Table [5]. With the pressure altitude Hn(QFE) = QNE, obtained from the above able for the actual atmospheric pressure at airport elevation, is: H,

= QNE -

H,.1

= H1>(QFE) -

HPI.

The setting corresponding to QNH for the subscale illustrated in Fig. 3b, is: SE,1. = -H,. (2) In a low pressure zone SE,i. is negative. Jn a high pressure zone SE,1. is positive. When SE 31 , = 0, the altitude QNE corresponding to the pressure QFE (specified by !CAO Standard Atmosphere) equals He1. The setting corresponding to QNH for the subscale illustrated in Fig. 3c, is: I with the supplement "~ed" for positive H, SE,c = H, 路 I and "green" for negative H, (3) Jn a low pressure zone the supplement of SE3c is "red". Jn a high pressure zone the supplement of SE,c is "green". When SE 3 c = 0, the altitude QNE corresponding to the pressure QFE (specified by ICAO Standard Atmosphere) equals Hei路 The setting corresponding to QNH for the subscale illustrated in Fig. 4, 1s: SE 4 = 1000 ft - H,. (4) In a low pressure zone SE, < 1OOO ft. In a high pressure zone SE, > 1OOO ft. When SE 4 = 1000 ft, the altitude QNE corresponding to the pressure QFE (specified by ICAO Standard Atmosphere) equals H,.J. The equations (2), (3) and (4) illustrate the necessity of measuring QFE with a barometer and then determining H, with the help of the ICAO Standard Atmosphere Table and knowledge of H.. 1. With the resulting H, one can derive the required QNH equivalent subscale settings. At an airport it is desirable to obtain the values of SE 3 1,, SE,,. and SE 4 with the help of indicators. The two instruments described here correspond to the QNH/QFE indicators described in [4], [7], [10], [13], and [15]. As the possibility of mixing up signs con arise in the case of SE 3 1,, it is recommended to have indicators only for SE 3 ,. and SE,. Both these indicators are mechanically constructed similar to the mountaineers' altimeter with a revolving ring scale, but other engraving of scales [8], [9], [14].

Table 1

Calibration curve

!CAO Standard Atmosphere

characteristics

(recommend.

elevation

for long dist. flights)

at airport

I I

Curr. altimeter with subscale calibrated to pressure units

Altimeters

Altimeters indicate 0m 0 ft

Altimeters

indicate

airport

= 0 ft

at mean

at airport

sea !eve! (ms!)

elevation

subscale setting

1013.250 [mb]

QNH [mb]

QFE [mb]

QFF [mb]

0 [m)

(H,. 1 -QNE) [m)

-QNE [m]

-H"(QFF) [m)

(according to Fig.3a) Altimeter with subscale calibrated to altitude units (according ta Fig.3b) Altimeter with subscale calibrated to altitude units

O[m)

(according ta Fig. 3c)

iONE-H,.,j

HJ>(QFF) [m] [ QNE [ [m) [m) green ar red green ar red green or red

--------------Fig. 5.

red

green

Indicator for SE,.. settings.

The aneroidal mechanism is encased in a metal box. The diaphragm and needle are connected, in a way that the latter indicates QNE on a linear scale fixed to the casing. Furthermore, another QFE scale is engraved in order to periodically correct the aneroid instrument with a mercur'. barometer. The revolving ring scale is set up on the casing. Fig. 5 illustrates the indicator for SE 3 ,. The following are the scales, commencing from center. a) a pressure scale fixed to casing, for the occasional .:cntrol by a mercury barometer; b) linear altitude scale;

Fig. 4

Symmetrical subscole with altitude units in ft. The rcoding 1000 ft canesponds to 1013.250 mb.

c) linear scale for QNH analogous "altimeter setting" (engraved in values of altitude).

(middle scale) is pulled out till 0 m coincides with the elevation (right scale). Then the cursor reading line is set on the measured QFE (left scale) and the resulting QNH analogous "altitude subscale setting" is read off the middle slider under the cursor's reading line. SE, in Fig. 10 is obtained in a similar manner, the only difference being that the slider is pulled out until the reading 1000 ft coincides with the elevation. The indicators and slide-rules illustrated in Fig. 5, 7, 9, and 10 are set once only for a fixed airport (H"1 = canst).

4. Final remarks

Fig. 6.

Positioning of the indicator Fig. 5 to determine SE, example illustrated in Fig. 2.

for the

To obtain QNH analogous altimeter setting, the outer scale ring is set with 0 m coinciding with the He1 reading on scale b (for this reason scale b has elevation etched in [m] ). Fig. 6 illustrates the reading for the example explained in Fig. 2; "red 50 m" is read off scale c. Other ranges, especially for elevation, are possible by use of other scales 12 ). The linearity of scales b and c are important for the function of the indicator. The scale a should on no account be linear, and scales band c corresponding to ICAO Standard Atmosphere distorted. The axiom of barometric altitude measureme.nt can here be once more repeated:

Flight Captain Willibald Partl of the Deutsche Lufthansa A.G., Hamburg, earns the merit of being the first, according to the authors' knowledge, of bringing attention to and making suggestions [6] for the above mentioned calibration of the altimeter's subscale in altitude values. Naturally, there is a lot to be done for this method of subscale calibration - which has many advantages - to possibly replace the present system. The change would hardly be restricted by technical or economical difficulties as the instruments with non-digital subscale in use today,

The vertical shifting of the calibration curve of an altimeter is only possible when the needle adjustment by the angel <t corresponds to the same altitude difference of ~H for all altitudes. This is only possible with a linear altitude scale - consequently all the altitude scales of aircraft and mountaineers' altimeters are linear. Fig. 7 illustrates the indicator for SE 4 • The scales a and b are the same as in the indicator for SE,c. The scale c is correspondingly changed. To obtain the QNH analogous altimeter setting, the outer ring scale is set with 1000 ft coinciding with the H,.1 reading on scale b. Fig. 8 illustrates the setting for the example explained in Fig. 2. The value 836 ft is read off scale c. To obtain maximum accuracy, a mercury barometer should substitute the aneroid instrument. The readings QFE at airport are measured with such a mercury barometer"). Figs. 9 ai1d 10 illustrate slide-rules for obtaining SE,,. and SE, from measured by a mercury barometer QFE. As in standard slide-rules, the middle scale is movable. The scales correspond to the Figs. 5 and 7 illustrated indicators. Instead of the indicator needle, the slide ruies have a movable cursor with a reading line. One notices in Fig. 9 in order to obtain SE,,. the slider

Fig. 7.

Indicator for SE, settings.

1013,25 QFE

io:co

[rnQJ

~eculiarity of QNH indicators is that to obtain better reading

13 )

accuracy different scales for different elevation ranges ai-e used The Kollsman company furnishes the QNH indicator from Colvin 115] in three different models each for a different elevation range. In question is usually' a Kew-pattern barometer and not a siphonbarometer.

Fig. 8.

Positioning of the indicoto• Fig 7 to deten111ne SE, for the excimple illustrated

F·g 2

QFE [mb]

ELEVATION [m] I- 1000

QFE [mbJ 900 -

ALT°IMEfE~·

..,,,,,

·:::·.;~;::::::

·.·.·.·:.:-:.·::::

940 __,

,~/:.:·~·q·g~:/;; _. ·::··.········

I-

b.. 920-1

I- 800

:.SETTINC?;"• 930 -: ·::..._ [m] .-....

I- 900

910 --1

0 920

[m]

t-1000

900--1

t- 900

910 -

ELEVATION

930 -

ALTIMETER I- 800 SETlilNG [ft ...20Q_ v

940-

600

1--

........

600

950--1

;;JVV

I-

500

--, 1--

400

960I- 1000

970I- 300

980I-

1500

:..... 200

9901OOO --1

i0i3,250--I

1--0

1013,250-

t---100

I-

Fig. 9.

-200

green

Fig. 10.

need only a change of subscale without any altering of Q

!'IC

Indicated reading (in m or ft) at airport elevation of an altimeter calibrated to !CAO Standard Atmosphere, i. e. pressure altitude of airport elevation. The Q-Code QNE is made use of for Hn(QFE) readings.

Hv(OFF)

indicated altimeter reading (in m or ft) at mean sea level (msl) of an altimeter calibrated to !CAO Standard Atmosphere, i. e. pressure altitude of msl.

True altitude (geometrical altitude above msl).

Pressure altitude.

Difference between QNE and H,,i, i. e. H, is equivalent to H1i(QFE) - H .. 1 = QNE - He!·

QFE altitude. Indicated reading of an altimeter with the subscale setting QFE or

Slide rule to determine SE, from measured QFE.

QFF altitude. Indicated reading of an altimeter with the subscale setting QFF or -HD(QFF). Q-Code equivalent for Hn(QFE). The pressure value used to adjust the subscale of an altimeter, so that the altimeter indicates the airport elevation in actual airport elevation.

QFE

Actual atmospheric pressure at airport (with subscale setting QFE, an altimeter indicates airport elevation as 0 m = 0 ft).

QFF

Actual atmospheric pressure at msl (with subscale setting QFF, an altimeter indicates msl as 0 m = 0 ft).

msl

Mean sea level. In German papers the symbol NN (normal Null) is usual instead of msl.

Flight level. Reading of an altimeter calibrated to ICAO Standard Atmosphere in units of 100 ft.

Airport elevation. QNH altitude. Indicated reading of an altimeter with the subscale setting QNH or -(QNE - Het).

200

QNH List of Symbols

J---

I- -

the main construction

-QNE.

--1 ~100

t- -100

Slide rule to determine SE". from measured QFE.

Hn(QFE)

2000

1030 -

1030 --1

red

1020 -

1020 --1

~ ~

-i

Setting of the subscale illustrated 1n Fig. 3b, corresponding to QNH. SE 3 ,.

Setting of the subscale illustrated In Fig. 3c, corresponding to QNH. Setting of the subscale illustrated In Fig. 4, corresponding to QNH.

Bibliography l. Betriebshandbuch fOr die Meldestellen des Synaptischen Dienstes (Beabachterhandbuch), Deutscher Wetterdienst, Frankfurt am Main, 1955/56 2. Terrain Clearance and Vertical Separation of Aircraft (Altimeter Setting), !CAO-Circular 26-AN/23, 1956 3. E. Roessger: Entwicklung und Stand der Luftnavigatian, Technische und Volkswirtschaftliche Berichte des Wirtschafts- und Verkehrsministeriums Nordrhein-Westfalen, Nr. 25, Herausgegeben von Staatssekretiir Professor Brandt, 1954 4. E. Roessger I G. Raenike: Procedure for ascertaining QNH, lnteravia, World Review of Aviation and Astronautics, 17 (1962) l 5. Manual of ICAO Standard Atmosphere, International Civil Aviation Organization, Montreal, Canada, Doc 7488 6. W. Part I: Why do we not have QNH-Settings in Feet? (lnternes Monuskript der Deutschen Lufthansa, Hamburg, 6. Dezember 1960) 7. E. Roessger I G. Raenike: Ein einfacher QFE- und QNH-lndikator sowie ein Rechenstab zur Ermittlung des QNH aus dem QFE, Bericht aus dem lnstiiut fOr LuftfahrzeugfOhrung und luftverkehr an der Technischen Universitiit Berlin, Der Flugleiter, 8 (1961) 4 8. Hohenmesser, Liste Nr. 13, Wilhelm Lambrecht, Werkstiitten fOr Technische und Wissenschaftliche MeBgeriite, Giittingen, 1/8 Li 13 (Firmenschrift)

9. Priizisions-HohenmeBbarometer Medell D 255, G. Lufft, Metallborometerfabrik GmbH., Stuttgart-S (Firmenschrift) 10. Altimeter Setting Indicators, M-98-2500-1155, Kollsman (Firmenschrift) 11. E. Roessger I G. Raenike: Die Ermittlung von meteorologisch bedingten Hiihenmesserfehlern fur die QNH-Hohen 3000 m und 10000 m uber Berlin in den Jahren 1959 und 1960 aus den Auswertungen von Radiosonden-Aufstiegen, Der Flugleiter, 8 (1961) 3 12. E. Roessger I G. Raenike: Barometrischer Hiihenmesser mit verschiebbarer sowie stauch- und streckbarer Eichkurve, Archiv fOr Meteorologie, Geophysik und Bioklimatologie, Serie A: Meteorologie und Geophysik, Springer-Verlag, Wien, 12 (1962) 4 13. E. Roessger I G. Raenike: Die physikalisch-meteorologischen Grundlagen der barometrischen Hiihenmessung, Zeitschrift fOr Flugwissenschaften, 10 (1962) 1 14. Altitude Barometers, Section 5000-S-59, Taylor Instrument Companies (Fi rmenschrift) 15. Ch. H. Colvin: Altimeter Setting Indicator, Journal of the Aeronautical Sciences, October 1943 16. W. Partl: A Proposal for QNH Settings in Feet, Navigation, Journal of the Institute of Navigation, 9 (1962) 1 17. Ein verbesserter Hiihenmesser, Lufthansa beeinfluBt die Entwicklung neuer lnstrumente, Lufthansa Nachrichten, 8. Jahrgang, Nr. 281 18. E. Roessger I G. Raenike: Sensitive Aircraft Aitimeter with Linear

Subscale Calibrated in Values of Altitude Units, The Controller, l (1962) 2

Annual Dinner of the British Guild of Air Traffic Officers One of the Guild's major social events, the Annual Dinner, took place on the 30th June 1962 in the Members Dining Room, House of Commons, London. Before the Dinner there was a cocktail reception and a very interesting tour through the debating chambers of the House of Lords and the House of Commons. A great number of high ranking aviation officials had accepted the Guild's invitation to join as guests, Captain J. T. Percy, Master of the Guild of Air Pilots and Air Navigators, being the Guest of Honour, and The Hon. Christopher Woodhouse, D.S.O., O.B.E., M.C., M.P., Parliamentary Secretary to the Minister of Aviation, sponsoring the Dinner. In his toast "The Guild" Mr. Woodhouse said: "I have great pleasure in proposing the toast tonight to the Guild of Air Traffic Control Officers.

I am therefore glad to see that in at least two ways the Guild has this year given evidence of its rapid maturity. The first is of course that it has decided to join the ladies, and so make a pleasant occasion even more pleasant. The second is that it has decided to join the International Federation of Air Traffic Controllers' Associations, a wise step on which I would, if I may, like to congratulate its governing body. Although the initials of the International Association might perhaps be thought to sound a little unflattering, I am sure that you will agree with me that Air Traffic Control is one field in which co-operation between nations and standardization of practices has most to achieve, now that the speed of modern air transport has rendered national boundaries insignificant from the traffic control point of view. As you know, the Government has been moving in this direction also by taking part in the formation of EUROCONTROL.

It is a Iways a pleasure to propose a toast to an Organ isation which displays the vigour and farsightedness which the Guild is displaying in so many ways. Especially so when that vigour is in a field associated with civil aviation, for anything which is not a step or two ahead of the rest will soon be ieft behind in the headlong speed with which civil aviation is developing.

I am glad to say that the United Kingdom ratification of the EUROCONTROL Convention is about to be deposited, so that we are the third country to ratify of the six which wi 11 comprise the in itia I Organisation.

I am reminded of the story of the two ladies sitting side by side in one of our newest airliners. One leant over to speak to the other, but the second hushed her into silence and proceeded to write on a piece of paper "!t is no good talking. We are travelling faster than sound".

I greatly hope that other countries will associate themselves with this Organisation in due course, so that the control of the upper airspace will become increasingly standardized, with all round improvement of efficiency and safety.

I hope that it is some good talking here, but we are already at the stage when deeds speak louder than words.

Already EUROCONTROL Officials have been in this country looking at the remarkable new equipments we are

developing here to cope with future Air Traffic Control problems and Defence requirements. We are now engaged in discussions with them on the many issues which arise in marrying their responsibilities into our far reaching plans for integrating civil and military Air Traffic Control over this country. That integration is itself, as you know, being energetically pursued. I do not need to emphasise the word "energetically" further than to say that the future integrated Organisation will be headed by Sir Lawrence Sinclair, who I am glad to see is among your guests this evening and who had the privilege of proposing this toast a year ago. Planning of the new Organisation has been going ahead between my Department and the Air Ministry and I am confident that it will soon reach finality. Not only are the plans well advanced, but bricks and mortar will soon be here to. We shall shortly be going out to tender for the building of a fine new Air Traffic Control Centre at West Drayton, which will control the airspace over the whole of the southern half of England on an integrated civil/military basis, and will be fed by information from a network of civil and military radars. At the same time as we are building up a vast new State system of en-route technical services and interacting aerodrome technical services, we are taking pains to see that there is a comparable standard of Air Traffic Control facilities and operation at aerodromes outside the State controlled system. As one move in this direction we are, as you know, bringing into effect a general licensing requirement for civil Air Traffic Control Officers in some six weeks time. All these changes, as I see them, should be of great encouragement to Air Traffic Control Officers generally and to this Guild in particular. On the purely arithmetical side, the expansion is remarkable - my own Ministry has doubled the number of Control Officers in its employment in the last five years, but the quality of the work is increasing perhaps faster than the quantity. Gone are the days when it was said of a certain ATCO "Give him the job and he will finish the tools". More and more sophisticated electronic equipments are being devised, but A&AEE., will not eliminate the ATCO. It can truly be said that the future Air Traffic Control Officer will be working on the very frontier of science in his particular field. Already most of the instruments he uses seem to have names so long that they have to be reduced to nicknames or strings of initials. The complexity of any job is reflected in the training which it requires, and in recognition of this we are setting up at Hurn a new Air Traffic Control Training School which will have equipment in it which will enthral! the heart of any young man interested in aviation. But he will find that interest fully catered for in the four years training that he will receive under the cadet scheme which we introduced at the beginning of this year, including flying instruction up to the standard of a private pilot's licence, and I am sure that we shall find this opportunity grasped by a growing number of young and ambitious entrants with an eye to an ever developing future. Jn short, I feel that the Guild can pride itself on being representative of a calling which has become a profession

in every sense of the word, one of high responsibility, of international standing and with a future of rapid expansion. The scope for development of Air Traffic Control, like the instruments with which it works, knows no horizons." The Master of the Guild, Mr. John Macdonald, replied to Mr. Woodhouse's toast: "May I first extend a warm welcome to all our guests. I should like to thank Mr. Woodhouse for his kind remarks about the Guild and also for making it possible for us to be here this evening in these most impressive surroundings. The Guild's view has always been that there should be some form of Unified Air Traffic Control Service, we shall therefore be very interested in the proposals for the integrated Organisation. A guest at a Lodge Dinner somewhat startled us with the suggestion that we are working with Stone Age equipment: ever since we have been apprehensive that Sir Lawrence may be planning to establish the Headquarters of the new Organisation in an ,absolutely splendid' cave in High Wycombe. We realise of course that all Controllers can't be at Headquarters but we hope that they will not be relegated to the Hindquarters. With regard to professional standards, The Guild entirely approves of the general licensing requirement for Civil Controllers to which Mr. Woodhouse has referred. To complete the picture it should be added that the Controllers in the Royal Navy and the Royal Air Force are also required to obtain qualifications of a high standard. The Royal Air Force also has a Cadet scheme leading to Short Service Commissions. In future any one who discourses ,wisely' on Air Traffic Control should be prepared to produce his 'little yellow licence' to show that he knows what he is talking about. In setting examination questions for Controllers licences it has been found that the papers generally tend to follow the same pattern. The reason for this is of course that in Air Traffic Control it is not the questions which change, but the answers. Some of the answers will, no doubt, be forthcoming at The Guild's Convention to be held at Bournemouth in October. We hope that all who are here will be there also. The Guild is already taking an active part in the International Federation of Air Traffic Controller's Asociations. Mr. Woodhouse has suggested that the initiale of the title are a little unflattering but at least we are spared the inclusion of the word ,common'. We already have Commonwealth, Common Market and even House of Commons - the word is rather common." Mr. Arnold Field, Past Master of the Guild proposed a very friendly and witty toast to the guests which was replied to by Captain J. T. Percy. Mr. Norman Vernon, a Warden of the Guild, proposed a toast to the ladies, on the occasion of their first invitation to the dinner. The editor, who was charged with the pleasant duty to represent the President of IFATCA at this event, wishes to congratulate the British Guild on the excellent arrangements, and expresses sincere thanks for the very kind EH hospitality he experienced in London.

The Proiects and Developments of EUROCONTROL Foreword At the outset I must emphasize that the EUROCONTROL Association is represented at this Conference on the understanding that the aims of IFATCA are technical and professional and that the Federation's constitution specifically excludes from its activities matters which are the prime objects of trade-unions or staff associations.

Introduction I have been asked to talk to you about the projects and developments of EUROCONTROL. These projects and developments are related to a comprehensive plan for the provision of air traffic services for general air traffic in the upper airspace of the member countries. This EUROCONTROL Plan cannot be the subject of my talk this afternoon, however, as it has still to be considered by the Council of the EUROCONTROL Association. I shall, therefore, confine myself to some general remarks about the background of the Plan and about our thinking on the principles of operation of the future EUROCONTROL ATS system.

Basic Concepts I take as point of departure the concept that segregation of general and operational air traffic in the manner widely practiced in the lower airspace is impracticable at the levels with which EUROCONTROL is concerned, i. e. from FL 200 upwards. The requirements of civil and military operators for both flexibility of operations and protection from collisions, as well as the high performance of the aircraft using the upper airspace, call for a comprehensive and flexible air traffic services system. In principle, all the upper airspace should be available to all users subject to proper measures to avoid collisions. As a general rule, airspace will not be permanently reserved for one category of traffic although exceptionally some temporary reservation may be necessary for flights not susceptible to other forms of air traffic control or direction. As we see it, in order to ensure avoidance of collision while imposing the minimum of restriction on the users of the upper airspace, air traffic control of general and operational air traffic will have to be provided jointly by EUROCONTROL and the military authorities. In the interests of operational efficiency and economy of staff, our aim will be to arrange for this air traffic control to be exercised from the upper airspace centres (UACs) to the greatest practicable extent. As an interim measure, or in areas where this aim cannot be realised, some part of the air traffic services will have to be furnished from remote radar units jointly manned by civil and military controllers working in close coordination with the parent UAC. EUROCONTROL's aim is to provide general air traffic with a "positive" air traffic control service throughout the upper airspace. !n order to simplify the ATS problem initially, general air traffic will normally be clear to fly along a restricted number of pre-determined routes established in accordance with the ICAO EUM Regional Plan. ~

At the First Annual Conference of IFATCA, Paris 1962.

R. M. Soward*

When circumstances permit, however, ATS clearances may be granted for more direct flights not along these routes. During the next five years the increasing numbers of first-generation jet airliners now using the upper airspace will be joined by second-generation jet aeroplanes of slightly higher - but subsonic - performance, while turbopropeller engined types will continue in service. The intermingling of these different categories of aeroplanes will continue to give rise to overtaking problems, as may be seen from consideration of the range of their approximate performance characteristics: Climbing Speeds

from 220 Kts to 300 Kts

Cruising Speeds

from 280 Kts to 500 Kts or more

Rates of Climb

from 1000 ft./min to 2500 ft./min

Rates of Descent

from 1200 ft./min to 3000 ft./min at speeds between about 220 Kts and 300 Kts.

The subsequent introduction of supersonic airliners will aggravate these overtaking problems particularly in view of their expected high rates of subsonic climb and descent; a wide choice of laterally spaced tracks would thus appear to be essential. It is, therefore, envisaged that the number of pre-determined routes will be gradually increased - in step with the capacity of the ATS system to handle them. Not all these routes will necessarily be available for general air traffic at any one time owing to the activities of other users of the airspace not following the route system. The aim is to provide as soon as practicable a system allowing all users the widest possible freedom of operation and the air traffic services the maximum flexibility in issuing clearances to ensure most effective use of airspace - in other words an area control system.

Upper/Lower Airspace and Civil/Military Co-ordination As most of the upper airspace traffic will climb from or descend into the lower airspace within the EUROCONTROL ~rea, often remaining in the upper airspace for a short time only, close liaison between the air traffic services of the upper and lower airspace must be assured. A survey over 47 routes in May 1961 showed that 35% of the gene~al air traffic between Fls 200 and 340 spent less than 5 minutes at cruising levels, 51% less than 15 minutes and only 270/o remained at cruising levels for more than 30 minutes. Close civil/military co-ordination is implicit in the type of upper airspace ATS system envisaged. Every effort will be made to simplify liaison: a) between civil and military controllers within an ATS unit; b) between separate EUROCONTROL units and military ATS units serving the upper airspace. Both upper/lower and civil/military liaison will be simplified by use of common sources of radar information, if

possible of identicol displays, and the use of interconsole marking. Secondary surveillance radar will provide all controllers with instantaneous and continuous identification of both general and operational traffic and with information on the vertical position of aircraft. Navigation Systems To give effect to the concept of flexibility in routeing which is necessary in order to achieve the best use of the upper airspace, aircraft will need the capability of following accurately any one of a number of laterally spaced tracks along which they may be cleared, of changing readily from one track to another at short notice if traffic conditions require and of accepting temporary detours from pre-determined routes. This capability calls for a navigational system providing coverage on an area basis with sufficient accuracy to allow use of separations comparable with those obtainable with radar. A sound balance is needed between improvements in the ground services and in the navigational capability of the aeroplanes. It is envisaged that information derived from a suitable navigational aid will in future be transmitted automatically to the ground in a form in which it can be fed directly into automatic ATC equipment. To attempt to provide the required navigational capability by ground radar would be impracticable in the EUROCONTROL area. Controllers and air/ground communications channels would be overloaded. Controllers would be distracted from their primary task of preventing collisions and the load imposed on air/ground communications would offset any reduction of communications to be achieved by full use of primary and secondary radar. The need to restrict the evergrowing demands for air/ground communication channels has recently been highlighted at the ICAO Limited EUM Frequency Assignment Planning Meeting. EUROCONTROL has issued to industry a provisional operational specification for the navigation system it considers will be needed for air traffic control. You will be aware from announcements in the Aviation Press that we intend to evaluate a navigational aid system which appears to hold promise of meeting our requirements and that other systems are under study. Radar -

Primary and Secondary

The EUROCONTROL ATS system will need a comprehensive, reliable and up-to-date picture of the traffic situation, and will rely heavily on radar to meet this need. Suitable radars sited in the right geographical locations will be essential. The radar service will have to be available, irrespective of weather conditions, at all times when aircraft are being controlled. The comprehensive radar picture will permit: a) Rapid detection of the air situation in time to allow ATC to intervene to prevent collisions or inadequate separation between both civil and military aircraft. b) Constant monitoring to verify that flights are being made according to clearances or directions issued. c) The expediting of traffic in flight by eliminating the imposition of unnecessarily large separations to take account of uncertainty about the relative positions of aircraft. d) Flexibility in control actions leading to a smooth flow of traffic. 38

e) Closer spacing of aircraft to be planned by ATC in view of accurate knowledge of the whereabouts of aircraft and the ability to verify at any time that clearances or directions are being adhered to. Secondary surveillance radar will be used in association with primary radar to reinforce the latter, to provide instantaneous and continuous identification of aircraft and information on their vertical position. The prevention of collision between general and operational air traffic will depend on the ability of civil and military controllers to see and recognise each others traffic and to check immediately whether or not aircraft observed are under some form of air traffic control or direction. Fully compatible civil and military airborne and ground secondary surveillance radar systems will be essential in order to permit the effective use of a common mode of interrogation. Display of Radar Information As just indicated, the air traffic services will use radarderived information in planning air traffic clearance, monitoring flight progress and intervening where necessary to expedite traffic or to avoid collisions or near misses. The type of display will not necessarily be the same for each purpose and evaluation of the alternative types of display will be carried out. Processed radar information may be displayed for the planning function, while raw video is more suitable for monitoring and intervention. As much as practicable of the raw radar information, both primary and secondary (including coded responses), will therefore have to be available in the UACs. Automatic Data Handling Methods of processing and displaying information by automatic means will be evaluated and where operationally satisfactory will be introduced progressively into EUROCONTROL Centres in order to: a) relieve controllers of routine tasks; b) simplify and speed up co-ordination between control positions in the same units, between different units and between the ATS and Air Defence organisations; c) predict potential conflicts and present the results of automatic conflict search to controllers in a readily interpretable form which will enable the best choice of clearance to be made rapidly. Communications

Rapid, reliable speech communications between controller and pilot and between ATS units will remain essential. There is every indication that the tempo of operation of the ATS system will continue to increase with corresponding demands on the communications system. Fu!I o~plicotion of primary and secondary radar - the explo1tot1on of the comprehensive picture referred to earlier - will. tend to reduce the number of routine 0 路1rI d groun voice communications needed for ATS purpo 路 h f ses in t e course o a flight and should thus provide increased channel space to cope with the growth of traffic and t permit rapid intervention by controllers in the event ~ radar detection of potential traffic conflicts. Autom a t~IC . . commu~1cat1ons ore envisaged as the ultimate objective for routine communications.

Controller Requirements

The introduction of EUROCONTROL services will call for an adequate provision of trained controllers. Measures to recruit and train the additional controllers needed are being actively studied in collaboration with the National Administrations of the member countries. Initially 4 categories of controllers are envisaged, Supervisor, Radar Controller, Procedural Controller and Assistant Controller. The aim is that radar controllers shall have first qualified as Procedural Controllers and have experience in this capacity. We envisage that the duties of Procedural and Radar Controllers will gradually evolve as the former make increasing use of radar-derived information, and that the two categories will eventually be merged. Nevertheless, at the UACs the work of controllers will probably be divided between "planning" and "executive" or "flight control" elements.

Traffic Statistics

The volume, distribution and characteristics of future traffic in the upper airspace are vital elements in the preparation of EUROCONTROL plans for air navigation services. Comprehensive estimates of future movements depend largely on a detailed knowledge of the current traffic, on a correct assessment of trends and on a quick appreciation of changes in trend so that estimates can be checked from time to time, and revised as may be necessary. Unfortunately, the basic data available on current traffic is generally inadequate. The EUROCONTROL Association, in collaboration with the member countries, has therefore initiated a series of surveys of actual air traffic in the upper airspace, the first of these in May 1961, a second in September 1961 and a third planned for the summer of this year. The surveys are based on the data recorded on flight

progress strips during a period of a week. This data is transferred to reporting forms, collected, processed and analysed in order to provide a basis for detailed forecasts of traffic in the coming years. What we strive primarily to obtain from these surveys is an instantaneous picture of the traffic distribution at the peak in each part of the EUROCONTROL Area, for it is the instantaneous peak load which is the principle criterion in assessing the required capacity of a control sector. Much other interesting information has come to light on the break-down and characteristics of the traffic; for example, military flights constituted 250/o of the recorded general air traffic in May 1961; 150/o of the general air traffic flights took place entirely within the EUROCONTROL Area, the remainder either entered or left the area or overflew it. To those of you from the Centres in the EUROCONTROL Countries the completion of the recording forms at the time of our traffic surveys no doubt seemed a boring and even irritating chore. I hope I have said enough to help you to realise that it is also an essential task and one which makes available much needed basic data for the planning of an improved ATS system. Summing-Up

Circumstances have prevented me from giving you more than a broad outline of our basic thinking on the future EUROCONTROL ATS system. To translate these concepts into an operational service calls not only for much detailed planning and implementation effort, but for simulation exercises and evaluation to prove ideas and equipment and to discover the best methods of application under various conditions. An intensive programme of work is entailed before EUROCONTROL services can be introduced, but these other aspects of EUROCONTROL's projects and developments are beyond the limited scope of my talk to you this afternoon.

Quartz Crystals

Quarze

for the whole aviation sector according to Mil.-Specification

flir die gesamte Luftfahrttechn ik nach Mil.-Specification

Wuttke-OUARZE Frankfurt/M 10, Hainerweg 271c, Tel. 62268

W.-Germany

The Name of the Game* In flying throughout these United States it has slowly, but surely, dawned upon me that pilots and tower operators have established a very subtle and most times friendly battle of wits. For lack of a better name we'll call it Dog Eat Dog. Actually, it's a traditional game that has gone on for years, but until now no method of keeping score has been devised. I intend to lay down some general rules and as you readers come up with your own ideas it won't be long before we will be able to dream up a score card and turn 1t in to the Ops Officer after every flight. The tower operators can send their's to the Federal Communications Commission in order to draw incentive pay for hazardous duty. Anyway, it's fun, and a standard opening goes like t~is: "Goforth tower, this is Air Force Jet 60954, a transient T-33, twenty miles North, landing information, over." The tower comes back: "Roger, 0954, landingrunwayonethreeright, windsouthsoutheastattwelveknots? usti n gtotwenty, a ltimetert"."'~~~~ n i nen i netyfrve, flytraff1cpatternatfrfteen hund redca 111n 1t 1 threeout." . Of course the tower gives out this vital information in such a machine gun rapid burst of phrases that it completely defres understanding. The pilot is still trying to frgure out what in heck has been said, but like the stalwart trooper he is he comes back with: ,_ "Roger Goforth" and starts fumbling through the iet' to frnd ' a diagram of the freld. If he 's Iuc kY down book Goforth will only have one runway and then all he has to frgure out is which way the wind is blowing. He might even be luckier and spot an aircraft landing or taking off, then he's got the direction hacked. The rest of the junk he can fake. The tower knows that the pilot hasn't understood one word of the landinq instructions and hasn't the faintest idea of where he is: but he knows where the pi iot is, so ~rinted with kind permission of the Editor, AEROSPACE SAFETY.

when the T-Bird should be on initial (provided, of course, the pilot has flipped a coin, guessed right, or looked out and has the landing direction figured) the tower operator picks up his spy glass, waits until the pilot is 31/a miles out and beats it to him: "954, threeoninitial, you'reclearedforarightbreak, callbasewithgeardown."

SCORE:

Tower-1;

Pilot-0

Then the tower closely watches the pitch into traffic and as the nose gear locks he beats him to the punch again. For effect, this simple statement is given slowly and distinctly, "54, recheck gear down, cleared to land."

SCORE:

Tower-2;

Pilot-0

The essence of this friendly game lies in the fact that no pilot wants to admit that he can't understand simple (even though rapid frre) landing instructions. After aii he's a pylut and it's really only a courtesy that he called the tower in the frrst place. If he doesn't want to play the game he can untrap himself by saying: "Goforth tower. You were cut out. Please repeat landing instructions, starting with landing runway and slow down a little bit, will yo?" This is clearly a foul, and forfeits the game. A guy like this would use a checklist,change underwear every day and attend flying safety meetings. To preserve the game, therefore, ways must be devised to let the defense catch up with the offense. As is common in these affairs, this means developing an offensive weapon for the defense. This must begin with the initial call, he must never say: "This is Air Force Jet 60954, a transient T-33, 20 miles north." He must say only: "Goforth, this is 954, landing instructions." This makes the tower think he should recognize the aircraft and you make small points if he comes back with: "Aircraft calling Goforth, say again your complete identification, please." The pilot says, "AF 60954". Then complete silence. You now have the tower on the run. He's even forgotten why you called, much less know who you are and where you are. You force him to say: "AF 60954, what is present location, are you a conventiona I or jet and what do you want?"

Like Tic Tac Toe, this is the key move - you must make him drag all this poop out of you - above all - don't volunteer anything. Then you say: "Goforth, this is Jet 54, I'm over the 'big trees', landing instructions." Naturally the tower doesn't have the faintest idea where the "big trees" are but you have mode him think he should know and he is flat shook by this time. He is so shaken that he gives you the landing info at a speed that even you can understand. Then he picks up his spy glass to find out just where in the blazes you really ore.

The tower troop has just poured himself a hot cup of coffee

.... When you get ready to taxi out, don't tell or ask the tower. Just go. When the tower sees you moving around he'll have to ask you who you are and where you're going. Score 1 point .

SCORE:

Pilot-1;

Tower-0

For extra points, you con reopen the game by saying: "Goforth, am I cleared into initial before these two other '33s out here?" You've got him on the ropes now and he's almost panicked 'cause he didn't know any other traffic was in the neighborhood (maybe there really isn't but why let him off easy?). He comes back bravely: "Roger, 54, cleared No. 1. The two other aircraft northsouth eastwest of the field, pullup, break out and re-enter traffic."

SCORE:

Pilot-2;

Tower-0

There are other ways to make points and I'll list some briefly. This isn't complete 'cause by using ingenuity, a cunning and devious mind, you can come up with at least one every flight .

.... Try to schedule your taxi to takeoff so you get to the No. 1 spot just as another plane is on a close final. Pretend you're going to take the active and listen to the immediate response from the tower. If you get away without a violation, score 3 points. .... Read back a very complicated and detailed departure without a single mistake. You've won the game for the whole day 'cause you've outhassled the ARTC sneakers and you've out shorthanded the tower. Follow these rules carefully (plus those you make up} practice a few hours a day and in a few months you will find that you have become a consistent winner.

GOOD LUCK! P. S. Please pass on any locally devised, underhanded, clever and/or cunning traps you think of. I'm always trying to add on to my list. Besides some of the tower operators have caught on to my tricks. Got skunked the last time out, 2 to 0. J LT

.... Listen to the tower give landing instructions to another aircraft, and when you make initial contact, you give the tower the ianding instructions. Score 2 points, one for initiative, one for trapping the tower . .... Circle the field listen to the tower instructions, don't say a word un,til you've pitched, then tell the tower where you ore. This is sometimes dangerous but score 1 point anyway . .... Wait until you're one mile out and request a straight in approach. This is very effective, particularly if you have reason to believe the tower troop has just poured himself a hot cup of coffee. Score 2 points, one for fiendishness, one for timing . .... When cleared for a touch and go landing, change your mind at the last minute and ask for a full stop. If there's another bird on the active, take 2 points.

Letters to the Editor Many letters have reached the editor since the first two issues of The Controller appeared. We appreciate the opinions of our readers and would like to thank them for the contributions. Industry has provided quite interesting information on new developments, which will appear in

the coming editions of the survey: Modern equipment, installations and systems for air traffic control and air navigation. Due to technical reasons the survey cannot be published in this issue.

Meinen herzlichen Gluckwunsch zur Erstausgabe der Zeitschrift "The Controller". lch hebe mich sehr gefreut, daf3 Sie mich mit dem ersten Heft bedacht haben und wurde mich freuen, wenn ich die Zeitschrift auch in Zukunft von Ihnen haben durfte. lch hoffe mit Ihnen, daf3 sich die in lhrem Artikel auf Seite 4 gesteckten Ziele, insbesondere, was die internationale Zusammenarbeit anbelangt, erreichen lessen. Mit grof3em lnteresse hebe ich die neue Ausgabe gelesen und glaube, daf3 ich in absehbarer Zeit mit einem Artikel Ober unsere Arbeit auf dem Flugsicherungssektor lhre Bemuhungen unterstUtzen kann. Mit freundlichen Gruf3en und nochmals besten Wunschen fUr lhre Arbeit.

I am writing, and am sorry to say, rather belatedly, to thank you for forwarding to me the first issue of The Controller. To say that you have produced a very excellent magazine is, to use an English phrase, putting it mildly. The articles that you have chosen in this issue have been of great interest not only to myself but also to the aircrew officers that I am associated with here at Headquarters. Air Traffic Controllers at the RCAF bases to whom I have circulated The Controller have expressed the desire to obtain copies of future issues as it is to the professional interest of us in the military as to our civilian counterparts to keep abreast of modern developments in the Air Traffic Control field. Your first issue has certainly satisfied this requirement. I trust that I am on the mailing list for future issues of the The Controller. You may be certain that they will be well read and well circulated.

Dr.-lng. Frhr. von Villiez, Technische Universitot Berlin, lnstitut fUr LuftfahrzeugfUhrung u. Luftverkehr

* In your very fine editions of The Controller, we, the radar technicians, and also other air traffic control personnel engaged in civil aviation electronics in Ireland, were very pleased to find a journal which published information which we require to keep up to date with modern air traffic control needs. We note with much pleasure your Editorial statement that this Journal will be used for both technical and procedural developments in the field of air traffic control and we look forward to your future editions of The Controller. I am writing you now as Staff Representative for the Radar Section, Dublin Airport and we hope that you will be able to help me contact the organization to which the radar technicians in Germany belong. It appears, from reading your Journal, that the radar technicians are members of IFATCA and if this is so could you give me the name and address of their Representative. If the radar technicians in Germany do not belong to the IFATCA, I would take it as a favour if you could send me the address of the organization to which they do belong. The staff here wish to congratulate you on your very excellent Journal. William Grant, State Radio, Dublin Airport, Ireland Germon Rodar Technicians ore not Members of IFATCA. Their Association is the Verbond Deutscher Flugsicherungs-Techniker e.V., President Mr. Heinrich, (505) Cologne Wahn Airport, Western Germany (Ed.).

E. F. McConvey, Squadron Leader, Royal Canadian Air Force

* I would like to congratulate you on the first issue of the "Controller". You have done a superb job with it ... ... I want to wish you continued 路success in your endeavor, and I am looking forward to your next issue. Kenneth W. Kowalke Manager, ATC Requirements IBM Federal Systems Division

* Already I have received my second copy of "The Controller" and to date my good intentions haven't produced a letter of thanks or appreciation. Please accept my apologies for not writing sooner and my sincerest thanks for kindly remembering my name and arranging for my copy. As a controller, I often wondered if there was a magazine primarily devoted to the publication of items of interest to the personnel of Air Traffic Control. In "The Controller" I have found such a magazine, and I am delighted by the high quality of its content. Again I thank you for your thoughtfulness and I wish you continued good luck in the production of this fine publication. T. G. Smith, Flying Officer, Royal Canadian Air Force

introducing

MIN

THE NEW GENERAL PRECISION MINIATURE INERTIAL PLATFORM Weighing only 14.3 pounds and occupying less than 113 of a cubic foot, the new MINS inertial platform, built by General Precision's Kearfott Division, achieves precise navigation with high reliability as well as the short ready time required by V/ STOL aircraft. It is fully operational in 4.5 minutes from -65 째 F, draws only 64 watts during warm-up, and only 14 watts while running. Utilized in a pure inertial navigation system, MINS is compatible with analog or digital computers and with high performance Doppler inputs.

GENERAL PRECISION-A WORLD LEADER IN GUIDANCE AND CONTROL SYSTEMS One or more divisions of General Precision have designed and produced guidance and control systems, subsystems or components for every major aircraft, missile or space program. GPL Division is a leading producer of Doppler navigation. Librascope Division is a leader in airborne computers. In addition , Link Division designs and manufactures aircraft simulators which are used throughout the world for flight training purposes. General Precision capabilities and hardware are available throughout the free world with field service back-up of highest professional quality. General Precision, Inc., Tarrytown, New York, the principal operating subsidiary of General Precision Equipment Corporation.

GPL DIVISION KEARFOTT DIVISION LIBRASCOPE DIVISION LINK DIVISION COMMERCIAL COMPUTER DIVISION

International Federation of Air Traffic Controllers Associations

Draft Recommendation

WHEREAS,

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

WHEREAS,

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

WHEREAS,

the Air Traffic Controller performs his exacting duty in close co-operation with pilots, which requires a high standard of practical knowledge and understanding of pilots' capabilities, flying characteristics of modern aircraft, operational performance of airborne equipment, and the operating conditions of aircrews in-flight; and

WHEREAS,

it is highly advisable for Air Traffic Controllers to become familiar with methods and problems of other ATC-units at home and in other countries by personal visits to such units.

THEREFORE,

the First Annual IFATCA Conference, held in Paris on April 26-27th 1962, recommends to all authorities responsible for the operation of Air Traffic Services: 1. to provide for familiarization flights in the cockpits of aircraft for Air Traffic Controllers with combined facilities to visit adjacent and distant ATC-units; 2. a) to encourage Air Traffic Controllers with flying experience to maintain their proficiency by offering special facilities, and b) to encourage Air Traffic Controllers without flying experience to gain such experience by providing facilities for pilot-training to the level of the Private Pilot Licence, and practice to maintain the validity of such licence; 3. to explore the use of linktrainers for the familiarization of Air Traffic Controllers with specific in-flight problems.

NOTE: "Familiarization 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 longdistance one.

the push button navigation system

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

AIR TRAFFIC CONTROL SYSTEMS

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SURVEYED · PLANNED· INSTALLED · MAINTAINED

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