IFATCA JOURNAL

OF AIR TRAFFIC CONTROL

N O . 4 .... ,

Safety by means of a closed system of radars

Surveillance radars for long-range and terminal area-coverage

Ground secondary radar stations Precision approach radars

Data processing systems Radar display and data transmission systems

for central evaluation

I . ' I ' t r1 1:~

. · ' . I 2i

z

z

...

Ill I-

Sat co

Efficient transport means prosperity

With the SATCO Free-route automatic air traffic control system, pilots at last have the ATC system that is custom-built for them. Originally designed for military aviation which required an ATC service that would enable pilots to fly any flight path or carry out any manoeuvre with minimum restrictions and maximum safety, the system has now been released for civil use. SATCO is a ground environment system: no special airborne equipment is required. It is exactly the system general aviation needs.

The system has been ordered by The Netherlands and German Governments. The first phase has been in operational use at Amsterdam since 1961 and the second phase has now been installed.

N.V. HOLLANDSE SIGNAALAPPARATEN - HENGELO - NETHERLANDS

Marconi 5264 Mk II 50 cm terminal and approach control radar

High perfor111ance, low power, lotN cost

Crystal contro lled transmitter with 50-60 kW power output

Bui lt-in parametric receiver of high sensitivity

Adjustable pulse recurrence frequency (500-800 p.p.s.)

Optional p.r.f . stagger

Capable of unattended operation for long periods- remote control faci lities are provided

Fully coherent and easily maintained MTI system of permanent-echo suppression

Conventional or 'broad daylight' display systems

~ I I I I

A target echo area of 3 sq. metres is seen from 80 miles out t o touchdown

Marconi air traffic control systems The Marconi Company Limited, Radar Division, Chelmsford, Essex, England LTD /554

Frequency range

Peak power output Aerial

Beam width

Aerial rotation speed Displays

Display ranges

9415-9475 Mc/s

70 kW nominal (60 kW minimum) 6' parabolic dish 1.4°

13 r.p.m.

12" PPI _high brightness (incorporating electronic bearing indicators which preclude parallax errors) 12±- 25, 50, 1 00, 150, 200 n. miles

Marconi Rainbow Radar

This low-priced meteorological radar is completely self-contained. The transmitter /receiver is housed in a specially designed aluminium tower. Installation, on any site, is simple and inexpensive.

Marconi meteorological radar The Marconi Company Li mited, Radar Division, Chelmsford, Essex, Eng land LTO/S8\

A Direct Bearing on the subject

of automatic vhl di equipment The EKCO VHF/OF equipment gives accurate bearing information on a transmission as short as 3 seconds

OF range About 100 miles for an aircraft flying at 10,000 ft. radiating 5 watts.

Ekco VHF/DF gives clear, fast presentation of bearings, essential for efficient traffic control and avoidance of R/T saturation . High accur­acy (maximum system error = 2°) is combined with complete reliability at remarkably low cost.

The system represents a return to simplicity, utilising a continuously rotated Adcock aerial and displaying the received sig nal as a radial trace on a 6 in . diameter C.R.T.

Single or two frequency systems can be supplied, with up to three local or remote displays.

Special features .;, Remarkably high accuracy with low cost. -:• Instant changeover from QDM to QTE. -:• ~ccura~y an.d steadiness of bearing indica-

tion. un1mpa1red by speech modulation or received tran smission.

'~ Aut~m~tic bearing indication, without sense amb1gu1ty, by a single radial line on the C.R. tube screen.

.;:- Periodical setting-up procedure unnecessary. -::- Facilities for remote control from the

indicator unit. -i:- Fully tropica lised construction.

The complete system is the indicator unit shown above, a floor-standing rack assembly and an aerial unit.

EKCO AVIATION ELECTRONICS EKCO EL ECTR O NICS LTD AV IAT I O N DIV IS I ON · S O U T H E N D - ON -S EA . EN G LAND

IFATCA JOURNAL OF AIR TRAFFIC CONTROL

THE CONTROLLER Frankfurt am Main, October 1965 Volume 4 · No. 4

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

Officers of IFATCA: L. N. Tekstra, President; G. W. Monk, Executive Secretary; Maurice Cerf, First Vice President; Roger Sadet, Second Vice-President; Ernest Mahieu, Hon. Secretary; Henning Throne, Treasurer; Walter Endlich, Editor.

Editor: Walter H. Endlich, 3, rue Roosendael, Bruxelles-Forest, Belgique Telephone: 456248

Production and Advertising Sales Office: W.Kramer&Co., 6 Frankfurt am Main NO 14, Bornheimer Landwehr 57a, Phone 44325, Postscheckkonto Frankfurt am Main 11727. Rate Card Nr. 2.

Printed by: W.Kramer&Co., 6 Frankfurt am Main NO 14, Bornheimer Landwehr 57a.

Subscription Rate: DM 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. a.n~ opinions expressed, it does only accept re­sponsibility for publishing these contributions.

~ontributions are welcome as are comments and criti­cism. No payment can be made for manuscripts submitted for publicaf · •Th . th

. ion in e Controller•. The Editor reserves e right to mak d' . . . h'ch h . e any e 1torial changes in manuscripts,

w 1 . e believes will improve the material without altering the intended meaning.

W_ritt_en permission by the Ed'1tor i·s printing any port of this Journal.

necessary for re-

Ad · · vertrsers rn ~his Issue: Cossor Electronics, Ltd. (15); The Dec~o Navigator Company, Ltd. (Back Cover'. Ekco Electronics, Ltd. _(4); N. V. Hollandse Signoolop~~raten (l);. The Marconi Company, Ltd. (2, 3); Selenia S.p.A. (Inside ~ack Cover); SODFLUG GmbH (36); Telefunken AG (Inside Cover); Wilcox (36).

Picture Credit: Bundesanstalt fur Flugsicherung (16, 17); EUROCONTROL Agency (18); Hazeltine Corporation (19, 20, 21); Solartron Electronic Group Ltd (13); Stan­dard Radio and Telefon AB (23, 24, 25, 26); Telefunken AG (27, 28, 29, 30).

CONTENTS

The United States Supersonic Transport

Raymond B. Maloy

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

Lessons learnt in nine Years SATCO

J. S. Smit

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

Bright Radar Displays ...................... · · · · · · · · · · ·

G. N. S. Taylor

Secondary Radar Implementation Dates in Europe .. · · · · · ·

Air Traffic Services at the IVA ......... · · · · · · · · · · · · · · · · ·

ATC Transponder Performance Pre-Flight Test Set .. · · · · · ·

Tirey K. Vickers and Edward M. Hunter

The SRT Philosophy on A TC Automation

J. Edwards

General Purpose Computers and CRT Displays in Air Traffic

Control ......................................... · · · ·

R. Arnolds

IFATCA Corporation Members .............. .

The International Federation of Air Traffic Controllers Asso-

ciations ....... · · · · · · · · · · · · · · · · · · ·

Altimetry at High Altitudes with a View to the Vertical Sepa­

ration of Aircraft · · · · · · · · · · · · · · · ·

Dr. Ing. Frhr. v. Villiez

6

10

11

14

16

19

22

27

32

33

35

The United States Supersonic Transport by Raymond B. Maloy Assistant Administrator, Europe, Africa, and the Middle East

The following paper was presented by FAA Assistant Administrator Raymond B. Malloy at the Annual Confe­rence of the Arbeitsgemeinschaft Deutscher Verkehrsflug­hofen, Munich, lOth September 1965.

It is a great pleasure to be with you here today to dis­cuss the next great step forward in civil aviation, the supersonic transport.

As you know, four manufacturers are conducting de­sign work on the supersonic transport, or SST, in the United States. Two are airframe companies - Boeing and Lockheed. Two are engine companies - General Electric and Pratt & Whitney. Federal Aviation Agency design contracts with these four companies began on June 1, 1964. As President Johnson stated recently in announcing a further detailed design and testing phase, a good deal of progress has been achieved in this design program in the direction of a safe, economical SST with excellent performance characteristics.

The present phase of design work is directed specifi­cally at enabling construction and test of preproduction prototypes to begin at the earliest possible time con­sistent with these objectives for a fine commercial air­liner. The development philosophy has been built on the principle that the detailed design and test phase is of the greatest importance in developing a sound aircraft. Part of this process is continuing technical, economic, and market analysis, of course, to determine and establish at this stage the aircraft that best suits airline requirements within the realistic and reasonable capabilities of indu­stry and developmental cost factors.

Twice the manufacturers' proposed SST designs have been evaluated in great detail, and further evaluation is scheduled later this year and next year as the work goes forward. Continual monitoring of contract work is, of course, also a part of the program.

The current state of manufacturers' designs as eva­luated demonstrates, specifically, the feasibility of build­ing a United States SST that can carry in excess of 40,000 pounds for 4,000 statute miles, at close to three times the speed of current subsonic jetliners, and do so at seat mile costs comparable to the best of today's jets.

Principal characteristics representative of the potential U.S. SST design, as evidenced by evaluation, are as fol­lows - and I will come back to some of these points.

6

1. Payload/range 42,000 pounds at 4,000 statute miles

2. Speed Mach 2.7

3. Primary Structural Material Titanium

4. Sonic Boom 2.0 pounds per square foot accele­ration and 1.5 psf cruise for dome­stic operation, with 2.5 psf in acce­leration and 1.7 psf in cruise allo­wed for long range international flights over water. Normal atmos­pheric pressure at sea level is of

course 2,117 psf.

5. Noise

6. Passengers

7. Takeoff Speed

Federal Aviation Agency

1,500 feet from centerline of run­way 116 PNdB; 3 statute miles from start of takeoff roll, 105 PNdB; 1 statute mile from runway on ap­proach, 109 PNdB. These, as you see, represent reduced community noise levels compared with cur­rent fully-loaded long range sub­sonic jets, with an increased noise level 1,500 feet from the airport runway from these large, high­thrust SST engines.

230 in mixed configuration (10% first class, 90% coach) with stan­dard seat spacing.

160 knots

8. Approach Speed 135 knots

9. Airports Capability of using existing air­ports.

10. Operating Costs Seat mile costs at transcontinental

and greater ranges less than cur­rent seat mile costs of the best of today's long range subsonic jet­liners.

11. Profitability Return on average investment, be­

fore interest and after taxes, of approximately 30%.

An important example of design progress in the pro­gram has been gro~th in percentage of payload. A few ~hort years ago, ma1or aviation manufacturers were talk­ing abou~ paylo.ads on the order of 6 percent of aircraft gross weight, with their aim of course somewhat higher. But these were the figu th · . . . . res ey were then seeing as rea-l 1st1c within the state of SST res h t d d d 'gn

h . earc , s u y, an es1

to t at point.

When th~ design phases of the U.S. SST program got under way in 19~3, ~he ,;ederal Aviation Agency consi­dered 8 percent typical in planning for SST operation, and 10 percent as a most desirable goal.

The best of the design proposals evaluated in our first design evaluation in early 1964 indicated a payload of 7 percent, but at an unsatisfactory range of 3,300 miles. The validated figures showed that this design would take a payload of 30,000 pounds to this maximum distance.

The second evaluation at the end of last year showed the figure at 9 p~rcent-more than 40,000 pounds for a rangke of 4,000 miles - on the basis of current design wor.

Th~re has been improvement over the past several years in a number of key areas - in materials lift-over­drag ratio, sp;cific fuel consumption, range figures. In the early 1960 s, for example, it seemed reasonable to think in terms of ranges that ran up to 2 500 miles for gross weights of 350,000 pounds or so '

Both figures have now gone up appreciably. Maximum gross weights are in the neighborhood of 500,000 pounds, alongside the increased range. But improved aircraft effi­ciency, very largely in the area of aerodynamics, has kept the increase in payload percentage comparatively "ahead" of the increase in gross weight.

In terms of passengers capacity, the primary compo­nent of payload, both manufacturers' designs currently provide for 200-plus passengers - once again an evolu­tionary increase from the concepts two and three years ago that provided in most cases for 100 to 125 passengers. The FAA request for proposals establishing performance objectives for the transport raised these sights somewhat, to the area of 125 to 160, in the summer of 1963, and the increase accelerated as design moved forward.

Weight, naturally, is a pivotal factor in achieving a satisfactory transport vehicle - with regard to both air­craft operating efficiency and airport compatibility -and the effort to hold down the weight of the aircraft is an important factor in development.

The subject of airport compatibility has received ma­jor attention from the start in the SST program. This was reflected in the request for proposals establishing aircraft performance objectives in 1963, and again in the design contracts with the two airframe and two engine com­panies that have continued since June 1964.

Under these contracts, the companies were directed to consult airport executives of fifteen large airports in the United States in connection with compatibility of designs. The airport operators stated their design views in writing to the Federal Aviation Agency as part of the second­round evaluation. The fifteen airports in every port of the country were not being "selected" for actual SST opera­tions, but were appropriate to provide the airport input for this evaluation purpose. Such airport participation will remain an essential part of development of the SST.

We surveyed airports throughout the United States a few years ago and found that more than 50 airports would be capable of handling SST operations, either at maxi­mum gross weight conditions for takeoff on interconti­nental operations or at lesser loads such as those asso­ciated with transcontinental or shorter route lengths. It is absolutely essential to the commercial success of the supersonic transport that it be capable of operation at these shorter route lengths, perhaps down as low as 500 to 600 .miles. I do not say that service requirements would necessitate the use of 50 or more fields in the United States for SST operations, but the capability would be there.

Let us turn to the matter of engine noise. This is per­~O_PS even n:o~e important to the airport's neighbors than it is to. the airline and airport operators, if this is possible.

Noise suppression hos been a factor in the U.S. SST program from the start of research in 1961. The work stateme~t fo~ each of the initial engine research contracts a~ t~at ~ime included the requirement for working toward d1minut1on and suppression of noise. So far as I know, this is the frrst engine program ever undertaken that in­clu?ed noises .as a primary factor from its inception. ~01se has continued to play an important role in objec­tives both for the engine and airframe companies as the program has gone through design phases.

Noise cha.ra.cteristics have been evaluated by noise ex­perts of the 101nt government team using the established and accepted standards of the Society of Automotive En-

gineers A-21 committee. Representatives of the airlines, airframe companies, and engine companies, along with the government, agreed to utilization of these proce­dures.

The SST engines could well achieve a real advance in this area.

As you know, the most usual way to describe aircraft engine noise today is in "perceived noise decibels", or PNdB. The largest current jets at maximum landing weights generate approximately 122 PNdB one mile from runway threshold on opproach. On the runway, at the start of takeoff roll, today's turbofan powered airliners create about 108 PNdB 1500 feet from the centerline of the runway. This figure represents a decrease of about 5 PNdB compared to the same airplane using turbojet en­gines. The community noise three miles from brake re­lease on takeoff is about 120 PNdB without power re­duction. These figures are for maximum operational gross weights and therefore represent maximum noise values. On an average, of course, noise levels will be conside­rably less because aircraft are so often operated at lower weights than maximum gross weight allowable.

Now how would SST noise levels compare? In June 1964 objectives for the SST stipulated 118 PNdB one mile from the threshold; 118 PNdB 1,500 feet from the runway centerline; and 108 PNdB three miles from initiation of takeoff roll with a cutback in power to maintain 500-feet­a-minute climb. For the design contracts since, on the basis of evaluated progress, these levels have been fur­

ther reduced to 109, 116, and 105 PNdB.

One of the primary community-noise-suppression. fac­tors for the SST will be the capability of the larger, higher thrust engines to take the aircraft to a higher altitude at any given point during the initial climbout. This increased altitude will result in reduced noise for the community.

A corollary capability for this high-thrust engine would be varying power settings in each specific airport-com­munity situation to reach the optimum setting so far ~s noise is concerned in any given case. This capability will be an outgrowth of the fact that the SST will not normally be thrust-limited during takeoff. In addition, as we have seen, a substantial number of SST operations would be expected at shorter ranges and reduced gross wei~ht conditions, once again a highly significant factor in noise reduction.

Industry has been working in this area since the start of the program. Major effort has been devoted to inlet noise reduction. Under one approach, variable geometry in the inlet design would have the capability of sig~ifl­cantly reducing the annoying compressor whine duri~g approach and landing, and during power cutback in mr­craft climbout. The inlet automatic control system would adjust the variable inlet area during these periods. In the choked configuration, the centerbody holds a Mach number grater than .85 in the inlet throat, suppressing compressor noise from the inlet. The low power setting combined with the high Mach number at the throat pro­

vides the noise suppression.

Another promising approach could be used, either in­dependently or in conjunction with variable geometry, to

suppress inlet noise. This approach wo_uld provide ~~r acoustically treating the long supersonic inlet ducts to e 11 -

minate discrete frequencies. Acoustical treorment would be applied to the inlet walls in much the same way as

7

acoustical ceiling tile is applied in an auditorium to help

eliminate noise. In itself, the lenghts of the inlet is expected to mitigate

noise to some extent. The solution to engine exhaust noise does not appear

as straightforward as the approaches I have discussed for inlet noise reduction. There are, however, a number of basic design approaches being pursued by the engine contractors to suppress these low frequency exhaust noises. Basically, the designers are hoping for important reduction through design on devices that lower the ave­rage velocity and smooth the velocity pattern of the jet. Engine nozzle designs that increase the shear area of the exhaust plume and promote mixing with secondary and tertiary airflows would promise a reduction of PNdB level for the engine exhaust. The design approaches being ex­plored include nozzle modifications and retractable ex­

haust noise suppressors. In connection with this noise design work and other

areas, it is important to remember that what we are talk­ing here today is theory - extremely solid theory, but still theory. Nobody should leave here with the thought that the noise problems of the supersonic transport have been solved, or that I have suggested they have been, but we do believe that important work is under way.

Let us look at some other SST characteristics around

the airport. This transport should have the capability of coming

over the threshold in the range of 135 to 145 knots. Lift­off speed, at maximum takeoff weight, will be in the range of 160 to 175 knots. The thrust of the engines will be in the order of 50,000 pounds per engine for a four engine transport. The aircraft will not take off with full power, because the thrust is not required for takeoff,. but for transonic acceleration. Therefore, from some view­points, this aircraft can be mu~h .more effective around 1·he airport than current subsonic 1ets.

For example, slush on the runway is a problem today from the standpoint of takeoff speed - where you rotate and how much of the runway you use up. If there is slush on the runway with the supersonic transport and there is a problem on takeoff, the reserve power is there to c~m­pensate for it immediately. If there is a loss of an engine on takeoff, there is no problem with respect to the total power required to insure a safe takeoff. From these stand­points 1 he transport should be better than what we have

today. With respect to fuel reserve, this transport will have

to meet all of the reserve requirements of the current sub­sonic jets, but how those requirements will be spelled out will have to be delayed until we know more about the requirements of the aircraft. Specifically, it will have to be able, as today's planes, to come down and take a look and then go to the alternate perhaps 300 miles away.

The reserve fuel required to perform this function is_ a factor of the configuration of the transport, the engine

design, and the fuel flow at low subsonic speeds. .

There has been some question about the manouverabi­

lity of this aircraft around the airport. It should be ~s . th t large subsonic capable of maneuverings as e curren

jets. ·11 The SST will climb faster after takeoff because it WI

h ·1 · t in order have to gain altitude at the t ree m1 e poin . to reduce the noise level on the community, but the_ air­craft will not be significantly different in its attitude

8

during climb. In the transonic speed range, passengers could note the increasing thrust of the engines but there should be little other sensation attached to going through the "sonic barrier".

In cruise, the aircraft will be much like any aircraft we know today. It will have adequate visibility to meet the stringent requirements of operational safety. The pilot will have weather radar better than we have today. There is relatively little weather, as you know, at the altitudes at which this aircraft will fly, in the order of 60-70,000 feet. There are thunderheads and clouds at those altitudes, although they are not as frequently encountered as at 35-40,000.

In descent, this aircraft will be quite normal. It will handle about the same as today's aircraft. The SST will require good low speed handling characteristics. Major attention is going to this in the design and development program.

How about sonic boom? This is another important area toward which major effort has been directed. The most notable recent programs were the study of public reaction in the Oklahoma City area and the study of structural and material response at the White Sands Mis­sile Range in New Mexiko. Extensive data on the Okla­homa c;ty program, and preliminary data in the White Sands program, has been available for some time now, and I am certain that many of you are familiar with it.

You may not be quite so familiar with some of the earlier programs. There have, actually, been eleven sepa­rate research programs in the United States in the past seven years.

One of these study efforts answered the question, "Will booms affect light airplanes?". Aircraft on the ground and airborne at Edwards Air Force Base in Cali­fornia were exposed to a series of booms at high over­pressures. Neither pilots nor aircraft were adversely af­fected.

In another study, at Nellis Air Force Base in Nevada, a large group of personnel were exposed to sonic boom pressures up to 120 pounds per square foot _ compared

to the 1.5 and 2.0 psf we speak of in connection with SST operations. Glass breakage did not occur in 214 window panes exposed to sonic boom until the overpressure rea­ched 20.0 pounds, something like fifteen times maximum stipulated for supersonic transport cruise. In another study a few years ago aimed at building response data, over­pressure levels were held to much lower levels between 2.0 and 3.0 pounds, a~d no damage was experi:nced with gla::;s or ~ther materials. These experiences agreed with later findings at v:'hite Sands, where 5.0 psf was the lowest level at which even poor quality glass was da­maged, and damage levels for other materials substan­tially higher.

Sonic boom study is continuing in the United States. The National Aeronautics and Space Administration in

its ongoing ~a~ic ~esearch program, is studying an 1

ap­proach to diminution of sonic boom through aircraft design t~at _appears promising, although it is not proven out at this lime. The U.S. National Academy of Sciences, at the request of_ the President, is providing guidance to the government in regard to sonic boom. Further flight research, and perhaps simulation as well, are also being planned.

All of this said, let me say that I do not feel the sonic boom should be seen out of perspective. It establishes

important design parameters, as do safety, economics, and other requirements, and in the case of sonic boom, the aim is to see that the supersonic transport will create no more than minimal and acceptable level. The design

challenge of the SST is obviously to develop an airplane that satisfies requirements in all of these aspects, and there is good reason to believe that all objectives includ­ing sonic boom objectives will be met.

In the field of aircraft control and display, the Federal Aviation Agency set up a major program in conjunction with the Air Force in 1961. This program has explored and

continues to explore such matters as handling qualities, cockpit workload distribution, performance, and opera­tional problems - an area that might today be termed "machine-man optimization". The objective here is to give the pilot the best possible flight control tools, including automatic tools, to assure safety and efficiency of ope­ration. The pilot remains the key element in the control loop. We must be certain that the displays available to him in some cases improve on what we have today, in some cases take the place of what we have today, and perhaps in some cases provide information that is not available today. For these purposes, we have used both

simulators and test flight programs.

Pilots from FAA, the Air Force, industry, and the air­lines have been test-flying twin-jet USAF T-39 aircraft equipped with experimental control and display equip­ment in the flight phase of this study at the Instrument Pilot Instructor's School, Randolph Air Force Base, Texas.

Major attention to date in this program has gone to the approach and landing phases. At the present time, of course, considerable attention is being devoted to all­

~e~ther operations independent of the SST program. Ob-1ect1ves for the supersonic transport provide that it be compatible with sophisticated all-weather equipments and

techniques that are themselves in the process of develop­ment and refinement in this time period.

In the air traffic control area as well, study programs have been under way for some years. These have been quite preliminary to date, but they have brought together an SST flight simulator at the NASA Langley Research Center and the FAA flight simulation laboratory at the National Aviation Facilities Experimental Center in New Jersey in a program that promises to be highly produc­tive as SST development goes forward. The two centers are joined for this purpose by land line in the manner that air-ground radio communications normally link pilot

and traffic controller. What I have been describing in general - and I am

sure there is not time to get a great deal more specific -is the rather wide-ranging research conducted prior to and alongside of design effort in the United States SST pro­gram. These programs have covered a broad range of fields - aerodynamics, materials, structures, propulsion, fabrication techniques, control systems, sonic booms, ope­rational environment, human factors, economics.

We must conclude, I believe, by answering a broad, very non-technical question. What will the supersonic transport really mean to air travel? In answering, I think it is far too easy to use the word "revolutionize". But I don't believe this word presents an accurate picture. SST's will, really, continue the evolution of air transportation that we have seen and experienced. The SST will, in fact, cut travel time in just about the same manner that the

subsonic jetliner did when it entered service. Civil aviation, through the years, has helped change

our world - shrinking it in a sense for business and go­vernment and the military, enlarging it immensely for the individual human being, and enriching the quality of human life. Supersonic transports will continue this pro­cess-safely, economically, and in the best interest of all.

General William F. McKee, FAA Administrator

General William F. McKee, USAF (Ret.), was nomi­nated Administrator of the Federal Aviation Agency by

:resident Lyndon B. Johnson on June 23, 1965, confirmed Y the Senate on June 30 and sworn in on July 1.

According to President Johnson, General McKee was rec~mmended by Defense Secretary Robert McNamara as .. one of the most knowledgeable and competent ad-m1n1strators ·1n th D f D /1 e e ense epartment .

On retirement from the Air Force in August 1964 Ge-ner~I .McKee was Vice Chief of Staff. In September 1964 he 1omed the N t. d · · . a ronal Aeronautics and Space A mrn1-strat1on (NASA) A . as ss1stant Administrator for Manage-ment Developme t . · FAA . n , a post he held prior to hrs ap-pointment.

M Born at Chilhowie, Va., on October 17 1906, General _cK_ee was graduated from West Point in

1

1929 and com-m1ss1oned a second 1· t . 1eu enant in the Coast Artillery Corps of the Regular Army.

General McKee se d · A · · I · rve in rmy assignments rn F ori-da, the Canal Zone c l"f · . . . . ' a r ornra, the Philippines, Puerto Rico and at the Norfolk Naval St t" V b f h transferred to H d a '.on, a., . e ore e

. ea. quarters, Army Arr Force 1n January 1942. He received hrs first star in 1945 d · t d . an was apporn e Chref of Staff of the Air Trans port Command in 1946. In August 1946 he went to Europe as Com d. G I man rng enera

of the European Division, ATC, with headquarters at Pa­ris. In December 1946 he transferred to USAF Europe (USAFE) headquarters at Wiesbaden and became its com­

manding general in January 1947. When the Air Force became a separate service in

1947, General McKee returned from Europe to work under General H. H. "Hap" Arnold in setting up the new ser­vice. He was appointed Assistant Vice Chief of Staff of the USAF in September 1947 and was promoted to Major General in 1948. He remained in this post for nearly six years.

In 1953 General McKee became Vice Commander, Air Materiel Command, USAF, and continued in that post when AMC's name was changed to Logistics Command. He gained his third star as Lieutenant General in 1957, and, in August 1961, was named Commander, Air Force Logistics Command, receiving his fourth star at that time. The following July he became Vice Chief of Staff, USAF,

under General Curtis LeMay. General McKee was awarded three Distinguished Ser­

vice Medals during more than 35 years of military service. He was also the recipient of the first annual Distinguished Management Award for outstanding contributions in ,A.1r

Force logistics assignments.

9

lessons learnt in nine Years SATCO by J. S. Smit N. V. Hollandse Signaalapparalen

Paper presented at the Fourth Annual IFATCA Conference, Vienna

One of the lessons learnt in the many years we have been active in the automation of air traffic control is about the controller and his attitude of mind towards automation. In an effort to make a contribution to the discussions at the Vienna Conference, I have chosen to make some remarks on this particular aspect of automa­tion as I believe they fit in your program more than any­thing else.

In the years I have been concerned with the automa­tion of ATC I have talked, worked, discussed and argued with many controllers from all over the world. And I re­gret to say that I have experienced more false notion than comprehension of the subject automation. Indeed, the controller who is afraid that automation will take away, maybe not his job, but anyway his status, does exist. Also the controller who thinks that automation will bring him heaven on earth, is not a fiction. Automation is unjustifiably condemned; there are also unjustified ex­pectations. As a result, automation is met by many disap­pointed controllers: some just because it is coming, others because it does not do what was expected.

What is so special about automation? Why is there more discussion about this type of equipment than there ever was about any other ATC equipment. The answer is obvious: automation penetrates into the controller's me­thod of working more than any other equipment ever did.

I am not trying to disparage the present role of equip­ment like radio, telephone, direction finders, radar, etc. when I col I these "tools of the controller". What I am trying to say is that h e is ~laying the_ orchestra of instru­ments; he is playing it with a considerable amount of freedom. And the orchestra arrangements vary per con-

troller. Automation will inevitably affect freedom. To a very

small extent in the beginning, but slowly it will go further. To make this clear, let us consider a strip-printing system,

0 simple form of automation. In such a system strips are printed in 0 standard way: the format is fixed, the type­size is fixed, the moment of printing is programmed in a computer. All this is identical lo every controller: a step to a more defined working method of the controller. The introduction of a keyboard for clearance and progress entries is 0 further step: the keyboard has certain input rules to be adhered to. Etcetera, etcetera.

Coming back to my figurative language: the controller will become a conductor leading a trained orchestra and he himself as an individual is no longer making the ar-

rangements. How far and how fast will it go? I do not feel com­

petent to answer that question. Eventually, I believe, it . ·11 f . We> may expect it will also go fast. But I am WI go al. ~ ·

convinced that the control responsibility - i. e. the deci-sion of how the traffic should be cleared - will, in what ioday we col I the foreseeable future, remain on the shoul­

ders of the human controller.

10

Why does the controller have to be bothered with automation now? Why does he have to get part of his work programmed by a machine? Why is his freedom going to be affected, even when it does not seem to go better or easier, or even it may be more difficult to begin with? Why does he have to argue with computer-mad people who ask him silly questions and eventually only produce a printed strip ... ?

The answer to all these questions is not obvious to everyone, although it is not difficult. Automation, automa­tic dot~ pr~cessing, automatic data handling, or whatever name is given to it, is the only way which will enable ATC to make good the arrears and catch up with aviation.

. The main reason why automation, and only automa­tion, can do this is that a central data processor will be­come the coordination-medium. The bottleneck of control­ler-to-controller coordination will be replaced by con­trollers working with a computer as 0 common source of information. They have to feed data into that computer, but also can extract data from it. And there we come to the crucial point: the data is available and can be distri­buted_ to and_ used by many who to-day are devoid of that information for the simple reason that the human coordination-capacity is saturated. There lies the enor­mous ?dvantage of automation: the ATC system can grow, 1t can do more things than it ever did before. This is the important issue at stake.

Automation will not necessarily make life easier for controllers .. In the beginning, maybe, even the contrary is true .. Espec1_ally_ of those controllers working in an admini­~tration ":h1ch 1s actively involved in the development and intro~uct1on of automation in ATC, much will be deman­

ded in terms of skill and perseverance. Automation will

?ffect their wor~ing_ ~ethod and quite likely not always ~n a wa~ every ind1v1dual likes to see it affected. But in introducing automation in ATC m b th. · h d to . . - ay e 1s 1s ar say for this audience - the individual controller is not the most important issue nor 1·s an · d. ·d I t I po

. . ' in 1v1 ua con ro -~1ti_on. The ATC system, and consequently a v i at ion 1s involved ~nd au~omation of ATC can only be judged from that wide point of view. This, I am afraid, is not alv;ays. e?sy,. in particular not for those faced with the daily d1ff1cu_lties of a particular control position.

_Automation will rationalize the ATC system. It may be painful that part of the controllers' freedom will disap­pear. In particular that part of "freed 11 h. h · fact

II 11

• om w 1c , 1n , means no rules . But this does not mean that the con-troller in an _automated system may be less skilled than to-day. I believe that automation will require different, but definitely not less and may be even more skill of the human controller .

T~e contr?ller of to-day plays an extremely important role in the history of ATC. It is up to him to take courage and face .automation with an open, positive mind. Then, I am convinced, the result will be positive for aviation, for air traffic control and for the controller.

by G. N. 5. Taylor The Marconi Company

Paper presented at the Fourth Annual IFATCA Conference, Vienna

In Air Traffic Control a radar display is used mainly for monitoring purposes and the ATCO does not normally expect to spend all his time looking at it. He has other things such as the flight progress board to look at as well. Unfortunately the low brilliance of the conventional radar display means that ATC rooms have to have a low am­bient light level if the radar displays are to be used effec­tively.

Where air traffic density is low a compromise must be struck between the need for a controller to see his radar display in almost darkness and his flight progress board, brightly lit, at the same time. In areas of higher density it is often necessary to have two controllers for each sector, one at the radar display in a dim ambient light and the other at the flight progress board in normal lighting con­ditions. This immediately introduces liaison difficulties. A­part from the operational problems there is also the de­pressing psychological effect of working in the sort of jaded night club atmosphere that most radar-equipped centres seem to produce.

Such a situation is obviously not tolerable and for the past ten years or so work has been proceeding on ways of producing a PPI display having sufficient brightness to enable it to be seen under normal room lighting and daylight conditions. In the last two or three years there has been an increasing interest in bright displays from ATCO's and at some centres in the world particularly in the United States a considerable number of bright dis­plays are already in operation.

What basically is the problem in producing a bright radar display? Essentially it is the fact that a PPI radar picture has a very slow data renewal rate, the whole screen being scanned once per revolution of the radar aerial. Any attempt to brighten the scanning trace alone adds nothing to the improvement of the display itself. What is required is some way of brightening the afterglow or stored part of the picture because it is this that the con­troller actually looks at.

The conventional PPI display using a cathode ray tube having an aluminium-backed sodium fluoride phosphor has now reached a high degree of sophistication. It has by far the best definition and sensitivity to weak signals of ~n~. type of display and is capable of more individual flexibility at lower cost than any bright display system. The ?ctual display unit which is built around this type of tube is compact and simple and is ideally suited to both simple r~w radar and complex computer-controlled systems with high speed alpha-numeric characters .

. If one could merely make this type of display 100 times brighter there · d b · I b . . is no ou t that 1t would supersede ot 1er

n.ght display systems overnight. Unfortunately it is not quite as easy as this although, as will be explained later, future ?evelopments in the display of radar and other in­f?rmat1on .for ATC purposes will probably be along the lines of this type of display.

. The first s~ccessful method of producing a brighter PPI display was in the conversion of the radar picture into

the form of a television signal which could be displayed on a normal type of television monitor. Initial experiments of pointing a television camera at a radar display were not very succesful although reasonable results were achie­ved by using special camera tubes. The system was much more successful when a special scan conversion tube was used and after several years work good systems have been produced in France and the United States. Basically the tube consists of a storage layer in the form of a plate in the middle of the tube, a writing gun faces one side of the plate and a reading gun the other side. The writing gun is operated in a similar way to a normal radar dis­play cathode ray tube and in effect "writes" a radar pic­ture in the form of electrostatic charges on the plate. These charges are stored on the plate which is mean­while scanned by the beam from the reading gun in the form of a television raster. The output signal is taken from a collector ring adjacent to the storage plate. As the storage plate is completely scanned 50 or 60 times a second by the reading beam a picture of normal televi­sion brightness is displayed on the monitor. The storage time of the converter tube can be adjusted to provide a gradually decaying radar picture of several minutes per­sistence.

The system is basically fairly simple if only a raw radar display is required. The monitors can be quite simple, provided they have good timebase linearity, and a large number can be used with a single converter tube. Diffe­rent sizes of monitor display can easily be provided as tubes are available up to approximately 27 inches (67 ems.) in diameter. The resolution is not as good as a nor­mal direct view fluoride tube but is probably adequate for short and medium range applications with conventio­nal ATC surveillance radars. Brightness is good enough for use in moderately lit rooms although it is not really high enough if a display is required in the control tower cab. The brightness level is of the order of 75 ft. lamberts compared with a frgure of 1 to 2 ft. lamberts for the after­glow of a fluoride tube. It is necessary to use about 1,000 lines to make up the raster if lineiness is not to be an­noying to the controller although the system itself is not at present capable of this degree of resolution. Flicker can be reduced a great deal by the use of a frame fre­quency of 60 cycles rather than the conventional Euro­pean frequency of 50 cycles. The difficulties start to arise as soon as flexibility is demanded. For example all moni­tors working from one scan converter are obliged to dis­play the same radar range. Similary the same degree of off-centring must be accepted at all monitor positions. The only satisfactory solution to this is to have one scan converter for each monitor display and although the writ­ing circuits and some on the reading side can be shared between a number of converters the increased cost is con-

siderable. Further complications arise when data handling has to

be added. Track markers must be fed in on the "reading" side of the systems if they are not to appear on all moni

11

tors simultaneously and to maintain accuracy between the reading side and the radar signal on the "writing" side demands a high degree of mechanical and electri­cal precision in the scan converter. In addition it is not very easy to produce even a simple ring marker on a tele­vision system and a considerable degree of complexity is required if markers and alphanumerics have to be dis­played. In fact, the further ATC systems progress towards synthetic displays, the more complex and less suitable scan conversion seems to become.

An alternative approach to the production of bright radar displays has been the development of the direct view storage tube (DVST). This also has a writing gun which directs electrons on to a storage plate. The plate is normally charged negatively and the radar picture is writ­ten on it in the form of areas of positive charge. A "flood" gun is mounted coaxially around the writing gun and this floods the storage plate with slow speed electrons. The plate acts like a stencil and allows the electrons through on to the phosphor screen only in the positively charged areas. The phosphor is of a high efficiency short persisten­ce type and emits a pale green light under electron bom­bardment. The plate has an exceptionally long storage capacity and, for use in a practical PPI application, means must be provided to allow it to recharge slowly at a con­trolled rate. As the whole of the storage plate is being flooded with electrons all the time the light output from the phosphor is continuous. The flood gun current is of the order of milliamperes compared with microamperes of beam current in fluoride and television displays, so the picture can be very bright. Figures of 1,000 to 2,000 ft. lamberts are normally realised and the display is quite bright enough for full daylight use in the control tower

cab.

In operation a PPI display built around the DVST is very similar to the conventional direct view fluoride dis­play. Each display has independent control of range chan­ging and off-centring; persistance is adjustable to suit operational and ambient light conditions and a switch allows the radar picture to be instantly erased when re­quired, for example when the off-centring is changed.

The resolution, although not quite up to the fluoride display, is now good and probably better than a scan converted picture. Accuracy is as good as a fluoride and in fact the whole display design is identical in practically all respects to the conventional type. The only differences lie in the provision of an intermediate high tension supply and the erasure circuits.

The development of the DVST hos been rather slow, first of all due to the problems associated with the tube

manufacture. Early tubes only hod a 4 inch (10 cm) use­oble diameter but an 11 inch (28 cm) tube is now available, having a useful screen diameter of 91/i inches (24,5 cm). Larger tubes have been made in the United States al­

though their resolution is not good enough for normal radar applications. There were a number of problems associated with the peculiar characteristics of the tube, these have now been solved and the daylight viewing PPI display has now reached the production stage. In pro­duction forrn it can be identical in size and shape to a nor­mal fluoride display and has the advantage that it can be designed to work from the same back-up equipment. Its introduction into ATC centres can therefore be made

simply and economically.

12

The outstanding problem has been the introduction of markers and alpha-numerics to these displays. If applied in the normal manner there is a danger of the markers "smearing" and tending to confuse the radar picture. This problem has now been solved in the laboratory and it only remains to apply the solution to a production design.

As far as its economics are concerned, the DVST comes out well. Although the tube itself is expensive, its life is confidently expected to be of the order of 1 O OOO hours or more. The cost per hour therefore compare

1

s very fa­vourably with a fluoride tube. As the actual display cir­cuits are very similar to those of the fluoride type the cost of a complete DVST display is also of the same order. In ~ractice,. therefore, the DVST display comes close to the ideal bright fluoride display postulated earlier in this paper.

Yet another type of tubes has been produced which may have so~e applications as a bright PPI display. This is the fibre optic tube. It consists of a conventional fluoride ca­thode ray tube but in front of the phosphor are placed a large number of small transparent fibres each lying with one end against the phosphor and the other towards the front of the tube. light from the phosphor enters each frbre, travels along it and emerges at the other end. In effect each phosphor acts like a small lens the sum effect being to concentrate the light output over ~ comparative­ly narrow ang~e. of view so that a brighter picture is pro­duced: In add1t10.n each frbre is coated with an opaque material so that light can neither enter nor leave it except ~t the. ends. C~nsequ:ntly extraneous light from the room in which the display is operating is not reflected from the front surface of the tub d th · · · proved.

e an e picture contrast 1s im-

No figures on the performance of the tube in radar dis.play .are available but the brightness is believed to be quite high. Whether a · · Id b narrow viewing angle wou e acceptable for ATC purpose is open to doubt.

What of the future? It is clear that in the next few years more data handling syste ·11 b d · h" h . . ms w1 e use in 1g traffic density areas and the 0 t t f h t . u pu rom sue sys ems will probably. be indicated on synthetic PPI displays. In these there will be no raw rad · I d I I . . ar s1gna s an no s ow Y rotating trace. Aircraft will be ind· t d b d "th .d _ . d h . h h ICC e y ots WI I en tity an e1g t s own by I h · h . . a P a-numeric characters. Ot er information can easily be indi'cat d II 8 .t . e as we . ecause 1 1s not necessary to show raw rad · f · h d t ar 1n ormat1on t e o s and characters can be cycled aro d · "di d th . un quite rap1 y an e present fluoride raw radar display A . I d' . . spec1a me 1um per-sistence phosphor can be used to fl" k I . . . remove any 1c er. n add1t1on to being bright the displ · h I d ay 1s very s arp y e-f1ned and of excellent resolution.

This type of display is available t d d d . . . o ay an pro uces a very good _picture. It is In fact virtually identical to the modern fluoride PPI but with 0 change f h h th . o p osp or on e tube face. The ob1ection to the fluo ·d t b f h .

. . . ri e u e o av1ng a low brightness 1s immediately remo d th t" . ve once syn e 1c displays are accepted. Scan conversion then becomes an unnecessary complication a corn pi· t. h. h ' 1ca ion w 1c gets worse the more data handling methods . t d d are 111 ro uce .

Summarising the plan ·t· d" . . . pos1 ion 1splay situation 1t can be seen that a logical developme 1 h t k 1 ' n as a en p ace over the years from the original two ph h t b th h . osp or u e, roug the fluoride frxed coil display on to th h" h d h . . . ' e 1g spee c a-r~cter wri.ting fluoride display and then to the synthetic display with only the latter being bright enough for use

in conventionally lit rooms. Scan conversion appears as a diversion from th is main line of development in order to achieve a bright raw radar p icture. As such it fulfi lls an immediate ATC need but it is not really suited to fur­ther development into the field of synthetic displays. At­tempts to adapt the technique to these ends can only re­sult in costly complexity.

The Direct View Storage Tube has also been develo­ped to meet an ATC need but a s both technically and

Canadair transportable Control Tower on Display at Paris Air Show

One of Canadair's latest developments is a transpor­table con tro l tower, wh ich in less than one day can be erected by two men and be fully operational.

The tower is designed for a number of applications such as a permanent air traffic control centre for small airfields or underdeveloped areas, temporary traffic con­trol for emergency use and control for rapid deployment of military forces on forwa rd airstrips. It con be trans­ported by on aircraf t or medium helicopter having a door opening size not less than 45" X 46" (l.143 m X 1.168 m) and a payload capability of at least 5,600 lb. (2,538 kg).

Completely self-conta ined wi th its own power gene­rator and batteries, the tower is equipped with survei l­lance radar, VHF v isua l direction finder, identification radio beacon, rad io communications foci lities and a com­munications logging recorder.

The structure consis ts of thirty-one assemblies that in­terlock together to form a hexagon-shaped control raom. Fully insulated, with six viewing panels of one-quarter inch heat absorbing trapezoid glass, the room is air-con­ditioned with ventilation and heating to match cl imatic conditions ranging from tropic to arctic.

Provision is made for levelling by screw jacks attached to the floor panel structu re.

operationally it is a close cousin of the conventional direct view fluoride display it is not diverging from the main stream of development and it probably has on assured future as a very bright synthetic display for use in h igh ambient l ight conditions. The storage characteristic may also be useful in reducing the load on the computer equip­ment by allowing a slower recycl ing time to be a chie­ved.

SOLARTRON High Resolution Video Map SY 2046 For the first time shown at the Paris Air So lon 1965, the Single Bay vers ion of SOLARTRON 's H igh Resolution Video Map is identical in performance to the Double Bay version w hich was on display at the IFATCA Conference, Vienna. It is intended to meet the case where equipment room is limited. The only disadvantage, from a mainte­nance viewpoint, compared with the Double Bay version, is tha t it does not provide room for a built-in oscilloscope.

. ..... . ... .. : .

0 0

• •

13

Implementation of Secondary Radar

Amendment to EUROCONTROL Information Circular N° 2/1965*

1. Since the publication of Eurocontrol Information Circular N° 2 dated 27th February 1965, it has become apparent that some of the earlier dates for requiring the carriage of secondary radar transponders, already published by certain States and incorporated in the Eurocontrol Circular, cannot be adhered to for two main reasons:

a) A large number of aircraft likely to fly in the upper airspace ore not yet equipped with the requisite transpon­ders;

b) The installation of ground equipment at ATS radar units has not progressed at the rate anticipated.

2. In these circumstances, and in order to achieve the best possible coordination in the use of SSR in the Eurocontrol Area, 0 revised date has been agreed for requiring the carriage of secondary radar transponders in the United Kingdom and the Netherlands UIRs. This new date, 1 st July 1966, coincides with that already published for part of the UIR France.

3. The table below, which supersedes the Annex to Eurocontrol Information Circular N° 2/1965, gives the amended timetable now envisaged, with additional information concerning the Shannon UIR.

Published in THE CONTROLLER, Vol. 4, No. 2 - April 1965.

Dates for Requiring Carriage

1. 7.1966

I 1. 4. 1967

I 1. 7. 1967

1. 6. 1968

Region

France UIR Paris Sectors

Amsterdam UIR

Scottish UIR London UIR Preston UIR

France UIR Paris Sectors

Brussels UIR

France UI R Bordeaux Sector

France UIR Marseille Sectors

Amsterdam UIR

Brussels UIR

Hannover UIR

Frankfurt UIR

Scottish UIR Preston UIR London UIR

Shannon UIR

I

Flight Levels

FL 250 & above

FL 200 & above

FL 250 & above

FL 250 & above

FL 200 & above

FL 250 & above

FL 250 & above

FL 200 & above

FL 200 & above

FL 200 & above

FL 200 & above

FL 250 & above

FL 250 & above

I Entire Eurocontrol Area ----- __ 1 _________ _

14

Transponders

Modes Codes

A-B 64

A-B 64

A-B 64

I A-B

I 4096

c 4096

A-8 64

A-B 64

A-8 64

A-B 4096 c 4096

A-B 4096 c 4096

A-8 4096 c 4096

A-B 4096 c 4096

A-B 4096

c 4096

A-B 4096 c 4096

D 4096

Remarks

Notes 1, 2 & 3

Notes l, 2 & 3

Notes 1, 2 & 3

I Note 2

Notes 1, 2 & 3

Notes 1, 2 & 3

Notes 1, 2 & 3

Note 2

Note 2

Note 3 Note 2

Note 3 Note 2

United Kingdom Civil Aviation Information Circular N° 63/1965 dated 28 June 65 refers. Note 2

Note 3 Note 2

Note 4

TYPE 1500 MILITARY /CIVIL TRANSPONDER The simultaneous use of common airspace by c i vil and military aircraft intensifies the critical !1ecessity for more efficient A .T.C. systems. Secondary Surveillance Radar provides this '":'P.rovement. Civil Aircraft fitted with transponders already.benefit from the advantages of such a system, as : 0 t~e ground control stations. Military aircraft can now fit transistorised transponders ~m racmg the entire range of performance features for operation in any A.T.C. Secondary T adar area in the world. .

.h~I Cossor SSR.1500 transponder is designed to meet the divers requirements inherent '" CIVI and "l't T _m1 • ary operations.

het. equipment reliability is extraordinarily high; yet the transponder is designed for ~tn muous operation at temperatures up to +140°C and altitudes up to 100,000 ft. (1 1~ e;,~emely compact, weighing only 27 lbs, yet inco~porates all militar_y and c_ivil modes T' ' ' B! C .and 0), and functions in 2 and 3 pulse side-lobe suppression environme.nts. f1 he.~~:11size1s achieved by unusually high component density; whilst retaining sufficient

exi 1 1 Y and accessibility fo r rapid maintenance. 'f~eAS~Ri500 complies with the requirements of Annex CCB. to 29/69 CANU KUS (military), · · · · nnex 10, and relevant sections of Arinc characteristic 5320.

f~ OSSOR COSSOR ELECTRONICS LIMITED (RADAR DIVISION), (Subsidiory o f A. c . Cessor Limited and ol Roythcon Company U.S.A.)

THE PINNACLES, ELIZABETH WAY, HARLOW, ESSEX. Telephone: HARLOW 26862

Flugsicherungs- Beratungsdienst

. ·.; ~""': ... ~ ·~ -

' "' ~ ': ~-2:·-'-

, ..

1

ATS

Air traffic constituted an essential part of the First International Traffic Exhibition , (IVA) which was held in Munich, Germany, from June till Sep­tember 1965.

It was an impressive show and there would be many interesting things to report about, for instance the ex­cellent displays of Deutsche Lufthansa AG, or the ve ry instructive airport mo­dels exhibi ted by the Arbeitsgemein­schaft Deutsche r Verkehrsflughofen . But printi ng space is limited, so we can o nly deal wi th a small cross-section of the subject which is our main edi­torial topic: Air Traffic Services.

The Air Traffic Services were wel I de monstrated at the Munich Exh ibi tion by the Bundesanstalt fur Flugsicherung (Federal Agency for Air Navigation Services) and by EUROCONTROL.

Simulating live conditions, the Bun­desanstalt fu r Flugsiche rung hod pre­pared several stands, manned by ATS staff, each representing a branch of

l AIS Office wilh airways chart ZelfoX facs i­mily transmiller, and visual ~ids for night plann ing.

2 Tclocammunicalians slalian. The stand a n 1he righl i ll uslral~s lhc objectives of ATS by moons o f va rious mock-ups and displays.

3 En(Jineering and technical maintenance stand wilh several lechn ical equipmenl, monilor­and conlrol desk, and mullichanne l recor· dc rs.

at the

IVA

the services. The visitors, passing from the AIS stand via Telecommunications, Tower, and Approach to o mock-up of on Area Control Centre, could thus fo llow on IFR flight in a ll its phases and gained a lively impression of the tremendous ground organisation which is necessary for the safe and efficient conduct of flight.

The information at the stands was supplemented by a film on radar con­trol, edi ted and produced by o Ger­mon controller.

On the very instructive EUROCON­TROL stand, the European upper air route sys tem was illustrated, and va­rious mock-ups and displays highligh­ted the particularities and problems of traffic control in the upper a ir space, which hod led to the creation of the European Organisation for the Safety of A ir Navigation.

(Pictures courtesy Bundcsonstolt !Ur Flugsiche­rung ond EUROCONTROL Age ncy)

4 Control tower cob.

5 Approoch control mock-up.

6 Arca control centre with Oight progress boards, vertical ond Oot tube rodor displays, oreo charts, ond Zetlox locsimily equipment.

Flugsicherungs-Kontrolldienst Ff ughafenkontrolle

'

• -. . . ~

--

·-------

18

ATS

at the

IVA

~ Symbolized upper o i r route system in the EUROCONTROL member countries. In front - three-dimen­siona l displ ay of o i rcroft in the upper ai r space.

~ Mock-up of the EUROCONTROL ATC Simu lator, Experimental Centre Bret igny.

ATC Transponder Performance Pre-FlightTest Set

Purpose

The Air Traffic Control Radar Beacon System (ATCRBS) is intended to provide the oir traffic controller with con­tinuous, accurate, and reliable information concerning the rho-theta pion position, identity, and altitude of the trans­ponder equipped a ircraft under his control.

More and more, aircraft separa tion is being based on transponder-derived data. Since 1962 in the United Stoles, a functioning transponder hos been o prerequisite for flight within designated Positive Control Airspace areas.

Because ATCRBS is o co-operative system, i ts successful operation depends on the proper functioning of the air­borne as well as the ground equipment. In the post, o malfunctioning airborne transponder could either foil to produce a secondary radar target on the controller's dis­play, or in some cases could degrade the display with un­necessary clutter.

Now that more sophisticated beacon equipment and a lphanumeric ATC displays are coming into use, certain malfunctions of on airborne transponder can produce on erroneous readout of aircraft altitude or identity data on the con troller 's display. These possibilities generate an increasing need for a fast and positive means of checking the performance of aircraft transponder equipment, at suitable intervals.

To meet this need, the Hazeltine Corporation has re­cently completed the design and construction of a new ground-based equipment which is known as theATCTrans· ponder Performance Pre-Flight Test Set. The prototype equipment was developed under o Federal Aviation Ag~n­cy contract, and was delivered to the FAA Nationa l Avia­tion Facilities Experimenta l Center (NAFEC) in October, 1964.

The Test Set is designed for instal lation near o taxi strip, or other convenient test area, at an airport. Its pur­pose is to verify the proper operation of aircraft trans­ponders, prior to take-off .

. The test set directs coded interrogations to a sing.le aircraft within the test area. If operating correctly, the air­craft transponder sends bock replies which are evaluated ?utom~tica lly by the test set. The test results ore presented immed.iately to the pilot, by means of o large bil lboard type display unit. They ore presented simultaneously to the to"."er controller, by means of a remote monitor display unit.

Hardware

The test set ·s . · t h . 1 comprised of the electron ic equ1pmen

group s own 1n F 1 h h · F. 2 ig. ' t e main billboard display s own in 1gure , and th h · F 3 It 1 . e remote monitor display s own in

higure . · F.a so includes a 5-foot L-Band horn antenna. As

s own 1n 1gure 4 the h d · I 150 f ' orn antenna is instol le approxi-

mate Y eet from the center of the destignated test area.

by Tirey K. Vickers and Edward M. Hunter Hazeltine Corporation

The main billboard display is located within 200 feet of the test area, and is p laced for convenient viewing from the cockpit of an aircraft parked in the test pattern.

The remote monitor display is designed for installation in the airport control tower. However, it may be located as much as five mil es from the electronic equ ipment group, if necessary.

The electr?nic equipment group is housed in a shelter hut, on the. airport, within 100 feet of the main billboard display. This equipment group contains on interrogator/ receiver, a video processor, a se lf-test unit and the re-lated power suppl ies. ' Fig. 1 Equipmenl Group

19

Test Functions

The test set is designed for continuous outomotic opera­tion, in checking the following transponder parameters :

Receiver Sensitivity Transmitter Frequency Pulse Spacing

Mode C Altitude Report

T ronsmitter Power Pulse Width Mode 3/ A

Identity Code Number Identification

of Position (l/ P) Feature

The var ious functions of the Test Set may be expla ined by referring to the simpl ified block diagram shown in Figure 5. Blocks ore numbered for easy reference.

The Coder (1) generates the tim ing and gate pulses for the Electronic Equipment Group. Essent ially, it divides the test cycle into Mode 3/A and Mode C intervals.

The T ransmilter (2) genera tes low-level RF inte rroga­tions.

The Attenuotor (3) limits the output of the transmitter to o level which, when detected by the tronsponder at the 150 foot operating range, will el icit a reply only if the tronsponder's receiver sensitivi ty is above the minimum specified level.

The Self-Test Unit (4) detects the RF transmissions and evaluates them for proper pulse spacing; during the dead portion of each du ty cycle, it gene rates o syn thetic rep ly (Code 0000) which is checked by the video processor in the some manner os the a ircraft replies.

The Duplexer (5) prevents transmissions from le ak ing into the receiver, and also routes the rep lies from the antenna direct ly to the receiver.

The Antenna (6} local izes the transmitter a nd receiver pattern to the test area shown in Figure 4. At the nominal operating range of 150 feet, the ante nna patte rn covers o 50-foot wide area, between 5 and 15 feet above the ground.

The Preselector (7), which is essentially o 1 090 mega­cycle bond pass filter, prevents undesire d frequencies fro m interfering with the ope ration of the receiver.

The Attenua tor (8) adjusts the re­ceiver threshold, a nd checks trans­ponder power by re jecting any re­ply signals which ore wea ke r than the establishe d norma l, based on the nominal operating ra nge of 150 feet.

The Receiver (9) converts RF re­plies to video for subsequent pro-cessing. It contains o freque ncy dis­criminator which generates a n ac­cepted signal only for replies which ore within the assigned transponder frequency range of I 090 ± 3 mega­

cycles.

fig. 4 Equipment Ins tallation Pion

20

Fig. 2

Fig . 3

..... . :·- . • • • • • • •• • ~·· •• :· .. r • • •• •• ·~t ... ~ . -· --·-I • .-... .. • re .... : ......... :

CODE • • -1Tf!ME AL! I I - u

,... . . • • t • I t ...

... . ·"''' .r-•a. • ' '.~I ... t I

'• I \ I ~ f ·~ --. ,

. .. .... ... ~!1

=199M • :'" :•i .. -: .. ·: ·+-::!~~Ills • ... . .. . ;:.I .. ..

ICENT

Main (Billboard) Displa y for Transponder Pre.flight Test Set

Monitor Displa y for Tra nsponder Pre-Fl ight Test Set

BILL80ARO DtSPLAY

OESIA(D C(NT£R lltl! FOA AIACAAH

BEACON ANTEN.l4A

I

I

TAX I STRIP

I

CODER TRANSMITTER

SELF - TEST

PULSE 1~10TH I POSITION

EVALUATOR

MOD~! 3/A J-=Ec..;_NA~B=LE:...........it-t---~ DECODER

1.3 EVALUATOR

ATTENUATOR

RECEIVER

12 MODE C DECODER

DUPLEXER

ATTENUATOR

14 MAIN

DISPLAY

ANgO~~:~LAY t---------~

fig. S System Block Diogram

15 MONITOR DISPLAY

The Pulse Width/Position Evaluator (10) rejects reply pulses which are either too narrow, too wide, or outside the time tolerance of the assigned reply positions.

The Mode 3/ A Decoder (11), detects Mode 3/ A bracket pulses, at which time it reads out the Mode 3/A reply and converts it into a binary coded decimal (BCD) format. The decoder also detects an 1/P indication if one is present.

The M~de ~ D~coder (12) detects Mode C bracket pul­~es, at which time 1~ reads out the Mode C reply, which is rn the SSR Automatic Pressure-Altitude Transmission Code (MOA Gilham Code). It translates this code first into bi­nary form, and thence into BCD format.

The E~aluator and Display Control (13) evaluates the selftest criteria and controls the d"ispl d" I Th . ays accor rng y. e unit also routes the decoded Mode 3/A d M d C -

I. · B an o e re p 1es, rn CD format, to the display.

The M~in D!splay (14) and the Remote Monitor Display (15) have 1dent1cal functions. They translate the Mode 3/ A and Mode C BCD information into numerical displays. They also decode and display the readout data associated with the self-test the 11 11

• d. · / d ' no go rn 1cat1on Mode 3 A an Mode C brackets, and the l/P function. '

Display Format and Test Criteria ~he main (billboard) display is designed for viewing by

a_ pilot up to 200 feet away. The display surface is six feet high by eleven feet long. The display surface of the re­mote monitor unit is approximately one foot square.

If the results of the self test in the Electronic Equipment Group are acceptable, the words TRANSPONDER TEST are lighted and the displays are permitted to operate. If a malfunction of the self test is detected, the entire display is automatically shut off.

If a satisfactory Mode 3/A bracket is detected, having correct frequency and power level, the normally illuminat­ed NO GO display is extinguished and the word CODE appears, followed by the numerical readout of the Mode 3/A (identification) code being received. The pilot checks this four-figure numerical readout to see that it corres­ponds to the code number set into his transponder control panel.

If an l/P function is present with a proper Mode 3/ A reply, the word !DENT is displayed.

Mode C data is not read out unless Mode 3/ A data is also being displayed. Processing of a Mode C bracket pulse causes the word ALTITUDE to appear, followed by a

plus or minus ( ±) sign (indicating altitude above or below sea level) and the decoded altitude value, in frve figures. As the displayed value corresponds to pressure altitude, to the nearest 100 foot increment (or 500 foot increment, depending on the reply code used), rather than to the actual altitude of the transponder above sea level, this readout can be expected to vary within a few hundred feet of the actual airport elevation (depending on the local barometric pressure); but should correspond closely with the pressure altitude setting obtained from an altimeter in the aircraft.

The pertinent test data remains on the display only as long as the aircraft transponder antenna remains within the antenna pattern of the test area. As soon as the air­craft leaves the pattern, the display reverts to the NO GO indication.

A complete check of transponder performance on Mode 3/A and Mode C, together with l/P, requires less than two seconds. If the pilot is watching the billboard, he can com­plete the check, while taxying across the beam of the test pattern, at a speed of ten knots or less.

Summary of Test Set Characteristics

Antenna:

Frequency Gain Beamwidth

VSWR

Transmitter:

Frequency Power

Modulation Pulse Spacing

Pulse Width Interrogation Rate

Receiver:

Frequency

Sensitivity

Pulse Width

Pulse Spacing

Horn type, vertical polariza­tion 1 020 to 1100 me. 20 ± 2 db. l 9J in H plane l 6c in E plane ;; 1 db.

1 030 ± 0.2 me. Established by variable atte­nuator (approximately 5 milli­watts) Pulse Mode 3/A Mode C

- 8 ± 0.1 /tsec. -21 ± 0.1 .usec.

0.8 ± 0.1 .usec. 200 pulse pairs per second, with Mode 31 A and Mode C interlaced 1 : 1

Accept: 1 090 ± 3 me.

Reject: greater than 1 090 ± 3.2 me.

Established by attenuator Accept: 18.5 dbw

(at 150 feet) Reject: 17.0 dbw

(at 150 feet) Accept: 0.45 ± 0.1 ."sec. Reject: less than 0.25 usec.

or greater than 0.7 usec.

Accept: ~t_- 0.5 .11sec. from nominal pulse position

Reject: less than 1.15 11sec. or greater than 1.7 11sec. from nominal pulse position

21

The S. R. T. Philosophy on ATC Automation by J. Edwards Standard Radio & Telefon AB, Sweden

Paper presented at the Fourth Annual IFATCA Conference, Vienna

Present situation

There are considerable extremes in the extent to which ATC is required or provided in the world. Therefore, there is little prospect of building a complete system which would satisfy the existing or forseeable requirements at all locations. It will not be disputed that there is a conside­rable requirement for modernising existing methods at the majority of ATC centres. The problem is in designing a system which is capable of partial integration, so that really constructive steps can be taken to build up a system which will suit the varying local circumstances.

In view of the development and operating costs of pre­sent and future aircraft, it is important that such aircraft should have an Air Traffic Service available which enables them to operate with maximum efficiency wherever they may be. All too often an aircraft leaving the upper air­space, entering a busy terminal area and eventually lan­ding at a comparitively little used airport is exposed to largely differing degrees of control capability which are caused by incompatible standards of equipment. Should an aircraft which is equipped for automatic landing not be offered a smooth transition to the commencement of the approach, then these incompatibilities will become in­creasingly embarrassing to aircraft operators, air traffic controllers, and the governmental authorities responsible.

We emphasize this point, because from the outset, it has been the aim of our company to avoid the situation where automated processes could only be offered as very complicated and costly installations which could only be fully justified in areas with a heavy traffic density.

Obiectives Based on the above philosophy, Standard Radio & Te­

lefon AB has designed a system which will: a) enable air traffic controllers to be presented with pro­

cessed data in such a way which will allow them to perform their planning and executive tasks with the least possible administrative hindrance.

b) allow a smooth introduction without having to use all the equipment immediately, therefore easing the train­ing burden and allowing time for gaining controller familiarization without undue pressure.

c) provide controllers with radar data and data from other sources at a reasonable cost.

d) provide means of realistic co-ordination between civil and military authorities, thus easing the existing limi­tations of airspace organisation.

e) fully utilize the existing separation standards and pro­vide a means of gradually reducing them as more ex­perience is gained.

f) enable governments to procure au:omated equipment as required, with the assurance that each step taken is towards a more complete system and in the process no equipment is rendered obsolete.

General Approach It is usually considered that not all the functions of

existing systems currently have the right emphasis. In ge-

22

neral, however, an examination of any particular situation would sho~ that '.he framework is correct and adaptable '.o automat10~ with no revolutionary change necessary m the allocat1on of functions to the sub-divisions of exist­ing ATC centres.

In the. S~T approach, the major difference to existing methods 1s m the question of displaying flight information to the co~trollers. Al.though radar has for a long time been cautiously described as only being a lubricant to a basic syste'?1, there can be no doubt that it has now be­come a ma1or control equipment.

By the introduction of a high-speed computer for co­operation with the radar, the data obtained by the radar can nowadays be utilized by the controller for a t t.

k. fl" h u oma 1c trac mg, 19 t progress prediction, conflict warning etc.

~ith these fu~ctions presented on the PPI and on elec-tronic tabular displays the controller can b "cl cl

· h · · 1

• e prov1 e wit a p1ctoria view of the area for which h · "bi Th" · h. e 1s respon-

s1 e. 1s gives 1m a continuously updated t t• . presen a ion of the traffic progress. For this reason we pi th _

h . . . ace e em

p as1s on. pictorial displays. The major function of the c~mputer m our system is to produce data for a real-time picture for the controller. Having provided th· ·t · th

• • IS, I IS en possible to ~xamme the auxiliary functions necessary for the completion of the control requirement Info t· . h . h. . rma ion on all fl1g ts wit m an area which is stored and ' proces-sed by the c~mputer can be shown both on the PPI and on tabular displays. ~he same information may also be presented ~y automat1ca~ly printed flight strips. When the constant display ?f all information in strip form is not necessary, the strips can be provided immediately upon request from the controller.

Basic Principle of the System

In order to achieve a fast accurate and ·1ne · . ' xpens1ve data processing and presentation system SRT h h . . , as c osen to use the d1g1tal data handling method through-out the ATC system presented here.

This digital principle, which is used not I . h b I . on y m t e

computer, ut a so m the PPl's and tabular d' I · the following advantages: isp ays, gives

Full correlation between flight plan 0 d d d . . n ra or ata.

Visual presentation of flight progress d t a a. Visual intercommunication between co t II . . n ro ers and ad-1acent centres and positive transfer of t

1 con ro. Automatic tracking and symbol identification.

Video-correlated or raw radar as well h . PPI picture available. as synt et1c

Narrow band radar picture transm· . 1

h lines. 1ss1on on te ep one

Composite display on the PPI of p' t f 1

I remote radars. ic ures rom oca or

lnterscan presentation of vector d DF 1. 'd . an - 1nes, v1 eo mapping and runway extension lines.

Bright daylight PPI presentation achieved by inexpen­sive additional equipment.

Automatic flight strip printing and updating. Conflict seorch by computer with a larm s ignalling on PPI. Magnetic lope recording of radar and flight progress data etc. Prepared for integratio n of SSR.

Building-block Units of the System

A brief ind ividual description of e a ch of the major equipments wi ll be given be low. The rea son for this is that our system is o typica l building block system. The re­q uirements of various custo mers con easily be met a nd economically integrated by this method. Furthermore, any system con be extended, as required, by the simple addi­tion of fu rthe r 'blocks '.

In the descriptions that follow, the main components, i. e. the p ictorial displays and the computer, ore dealt with first.

The PPI

The control desks used in the SRT system ore provided with one or two PPls depending upon the requi re ment for different positions. The input information consists of radar sweeps and symbols fed in digital form which means that no e rror be tween symbols and sweep wil l occur. The video signals ore fed in the tradi tional form. It is possible to choose between row or correlated video, or composite video of the corre lated signals from two o r more rada r stations. All symbol markers and vectors lines ore display­ed as interscons. Instead of presenting both radar sweeps and interscons, the PPI con be used for d isplaying syn­thetic information. It is possible to move the picture in the x and y direction, by means o f off-centering controls up to o distance corresponding to four radi i of the screen.

Video mops and calibration markers, vector and DF­lines a s well as runway extension lines con be presented o n the PPI screen. The controller con automatically read the azimuth a nd le ngth of the vector line. Runway exten­sion li nes for 5 runways ol different airports con be chosen from 16 runway extension lines stored in the computer. Each controller hos been allocated o specific pointer sym­bo l which he controls by o ro lling boll. The coordinates of the symbol ore continuously stored in the computer. When transferring the control of on aircraft, the symbol disp layed on the PPI con be transferred to another con­troller's PPI. This transfer con be to on adjacent contro l­ler, or over telephone lines lo o controller in o distant centre.

By means of o special process, developed by SRT, it is poss ible to produce a bright radar picture on the PPI. This enables the controllers to work in daylight conditions instead o f o ~peciolly darkened room as is normally ne­cessary. Briefly, the process entails storing the target co­ordinates in o ferrite core memory, where they ore pro­gressively introduced at the some rote as they ore recei­ved by the radar. Then in on independent reading cycle, the memory is scanned at o high repetition rote which determines the target coordinates for presentation on o cathode ray tube. As the PPI screen is being scanned more rapidly with this method than if row video is presented, the 'b lip ' which represents the target position will appear more frequently and not decoy as in the case when the PPI sc reen sweep is synchronised with the antenna revo­lution.

Daylight picture of PPI display, photographed under normal ambient light conditions. The Daylight Presentation System is based on d igi­talizing the rodor information, storing it, ond presenting it 16times per second on the PPI screen.

The Tabular Display

The tabular display is used for the presentation of ad­ditional informat ion about the targets which appear on the PPI, or information processed by the computer. The presentation is mode on a rectangular cathode ray tube, which con show fl ight progress data for six aircraft simul­taneous ly.

Doto presente d on the tabular display con be : track number, co ll sign, type of a ircraft, speed in knots and in km/ h, route, leve l in feet and in meters and ETA at fixes. By using his keyboard, the controller con transfer data to other controllers either in the some centre or to on adjacent one.

The Computer

The CENSOR computer, deve loped by SRT is o multi ­purpose high speed data processor primarily intended for real-time data handling. It performs the necessary ope­rations for the automatic tracking process, administration of symbol presentation, intertrock computations and pro­vides information for flight strip printing.

The main units in CENSOR ore the arithmetic unit, pro­gramme cont rol and the magnetic core me mory. CENSOR is connected to its own input/output equipme nt and hos ~ertoin specia l fea tu res to make it extremely fast , which ts necessary for real-time data processing. These include connection to a common bus line, semi-permanent instruc­tion memory, direct memory access, and all programmes executed on a priority basis.

CENSOR is connected to o common bus line which is o two way information chan nel connecting all ports of the processing system, i. e. CENSOR itself and its asso­ciated ex ternal devices such as keyboards, tabular dis­plays, character generators radar extractor units, data links, tape ~ecorders, extra ~emory etc., etc.

The rapid transfer of data between external equipment and CENSOR is very important in this type of real-time processing. In most computers one programme hos to be completed before another con be started, but in CENSOR 0 method of direct a ccess to the memory hos been incor­porated. This hos the advantage that on external un it wo nt ing to communicate with CENSOR instead of having to wait until a programme is comple~ed, will deliver o signal to the Priority Unit in CENSOR, where the relative

23

priorities of all possible colls ore determined. The coiling units ore then connected to the memory in order of prio­rity. The direct memory access facility also hos the benefit that transfers to and from external equipment con be mode without disturbing the running computations in the arithmetic unit. One programme is usually completed be­fore another is started, but if it is necessary to interrupt a programme on interrupt signal is inserted at a con­venient inte rval. Such on order, when delivered to the programme selector, causes a 'jump out' of the running programme. When the new programme hos been com­pleted, the interrupted programme is then continued from the interrupt point.

Flight pion doto con be received by teleprinter from adjacent centres and ore fed directly into the computer. The keyboards at the control positions con also be used for this purpose. The computer stores the flight plans, cal­culates the ETA at fix points and searches continuously for conflict risks . Flight progress strips may also be printed if required. Each radar controller is presented the some data on his Tabular Display for those aircraft he is inte­rested in. The computer continuously updates the flight progress situation by printing new strips. By means of the teleprinter network, the computer transmits updated flight plans in real time to adjacent centres.

Tracking con be semi-automatic or automatic; semi-au­tomatic tracking is used in disturbed conditions, but in normal conditions automatic tracking is used.

The tracking is also programmed (boll unit) in the com­puter and started by means of the keyboard and the rol -

Typical row of controllers desk in on SRT ATC Centre Syste m.

24

ling boll unit. The tracking will automatically correct the flight pion if a deviation is discovered. The computer pre­dicts conflict situations and the controller may accordingly update the flight pion at any time.

The design of the computer enables successive exten­sions of programming faci lities, and also the easy connec­tion of further external devices in the future.

The Video Correlator

The video correlator, which is connected to the CEN­SOR computer, analyses on a digital basis the radar vi ­deo signal and 'reports' a target if the hit pattern com­plies with predetermined criteria. This is a most efficient way of detecting disturbed targe ts and makes it easier for the controller to survey the traffic situa tion.

The output from the video correlator is one well de­fined pulse for each target, which con be used for the extraction of target coordinates (in x and y), which in turn ore fed to the computer to be used for automatic tracking purposes.

The storage function contained in the video correlator con also be used to enable the information from different radar stations to be presented simultaneously on one PPI without any loss of radar informat ion (composite display).

The Input Media The input media to the computer, i. e. the ro lling boll

and keyboard unit, ore both situated at the controller's desk.

The rolling boll controls either a track symbol or the pointer symbol. As already mentioned the pointer is used mainly for designation of tracks and for positive tronsfe r to othe r controllers. The rolli ng boll is connected to the selected symbol when a wrist-key is pushed. This key hos two depressed positions, the lower position increases the manoeuvre speed of the ro lling boll four times. By the operation of a thumb-key, the target position is fed into the computer. The movement of the rol ling ball is followed by two e ncoders, which ore mounted one in the x and one in the y axis (i . e . 90°). These give the x and y coor­dinates of the target position to the computer.

The keyboard is ma inly used for communication wi th the computer. It has s ix rows of spring-loaded buttons and four buttons spring-loaded general keys.

The buttons in the keyboard are connected to input devices in the keyboard input unit contained in the input rock of the CENSOR computer. By means of the keyboard, the controller can for example insert data to complete a tra ck or a sk for addi tiona l data to be presented o n his tabu lar display, e. g. to change flight plan information of any or all o f the aircraft presented.

Narrow Band Transmission of Radar Pictures The NATRAP system, develope d by SRT, is a syste m

used to transfer all the useful rodor information on a ra­dar display by means of ordinary telephone lines.

The equipment use d for the NATRAP system includes equipment for the ext raction of radar data, a buffer me­mory for the storage of data and da ta link terminals at

both ends. An ordinary PPI w ith fixed deflection coils as described above is used for the display. The PPI can easily be connected to data handling units for the presentation of additional data-handled information.

The principle of the syste m is to reduce the bandwidth by ig noring irrelevant information in the received radar signal and by preventing the transmission of fixed echoes, noise etc. This is achieved in the NATRAP system by means of a data extractor (The Video Correlator). The rece ived radar signal is processed, as already described, by digi­ta l technique with the result that only one signal is relayed for e a ch target and o nly very few of the signals at the receiving e nd ore related to fixed echeos.

Azimuth information is obta ined from the radar an­tenna by means of a d igital incremental encoder. The in­formation is fed to a digital un it where binary sweep waveforms for x and y coordinates ore generated in rea l time. The o utput pulses from the v ideo correlator are used to read the x and y coordinates, thus information is given on the positions of all targets a s seen by the radar. At the receiving end, the information is demodulated and converted from serial to parallel form. The information is then suitable for processing in a binary computer. A di­gital to ana logue converter is used to present the infor­mation on a conventional PPI. One or more PPls can be coupled to the system.

The NATRAP syste m gives independe ncy of terrain ob­stacles, increased sca n presentation, improved coverage by easy connection of severa l radar stations to the same centre and economic connection o f re mote radar stations.

Close -up view o f twi n 16" PPI controllers desk, showing comp~ter input .keyboard with te ll -bo ck un it, rolling boll unit and tabular display'. Picture on the le ft is 0 row radar presenta tion .sent over a microwave link, whilst the picture on the right shows the some doto as tronsm1ttod by 0 narrow bond l ink on a normal telephone line.

25

Picture token in Stockholm showing the current traffic situation in the adjacent So uthern Swedis h ond Danish oreos provided by the use of NA TRAP.

Tape Recording

Normol commercial tape recorders con easi ly be used in the SRT system. The type suggested is the con­ventional stereo tape recorder, using normal magnetic tape.

In the ATC centre, tape recorders con be used to make the necessary legal recording of all ATC communications, of flight movements, transfer of control, radar pictures

etc. The tape recorder is also used in coses of emergency

when con tinuous flight strip p rinting is not required. Should the computer break down in such a case the fl ight progress information is sto red on tape and the actual fl ight pion information is automatically printed by the

fl ight strip printer. The simulator suggested for tra ining also relies on the

recorder for many of its operat ions. It con have taped information as 'background tracks ' and much of the si­mula ted fl ight information is provided from tape recor­dings. The whole simulation process is recorded on tapes and late r 'played bock' for purposes of onolysis by the instructor and controller, enabling useful experience to be gained. In the simulation p ro cess, the tapes with si­mulated flight information may be used many t imes or may be altered sl ig htly so that a different flight program­

me may be introduced .

Simulator for Training In general, the ATC simultotion equipment consists of

two ports, o ne for radar simulation and data presento-

26

lion and a second port for the procedural control. Both ports should operate together in the integrated system.

The simulator system is very flexible and is capable of step-by-step expansion. The basic equipment in the system is the digital computer, which con also be used a s a spore for the ATC centre computer. The equipment content and capability is very sim ilar to that of the centre. Extra equip­ment bui lt into the simulator system is for use by the in­structor who simulates the pilot or pilots. The instructor may hove up to two assistants. The number of pilots being simulated depends upon the number of aircraft the centre is capable of handling.

The simulator system is used to simula te, in real time, all aspects of on aircra ft 'fl ight' and to feed in suggested conflict possibilities so that the controller is trained to handle and respond to all possible variations he is likely to meet in actual situations. The simulation is usually done in three phases, preparat ion, the 'flight' and afterwords, the analysis.

The whole exercise, as already mentioned, is recorded on l ope for subsequent analysis, the simulation itself can be on tape or controlled manually by the instructor, or a combinat ion of both methods.

Thus, by use of the simu lator, it is possible to repro­duce all the normal flight characteristics met by a con­troller, as well as feeding in many variables to simulate al l known situations and to test the controller's capabi lity when meeting new situations.

1 Oth Annual ATCA Convention to be held at Los Angeles

" A Decode of Progress" is the theme of this year's Annual Convention of the U.S. Air Traffic Control Asso­ciation, .to be held from October 11 th through 13th at the lnternottonol Hotel, Los Angeles, California.

The Conference will highlight accomplishments of the past decode and emphasize the goals of the coming ten years. I FA TCA Vice President Maurice Cerf and Treasurer Henning Throne will officially represent the International Federation of Air Traffic Controllers' Associations and many representatives of IFATCA Member Associations wi ll also attend the Convention.

Meeting of IFATCA Officers at Amsterdam

The Elect ive Officers of IFATCA, the Executive Secre­tary, and the Chairman of Standing Committee I met in Amsterdam from September 20th till 22nd to discuss cur­rent matters. Items on the agenda were, inter olia, the R~port ?f the Annual Conference, Vienna, 1965, cooper­at ion w ith IFALPA, the ATCA Conference in Los Angeles, ICAO matters, w_ork programme of Standing Committee I, European Regional Organisat ion, THE CONTROLLER nam in~tion of Officers, IFATCA budget, appointment of Executive Secretary, Annual Conference 1966 _ Rome and an IFATCA glossary of ATC terms. '

On the second day of the meeting, the Officers were joined by Mr. Koemos, European representative of the In­ternationa l Council of Aircraft Owners and Pilots Asso­ciatio ns and by members of the Netherlands Guild of Air Traffic Cortrollers. Details wi l l be published in the next IFATCA Circular.

General Purpose Computers and CRT Displays in ATC by R. Arnolds Telefunken A. G .

Paper presented at the Fourth Annual IFATCA Conference, Vienna

General Purpose Computers

As is we ll known, the Federol Germon ATC authority, the Bundesanstalt fUr Flugsicherung (BFS), decided at quite an early date to use generol purpose computers for the outomation of air traffic control technical aids. As early as at the beginning of 1959 the BFS issued a co ll for ten­ders for the supply of a general purpose computer for the first step towords automotion of air traffic control. This decision was not so much at hands as it may seem today. Even the American Federal Aviation Agency (FAA) did experimental work at that time by meons of specia l pur­pose computers and specia lly developed input/output de­vices. However, after the "Beacon Report" was published in November 1961, the use of general purpose computers was adopted also in the United States.

In November 1963, the Telefunken genera l purpose computer TR 4 was set running in the tower of Frankfurt Airport. It is one of the large-scale digital data proces­sing systems. The number of about 100.000 operations per second may serve as an example of its great capacity.

Figure 1 shows a partia l view of the TR 4 Computing

Centre at Rhine-Main Airport. The first seven electronic cabinets on the left side be-

~81::1 I

CJ ' CJ

~ .~ ,

• ; •

Figure l TR 4 Computing Centre, Rhine-Main Airport.

long to the central computer. Apart from the power supi:-· ly system they hold the arithmetic, the instruction and the contro l units as well as the ferrite core memory and the input/output units. The adjacent four cabinets contain a teleprinter distribution unit by means of which 24 tele­printing channels can be linked directly to the computer. The number of channe ls can be increased to 62. Fu rther­more, this unit holds an electron ic clock system by means of which normal or real time respectively is indicated to the computer every 10 seconds.

In front there is the control desk with an electric type­w r iter and the indicator and control panel for the real time clock. The monitor typewriter is a means of direct communication between the computer operator and the computor. The same applies to the 24 telepr inters, o ne of which can be seen in the background. It is of g reat impor­tance that by these means rea l time operatio ns can be carried out, i . e. via each teleprinting channel data can be fed into the computer at any time without previous an­nouncement or de lay being necessary un less information is put out by the computer on the respective channel.

Figure 2 shows the arrangement o f t he equipment as it is provided for the first stages on the way to automa­tion of air t raffic contro l. During the initial stage a bove

27

all automatic computation, assembling and printing of flight progress strips and the pertinent processing of flight pion data, meteorological dote ond corrections ore tested. Thus certain operational odvontoges ore expected, e. g. greeter legibility of the strips, fos_ter ond more reliab le execution of the routine tasks related to their preparation, focilitotion of certain coordination tasks, etc. It is also of great importance that thereby operating staff and tech­nicians get on opportunity to fami liarize themselves w ith such equipment and the special rules for its effective app­lication.

The necessity to form a group of qualified program­mers and system plann ing staff is only one example for new requirements imposed by the use of a digital com­puter for ATC purposes. In this respect the BFS is fol­lowing the practice to train, above all, air traffic control­lers for programming and operating the digital computer in a one-year specia l course. Also in the United Stoles this way hos turned out to be advantageous as it usua lly assures good compatibility with the particular operotionol circumstances and requirements when the computer is used for ATC tasks. Moreover, p rogramming is in many aspects simi lar to the activity of on air traffic controller, so that the controller, as experience hos proved, is in ge­nerally well qualified for programming.

As con be seen on Figure 2 the input of data necessary for strip printing, i. e. especially fl ight p ion and meteoro­logical data, is carried out via normal teleprinters. It is quite on advantage that th is relatively inexpensive seria l equipment con be used for other purposes at o later time when the printing of control strips will be reduced or even replaced by more effective procedures as e. g. synthetic air traffic presentation on CRT displays.

The first step towards testing the system consisted in a long term comparison of flight progress strips generated

ACC FRANKFURT

RADAR HEAD

by the computer with those written manually. This was o means for eliminating from the computer programs any inadequacies which become apparent only under opera­tion. Today the controllers in Frankfurt ore provided with printed departure strips. In the near future the area con­trol centre, approach control and tower control o f Frank­furt wil l be suppl ied more and more with printed strips as shown on Figure 3.

For the time being the computer is not provided with stand-by equ ipment. Therefore, only such tasks, which i n case of a breakdown of the computer con be continued manually or accord ing to the procedures used up to now, con be consigned to the computer. The generation of flight progress str ips, however, is a task of such kind. In this case the transition from automatic to manual opera­tion can be secured with relative eose by an appropriate operational orgonizotion. In other coses where this re­quirement cannot be met reliably, those tasks ore to be tested in parallel with the genuine A TC service. As soon os the computer shell be really used for such tasks, how­ever, its rel iabi l i ty wi ll be of utmost importance. W ithout going into detail, it may be mentioned that the problem of rel iabili ty is under investigation and that satisfactory solutions a lso for the most stringent requirements o f air traffic control ore emerging.

Some tasks which will be treated in the course of the first test and evaluation stage shall briefly be mentioned here: Transmission of flight pion data from the Munich a nd Ha nnover centres to the computer via telepr inting channels; strip pr inting in Munich and Hannover; con­flict search and conflict solution calcu lations. When and to what extent such tasks ore performed con only be de­cided by virtue of the increasing experiences gathered during the current test period. The some applies to the answer to the question wether the computation results ore

-·-·-·-·-·-·...:.. ·-·-···-·-·-·-·-·-·-·-·-·-·-·-·- ·-·-·-· ·-·· ·-·-·- ·-·-·-! APPROCH CONTROL

FRANKFURT - ·-·-·-·-·- ·-·-, I CONTROLDESK ACC HANNOVER • j

FLIGHT PlANS

! TELEPRIN- • ITINGLINES I .APPRJOOkm i

II . . I I . --.·__, I

-·-·-·---·-·.J i -·-·---·-·-·,

ACC MUNICH i FLIGHT PLANS

! -

I I I i

I FLIGHT PROGRESS STRIPS

~·- · -·-·-·-·-·-j AERODROME TOWER CONT

i FLIGHT PROGRESS STRIPS

r-·- ·- ·-·-·-·-1. AERONAUTICAL INFORM • SERVICE

FLIGHT PLANS

~·-·-·-=·-·-!

MET DATA

i COMPUTING CENTRE CONTROL I -" TELEPRINTER 1-·-·-·-·-·-·-

OTHER ATC COMPUTERS L.-·-·-·-·-·-·-·-·-·-·-..·-·-·-·-·-·-.. -·-·-·..J

Figure 2 ATC Au lomal1on, Initia l Sys tem Syste m Eval ua tion Pho se·BFS .

28

1609 SIE 150 150 L49 GMH • y FBELI EHAH 81 FFM CHA

280 EDDF •

Figuru 3 Printed Flight Progress Strips.

to be presented to the controller in writing vio the tele· printers or whethe r they ore to be shown on a CRT dis· ploy as it is used in the second trial phase.

It need no further discussion to show that a general purpose computer with its g reat versatility with respect to programming, program alterations and exchange as well as to its va rious possibilities for data input and out· put is sui ted best for the variety of experiments and in· vestigot ions necessary before the general introduction of d igita l computers into air traffic control. The advantages offered by a general purpose computer remai n valid even after the operational introduction of d igital computers into ATC because the requirements lo be fulfilled by the ai r traffic control system wi ll change and increase due to the dynamic development of air traffic.

A very remarkable example of the advantages offered by o general purpose computer is the fact that tests for automatic processing of pr imary radar data ore present· ly carried out at the Frankfurt TR 4 Computing Centre. It is possible to switch over rather quickly to this completely different testing task by subst itu ting the programs for flight progress strip print ing stored usually in the corn· puter by radar data processing programs.

RADAR/TV SCAN CONVERTER

TV ·RAIYIR VIDEO

DISPLAY UNIT

Figure 4 Air Troffic Display for Rodar. and Computer lnformolion.

EQDL • CRT Displays

For the second stage of the automation efforts it is planned first of all to test o CRT display developed for universal application in ATC and procedures for digital processing of radar data. This phase will run mostly in parallel with the first one. Practically it hos already begun with the tests for automatic radar data processing men· lioned before.

The display equipment is presently being developed by Telefunken and will be used in Frankfurt from the be­ginning of 1966 onwards. Figure 4 shows the set-up of th is equipment. The display console will be built with re· ference to the FAA specifications for radar bright display equipment and contains o cathode ray tube of 22 inches diameter with extremely flat screen. On the one hand the display unit is linked to the TR 4 computer via the dis· ploy control e qu ipment so that synthetic air traffic pie· lures and other control data generated by the computer con be displayed . In order to obtain o flickerfree picture for daylight presentation, o picture repetit ion store causes the pictorial data lo be presented 50 to 60 times per se· cond. Thus the presentation of moving data will not be spoilt by afterglow effects.

DISPLAY CONTROL EQUIPMENT

~ SYNTHETIC DATA FROM ATC COMPUTER

TEST UNIT

CONTROL UNITS

SYNTHETIC OllTA FROM COMPUTER

TR4

REQUESTS AND INSTRUCTIONS TO ca-tPUTER

TR4

29

63 different characters a s well as vectors con be dis­played. The character generator used allows a writing speed of 100.000 characters per second. That means !hot up to 2.000 characters con be re presented flickerfree. A rolling boll unit enables the operator to move o morker over the screen and to feed the correspo nding co-ordi­nates into the computer.

On the other hand the d isplay un it con be con nected with a scan converter, and thus the row radar picture con be disp layed according to the FAA TV-standard with 945 lines. Simu ltaneous display of the TV radar picture and compute r data is possible. In this case the amount of com­puter data is reduced to o maximum of 150 characte rs or 300 characters at a picture repetition frequency of 60 c/s or 30 c/s respectively.

The displa y unit is equ ipped with o keyboard by means of which the following information con be fed into the computer: 1) Orders demanding to change the picture displayed, to

odd supplementary information (e . g. tabular data) or to exclude certa in data from the presentation.

2) Confirmation of receipt of certain control data gene­rated by the computer.

3) Input of new control da ta (e. g. he ight information) by means of number keys, various interpretat ion keys end, if needed the roll ing boll. In order to increase the clearness of presentation, the

following alte rat ions may in addition be carried out on the picture without affecting the computer :

Decentering and change of scale, brightness contro l of different categories of data which con portly be selected by means of the computer program (e. g. dis­play of mop information with lower brightness). For tria l purposes the display unit has been designed

in such a way that the actual viewing unit con be mounted with either nearly horizontal or nearly vertical screen. As indicated on Figure 4, a combination of two screens con

Fogurc 5 Horozonto l Display Unit.

30

thus be real ized. In the latter case both d isplay units con be connected with one display control equipment.

This short survey illustra tes the great flexibility of the whole concept of development with respect to display of radar and computer data, various possibi lit ies to make use of the control keys being interpreted by the computer program as well as the d ifferent ways to mount the d is­play system. It is intended to use the equipment for area and approach control as well a s for input of radar data into the computer and semi-automatic processing of these data.

Figure 5 shows a mock-up of the display un it, whereas screen pictures d isplayed on a first laboratory vers ion con be seen on Figures 6, 7 and 8.

Figure 9 shows a schematic representa tion of the air traffic picture by means of which tests will be carried out after the installation of the CRT display equipment. Air­craft data coming from the computer ore presented in the way indicated enlarged on the right side of the picture. The aircraft position is marked by a symbol with a smell vector indicating fl ight direction and approximate a ir speed. Control data belonging to this target as e. g. flight number, coll sig n a nd height ore presented as a labe l which may comprise a maximum of 3 lines at 7 characters each.

The computer program causes the label to be indicated always in that one of the four quadrants surrounding the target symbol which li es opposite to the direction vector. If the labels of two ad jacent ta rgets overlap, one of them con be e rased for some time. This is done by means of the rolling boll a nd a cancel key unless the two aircraft symbols ore overlapping too.

Furthermore, the position of radar blips in case o f si multaneous presentation of the television pitcu re is hown on Figure 9. As mentioned above, in this case the presen­tation o f computer data is limited. Therefore it is useful to display the fixed information necessary for the mixed

z tl / ( 3 B J R y ~ ) 2 A 0 x () /\ * 1 9 H p

w ~ ** fr 0 B G 0 ~ ) 0 7 F N v t ~ ( - 6 E M u 0 0 - \} 5 D L T @ - ~ +. 4 c K s

Fig ure 6 Characters available in norma l writing . Some characters will still be a ltered in shape, e . g . the letters A and W. The se changes or even the replacing of certain cha racters by cam· pletely new ones con be easi ly ochieved by the exchange o f plug· in boards.

l b. / <. 3 8 ) R

~ • ) '2. ~ \ n 'l ('\ " • ' g \-\ p

w (!) - 'ft 0 9 G 0

~ ' a 7 f ~ \J

' ~ \ - e, [ M \J

0 () - .., ~ {) L 1

• ... -+ 4 c. \(. s Figure 7 Characters available in Ita lics and with increased brightness.

In order to d ist ingu ish certain information from the o ther data displayed , such information con be presented controlled by the computer program brighter, Oickering, in itolics or spaced with increased character height.

presentation as e. g. map and repo r ting points as part of the television picture.

The operational use of this kind of air traffic presen­tation presupposes thot at least for all controlled targets the raw radar data ore digitalized and that they are pro­cessed by he computer. In general, the controller will then ~e able. to make use of the synthetic air traffic picture and in special cases or in cases o f doubt only he will return to the mixed display.

TABULAR INFORMATION

REPORTING POINT WITH NUMBER OF EXPECTED APPROCHES

FIR BORDER

AIRPORT

RADAR SITE

Figure 8 This is a simplified a ir traffic picture far the purpose of study­ing moving data on the screen.

As to the input of radar information into the computer and the processing of these information, a second display unit of the described ki nd is planned to be used fi rst ly. This equipment is controlled by a radar operator who constantly uses the mixed display of computer and radar information. His main task consists in track initiation and deviation control for rote aided track ing by the computer. The necessary expedients are rolling ball and interpreta­tion keys. Only at a later stage a fully automated proce­dure for track initiation and tracking will be tested opera­tionally and in coordination with the controller working at the ATC display. In both cases it is provided that the identification of the rada r tracks is carried out by the air

traffic controller.

....,.(- FLIGHT DIRECTION

~-POSITION C

688 - RAOARBLIP

100 -AOO INFORMATION

AIRCRAFT DISPLAY

Figure 9 Air Tra ffic Display, Radar- and Co mpu ter Info rma tion Horizontal Projection.

31

32

Corporation Members

of the International Federation

of Air Traffic Controllers' Associations

The Air Traffic Control Association, Washington D. C., U.S.A.

Cessor Radar and Electronics Limited, Harlow, England

The Decca Navigator Company Limited, London

ELLIOTI Bros. Ltd., London

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

IBM World Trade Europe Corporation, Paris, France

ITT Europe Corporation, Brussels, Belgium

The Marconi Company Limited Radar Division Chelmsford, Essex, England

N.V. Hollandse Signaalapparaten Hengelo, Netherlands

Philips Electronics, Netherlands

Selenia - lndustrie Elettroniche Associate S. p.A.

Rome, Italy

The Solartron Electronic Group, Ltd. Farnborough, Honts., England

Telefunken AG, Ulm/Donau, Germany

Texas Instruments Inc., Dallas 22, Texas, USA

Whittaker Corporation, North Hollywood, California, USA

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

~orpora~ion Members support the aims of the ~e~eration by sup~lyi,ng. the Federation with technical information and by means of an annual subscription. The Federations international journal "Th C _ troller" is offered as a platform for the discussion of technical and procedural developments ~n ~h: field of air traffic control.

For further information on Corporati~n Membership please contact Mr. Ernest Mahieu, Honorary Secretary, IFATCA, Cologne-Wahn Airport, Germany.

lf'he ~lnl~eirnational Federation

of Air Traffic Controllers Associations

Addresses and Officers

AUSTRIA

Austrian Air Traffic Controllers Association Vienna Airport Austria

President First Vice-President Second Vice-President Secretary Deputy Secretary Treasurer

BELGIUM

H. Brandstetter H. Kihr H. Bauer R. Obermayr W.Seidl W. Chrystoph

Belgian Guild of Air Traffic Controllers Airport Brussels National Zaventem 1 Brussels Belgium

President Vice-President Secretary Treasurer Editor

CANADA

A. Maziers R. Sadet R. Tamigniaux R. Maitre 0. Haesevoets

Canadian Air Traffic Control Association

P. 0. Box 24 St. James, Man Canada

President Vice-President Managing Director Secretary-Treasurer IFATCA Liaison Officer

DENMARK

J. D. Lyon W. B. Clery L. R. Mattern E. Bryksa J. R. Campbell

Danish Air Traffic Controllers Association Copenhagen Airport - Kastrup Denmark

Chairman Vice-Chairman Secretary Treasurer

FINLAND

Henning Throne H. Dall J. Thilo P. Bressam

Association of Finnish Air Traffic Control Officers Suomen Lennonjohtajien Yhdistys r.y.

Air Traffic Control Helsinki Lento Finland

Chairman Vice-Chairman Secretary Treasurer

FRANCE

Fred. Lehto Jussi Soini Heikki Nevaste Aimo Happonen

French Air Traffic Control Association Association Professionnelle de la Circulation Aerienne B. P. 21 Aeroport du Bourget, Seine France

President Vice-President General Secretary Secretary Treasurer

GERMANY

Maurice Gregoire Francis Zammit Maurice Cerf Jean Flament Emile Mercier

German Air Traffic Controllers Association Verband Deutscher Flugleiter e.V. Cologne-Bonn Airport Porz-Wahn Germany

Chairman Vice-Chairman Vice-Chairman Vice-Chairman Secretary Treasurer Editor Director Deputy

GREECE

W. Kassebohm E. Reddmann M. Bahr H. W. Kremer F. Werthmann H. Prell J. Gartz G. Riediger H. Krause

Air Traffic Controllers Association of Greece Air Traffic Control Athens Airport Greece

President Vice-President General Secretary Treasurer Councillor Councillor Councillor

Chr. Tzamaloukas G. Elias C. Kioupis P. Vasilakopoulos B. Egglezos P. Math ioudakis H. Kopelias

33

ICELAND

Air Traffic Control Association of Iceland Reykjavik Airport Iceland

Chairman Vice-Chairman Secretary Treasurer

IRE LAND

Valdimar Olafson Jens A. Gudmundsson Einar Einarsson Guolaugur Kristinsson

Irish Air Traffic Control Officers Association Aeronautical Section O'Connel Bridge House Dublin 2 Ireland

President Vice-President Secretary Treasurer

IS RAEL

D. J. Eglinton P. J. O'Herbihy M. F. McCabe P. P. Linahan

Air Traffic Controllers Association of Israel P. 0. B. 33 Lod Airport Israel

Chairman Jacob Wachtel

ITALY

Associazione Nazionale Assistenti e Controllori della Civil Navigazione Aerea Italia Via Cola di Rienzo 28 Rome Italy

Chairman Secretary

LUXEMBOURG

C. Tuzzi L. Belluci

Luxembourg Guild of Air Traffic Controllers

Luxembourg Airport Luxembourg

President Secretary Treasurer

NETHERLANDS

Alfred Feltes Andre Klein J.P. Kimmes

Netherlands Guild of Air Traffic Controllers Willem Molengraafstraat 22 Amsterdam-Slootermeer Netherlands

34

President Vice-President Secretary 2nd Secretary Treasurer Member Member

NEW ZEALAND

J. van Londen J. L. Evenhuis W. G. van Blokland P. J. Stalpers J.C. Bruggeman G. J. Bakker L. D. Groenewegen van Wijk

Air Traffic Control Association Air Traffic Control Centre Dept. of Civil Aviation, 8th Floor, Dept. Bldgs. Stout Street Wellington, New Zealand

Hon. Secretary

NORWAY

Lufttrafikkledelsens Forening Box 135 Lysaker Norway

Chairman Secretary Treasurer

SWEDEN

R. G. Roberts

F.Oie P. W. Pedersen A. Torres

Swedish Air Traffic Controllers Association Air Traffic Control Bulltofta Airport Malmo 10 Sweden

Chairman Secretary

SWITZERLAND

Carl Ahlborn Lennart Jogby

Swiss Air Traffic Controllers Association V. P.R. S. Air Traffic Control Zurich-Kloten Airport Switzerland

Chairman

UNITED KINGDOM

Bernhard Ruthy

Guild of Air Traffic Control Officers 14, South Street Park Lane London W 1

Master Clerk Executive Secretary Treasurer Director Deputy

L. S. Vass G. Monk E. Bradshaw A. Field R. W. G. Mundy N. Alcock

URUGUAY

Asociation de Controladores de Transito Aereo del Uruguay Potosi 1882 Montevideo Uruguay

Chairman Secretary Treasurer

VENEZUELA

U. Pallares J. Beder M. Puchkoff

Asociacion Nacional Tecnicos Transito Aereo Venezuela Avenida Andres Bello, Local 7 8129 Caracas, Venezuela

President Vice-President Secretaries

Treasurer Vocals

YUGOSLAVIA

Dr. Carlos G. Osorio Manuel A. Rivera Dr. Alfredo Monque D. R. Solazar J. Blanco Villanueva Miss Amelia Lara F. Arturo R. Gil Prof. Vicente Smart D. Alfonso Parra

Yugoslav Air Traffic Controllers Association Jugoslovensko Udruzenje Kontrolora Letenja Direkeija Za Civilnu Vazdusnu Plovidbu Novi Beograd Lenjinov Balevar 2 Yugoslavia

President Secretary

I. Sirola A. Stefanovic

Altimetry at High Altitudes with a View to the Vertical Separation of Aircraft

EUROCONTROL Report 1/65 by Dr. Ing. Frhr. von Villiez

With the introduction of high-flying jets, and even more so, with the advent of SST, the problems of vertical separation at high altitudes have developed into a press­ing issue and various national and international bodies are working on their solution.

In view of the fact that pressure altimeters will pro­bably continue to remain the most suitable means of determining altitude, a decisive step forward was achie­ved when, in 1964, agreement on the extension of the Standard Atmosphere from 20 kms to 32 kms was reached.

In a recent study, the Eurocontrol Agency examined the suitability of pressure altimetry for the vertical sepa­ration of aircraft at high altitudes and looked into the possibilities of applying other methods for the determi­

nation of altitude. A review is given of the various physical principles

of altimetry, followed by a discussion of the extended Standard Atmosphere and an analysis of the errors in pressure altimetry. Methods for the determination of height are also considered. The conclusions of the study

can be summarised as follows:

Only pressure altimetry has sufficient potentialities for the application of vertical separation standards presently used above Flight Level 290 for aircraft which, in the foreseeable future, will operate in the altitude bracket

from 40.000-80.000 ft. Present day altimeter instruments have an accuracy

in the order of ± 1 mb (3 times standard deviation figure), which amounts to ± 720 ft at 80000 ft according to the standard atmosphere. It has been shown that this figure

can best be used for all practical applications. Any im­provement beyond this figure, e. g. down to ± 0.75 mb, can only be achieved by much more sophisticated cali­bration procedures, which will never be reached in daily operation. It is imperative, however, to agree a common calibration procedure in order to benefit from the instru­ment accuracy presently available. Recently the FAA adopted a rule on altimeter tests and inspection, which confirms the conclusion drawn in the report.

With regard to the flight technical error, the report accentuates the lack of statistical data for other cate­gories than civil jet aircraft, as well as for flights at higher levels than ~hose usually used, i. e. above 40 OOO ft. A separate study within the Eurocontrol Agency is being de­voted to a theoretical determination of the flight technical error with the assumption of several error distributions. This is going to be a very important contribution for the assessment of vertical separation standards.

Attention has been drawn to the fact that the growing utilisation of secondary radar and there particularly the extension to Mode C operation (automatic altitude re­porting) will undoubtedly be helpful to monitor and avoid deviations from assigned flight levels induced by flight technical errors.

Referring to a pr-evious study the author unde1·lines once more the importance of a clear presentation of alti­tude indication to the pilot. A digital altimeter read-out is being described as a favourable solution to overcome the ambiguous or at least difficult to inte1·pret cockpit instru­ments still in current use.

35

36

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Selenia products are V11arking far safety in the air

ATCR systems and ~ETEO~ radars from SELENIA have been chosen and are in operation for the Air T raffle and Weather Bureaus Authorities of 15 Countries.

It is not by chance that thes~ highly specialized products, often connected into large systems, have been designed by Selenia for so many ex.acting user~ and operate in such different environmental conditions. . Selenia has a staff of engineers ~ork.mg on t~~ problems connected with safety in the air: all the experience acquired by years of research and production in the military and professional electronic field is put to good use to reach one basic goal: Keep the Ai.r T raffi~ safe. . . . Selenia is prepared to give a~I .kind of assistance in solving the problems concerning Air Traffic: from the study of the best system to the training of personnel, through research, design, construction and installation of complete networks, including Terminal and Air Route Control radars, Weather radars, data handling and display systems, microwave links, remote control and data transmission equipment, etc.

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Precision or improvisation? Decca/Harco is the only system that provides all the f acilities for the ~uto.matic, .accurate navigation of sub- and supersonic aircraft. With the Data Link this in -fl ight information is continuously relayed to the ATC centre.

In the air Decca Omnitrac-:-the world's most advanced light-weigh t airborne di~ita l compu ter-provides undis­torted charting with automatic cha~t changing and the ghost beacon facil ity which g ives bearing and distance to any point. Its function also includes auto-pilot coupling and automatic al titude control which maintain respectively any desired f light path and the required fl ight profi le. The departure, if any, from the scheduled time of arriva l at any selected point is indicated on the ETA meter. On the ground the Data Link permits the accurate display of the identity, altitude and position of all co-operating aircraf t. It is economical in the use of the radio frequency spectrum, is not ambiguous and has a service range to the limit of the communications band being used. Its twoway faci lity reduces use of speech and eases the work- load by eliminating routine reports and messages. With the Data Link the Air Traffi c Control ler can interrogate aircraft in the order he requires, and he can be sure also that he and the pilot are using the same navigational data.

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