IFATCA The Controller - October/December 1968 by IFATCA

D 20418 F

i f a T ^ I FAT C A J O U R N A L OF AIR TRAFFIC CONTROL

THE^NTROLLER

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FRANKFURT AM MAIN

CAN YOU SEE THROUGH A CLOUD? ASEA KNOWS HOW

Our laser ceilometer YLAMB can normally penetrate

the lower cloud strata and indicate high clouds at heights well over 15,000 ft.

YLAMB with an oscilloscope will furnish the .> meteorologist with a picture of cloud structure,

multiple cloud layers and temperature inversions,

while the basic unit precisely records height of cloud tÂťr;.

base on a strip chart. YLAMB is a small, rugged unit with low installation and operating costs.

Cloud structure obtained witti

oscilloscope and camera. Cloud layers

mm.

Ground

'"i'hi.-

W E A L S O M A K E L A S E R R A K G E - F I N D E R S F O R TA N K S . A E R O P L A N E S A N D L O N G - D I S TA N C E A P P L I C AT I O N S . W R I T E TO M I L I TA RY D E P T. , A S E A , VA S T E R A S , S W E D E N

Runway: Atphaltl

J TWR^j

500

1000 SCALE 1 : 31

Instantaneous communication.

A comforting thought for the aeronaut. Anyone knows that flight without communication is almost impossible nowadays. Communication - instantaneous communication - only comes into its own when used in the form of a carefully worked-out project. For that you need a firm like Philips which combines an extensive range of products with expert project engineering. The result is a turn-key project like the one at Accra International Airport in Ghana.

That project comprised the supply and installation of HF and VHF equip ment for Accra and outlying stations, extended range VHF. operators' positions, a telegraph centre, TMA radar, VOR and a passenger-handling system.

But also the training of personnel to operate and maintain all that equip ment. A training you take for granted if you think in projects.

N . V. P H I L I P S ' T E L E C O M M U N I C AT I E I N D U S T R I E - H I LV E R S U M - T H E N E T H E R L A N D S

M a r c o n i

complete air

t r a f fi c

c e n t r o i

Airways Surveillance Radar Terminal Area Radar Secondary Surveillance Radar

Signal Processing Systems Radar Data Processing Systems Flight Plan Processing Systems Automated A.F.T.N Systems Radar Display Systems Data Display Systems

Bright (Daylight) Displays Distance-from-Threshold Indicators

Video Map Generators The Marconi Company Limited

Radar Links

A N ' E N G L I S H E L E C T R I C C O M PA N Y

Radar Division, Marconi House, Chelmsford, Essex, England T H E Q U E C fi

a AWAHD 70 INOUSTI

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MARCONI RADAR S600 SERIES ■ a CD

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RADAR DATA EXTRACTION m e a n s :

requirement for:

Digitizing of signals Selecting the radar information on

Narrow-Band real-time transmission

preset criterias Freedom from disturbances

Compatibility with data handling equipment involving: Auto-tracking Flight plan calculation Daylight digital display presentation

achievements:

Installations of military and air traffic control centres in many places in Europe illustrate the flexibility of the

SRT Radar Data Handling System.

Comprehensive symbol display

STANDARDRAD O I &TELEFONABoBARKARBYâ&#x20AC;˘SWEDENTIT

I FAT C A

JOURNAL

AIR

TRAFFIC

CONTROL

THE CONTROLLER Frankfurt

Main,

Oct./Dec.

1968

Volume

â&#x20AC;˘

No.

P u b l i s h e r : I n t e r n a t i o n a l F e d e r a t i o n o f A i r T r a f fi c C o n -

trcllers' Associations, S. C. M; 6 Frankfurt am Main N.O. 14, Bornheimer Landwehr 57a.

Officers of IFATCA: M. Cerf, President; J. R. Campbell, First Vice President; G. Atterholm, Second Vice Presi

dent; G. W. Monk, Executive Secretary; H. Guddat, Honorary Secretary; B. Ruthy, Treasurer; W. H. Endlich. Editor.

Editor: Walter H. Endlich, 3, rue Roosendael,

Bruxelles-Forest, Belgique Telephone: 456248

Publishing Company, Production and Advertising Sales Office: Verlag W. Kramer & Co., 6 Frankfurt am Main N014, Bornheimer Landwehr 57a, Phone 434325,492169, Postscheck Frankfurt (M) 11727. Rate Card Nr. 2. Printed by: W.Kramer&Co., 6 Frankfurt am Main N014, Bornheimer Landwehr 57a.

Subscription Rote: DM 8,â&#x20AC;&#x201D; per annum (in Germany). Contributors ore expressing their personal points of view and opinions, which must not necessarily coincide with t h o s e o f t h e I n t e r n a t i o n a l F e d e r a t i o n o f A i r Tr a f fi c

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Written permission by the Editor printing any port of this Journal.

is necessary for re-

C O N T E N T S

The Role of the Touch Display in Air Traffic Control N. W. Orr and V. D. Hopkin VOR/DME Area Navigation Glen A. Gilbert

Advertisers in this issue; ASEA (Inside Cover); The Dacca

Navigator Co. Ltd. (Back Cover); The Marconi Co. Ltd. ' )/ N. V. Hollandse Signcalopparaten (Inside Back

ATC and the Airport T h e U . K . G u i l d o f AT C O s

qpi^cm' Telecommunlcatie (1); bbLbNIA S.p.A. (6); SOTRAMAT S. Industrie A. (25); Standard

ATC and the Supersonic Transport

Picture Credit: Board of Tracde

ATC and the Supersonic Transport Copt. A. G. Payne

Radio & Telefon AB (4).

Associates (11. 19. i? lA)

(7, 8); Glen A. Gilbert &

The U. K. Guild of ATCOs

selenia

air traj^c control radars Twenty-three Selenia air traffic control radars have been ordered by Austria, India, Italy, Norway, Rhodesia, South Africa and Sweden. Selenia microwave links, analog PPI displays and digital display systems are used in many of these installations. Television-type scan conversion bright display and SSR

can also be added. Where performance, reliability and quality count, Selenia air traffic control radars are regularly selected.

The Role of the

Touch Display In Air Traffic Control By N. W. Orr and V. D. Hopkin

About the Authors

N. W. Orr is an Operations OfFicer I at the United Kingdom Board of Trade. He gathered first hand experience with the touch display as project manager in the computer (EUCLID) group of the U. K. Air Traffic Control Evaluation Unit, Hum. Mr. Orr is now Head of Section CP 7 (Planning of Future ATC Systems) in the Direc t o r a t e o f C o n t r o l P l a n s , N a t i o n a l A i r Tr a f fi c C o n t r o l S e r v i c e s .

V. D. Hopkin is a Principal Psychologist at the Institute of Aviation Medicine, RAF Farnborough. One of his main areas of interest is Human Engineering Problems in Air Traffic Control and Air Defence Systems; this has included work on the evalu ation of Touch Display principles. He is now preparing a study of Human Factors in Ground Control of Aircraft for AGARD.

Introduction

Communication between controller and computer has

hitherto relied heavily on the electro-mechanical keyboard At the present stage of its evolution the application of

in one form or another â&#x20AC;&#x201D; a medium which may set the

automation to Air Traffic Control is, in large measure, a matter of using computers to drive or print tabular traffic

puter, so that the success of any automated system de

maximum pace at which information can be handled by the system. R/T messages normally cannot be passed to the computer in the form in which they are received but have to be converted, by the controller, into terms acceptable to a particular keyboard format. For example, items of ATC data such as aircraft callsigns may have to be coded

pends to a considerable degree on the effectiveness of the

by designating them with a letter or numeral. This conver

communications between the controller and the computer. of the weakest points in the Controller-Aircraft-Computer

sion process is time consuming, adds ta the Controller's workload and is subject to human error. Additionally, the characters/symbols available on an orthodox keyboard

Loop.

are limited and inflexible. These characters and the key-

displays. The current state of the art is such that much of

the updating and amending of these displays has to be done by the controller or his assistant, through the com

This man/machine interface is generally regarded as one

Figure 1

Operator using Touch Display. 7

board layout hove to be learned by the operator and it may take a considerable time to acquire operating pro ficiency. Another limitation is that the feedback from the computer, which allows the operator to check the accuracy of his input, has to be presented on a display remote from the keyboard and this may lead to problems of head

to activate a digital computer. In the version illustrated here (Figs. 1 to 3), twenty-four touchwires ore arranged in four rows of six wires per row.

A Touch Display coupled to a computer con be regard ed as a keybord, the "key" labelling of which may be varied by computer program to suit any particular require

movement and visual accomodation, and introduce ambi

ment. In addition to the key labels, further information

ent lighting difficulties. The Touch Display principle offers the means of over coming, or at least reducing, all of the above limitations. The Touch Display, in its original form, was invented

may be presented on the display, by the computer, as and

at the Royal Radar Establishment by Mr. E. A. Johnson, a n d t h e fi r s t e v a l u a t i o n o f i t s u s e i n a n a i r t r a f fi c c o n t r o l context was carried out at the Board of Trade's ATC Eva

when required. A Touch Display therefore combines the f u n c t i o n s o f k e y b o a r d a n d d i s p l a y. I n o t h e r words — the input and output functions ore integrated.. A simple example of its use in a suggested ATC role is illustrated in Figs. 2 and 3, and the touch display function involved are described in the captions.

luation Unit at Hum in 1965/66. Since then several further e v a l u a t i o n s i n v a r i o u s AT C e n v i r o n m e n t s h o v e b e e n c o n

ducted at the ATCEU in conjunction with the RAF Institute of Aviation Medicine.

The advantages of the Touch Display as an input device for some ATC tasks appeared so self-evident that certain

plans for including it in future systems were formulated b e f o r e t h e e v a l u a t i o n t r i a l s h a d c o n fi r m e d i t s w o r t h . F o r

tunately these decisions hove largely proved sound as the evaluations have confirmed that the Touch Display func

tions very efficiently as an input device and, in the main, is preferable to the conventional keyboard for most in putting tasks.

Advantages of the Touch Display over the Conventional Keyboard The first evaluation conducted by the ATCEU compared results obtained by operators using the Touch Display with those obtained in an earlier trial in which a conventional

keyboard had been used in an otherwise identical opera tional role ("en route" Sector Radar Controller). Among

the findings of these trials were the following: 1. The training time necessary for operators to reach an acceptable level of proficiency using the Touch Display is significently less than that for the conventional key board.

Description of the Touch Display

2. Most of the searching and coding problems hitherto

A Touch Display is a touch sensitive electronic data

display designed to exploit the operators' body capacity in such a manner that a finger touch on an electronical contact — a "touch-wire" — produces a capacitance and resistance to earth which unbalances an inductance capa citance bridge. This produces a signal which can be used

associated with locating displayed information are avoided. Only information essential to the operator's immediate requirements need be displayed — the rest is stored but can be made instantly available when required. Information on touchwire labels can be writ

ten in full or with only partial abbreviation. This dis-

SARPZ T/OFF NOK '

TRI LEFT TURN FAI *2 RADAR 128,5

5ARPZ OiJ03 A1 138 GARP.4

ENIS

BACJCIK

R/ir EAST

GAR^ OA 408 AI 108 GARP.H

Figure 2 and Figure 3

Suggested Use of the Touch Display for Aerodromes Control. (A method of meeting the requirement to inform the computer In a cen tral processing complex, of the "airborne" times of aircraft departing from an aerodrome.)

in Fig. 2 (the "REST" picture) an Aerodrome Controller is presented with the callsigns of aircraft about to depart from his airfield. These callsigns

action immediately informs the main processing computer of the time of take-off and initiates the necessary action to notify the "en-route" con trollers of this event. The aerodrome controller's display then returns to the "REST" position — but the aircraft which has just departed will now be omitted from the list of callsigns (which will all move up to the left to "fill the gap").

have been "fed" to the display by the Ground Movement Controller

Should the controller at any time wish to return to the "REST" position

shortly before they reached the runway holding point.

from the "Flight Plan" display (Fig. 3), before the aircraft concerned

The take-off direction is also displayed and a digital clock appears in

becomes airborne, he may do this by touching the wire under "BACK-

the top right hand corner of the display.

TRK".

If the controller touches the touchwire under any collsign he will be presented with the aircraft's relevant flight data (Fig. 3: GARPZ).

It will be seen that this Touch Display format also provides the aero drome controller with the means of notifying the computer of changes

When the aircraft takes off he touches the wire under "ENTER" and this

of take-off direction (Fig. 2).

penses with the clumsy data line and field identification

procedures necessary in some systems which use ortho dox keyboards in conjunction with independent dis plays. Both these features effectively contribute to

lightening the operator's workload by substantially reducing the search aspect of the task. 3. The operator can be "led'' through any desired se quence of displays by appropriate computer program ming — by presenting him with the set of touchwire labels which must be used next. (This is one of the factors which helps to reduce operator training time).

4. By showing only information directly relevant to a given input both on the display proper and on the touchwire labels, it is possible to present an identical layout on each. This avoids the problems associated

with a fixed keyboard of making its layout logically compatible with the other displayed data.

5. Because the orthodox keyboard requires mechanical depression of the keys it is slower and demands more effort to operate than a touchwire system. Potentially therefore the Touch Display can provide a faster rate of input.

6. The Touch Display is silent in operation. Perhaps the most important finding of these trials, how ever, was that the operators seemed to derive genuine pleasure from using the Touch Display, and all of them were extremely enthusiastic about it. This contrasted mark edly with the attitude encountered in the trials using the conventional keyboard.

In a later project (North Atlantic Oceanic Control environment) operators worked at their own pace rather than at the rate set by incoming messages. The superiority of the Touch Display over the keyboard in this role was

touch display by employing books of illustrations of the various display sequences, in which the turning of a page corresponds to the touching of a wire. By this method operators can be familiarised with the way in which the

touch display works and has been programmed. It is thus possible for potential operators to become familiar with touch display formats and routines without having to use the actual device itself, thus effectively reducing the

amount of costly computer tim.e otherwise necessary dur ing training. It has been found that after such introductory training it is possible for operators to become rapidly proficient on the touch display itself.

Ergonomics The angle of slope of the face of the Touch Display presents the most important of the ergonomic problems associated with this equipment and has been examined by the ATCEU/IAM. It would appear that an angle of be tween 30° and 40° to the horizontal is the optimum angle,

which is a compromise between treating the Touch Display as a keyboard — when it should be nearly horizontal — and treating it as a display — when the face should be perpendicular to the operator's line of sight (usually about 60° to the horizontal for a seated observer with the dis play at desk top height).

N. B. The angle of the face of the Touch Display shown in Fig. 1 (62V2°) although ideal for viewing purposes was

found by the majority of operators to be much too steep for comfortable touching.

However, any display at 30° —40° to the horizontal normally presents considerable problems of lighting and

with the Touch Display could be further improved by suit

reflections. One possible solution to this dilemma is to detach the touchwires from the display. This would allow touchwires (keyboard) and display each to be set at its

able computer programming designed to reduce the num

own optimum angle although retaining their same relative

confirmed, and the trial also showed that performance

ber of touches required to input any given message. In addition to the updating of controllers' traffic dis

plays, an important role to which the Touch Display may be applied is that of liaison between one controller and

another, through the computer. Any system which might help to lessen the ever growing volume of ATC verbal communications — already near saturation point — can

not be lightly dismissed. Employment of the Touch Display in the "liaison" data

positions In the other planes. Thus other ergonomic pro

blems such OS lighting difficulties could be largely over

come. If such a system-were to be adopted, then conven

tional keys m.ight be used instead of touchwires — the lay out of the keys corresponding to the layout of the labels on the display above, thus preserving most of the advant ages of the Touch Display principle. However there are some obvious operating difficulties in such an arrange ment and these are to be examined experimentally in the

t r a n s f e r r o l e h a s b e e n e v a l u a t e d a t t h e AT C E U i n b o t h

near future at the ATCEU.

Controlled Airspace and Middle Airspace environments and these evaluations have produced encouraging results which give reasonable grounds for optimism that the

In Conclusion

Touch Display's contribution to this aspect of ATC will be an important one. The points which most impressed those who witnessed these projects were, once again: a) the speed, ease and accuracy with which data could be transferred and displayed;

b) the relatively small amount of training and practice needed by operators to acquire proficiency with the Touch Display;

c) less susceptibility to human error than a system rely ing on verbal communications;

d) the silence of the operations room.

A Note on Operator Training Experience on a series of trials has shown that it is pos

sible to introduce operators to the principles of using the

This article has covered only a few of the possible applications of the Touch Display to ATC of the future,

and everyone who has been concerned with the evaluation of this device is convinced that many other ways will be

found of exploiting its latent potential. The evidence to date suggests that the touch display principle represents

a major advance in the field of man/computer communica tions, and that it is particularly suited to Air Traffic Con trol. The few problems associated with its use should be overcome fairly quickly.

The enthusiasm commonly shown by those who have used the Touch Display may indicate an appreciation that

the application of automation to Air Traffic Control, at least in this instance of its evolutionary progress, can help to make the controller's task an easier and more con genial one. 9

VOR/DME Area Navigation By Glen A. Gilbert

introduction Although area navigation has been recognized for the

past some twenty years as being desirable, it has not gain

ARNAV equipment and as to introduction of area navi gation concepts into the Air Traffic Control System. In Europe, the U.S. Federal Aviation Administration

ed significant usage for two principal reasons:

has demonstrated area navigation capability using VOR/ DME inputs on a significant basis during the past two

1. The Air Traffic Control System had not been organized in a way such as to give most effective application to

years. Eurocontrol also is giving considerable attention to area navigation concepts in its ATC planning.

area navigation-equipped aircraft; and 2. Airspace users were reluctant to spend money for the installation of airborne area navigation equipment un less they were assured that the Air Traffic Control Sys tem would permit them to achieve the various capabi lities provided by area navigation. In more recent years, this sort of "impasse" has been

rapidly changing. For example, the U.S. Federal Aviation Agency in a 1965 Advisory Circular said: "It is the FAA's policy to encourage orderly progression towards the fur ther development and operational use of airborne area navigation equipment."

Thus, the stage now has been pretty well set to move into the age of area navigation on an increasing basis in many parts of the world, and it may be expected that these concepts will be the basis for the development of Stan

dards and Recommended Practices by the International Civil Aviation Organization at a relatively early date.

Advantages of Area Navigation A number of different concepts for area navigation have been developed, including such self-sufficient sys tems as inertial and Doppler, and others based on inputs

mum efficiency in the utilization of the air space, it is desirable that pilots and controllers be permitted to change or assign routes respectively on an area basis

from hyperbolic transmitting chains. However, the wide spread installation of VOR/DME (VORTAC-TACAN) ground stations in North America, Western Europe, and other parts of the world, would appear to give this system the greatest capability to the largest number of airspace users airline, general aviation, and military — as a common

rather than be restricted to the use of certain prescribed routes." The same report went on to say: "Unnecessary

gation equipment.

The U.S. Airline Pilot's Association in a 1966 symposium on Air Traffic Control problems stated: "To achieve maxi

navigational instructions not required for separation of aircraft are being given which causes controllers to devote less time to approach planning, and distracts pilots with unnecessary radio communications and workload." The report of the ICAO Fifth EUM/RAN Meeting con ducted in 1966 urged that "States be encouraged to con tinue studies and experiments intended to improve and

further develop the use of VOR/DME, especially with re gard to its use as an area type navigation and that any

results of such studies or experiments be made available to ICAO for transmission to other interested States".

In June of this year, the Air Transport Association of

America pointed out that "area coverage navigation (from VOR/DME stations) can offer distinct advantages through

the capability to fly routes using cockpit navigation which would otherwise not be practical without radar vectors or other navigation from the ground". Where we are now In the United States, the Federal Aviation Administra

tion, in cooperation with airlines, general aviation and the military services, as well as with avionics manufacturers, is developing standards for "approved" area navigation — "ARNAV" — airborne equipment. Along with these

standards, the FAA is establishing the operational proce dures to be followed as area navigation becomes incor

porated into the U. S. Air Traffic Control System. Airborne ARNAV equipment of several different manufacturers is now being used by various airlines for operational appli

reference input source for economical airborne area navi

One of the area navigation systems using VOR/DME (or TACAN) inputs is the Vector Analog Computer, or

VAC , manufactured by Butler National Corporation of

the United States. This equipment is the result of over ten years of research, development, and successful evaluation,

with many thousands of hours of flight time experience. It is now in production on on off-the-shelf basis for use by

airline, military, and general aviation aircraft. The military version can operate from pure TACAN facilities (as well

as from the VOR/DME input). The general aviation version will be produced at a price sufficiently low so that it should be attractive to a large segment of this class of a i r t r a f fi c .

An explanation of how the VAC equipment functions and its application in different air traffic environments should be representative of the manner in which area

navigation equipped aircraft may be expected to operate

and the resultant implications to the Air Traffic Control System.

Such an area navigation airborne system will permit aircraft to be flown on the most direct routes, along close ly spaced parallel tracks or other routings which the ATC System may prescribe, so long as the aircraft are in receiv

ing range of a VOR/DME ground station. Fig. 1 shows the theoretical altitude/!ine-of-sightrelationship forVORsignal coverage; elevating the ground stations by appropriate siting will, of course, improve the line-of-sight coverage.

In any event, depending upon the altitude levels at which

signals from VOR/DME stations should be received, it is obvious that proper location of ground stations on a

cation. It is clear that introduction of area navigation in

more or less "grid" basis would permit significant area

the United States — particularly using VOR/DME (and TACAN) facilities — is well under way, both as to airborne

navigation coverage over any desired ground area with a

minimum of VOR/DME facilities.

Economic benefits will accrue to the airspace users by virtue of their ability to fly more direct routes and save flight time. In addition, thousands of airports — and un prepared landing areas — can be given some level of instrument approach capability, without the need for local instrument landing facilities. Thus, numerous communities

and areas can be opened to more reliable air services, both commercial and private, and by both conventional and V/STOL aircraft.

The Air Traffic Control System will benefit by being able to increase efficiency in the utilization of airspace; it will have greater flexibility in providing lateral separation between aircraft through assignment of multiple flight paths and closely spaced parallel tracks; diversified route structures will help reduce the possibility of midair colli sions. Routine communications workload of controllers —

and pilots — will be reduced substantially, particularly in terminal areas, by transfer of navigation from the ground into the cockpit. Controllers will thus hove more time to

devote their attention to their primary function of col l i s i o n p r e v e n t i o n a n d e x p e d i t i n g t r a f fi c

flow; air safety, consequently, will be raised and de lays due to traffic congestion will be reduced.

H o w t h e " VA C " w o r k s

The Vector Analog Computer System permits flight over any desired path in the airspace, as well as to any loca tion on the surface (if within receiving range of a ground VOR/DME station) by selecting one or more locations on the surface, called "waypoints". Each waypoint is defined by its distance and bearing from a VOR/DME station. These distance (Rho) — bearing (Theta) "coordinates" are dialed into the waypoint selector control illustrated in Fig. 2, and the desired track to be flown to the waypoint is then set into the cockpit instrument known as the Sym

bolic Pictorial Indicator (SRI) shown in Fig. 3. The Symbolic Pictorial Indicator incorporates two crosspointers — horizontal and vertical. The vertical pointer displays distance to the left or right of the selected track while the horizontal pointer displays distance to or from the waypoint. In addition to the crosspointer indicator, a digital indicator (see Fig. 4) is provided to continuously display distance in nautical miles to and from the waypoint. A rotatable aircraft symbol in the center of the Symbolic Pictorial Indicator shows the relative heading of the aircraft with respect to the waypoint. Keeping the ver tical pointer centered means that the aircraft is on the

S I G H T D I S TA N C E I N M I L E S

Figure 1

Theoretical Linse of Sight Coverage of VOR/DME Facilities in Relation to Aircraft Altitude.

Figure 3

Symbolic Picforial Indicator (SPI).

Figure 4

Digital indicator Showing Distance (up to 200 n.m.) TO and FROM a Woypoint.

,,fj

desired track; when the horizontal pointer intersects the vertical pointer at the center of the indicator, the aircraft is over the woypoint. Vertical and horizontal hash-marks representing "deviation lines" ore provided on the face of the SPI. Each hash-mark can be equivalent to 1, 2 or 10

nautical miles, depending on the scale factor selected by the pilot.

An optional feature provides that two waypoints may be set into the computer at the same time by means of a dual woypoint selector control, as illustrated in Fig. 5.

When the pilot wishes to use the next woypoint, he merely

Figure 6

Representation of a Waypoint on the SPI.

switches over to the other preset woypoint selector. Thus, waypoints can be "leap-frogged", giving the pilot time to set in the next woypoint leisurely as the flight proceeds. An optional feature permits pre-progromming as many waypoints and tracks as may be desired. When the aircraft is at predetermined points in space during the flight, the

next woypoint and new track ore set in automatically at the some time that the aircraft's VOR/DME receivers ore

automatically tuned to The drawing in Fig. interpret his position on ed woypoint and track

the new ground station. 6 shows how simply the pilot can the SPI once he has set in a desir to be flown. In this illustration, thf

woypoint is 45째 to the right of the pilot (1); the woypoin is 3, 6, or 30 nautical miles ahead of the pilot (2), depend ing upon the scale set into the woypoint selector; the pilo

is flying 4, 8, or 40 nautical miles parallel to and to th( left of the track to the woypoint (3), as per selected scale To reach the woypoint, the pilot would turn the aircraft t(

the right, heading towards the intersection of the cross pointers, and the vertical pointer would start moving tc

Figure 7 Figure 5 VAC Dual Waypoint Selector

Rectangular Pattern for VAC Approach to a Runway Showing Relative SPI Readouts.

As the vertical pointer approaches the aircraft symbol, the pilot would commence a left turn and get the aircraft back crosspointer. At the same time, the horizontal crosspointer

another waypoint set in at the runway threshold. Fig. shows the type of ''software'' in the form of approod charts that might be developed for selected airports a which VAC approaches would be planned on a regulo

would be moving downward continuously showing dis

basis.

on the previously selected track by centering the vertical

tance still to go to the waypoint.

Approaches to Airports

Holding Patterns

In making an approach to an airport (or any landing area) without the need for a local landing aid, such as an ILS, the pilot may place the waypoint in the center of the runway to be used (refer to Fig. 7). In this illustration, the aircraft is approaching the airport on a track of 45°, and obviously would remain at whatever the minimum approach altitude was established for that particular location until over the waypoint. Once over the waypoint (center of the runway), the pilot would change to the track or bearing of the runway [in this illustration shown as 00° — or 360°). A standard

In the event that ATC requires an aircraft to hold either enroute or on approaching a terminal area, th( controller would identify to the pilot what waypoint he i to use as a holding point. This may be done by giving th<

coordinates of the waypoint, or by reference to predeter mined waypoints shown on charts. Fig. 9 illustrates th( simplicity and accuracy with which a pilot may carry ou a holding pattern (in this case circular) by orbiting arounc a waypoint. Alternatively, a "racetrack" holding patten

could be carried out readily using the same flight tech nique as that illustrated in Fig. 7.

pattern is then followed involving a downwind leg, a base l a a . a n d t h R fi n n i n n n r n n r h I r h : a t f ; e l e c t e d D o i n t s a l o n a

i n Te r m i n a l a r e a o p e r a t i o n s , r n e v e c t o r A n a i o g c o m

puter will permit pilots to follow pre-organized arrival and departure flight paths laid out in accordance with the most efficient traffic patterns. These patterns also could specify "standard" altitudes to be followed at specific

points along the flight paths. Fig. 10 illustrates this concept on a hypothetical basis for departure flight paths using one waypoint at the end of a departure runway. A similar technique would be followed in setting up arrival flight oaths for a onrtirulnr rtinwnv

Summary One of the most pressing problems in the field of air

transportation is how to use the airspace more efficiently, both as to conventional fixed wing aircraft and as to V/STOL s. Multiple airports and other landing areas must be made available for reasonably reliable service in all weather conditions without the necessity of having ex pensive ground landing aids at each such location. En-

route flying must be possible using direct routes, rather

than circuitous "airways", so as to reduce unnecessary, costly flying time to the minimum. Delays due to air traffic congestion now costing millions of dollars every month

-- must be sharply reduced. More capability must be pro vided to the ground-based air traffic control system and the pilot to effect precise lateral separation by being able to follow pre-established parallel and multiple flight paths between airports and within airport terminal areas. New concepts of super-highways" of the air, over-passes and

under-passes, will greatly improve protection against mid air collisions. Area navigation effectively meets these challenges.

VOR/DME area navigation can economically serve all classes of airspace users. The challenge is for States to C o n c e p f u a l G u i d e f o r VA Te r m i n a l A r e a O p e r a t i o n s .

Pre-Orgonized Departure Flight Paths in

The pre-organized flight paths would be shown on spe

cially prepared terminal area charts, and each path would be given a discrete identification. It would then be pos sible for the controllers to supply precise routing instruc

tions to pilots, merely by stating the desired flight path identification. Each pilot would follow, on his own respon sibility, his assigned flight path by reference to his Sym

provide more effective coverage of VOR/DME ground facilities the ICAO approved short range navigation aid â&#x20AC;&#x201D; so as to give greater area navigation capability to

all significant airspace over their national territories; for

airspace users to install suitable airborne area navigation equipment with all possible speed; and for the Air Traffic

Control Systems of the different countries to adopt their procedures for the early introduction of area navigation concepts.

b o l i c P i c t o r i a l I n d i c a t o r. T h e c o n t r o l l e r w o u l d d o n o d i r e c t

vectoring unless, by radar monitoring, he determines that a particular aircraft is not following the specified path, or that some modification to the standard traffic pattern is needed.

If desired by a particular user, the VAC can drive vari ous types of pictorial displays of X-Y plotters with mop background to supplement the Symbolic Pictorial Indicator during terminal area operations. With such a supplemen tal display, the pilot con double-check track being made good by occasionally referring to the position of the trac ing or cursor showing his location on the background map. Such combination of the VAC with a pictorial display is being used by the U. S. Federal Aviation Administration in their area navigation demonstrations in Europe, referred to earlier.

Accuracy The Vector Analog Computer Area Navigation System

provides unique accuracy because of the high grade com puter used in the system, the large scale which may be shown on the Symbolic Pictorial Indicator (as great as 4 nautical miles to the inch) and its special distance-

proportional filtering feature which minimizes the effects

About the Author

A principal organizer and founder of the U.S. Air Traffic Control System, Gilbert became the first head of

the Federal Air Traffic Control Service when this activity was assumed by the Government in 1936. He served in

this capacity until 1947 when he was named as a Special

Assistant to the Administrator of Civil Aeronautics in the

development of United States air policy in the post-war years. During the next five years, he served on numerous United States delegations to international aviation con-

ferences throughout the world os delegate or head of delegation. After 15 years of service, Gilbert left the

Government In 1951 to enter the field of aviation consult ing. During the next six years he served as an Aviation Advisor in the United Nations' Technical Assistance Pro

gram, and amongst other activities In this capacity he organized and directed a civil aviation training center In Mexico, serving all of the Latin American countries. In 1957 he established his consulting headquarters In Miami

as Glen A. Gilbert & Associates, specializing In studies and analyses, product evaluations and operational pro

blems on a broad basis In the field of aviation â&#x20AC;&#x201D; airline, general aviation, and military. An active pilot for over 30 years with multi-engine and Instrument ratings, Gilbert

of reflections, course bending, and scalloping in the radi

has written many papers and articles on various aviation

ated signals of the VOR ground stations. Operational accuracy of the VAC System (exclusive of any errors which may be generated by the ground station or aircraft re ceivers) permits track accuracy within 1% (RSS) of the air

subjects but with considerable emphasis on the problems of Air Traffic Control. Gilbert Is now completing a book, soon to be published, which will treat the subject of Air

craft's distance from the computed woypoint.

international in scope.

Traffic Control In all of Its diverse aspects and will be

ATC and the Airport Presented by the U. K. Guild of Air Traffic Control Officers, at the Guild's Annual Convention, Bournemouth 1968,

Introduction

This Paper attempts to highlight some of the ATC aspects at the airport, and The Guild recognises that the needs of airports are as varied as the airports themselves and the traffic flow they generate. It is on this occasion impossible to cater specifically for the smaller aero dromes, and a bias will inevitably be directed to the re quirements of a major international airport. The emphasis is upon the operational problems, but we do not forget the inseparable association existing between air traffic control, the Airport Authority, airport users and those other agencies necessarily involved in overall airport ope ration; we are all aware that aircraft delays can ripple far beyond the airport boundaries and hence the need for every effort to avoid them. This is a vast and absorbing subject, some ATC aspects in themselves, for instance Ground Movement Control at large terminals, provide enough subject matter for a full symposium. We will start with a short history.

The Early Days Airport ATC in this country has made a considerable

advance from 1st introduction by the Civil Aviation Depart ment of the Air Ministry at certain civil aerodromes dur ing the 1930s. Those were the days of grass aerodromes, with little more than Aldis Lamps and Very Pistols to assist the civil controller and his military counterpart — the "duty pilot''. He had to position the landing Tee, and the paraphernalia contained within the Signals Square, and lay a Flare Path at night as near into wind as his experi ence and that of his Met. colleague could predict. Later he was able to communicate with some aircraft by means of W/T and a device called the "Q" code; this enabled him

tinued through the introduction of ILS, Surveillance Radar, PAR and ASMI to the present day. ATC has developed, in parallel — although not always in step — with the growth of airports from grass fields to concrete jungles, and from the days of elementary local control, progressing from the provision of separate Aero drome and Approach Controls to the complex Terminal Area systems which exist today. This has been dictated by an aviation growth rate far in excess of that in other industries.

Movement Increases An immediate indication of annual movement increase

is obvious by the fact that the movements for Heathrow in

1947 (29,590) were nearly met within one month this sum mer. The sustained increases over the following twenty years indicate a trend which allows a forecast movement

rate for 1977 of over half a million, but the saturation ceil ing is considered to be nearer 400,000. Having mentioned this much, however, ATC and the airport are primarily concerned with the hourly rate of movement, as it is on this factor that capacities are established — but more of this later.

In keeping with the increased movement rate, transport aircraft have changed dramatically in both size and per formance over the last 20 years, and more is yet to come! The normal commercially healthy game of airline econ omics sets the pace, and we who are operationally con cerned desperately try to keep up, but never quite make it.

Development of Radar Sequencing The Approach Control Service provided procedural

to advise "engines overhead", an early form of CAT 3! In 1938, the situation was still much the same, though

separation to the traffic circuit which aircraft normally

a number of Control Towers had been built — as opposed

radar techniques within the local traffic zone demonstrated

to the early wooden huts on stilts — HF/RT was entering

that aircraft could be marshalled more expeditiously than by pilot or controller-applied visual methods. The civil ATC at Northolt (I think) can take the credit for being the first to introduce radar sequencing procedures as we now know them. Subsequently improved radars and instrument approach aids have enabled the approach separations between aircraft to be reduced to cope with higher land ing rates demanded by increased traffic. Correspondingly, the excessive intervals between departing aircraft have been considerably reduced by the use of Area/Approach

the communication scene, and early forms of Standard Beam Approach underlined the future trend. No Area

Control Centres existed, but some major international air

ports were beginning to provide an Air Traffic Service on routes established by scheduled airline services (e. g. Croy

don — Le Bourget). Considerable advancements were made between 1939 —

1945 in equipment and facilities to serve ATC and the aerodromes. VHF/RT was the standard communication

link when the next generation airports, such as Prestwick

and Hum, were opened, but the "Q" Code continued to be used for a few more years for W/T purposes. Some MF Radio Ranges were available for naviga tional and approach use and GCA radar followed shortly.

Airports had hard surfaced runways and taxyways with approach and runway lighting. These improvements con

joined in the Downwind position. The introduction of GCA

C o n t r o l r a d a r s a n d t h e a l l o c a t i o n o f n o n - c o n fl i c t t r a c k s

between arrivals and departures as much as possible.

Hindsight indicates a lack of foresight in some respects concering ATC planning, and the introduction of radar sequencing is a good example of a procedure being intro

duced through sheer necessity by the controllers on the job seeing the problem and providing their own solution. 15

factors, not the least being the ability of the en-route sys

The Present

Today, civil aerodromes in the United Kingdom are

operated either by the British Airports Authority, local authorities or by private companies, ATC service is pro

vided by the National Air Traffic Control Services, but many local authorities and larger private aerodromes employ their own ATC personnel. Controllers at all li

censed civil aerodromes ore required to hold a Board o f Tr a d e AT C L i c e n c e .

The Guild stated, at its last Convention, the operational

desirability in the United Kingdom for this "mixture" of Government, Local Authority and private company air traffic control to be brought within one independent natio nal Aviation Authority embracing all flight safety aspects.

It is not the purpose of this particular paper to pursue this

point but we would emphasise the need stil exists for ATC

loyalties to be channelled within one "Trinity House -type

structure able to meet the flight safety demands of the day and age with vigour and operational flexibility. In Terminal Areas, where military or small civil aero

tem and adjoining systems to accept departures from the airport, and the airport's competence to accept arrivals from Area Control. This competence in turn is affected by a number of things — the number and direction of run ways, the taxyways layout, the aircraft apron complex,

approach and ground aids, the method of handover from one control function to another, and so on.

It is stating the obvious but the conclusion drawn here is that the airport, TMA and Area Control systems must be planned as an integrated system and not in isolation; one factor which can have an adverse effect on the spacing of the inbound flow at an airport concerns traffic overflying

the TMA at slow speeds in the lower flight levels. Intelli gent new aerodrome siting and careful consideration of new routeings to prevent this are necessary.

This then leads us to runway utilisation and capacity. Runway utilisation is something which has changed con

siderably over the years. Once upon a time airports had a conventional 3-runway layout and aircraft took off and landed on the duty runway, then there came a trend to

dromes ore located sufficiently close to the major airport either to warrant the co-ordination of all or some air

make greater use of the main instrument runway due to its

traffic, or the provision of Approach Control Service by the major airport, the air traffic controllers concerned,

less use was made of the subsidiaries. This has been fol

whether Government-employed, non-goverment or mili

doubt "London's No. 3" will have at least two sets of par

tary, are all working to a common aim —- the safe move

allels. But whatever the layout, the utilisation of single,

ment of air traffic within and adjacent to their own areas.

All controllers must first qualify at an Aerodrome Unit,

although within the NATCS some will subsequently trans

fer to Area Control duties. It is probably true to say that

the majority of controllers, if given the choice, would pre

fer to work at an airport because it is only there that they can actually see the aircraft they are controlling.

At airport there is a sense of "involvement" from see

ing the effect of a cross wind component or water on the

runway to the provision of RVR, the effect of snow clear ance action, bird strikes, and full emergencies — it's all happening!

Another aspect which is not generally appreciated is that no airport is ever complete — it is always being main

tained or under development — and ATC have to operate

in spite of the work in progress. Area units do not have to suffer 5 miles of Amber One being dug up!

Probably because Aerodrome Units are on the spot as

opposed to the normally remote Area Unit, there is grea

ter contact between pilot and controller, although not to the extent that the Guild would wish. There is also a close tie with the operating companies, though a disadvantage of this is that the airport ATC has to shoulder the first blast when delays occur.

Current and Future Aspects

ATC at most airports is inextricably interlocked with the Area Control system and is the essential link between the Terminal Area complex and the runway — that valu

able piece of real estate which is so expensive to lease for G very short period, and when you do manage to get on

it, sometimes after waiting in a queue, ATC are immediate

better facilities and improved aircraft performance, and lowed by the construction of parallel runways, and no

dual, parallel, tangential or crossing runways depends on a number of factors:

Preferential direction procedures, distance apart, point

of runway intersections, compatible lengths, availability of aids, effect of development and maintenance work on the airport, to name but a few. At busy airports with a high traffic offering ATC must make the best use of all avail able concrete, bearing all these factors in mind.

Runway capacity in turn is infinitely variable. If all

aircraft had a common performance, if there were no equipment unserviceabilities, if the weather was always good, and if everything went just right, very high move

ment rates could be achieved — but life's not like that, for indeed we have to consider the following factors:

— Aircraft from high performance jets to single engined private and executive aircraft with widely different approach speeds,

— Noise abatement procedures leading to less flexible techniques.

— At international airports the language factor. (At O'Hare everybody speaks American)

— Availability of good turn-on and fast turn-off taxyways, and adequate holding areas, — Wa k e t u r b u l e n c e .

— Requirement to cross active runways by aircraft under tow positioning to/from maintenance areas, and air port vehicles. So what can ATC do? Radar sequencing with speed control on approach is used to achieve the minimum spac

ing and the highest landing rate. Use of subsidiary run ways and short take-off techniques from intersections can

ly serving you notice to quit. The technique of Terminal

increase the departure rate, but the greatest contribution

but the Airport Approach Control is very directly concern ed with arrival and departure tracks, holding procedures and the availability of airspace. The volume of movements

achieve the minimum runway occupancy. Pilots used to

Area Control is properly the subject of a separate study,

at an airport is influenced by a number of contributory 16

to high runway capacities is slick operation by pilots to busy airports will accept this situation because they have been conditioned to the high tempo, but pilots normally

operating in quieter zones need to be urged to "get on

and off" without delay. Similarly controllers need to appre ciate that it is only they who can initiate the tempo. Cer tainly the mutual programme of education at Heathrow over the post two years has paid off, and hourly rates have increased. A final word about parallel runways, the

is a high intensity centre line lighting system which should

c u r r e n t t r a f fi c d e m a n d w i l l d e c i d e w h e t h e r i t i s b e t t e r t o

for conditions below 50 metres. V/hichever system is used, ATC will be concerned with controlling ground move ments, selecting route guidance and generally monitoring the progress of all traffic. Monitoring can be done from

use them in a dual configuration but as traffic increases and all hours become peak hours, parallel operations must

apply to a for greater degree. And so to the Future Much has already been published about All Weather Operations, but our purpose here is to see what part ATC has to play, and what problems we may have to face. On this basis AWO are split into two phases: (1) from com mencement of final approach to end of roll out, and (2) taxying from runway to apron and vice versa, using CAT 3C criteria.

For the first phase it seems likely that a "Final Con troller" position will need to be established in Approach Control for communication with the pilot during the ex tent of this phase, though not "monitoring" the approach as the PAR controller does now. Whilst his precise func

tions and responsibilities have not yet been established, the Guild is aware of a proposal that the position be

equipped with displays indicating the availability and ser viceability of all the essential guidance systems required for this operation, so that in the event of a total or partial

be adequate for conditions down to about 50 metres. The

second, still very much in the development stage, includes leader cable, and radio active isotope systems, and it is

suggested that instrumental guidance will be necessary

ASMI displays, but as movements increase under very low visibility conditions it will be necessary to identify indi vidual aircraft on the display, perhaps by some means similar to SSR.

Route guidance by centre line lights would in all prob

ability be installed in all taxyways of the airport, and selection and protection of routes can be undertaken by ATC using established methods. It is not known whether

this would applyto an instrumental system, but the require ment remains the same.

In addition to aircraft movements, ATC ore also con cerned with the movement of emergency services and other essential vehicles. If a visual guidance system is installed, route indication con be given by ATC as for aircraft. Ve hicles can similarly be monitored on ASMI, but at the same time such vehicles should be able to navigate inde pendently on a system contained within the vehicle — several of these have already been evaluated.

failure of any one of them the pilot would be immediately

Next Generation Aircraft

advised. Rather than make the "Final Controller" become

a systems analyser, we suggest that any such display panel incorporate a computing device which would simply indi cate a down grading of category, and would in effect raise the minima for the approach. A nice balance needs to be

Three new types of aircraft need to be considered to gether with their effect on ATC and the airport in general; these are the 747, the SST which is the subject of the next Guild paper and the Airbus (L.lOll, DCIO, A300 etc.). The Guild considers that the 747 will have no significant im

struck over the amount of information that can be passed

pact on ATC — in fact for a short while there may be a

on on R/T frequency; pilots naturally want as much infor mation as possible, whilst controllers ore naturally con cerned about frequency loading and question whether the pilot can assimilate it all. A flight deck datalink TV display of information would assist pilots and reduce R/T con gestion.

In progressing towards the CAT 3C era, experience will show the extent to which spacing on final approach must be increased to allow sufficient time to "pick-up" the

runway turn off system (instrument or visual), and be clear before the next aircraft is at the threshold.

The single runway airport would be further penalised if the CAT 3C ILS is sufficiently critical as to prelude a

departure being over the locoliser whilst on arrival is on

slight reduction in movements as one 747 capacity equals that of about three 707's and its performance characteris tics would appear closely to resemble those of the latest 707 variants. Its size however, with gross weight more than

twice the 707, will provide a considerable impact on the airport; runway, taxyway and apron LCNs, taxyway cur ves, clearance limits etc., all need to be revised to estab l i s h w h e t h e r m o d i fi c a t i o n s n e e d t o b e c a r r i e d o u t b e f o r e

the first one arrives. The SST is another matter though, and whilst the major ATC problems are likely to exist in the en-route phase, the following aspects need to be consider ed in the airport environment:

— High approach speeds mean that greater spacing must

approach due to interference set-up. In this event no air

be given between the SST and aircraft of lower (con

craft could be positioned on final approach until the pre ceding departure was airborne and upwind of the loco

ventional) performance. One early simulation at the Air Traffic Control Experimental Unit established that one landing was lost for every SST on approach.

liser; i.e. runway sterilisation for about 6 to 7 minutes. Aircraft must continue to be held as close to the runway as possible to preserve maximum utilisation. If future glide

path restricted areas become extended so that the depar

ture holding point is compromised, the glide path element will need to be resited further upwind and a displaced landing threshold introduced. Phase 2

Taxyway guidance systems, including runway turn offs, fall into two categories, visual and instrumental. The first

— At what minimum distance from touch down can on

overshoot be executed? Runway capacity may need to be reduced to "ensure" a landing.

— If any special minimum noise procedures on arrival or departure become necessary, this would also affect run way capacity.

— Capability of executing turns on the ground when fol lowing a centre line taxyway system, with the flight deck a very considerable distance ahead of the main wheels — particularly in poor visibility.

V\^hen the SST arrives the airport will hove had perhaps 17

two or three years experience of 747 operations and should by then be able to take both SST and the Airbus in its stride.

It seems likely that the next mutual concern will be about the civil version of the Lockheed C5 and Super Jumbos.

Inter-Airport Helicopter Service The New York and Los Angeles areas currently operate

inter-airport helicopter services with connections to "cityterminals", and it is possible that scheduled services will be introduced at some time in the future in the Lonaon Area.

At the moment, in the United Kingdom terminal areas,

helicopter movements ore light and present no real problem.s. If regular thirty minute shuttle services are to be planned between Heathrow, Gatwick the "No. 3" and London, the establishment of on acceptable route system

will depend on the location of the airports in respect of the city, the proximity to densely populated areas, the separation from each airport's arrival and departure tracks, the method of navigation, the ability to operate

under IFR, and finally the capability of integrating increas

ed helicopter movements with fixed wing operations with out undue effect on airport capacity. These are some of the aspects that need to be considered in detail before such a

figuration should be tailored for the specific operations

and physical characteristics of each individual airport. The Air Controller wants an unimpeded view of the approach

and departure paths and the length of the runways for which he is responsible. In the case of an airport having a parallel runway layout with the Control Tower building in the middle of the runway layout, and where there are high movement rates, it may be necessary to effect a divi

sion of the Air Controller's responsibility between two controllers to achieve and maintain high runway utilisa

tion. Regardless of whether parallel landings and departures or a dual runway mode is in operation the practical

division is for each controller to have jurisdiction over one

of the parallel runways. The controllers should be located close enough for rapid physical liaison without obstructing

the view of their respective areas of responsibility — most communication systems do not have the capacity to alert

as quickly as a sharp tap on the arm. Where a separate

GMC function is provided the same requirement for an unimpeded view exists, in this case through 360°. The location for the Aerodrome Control building and the

operating desk and equipment layout should be the result of full consultation between the airport design authority,

ATC, the technical furniture designer and those respons ible for the installation and maintenance of the opera tional equipment.

system could be introduced.

Reverting to the "Island Site" with the provision of two Air Controllers and GMC, a conflict of interests for an

AT C F a c i l i t i e s

Mir Controllers should be positioned for close liaison, this

Having considered some of the ATC aspects of airport capability and requirements pertinent to present and fore cast operations, aids and runway utilisation, perhaps it is appropriate for us to reflect upon the provision of facilities

can be effected by locating the controllers facing their

unimpeded view exists. If we accept the principle that the

respective areas of control side by side but looking in opposite directions, affectionately known as a "love seat".

Ideally this should be centrally placed above floor level to

prevent cut-off from the sills and to permit movement

to enable the controller to effect his task. It must be re membered that the number one principle is that at all

around the room and withdrawal of equipment for main

times the relationship between safety and expedition must

tenance. If we assume that the Air and Ground Movement

be maintained. It is now generally recognised that ATC

Controllers with their closely related functions, are to be

experience can provide a significant contribution to air port design and layout, but co-operation should be reci

accommodated in the same room to effect liaison and to

procal. Airport design authorities should ensure that ATC

is accommodated where it can provide the most efficient

service, compatible with the airport layout of runways, taxyways, aircraft stands, foreseeable movement rates and essential equipment. The two major ATC services asso

shorten communication links, a compromise can be made whereby the Ground Movement Controller — or Con

trollers — are so placed that it will be necessary to stand to view that segment of the taxyway complex in line with the Air Controllers but will not impede the Air Controllers view of the runways, and approach and departure paths.

ciated with an airport are Approach Control and Aero

This is the type of problem one encounters when attempt

drome Control, both self explanatory terms, and Aero drome Control may be further divided into two functions

ing to decide the most efficient layout for an Airport Air Traffic ^^ontrol Unit. It is too easy to fall into the trap of suggesting the use of CCTV to cover "blind spots" or even ASMI. It is not an economically sound practice to run ASMI twenty-four hours a day throughout the year and it is difficult to monitor a radar tube or CCTV picture pro

— Air Control and Ground Movement Control.

Aerodrome Control should be sited to provide a clear

unimpeded view of all traffic patterns for efficient visual control of the primary runways and the subsidiaries, based on the premise that at most airports, for a very high per centage of the year, traffic problem and conflictions on the manoeuvring area can be resolved by visual reference without the need to interpret displays. Thought should be given to the number and configuration of the runways, their dimensions, turn offs and holding areas, taxyways

and the airport terminal area and apron layout. One should not lose sight of long term requirements and must allow a space contingency within the Aerodrome Control Room to house equipment for automatic data processing inputs, electronic data displays and whatever the all weather operation requirements will be. Operational desks, consoles and display equipment and the desk con 18

perly and maintain visual surveillance of aircraft and vehicles.

Nothing has been said up to this point about the loca tion and design of Approach Control. Approach Control, like Terminal Area Air Traffic Control methods is based

for the most part on a radar concept. There is doubt in

some quarters whether this reliance on radar vectoring, with the heavy communication work load between control ler and pilot is the most efficient method for control in the

TMA and Approach phases. The TMA and airport naviga tion capability perhaps should play a greater part, with radar performing a predominently monitoring function.

Approach Control is responsible for the critical ap proach phase, and in some circumstances the initial depar ture phase of on aircraft's flight and because of its radar environment has no requirement for visual reference to

In addition to air-ground communication. Approach Control will require radar equipment, or whatever super sedes it, to sequence aircraft and a means to identify the

the airport manoeuvring area or the runway approach and departure path. Its location is therefore, not so critical as

primary, processed, labelled and bright displays. Data and

that of Aerodrome Control but the Aerodrome and Ap proach Control functions are very closely linked and tradi

tionally are generally located within reasonable distance of each other. This effectively achieves short communica tion links, and permits the controllers to alternate between Aerodrome and Approach positions without incurring ad ministrative and economic penalties. Very briefly the lay out in Approach Control will vary according to the de mands of the airport it is serving but should follow in sequence the phases of the aircraft's flight path from the position of transfer from the TMA control until established on final approach and transferred to Aerodrome Control. Inevitably reference must be made to ATC instrumen tation and displays, the Guild's paper on ATC Displays presented at the 1966 Convention emphasised that with

any equipment the use of the information available will

aircraft. Radar is used here as a generic term and includes communication links between Approach and parent ATCC and Aerodrome Control ore essential. Displays should in

clude amongst other things information on all traffic com ing under their control, weather information and facilities state.

Where precision approach radar is provided the con troller will want displayed the next aircraft identity, con tinuous descent glide path checks when there is no ele vation data, obstacle clearance limits, clear to land indi

cator, RVR and wind speed and direction. Aerodrome Control, which includes Air and Ground Movement Control, require equipment to communicate with aircraft and vehicles on the manoeuvring area. The amount of "natter'' in the U. K. with regard to service vehicles on the manoeuvring area is overdue for review and revision of procedures. The facility to check aircraft

position on final approach or during the departure phase

only be as good as the quality of the controllers using the

can be supplied by equipment such as the distance from touchdown indicator and/or a SRE using Bright Display

equipment. Controller calibre and equipment quality are

techniques. By the use of Direct View Storage Tube tech

two distinct items but one is obviously complementary to

the other and the two together will determine any flight

safety factor within on Air Traffic Control system. The degree of equipment and displays will have to be econo mically justified with regard to the airport configuration and the density of aircraft movements. In short the system should be geared to provide the airport with the ability to accept and dispatch aircraft within a standard of rules to achieve maximum runway utilisation. The requirements

can range from a one man band Approach-cum-Radar Controller to a complete dual system of radar directors for

niques the DFTI is capable of being viewed in open day

light. This is an essential specification for any radar to be viewed in Aerodrome Control. In restricted visibility con d i t i o n s o n A i r fi e l d S u r f a c e M o v e m e n t I n d i c a t o r w i l l a s s i s t in the direction of aircraft on the surface but a means of

incorporating identification is on outstanding need. The Guild has, over the years, pursued a policy for the wider introduction of Bright Display techniques and we would very much like to see the development of a daylight view ing display for the type of ASMI equipment installed at H e a t h r o w.

the intermediate and final approach sequencing phases

Other requirements for Aerodrome Control are the

feeding parallel runways independently and simultaneous ly, with further radar controllers for general aviation and special VFR traffic added for good measure; and master minding the traffic flow, spacing of landing aircraft in relation to departures and integrating General Aviation

display of data for identification of departing aircraft,

into a predominently air carrier environment, a co-ordinotor, flow manager, crew chief, call him what you will but a key man nevertheless.

landing sequence of arriving aircraft, allocated parking area, meteorological data, a compact back indicating Run way and Approach Lighting Panel, and a taxyway route

selection system, preferably miniaturised with no delay between selection and activating in the field and protec tion against the selection of conflicting routes. Automation

Aerodrome Control and Approach Control capability

The speeds and numbers of aircraft using the United Kingdom Airports have been steadily increasing and will continue to do so, particularly at the major international

runway utilisation than baulked landings due to insuffi cient separation on final approach or wasted runway time due to unnecessarily extended separation. The most essen tial displays and instruments must be, as far as is possible, directly in front of or near to the hand of the controller. It has been said before: equipment and displays should be designed and located to present information to the con

fields. It is recognised that the basically manual system

troller in such a manner that it is readily assimilated, re

to provide a safe and effective ATC system. It is refreshing

quiring the minimum interpretation or physical effort and

that some of this energy and expertise has now turned

must be matched, and efficient data links established. Nothing con be more frustrating or designed to decrease

employed is likely to impose limitations on the processing and transfer of essential data and introduce what could

well become a high potential for human error. A great deal has been written and talked about the use of high

speed computers for collecting, processing, transferring

and automatically displaying flight plan and profile data

leaving the controller free to arrive as quickly as possible at an executive or planning decision. It should be the

towards Terminal Area and airport problems. These can not be isolated and arrival and departure capability is a

iT^inimum amount of data consistent with the ability to

significant factor in the overall system. The ability of the

c a r r y o u t o n AT C f u n c t i o n a n d d e t e c t u n s a f e s i t u a t i o n s .

airport to maintain, or not, its acceptance and departure

The controller should be able to acquire further informa tion quickly, this will range from physical contact with an adjacent controller to more advanced technologies with rapid address and retrieval of data.

rate can have a marked effect on the en-route phase. The introduction of modern electronic data processing, trans

fer and display techniques at airports maintaining high movement rates will relieve the controller of some of the

routine tasks and communication load, leaving more time to arrive at executive or planning decisions. We must,

queue for both runways and runway assignment computed to permit departures from both runways. It is likely that

h o w e v e r, b e c a r e f u l n o t t o u s e a s t e a m h a m m e r t o c r a c k

the computer could assess a dual runway operation as the

a nut, and use a computer as an end in itself. Considera tion must be given to the demands of the particular air

more efficient strategy for a particular spread of depart

port and its potential. At fields with relatively low move ment rates sophisticated techniques could well slow down the processes, whereas a sharp crack on part of the ana tomy or a well directed finger, dirty or otherwise, could well be the most efficient data link. Perhaps this story is

tional system for Area and TMA, based on a pictorial cockpit presentation of an area navigational capability

pertinent "A British Diagnostician was touring a gleaming new hospital in the States to see the practical application of computers in diagnosis. Each patient was given a data

The assignment of a runway for departing traffic is not so flexible since, for example, a northbound aircraft de parting from a south runway sterilises the take-off path of the north runway until it is clear of that path. We consider the programme should be extended to include part of the ground movement environment; it has particular significance at Heathrow. When parallel land ings are taking place a closely knitted network of taxying

sheet on which every detail of his condition was listed. The computer then diagnosed the complaint. The visitor was duly impressed but asked how the trainees coped when they left the hospital and set up practice in small town and village hospitals where there were no computers to aid diagnosis? What in fact happened to the patients? The answer was as positive as it was resigned. "Ah, they die

doctor, they die." Getting back to automation and air trafFic control at the airport a developm.ent we look for

ing and arriving traffic. The use of a multi-track naviga

of given accuracy limits could be integrated into such a

system to meet the demand for increased airport move ments.

traffic could evolve around the Central Terminal Area if

aircraft landing on the north runway are proceeding to aircraft stands to the south of the Control Terminal Area and vice-versa.

ward to is the computer assisted approach sequencing of

There are many ways in which a computer can be used

aircraft to the landing runway. The rational spacing of

to effect data transfer but there is one other field in which

aircraft at touchdown will achieve a high degree of run

a high speed computer could assume a significant role;

way utilisation. It is envisaged that the computed tracks and speeds to be flown to make good the desired separa tion at touchdown can be displayed either by an alpha

the automatic route selection for ground taxyway routeing. Very briefly the requirement is for busy airports with a

numeric label on the radar screen with symbols for any

departure procedures, to have the capability of request

computed turn onto another leg or by an electronic dis

ing from a computer store the most expeditious route from the point of leaving the runway to the aircraft stand or

play with the callsigns tabularly displayed in sequence

with other pertinent information such as type, adjusted airspeed, track, applied separation and runway; this last item is particularly significant when the parallel landing and departure mode is in operation. For Radar Directors the labelled display would be a better choice because it requires no correlation of the radar picture and data dis play. It can also be readily assessed if the aircraft has left the computed leg and if necessary adjusted for up-dating.

complex taxyway system and multi-runway landing and

from the stand to take-off point, graphically displaying the route with conflictions indicated, automatically selecting the appropriate lighting or taxyway guidance system and resolving or protecting against conflictions at intersections. Conclusion

To conclude we must stress the futility of ignoring the interests of other airport agencies; recriminations and

An electronic tabular display of the landing sequence

accusations will not help to solve the type of airport satu

could be displayed to the Air Controller together with type, runway and spacing. This would effectively form a data link between the Approach Radar Director and the

ration crisis which affected the New York Area this sum

mer. The lessons to be learnt are there for all to see,

particularly their delay in selecting a fourth airport. At

Air Controller. To further the process where there is a

least one of their major problems does not exist at

separate ground movement control unit, the callsign of arriving aircraft could be displayed on an EDD to the Ground Movement Controller together with the aircraft stand designator as allocated by the Airport Authority.

Heathrow, where for some years the hourly movement rates have been stated by ATC, and then filled by an effi

The problems posed for processing an approach sequence onto parallel runways from more than one holding stock or gate while departures from the same runway are in operation present an ideal set of factors for using a digital computer to assess the control strategy. The holding areas or approach paths to the commencement of approach sequencing to the runway should be treated as a joint

cient Airline Operators Scheduling Committee.

However the overall problems could perhaps best be

met in this country by the formation of a "Board" â&#x20AC;&#x201D; of

workable size â&#x20AC;&#x201D; incorporating all interested parties such as Airport and Local Authorities, Airline Operators, the

NATCS and independent ATC, and surface transport orga nisation. The purpose of the Board would be to develop a National Airport plan to provide for the present require ments of air transport and general aviation in the U. K.

fotgQf March 1969 8th Annual IFATCA Conference

Belgrade, Yugoslavia 20

ATC and the Supersonic Transport Presented by the U. K. Guild of Air Tr a f fi c C o n t r o l O f fi c e r s a t t h e G u i l d ' s

Annual Convention, Bournemouth 1968.

indicate some of the problem areas to which ATC atten

It was not without some misgivings that the Guild adopted as a theme for this Convention "ATC and the

tion should be directed. For example:

Supersonic Transport", for it is recognised that there are

a) In military experience, the weather factor on the climb

many experts in this field, and probably in this audience,

some of whom may disagree with each other on certain aspects of the subject. However, on one thing, all must

agree: that air traffic control systems throughout the world must be sufficiently flexible to meet the requirements of

all operators and that standardisation of operating proce dures and facilities should be vigorously pursued in order to facilitate transfer of control responsibility, co-ordina tion of traffic and the preservation of safe separation at all times.

This may seem to be a strange introduction to the sub ject but, OS each new aircraft with more advanced facili ties and capabilities comes into operational service, the cry is heard that it cannot be integrated into the existing

ATC system and therefore new procedures and facilities must be provided to ensure its safe and expeditious hand ling. This, of course, might result in specialist and priority treatment being provided for those aircraft able to com ply with the new requirements and a second class service for those unable to comply. Is a two-tier ATC service really what is wanted? The Guild does not think so. Air

craft operational performances have increased remark ably since World War II, and have strained almost to breaking point the resources of the air traffic control organisations of the world which never quite manage to

is not significant, a combination of meteorological fore cast and radar CRT "look-see" having proved adequate before the commencement of climb.

b) Precise positional and time estimates are essential to permit straight line descent to Terminal Area Final

Approach for stroight-in landing, delays and decisions regarding diversion being determined before any des cent is commenced.

c) Radar surveillaince is required throughoutsubsonic and transonic stages into the supersonic profile and simi larly on recovery.

d) Speed control of military supersonic aircraft on re covery has been found to be unacceptable.

In considering the applicability of this practical ex perience to the supersonic transport aircraft, due account must be taken of the different environment in which it will

be operating, i. e. integrated with sub-sonic aircraft of

widely differing performances in busy Terminal Control Areas, of the different roles of the civil and military air craft and of the significantly greater stresses acceptable to both airframe and occupants in the case of military aircraft.

By 1971, the frst Concorde aircraft are likely to be on the air routes. The Boeing 2707 is forecast for regular

keep pace with the rate of development of new aircraft. The rate of progression from sub-sonic to supersonic per formance in the case of jet transports con be expressed in terms of speed as being from Mach 0.8 to Mach 2.2, a staggering increase which must inevitably result in a care ful reappraisal of existing ATC systems to determine their

service in 1975 and a Russian built SST with characteristics similar to the Concorde will concern ATC in Western

weaknesses and to ensure that steps are taken in time to

will be utilised on North Atlantic services. The need for a

improve, and where necessary change, facilities and sys

high and economic utilisation of each individual aircraft,

tems to enable the air traffic control organisations to inte

grate these new generation aircraft with those at present in operation.

This paper is concerned with supersonic transport aircraft and the impact of their introduction on air traffic control. In this connection, a great deal of work has al ready been done both in the UK and the USA, and this paper is based largely on UK and USA dynamic ATC

simulation results so for, plus what might be called "Guild

crystal-ball gazing". In addition, through the medium of

Europe during the some time scale. The options currently announced indicate that, for Concorde and Boeing SSTs, a total of 133 aircraft have already been ordered. The majority of these, during the first few years' operation,

and the knowledge that the options are far from com plete, makes it reasonable to assume that by 1976/77 about 150 SST aircraft will be operating daily in the Western Europe airspace. This will give a total of approxi mately 300 SST departure and arrival movements per day.

Routes and Separation Standards

the handling of military supersonic aircraft has been made available and, whilst it is appreciated that military

The movement of supersonic aircraft presents certain problems to ATC, and it has been necessary to suggest discrete routes and increased separation standards even for a single movement. The operation of larger numbers

supersonic aircraft operate in a virtually unrestricted en

necessitates a complete re-appraisal of current ATC tech

the Guild's military members, operational experience in

vironment and are concerned with achieving maximum

operational performance and flexibility rather than eco nomy of operation, nevertheless such experience may well

niques and procedures. It has to be recognised that the SST has distinct and unique requirements for the various phases of its flight, particularly those concerned with the 21

climb and descent to and from the cruising levels involv

tracks, and it will be possible to ensure — by liaison be

ing subsonic, transonic and supersonic speeds and per

tween Paris and London — that the westbound track struc

formances.

ture will receive aircraft at intervals appropriate to the

longitudinal separation standards. It should be noted,

A typical SST Flight If one now looks at a typical flight, starting at the

ramp, the first problem is encountered. lATA have said that a stated departure time is required for the SST which must be made good within plus or minus five minutes. This will clearly cause problems to ATC who are currently quite unable to predict precisely what the traffic situation will b e i n t h e n e x t fi f t e e n m i n u t e s . I t i s d i f fi c u l t t h e r e f o r e f o r

ATC to assess at this stage how the lATA requirement can

be implemented unless a high degree of preference is given to the SST and, even if this is accepted, then taxiways and holding areas will have to be wide enough to allow SST aircraft to by-pass other aircraft.

Assuming that our SST aircraft has moved onto the take-off runway, it will be necessary to provide a clear

however, that the use of a cruise/climb technique would

severely restrict the capacity of each track in the route structure, due to the inability flight levels simultaneously. As aircraft increase, therefore, a will be required, and the route

to utilise several separate the number of supersonic greater number of routes structure will become more

complicated. For example, an increase in the number of departure

airports on the Continent will prohibit any simple form of flow control liaison, and aircraft may have to be delayed en route in order to enter the NAT tracks at the appro

priate times. This may be achieved without any great economic penalty to the operators by requiring the aircraft to remain at subsonic speeds for a given number of minutes. However, it might result in westbound Concordes

ance to climb, without restriction, to FL 260 or thereabouts.

going out of radar coverage whilst still at subsonic levels and thus being required to climb using procedural separa

This is difficult to arrange even now during periods of high

tion standards. It seems doubtful that this situation would

traffic density, and later it will undoubtedly become a

be either acceptable or practicable. As numbers of super sonic aircraft increase, so the numbers of NAT tracks must be increased. These will inevitably become further away

major problem. A f t e r t a k e - o ff t h e a i r c r a f t w i l l h a v e t o c l i m b w i t h i n t h e

airways system through conventional traffic with all the attendant problems imposed by the current width of air ways of 10 NM — this will undoubtedly give rise to restric tions to the SST. One other factor which may introduce restrictions on SST operations at this stage, is that con cerning the sonic boom. Despite the intensive experiments

from the great circle tracks, and may therefore be outside

carried out, so far mainly in the USA, by subjecting popu

the traffic safely. Once the supersonic aircraft is at its cruising level, ATCproblems diminish, but unknown factors

lated areas to sonic boom over-pressures, no clear indica tion has emerged of what is likely to be an acceptable level of noise from SSTs. Further tests will undoubtedly have to be made with an aircraft of at least Concorde

dimensions in order to gain conclusive evidence which will lead to a sound basis for determining what, if any, restric tions have eventually to be applied to the subsonic climb of the SST. Due perhaps to the inconclusive nature of research to date, no firm policy has yet been stated by the

United Kingdom on whether the boom can be permitted

the coastal radar coverage for the initial climb or final

descent phases of flight. For increased coverage, there fore, it may be necessary to provide an ocean radar plat

form. Additionally, there may be a requirement for step climbs and Mach. number limitations in order to contain

(for example solar flare radiation, CAT, or loss of one engine) may require the immediate descent of the aircraft to levels occupied by subsonic traffic, which would, of

course, present considerable problems to ATC. But how ever interesting it may be to speculate on these things, time does not, unfortunately, permit further discussion in

a paper of this length. When decisions on SST routes have been taken, the

transonic climb, therefore, it is assumed for the purpose

problems of R/T communication and radar coverage will also have to be reviewed. The points of handover between various authorities will have to be agreed — certainly the

of this hypothetical flight that the boom must be projected

current short route segments with frequent handovers will

over the sea.

have to be modified or abandoned, since already the

over land. In considering the routeing of the SST for its

speed of aircraft has overtaken the speed of ground

Track Systems The SST will wish to commence its transonic climb to

cruise/climb conditions as soon as possible, and then take up its North Atlantic track. A standardised track system is required with alternative tracks to take account of adverse weather conditions, and these tracks must be promulgated to all interested ATC and other operational agencies. It is essential that aircraft on these routes are afforded the

protection of controlled airspace with no upper limit. Radar cover is considered to be essential for at least 180

nautical miles from the furthest point at which the tran sonic climb will normally commence.

liaison and communications. It will be necessary, there fore, to arrange for the projection of information well ahead of the aircraft's arrival at a given point, and it will probably be necessary also to have a central autho rity for the co-ordination of all traffic in the critical area of the UK south-western approaches.

The abandonment of short route segments and the

requirement for increased sector lengths means that Radar Controllers will have considerable areas under their sur veillance. It will be necessary therefore to decide on the

optimum size of radar displays, the scale and the area to

be controlled by a Radar Controller, and the method of

displaying traffic data.When one realises that on a 16-inch

radar display representing a 200 nautical miles radius, five nautical miles separation is represented by one fifth of an Route Structure

The simple route structure for the early days of the Con

corde operations requires only single west- and eastbound 22

inch, it is evident that one of the problems to be investigat ed will be the ability of Controllers to work down to radar resolutions of this order. Radar beam width is relevant to

this problem and will determine, to some extent, the radar separations which can be applied in practice, especially at long range.

With regard to inbound flights, some 120 nautical miles from landfall the SST will require descent to become sub sonic before reaching land. Here again, provided ad equate radar coverage can be given, this requirement can probably be met by Air Traffic Control in a low density environment, as this presents a less critical problem and

a less sensitive phase of the flight than that concerned with the transonic climb.

what will be the responsibility of the controllers in this respect?

The problem is therefore a joint pilot/ATC one. On the one hand pilots will wish to monitor their flight through the use of airborne radar; on the other hand ATC should

equally be in a position to have continual sight of the weather picture, so far as it can reasonably and realisti cally be portrayed on radar. This combination of "weather

watch" will complement the en-route forecasting service. The Guild would therefore like to see a system introduced by which Radar Controllers would have immediate re ference to radar-derived weather information available at

Integration of SST and Subsonic Aircraft It is not anticipated that any new problems will be encountered in the integration of SSTs, once they are sub sonic, into the general pattern of airways traffic provided, as previously mentioned, the width of current airways is

their operating positions. Whatever decisions are taken in

this respect, however, the Guild is convinced that pilots of supersonic transport aircraft will not wish to commence t r a n s o n i c c l i m b u n l e s s t h e r e i s s o m e fi r m a s s u r a n c e t h a t

their flight path is clear of unsuitable weather.

increased. Difficulties will arise however if and when

diversions are required, the earlier decisions of this nature can be made, the more efficient service the Air Traffic Control authorities can provide, the more economical will be the operation of the SST aircraft concerned. For the

landing phase, ATC seems to be in a somewhat "grey

area" as far as the knowledge of aircraft requirement is concerned. Because of congestion in busy terminal areas (e.g. 2V2-hour wait recently at Kennedy) and the high

Navigational Requirements It is clear that, for reasons which will become apparent later in this paper, ATC considerations will have a major

effect on the operational requirements for SST naviga tional capability.

The principal factors governing these navigational re quirements may be stated as follows:

SST integration with conventional aircraft. It must also be clearly understood that ATC cannot guarantee priority

Flexibility, Accuracy, Reliability, Profile guidance. Common reference. Data display. Automation. From the preceding it is possible to draw some firm conclusions as to the type of system needed. The term "system" is used deliberately since navigational functions will need to be performed by a combination of naviga tional aids operating through a digital computer, outputting data to a comprehensive flight deck navigational display and to the auto pilot. Flexibility can be achieved through the medium of an area navigational system, deriv ed either from a ground radiated pattern of a true area

approaches for all inbound SSTs, as the efficiency of any ATC system depends on the ability of all airspace users to

coverage type, or from "self-contained" data computed in the aircraft. In the latter event, the information will require

follow the same procedures. Once on the runway, the SST will be required to clear it at speeds no less than those applicable to current types, if delays to subsequent traffic

to be updated periodically by an external reference aid. The accuracy requirement will be dictated by the hori zontal separation standards to be employed, which in turn are a function of the ATC system capacity and operat

runway utilisation necessary at major airports in order to

handle the ever increasing traffic. Air Traffic Control will be vitally concerned with any special arrangements or requirements necessary to accommodate supersonic trans port aircraft. The difference in the supersonic transport

approach speed and that of the slowest conventional air

craft will be extremely significant, and this differential will complicate ATC sequencing problems. Terminal Area con trol must therefore always be flexible enough to permit

are to be avoided.

ing economy. Reliability is a pre-requisite, again in terms of separa Weather Effect

Many theories have been presented (some of them quite alarming) concerning the impact ofweather upon the SST in the critical phases of transonic climb and descent, and mention has already been made of military experi ence in this area. In UK latitudes it is unlikely that preci

pitation or turbulence, associated with Cu Nim, will be encountered above PL 400; the effect of weather on SST

should be confined mainly to the transonic climb until above FL 400, and to a lesser extent to the transonic des cent. Alternative solutions may lie in the use of airborne detection equipment and ground based radar, but, in the case of the latter, the following questions arise:

tion standards, since their safe adherence depends to a large extent on the elimination of gross errors. As an illus tration of the combined roles played by accuracy and reliability in their application to separation standards, a lateral separation of 60 nautical miles between tracks in the North Atlantic will require an across-track error hav ing a standard deviation of approximately 8 nautical miles, with a capability of maintaining track within 30 nautical miles for 99.95% of the time. Precise profile guid

ance is dictated by the need to conform to the air traffic control clearances issued for the flight and to any changes to profile necessitated either by reclearances or by mete orological conditions. Additionally, noise and sonic boom considerations may impose a strict limitation on the area

1. Who operates it and what presentation is required?

over which transition to supersonic flight is permitted. Pre

2. Will the particular radar see all the weather or only

cise 3-dimensional data is therefore essential. Concerning

certain selected parts of it?

3. Will the pilot of a SST be prepared to accept delayed climb or rerouteing on weather radar advice only, and

a common reference, it is obvious that for a high pro

portion of the supersonic phase of flight, certainly across the North Atlantic, the supersonic aircraft will be outside 23

radar coverage and therefore outside one of the common

frames of reference used by air traffic control to preserve separation. It is therefore essential that any navigational

device used as a basis for a horizontal separation must

requirement. It is certainly our view that a much more expeditious ATC handling for SST is possible where par allel one-way tracks can be provided, but if even a

single SST has to be separated from the

have a common reference, both to absolute ground posi

subsonic

t r a f fi c

tion and time, to minimise the accumulation of random

situation

must

errors between the representation of different aircraft

surveillance during the critical climb from subsonic through transonic to the

positions.

The requirements for data display and automation of the navigational functions can be considered in combina tion since essentially both aspects are most pertinent to the flight crew; also both have a consequential effect upon ATC. Cockpit pictorial displays are currently gaining wide acceptance and these should be associated with a dis tance, time-to-go and required track to any desired point, plus along/across track readout. Associated with these displays should be an autocoupling facility on any series of predetermined tracks with a facility to over-ride or amend the preselected tracks to accord with changes in air traffic control routeing instructions. The ATC purpose

in both cases is to achieve minimum flight error whilst adhering to the track and profile. Automation of the navi gational functions is required in order to provide more

time for concentration upon operational (including air traffic control) aspects of flight management. Additionally, automation by digital computer will provide for the trans mission of aircraft positional data by an automatic digital air/ground data link to a central ATC data processor. There are other areas in which ATC will have to rely

more on automation and computer aid and less on the traditional empirical approach. Apart from the require ments for en-route control the ATCO needs help to tell

him the optimum time at which to turn an aircraft in an approach sequence and the amount of turn necessary.

Work has already commenced in this field, and it is hoped before long that a suitable approach control aid will be come available. (We shall certainly need one!) Further out from the airport, some sixty or seventy miles away, there is a requirement for speed control and sequencing to start â&#x20AC;&#x201D; this will have to be done initially by "guestima-

fl o w , be

the

under

whole constant

t r a f fi c radar

supersonic phase. In addition to the suggested parallel one-way tracks, consideration should be given to the provision of ultra-high sectors. These will be sectors above the normal subsonic jet operating or cruising levels and will possibly extend from 40,000 upwards. Although we mentioned previously the requirements for navigatio nal equipment for SST, air traffic control are equally con cerned that protection for these aircraft by all means at our disposal can and must be afforded. In the early 70s the primary instrument for this purpose will be the extend ed use of radar and an increase in radar coverage. This, coupled with the intensive use of secondary radar, which can be utilised to its maximum efficiency when the carri age of transponders is made mandatory for all aircraft, should considerably assist ATC in controlling and protect ing the supersonic aircraft.

Civil/Military Co-Ordinatlon The UK authorities concerned with planning the ATC system for supersonic aircraft operations have been con sidering for some time how best to co-ordinate, in the airspace available, movements of civil and military air craft capable of following a flight plan with those move ments of military aircraft on operational missions which are not answerable to such a plan. Hitherto, these two types of traffic have been controlled by different authori ties and experience has shown that this is not an entirely satisfactory state of affairs.

Military and civil co-ordination in the upper airspace has, however, already been developed to a high degree of efficiency at the Joint Air Traffic Control Radar Units, and

lief from this difficult chore, but it is hoped that in the

the future ATC system (Linesman/Mediator) planned for the United Kingdom, will create an integrated civil/mili

not-too-distant future he will be able to obtain from a

tary organisation designed to cater for the needs of all

tion" and the overworked Controller will welcome any re

computer the speed control requirements and the optimum

users of the airspace in which air traffic services will be

sequencing for any circumstances. In simulation exercises concerning supersonic transport

provided.

aircraft combined with subsonics and military traffic, it has been found necessary to devise special techniques in

joint planning organisation, which was the intention be hind the formation of NATCS, must provide the answer to

order that the Control Officer may have sufficient warn

ing of the intention of the pilot of the SST to carry out a particular manoeuvre. Equally, the air traffic control officer must create sufficient lead time to warn the pilot of the SST of a requirement to carry out any m.anoeuvre neces

sary for ATC reasons. It will clearly be necessary to speci

Mutual appreciation of each other's problems in a

conflicting requirements to ensure that SST operations will be afforded the same high standard of ATC protec tion that operators have come to expect of the National Air Traffic Control Services of the United Kingdom in respect of current operations.

fy adequate lead times in order to enable SSTs to level off

Automation of Navigational Facilities

at specified levels.

f o r AT C a n d P i l o t s

Radar Coverage

ance of radar as the Controller's primary tool to solve the immediate ATC problems of threading individual SSTs in small numbers through the present main flow of subsonic

So far m this paper the Guild has stressed the import The main considerations regarding separation stan

dards applicable particularly and peculiarly to the SST, require intensive study before a satisfactory solution can evolve. In test separations during simulation, 4000 ft. verti cal and 10 nautical miles spacing on radar have been applied, but these may not necessarily be the optimum 24

traffic. It is the Guild's view that this is a short-term ex

pedient which will break down when the density of SST t r a f fi c i n c r e a s e s .

Let us consider an instantaneous forecast traffic situ

ation in the UK south-western approaches on a day in 1974

when tracks are south-about. In such an environment, us

efficient traffic flow and to detect and display specific con

ing present control techniques, it seems likely that the limitation on system capacity will be the number of air craft which each individual Controller will safely be able to monitor for the purpose of predicting and avoiding possible future conflict situations, and the number of indi vidual controllers between whom responsibility for such a

fl i c t s i t u a t i o n s f o r C o n t r o l l e r i n t e r v e n t i o n . I n t h e l o w e r

complex situation could be efficiently sub-divided, with out creating impossible liaison problems. In this environment, and wherever else over the face of

separation minima are not to be imposed by ATC in order

density and en-route environments, there is a functional requirement for designated pairs of aircraft to be able to

exchange navigational information, for the purposes of maintaining their own separation in relation to each other

during specified periods, if large and possibly uneconomic to prevent the possibility of conflict outside areas of avail able radar coverage.

the earth two or more SSTs may wish to accelerate, de celerate, cruise, climb or descend, in the same area at the

will not be able to offer safe, orderly and expeditious

same time, the real ATC requirement is for information

service to SSTs and subsonic aircraft unless:

To sum up, therefore, it is the Guild's view that ATC

on position, altitude and intention from all aircraft, to specified tolerances of accuracy in relation to a common

a) in the short term, adequate radar coverage and suffi

frame of reference, at specified intervals of time, together with 0 system for collecting and processing this informa tion for purposes of conflict detection and resolution.

cient controlled airspace is available, even for an indi vidual SST which requires to climb or descend through existing subsonic traffic, and

Since it is inconceivable that the long-term solution

b) in the longer term, all SSTs and long-distance subsonic traffic flying the same route sectors ore equipped with an airborne navigational capability to fly specified tracks and profiles, to specified accuracy tolerances, in

will be to carpet the earth, and particularly the oceans, with extended secondary radar coverage, it is absolutely essential that the aircraft's novigotionol system must be utilised to provide the required data, and it is primarily

relation to a common frame of reference, with the capability to communicate this navigational informa

fo r th i s r e a s o n th a t i t i s th e Gu i l d 's vi e w th a t i t i s th e se

tion to each other and to ATC Centres, and that these Centres are equipped to process this information for

ATC requirements and not the comparatively simple task

of getting from A to B which dictate the accuracy and

purposes of conflict detection and resolution. Bearing

navigational capability required by SSTs. In high density areas of operation, ATC will require computer processing of this moss of incoming four-dimensional data to plan an

in mind the gap between concept and implementation, the longer term in this context means yesterday!

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32331

A i r Tr a f fi c C o n t r o l

and the Supersonic Transport Presented by Captain A. G. Payne* at the Guild's Annual Convention, Bourne mouth 1968.

Mr. Chairman, Ladies and Gentlemen,

fuel which will be consumed as a result of the early des

1 am here to talk to you about the SST and its likely impact upon ATC, that is from the pilot's point of view. Although we all have a fair idea where the problem

to level out at various stages of the descent frequently

areas are likely to lie, until a considerable number of hours have been spent on flight deck and ATC workload studies with Concorde prototype in flight, it is unlikely that any firm conclusions on new problems will emerge. We do, however, even in the subsonic age, have cer

tain problems which concern the Air Traffic Controller and the pilot. It is unlikely that the introduction of the SST, combined with a new generation of subsonic jets, would moke these problems any easier to live with. I am sure that the reverse would be true. It is for this reason that I hope

no effort or expense will be spared to investigate the pre sent problems and find the answers to them now. If this is not done, then I fear that the whole situation will snowball and may end in chaos, as evidenced by the state of affairs which have existed over the New York Terminal Areas in

cent. Again, because of the presence of other traffic, the descent profile usually bears no resemblance to that which was planned about nine hours earlier. The pilot is asked change VHP frequencies and wait his turn to establish contact on the new frequency, change transponder codes and in the latter stages of the descent, vary his aircraft's airspeed either up or down. During these operations the constant flow of VHP patter, to and from all aircraft, has to be monitored, and, thrown in as it is to the flight deck

arena, relentlessly punctuating the orderly progression of flight deck work, seems to have the effect of disproportio nately increasing the workload. I am sure that the need for the ground controller to constantly transmit and re ceive on VHP R/T results in his also having a high work load. The controller is there to ensure that there is a safe,

smooth and expeditious flow of air traffic, but, with things as they are, he has to constantly interrupt his real work with the need to talk and listen. In this respect, his job is

recent months.

more exacting than that of the pilot, and sometimes, by

What are the problems? The one which immediately springs to mind is that of maintaining verbal communica

the tone of his voice, one can tell that things are getting

tion between the controller and the pilot.

My first experience of civil ATC was back in 1944 when

rather hectic down there.

Am I telling you all this because I want to enlist your

I was on flying boots. The controller, in his pinnace, and the pilot, in his flying boot, maintained communications by

sympathy for the pilot and the controller? No, ladies and gentlemen, I am telling you all this because I think that, the way it has gone, the present system is wrong. I would

means of loud hoilers, oldis lamps, semaphore and occa

like to see us have done with it.

sionally, when the situation called for it, the controller

V\/hat is the alternative to the present system? We leave

would fire a rocket. Later on we were ftted with VHP R/T

the details to the experts, but BALPA would be only too

and we then thought what a marvellous innovation, and

pleased to help.

indeed, it was compared with our flags and lamps. As its uses have developed, however, and with the phenomenal

growth of air traffic over the lost 25 years, one could say

that VHP R/T has become a two edged sword. I am sure it would be illuminating for any one of you to sit on the flight deck of a large jet aircraft, wearing

If we had equitably staggered scheduling between air

lines, airborne pictorial displays, alpha-numeric identifica tion, data link, good autopilots coupled to accurate navi gation equipment, good statutory approach patterns and profiles involving accurate speed and height keeping on

earphones and listening as she approaches terminal areas

each section of the approach, the controller would be free to monitor the traffic and only need to speak when an air

edged sword. The pilot is coping with the terminal area navigation, weather, descent approach and landing check

height. The pilot would have to leave the holding point right on his appointed time, and if he failed to achieve the time

volved with communications from and to the controller.

exactly, he would immediately adjust his speed by a precomputed amount to quickly regain his station in the pat

such as New York, Chicago and Detroit. Only then would you appreciate why I say that VHP R/T has become a two lists and, at the same time, frequently finding himself in

As you know, the descent, approach and landing phases of a flight can be fairly critical, particularly when the ter minal area is busy. It is at this stage of a sector that the flight deck workload really "hots up". The pressure starts mildly when the pilot is instructed to start his descent at an earlier point than that shown on his flight plan. This, of course, is done to separate his aircraft from outbound or

over-flying traffic, and in North America is the rule rather

than the exception. The pilot s first thought is for the extra 26

craft begins to stray from the published pattern, speed or

tern. This would require disciplined flying on the part of

the pilot but, with his improved equipment and with the absence of the need to communicate leaving him free to

concentrate, would not be beyond the capability of any present day pilot who is checked out to fly to any of these

Chairman, Concorde Evaluation Team, British Air Line Pilots Association.

busy areas. In other words, let the whole operation be properly planned; let us look after the navigation and you look after the monitoring, and away with the need for continuous radar vectoring, with its attendant surprise

in their capacity to effectively carry out their proper re spective functions.

Now let us have a look at the supersonic aircraft, to

try to see how its operation will differ from that of a sub

element and workload.

sonic jet and how this may affect ATC.

Likewise, the departure aircraft would be released on time and then expected to maintain an accurate, but ground radar monitored, departure profile. This all sounds as if I am asking for Utopia, and is only one suggested alternative. One thing is certain, the pre

We do know that the SST will use considerably more fuel during taxy than will the subsonic jet and other air craft types. Its pilot will therefore not want to spend much

sent system cannot survive.

You may say: ''All that he has told us refers to North

America." This, talking of the present, I acknowledge. I am pleased to be able to say that the ATC in and around

the British Isles is second to none. What pilot, of any natio nality, can say nay to this when he is taken over by the final controller at London Airport. He gets the same sort of treatment that he would expect from a Harley Street spe

cialist, and that without the expensive bill at the end of the treatment.

The North American airspace does, however, at pre sent, have more traffic but the reasons for the relative calm

which exists in the British airspace need to be examined so that the better facets of our system can be developed and built upon. T h e r e i s o n e Te r m i n a l A r e a i n t h e M e d i t e r r a n e a n

where the controllers, when there is a little weather around, and when there are more than three aircraft approaching, give one the impression that all hell has

been let loose. In fairness to the controllers, one has to say that for years their VHP equipment seems to have

been consistently bad. The airfield in question shall be nameless, but this does serve to illustrate that even in

areas which are not busy, the quality of ATC can be poor and will require improvement before the introduction of

time on the ground after start up. There seems to be a

requirement for the time between start up and take-off to be not longer than 15 minutes. If this were accepted, and

I hope it will be, there would hove to be a by-pass taxiway to moke it feasible. This by-pass taxiway would lead to a direct access loop at the take-off point thus allowing

the SST to circumnavigate the other aircraft in the queue. Por the first few years of SST operation, this priority would not excessively penalise other aircraft and could

subsequently be modified in the light of experience. Airport noise abatement techniques have since their

introduction, plagued the lives of pilots of large aircraft, especially at a place like Zurich in the middle of summer,

with the aircraft at top weight. A high airfield, mountains, high temperature, thunderstorms and a heavy aircraft on a flight, say, to Nairobi, all spell trouble if you are caught with an engine failure whilst carrying out a noise abate ment procedure. These techniques ore, of course, the con

cern of airport authorities rather than ATC, so I hope you will forgive me for using this platform to state plainly, on behalf of all pilots, that when the SST comes along, noise abatement techniques must not become any more compli

cated or difficult to execute. Remember, that pilots, by the very nature of their work, ore subject to a lot of noise themselves, and are therefore very sympathetic towards people working and living close to airports. Sympathy, however, must be tempered with safety. I have heard that

supersonic aircraft.

some backroom specialist is looking at the possibility of

Still on the subject of communication, I would like to see the areas in the cruise phase, which are not easily

asking SST pilots to fly the approach glide path in two sections, i.e. starting with a 6째 glide path and converting

covered by VHP, served by something other than our pre

sent archaic H. P. R/T. At the very least, the controller and the pilot will need very much improved single side band H. P. Even this will probably be subject to static interfer ence when it is most needed. If a blanket of solar radi

ation descends unheralded, there will be static interfer ence, and there may be a need for several SSTs in close proximity to ask for descent clearance at the same time. Airborne radio teletype is a form of communication which I feel has never had a fair crack of the whip. I would

like to see manufacturers encouraged to develop such equipment for use on supersonic aircraft. The airborne

radio teletype could be used for receiving a whole host of instructions and information. Such equipment would need

a Seical type warning to go with it and easy means for the pilot to acknowledge receipt of the message. The advant

age of radio teletype is that it needs little attention, and does not seem so susceptible to interference as do other forms of communication.

VHP satellite communication will probably be available when the SST comes into service, but it is not likely to work in the polar regions across which some airlines are al ready planning their routes. Please forgive me if I hove laboured the subject of communications, but believe me, release the controller and

the pilot from the bulk of this time-consuming and some

times irksome chore and you will find a marked increase

it to a 3째 glide path close to the airfield. This sort of "trick

cycling" is not on. The best way to minimise the effect of noise from landing aircraft and, incidentally, the best way to keep passengers alive, is to get into the slot of a glide slope, which is not more than 3V2 , early on and stay there. Approach profiles which required any significant change of glide slope would inevitably result in a large increase of engine power at the changeover point, and what is more important, could result in serious undershoot ing. I would like to now look at a Concorde climb out.

Quite soon after she is airborne, her speed will be 400 knots, the variable nose will be up, the glazed shield will be up and her rate of climb will be high. It will not be easy, in this configuration, for Concorde's, or for that matter any SST's pilot, to see ahead. I do not think that

he will expect to have a permanent climb out corridor, as exists today for some military aircraft, but I know that he will be grateful for a straight uninterrupted climb from a point not too far from his departure airfield. He will want

to be doing around Mach .93 at 25,000 ft. as soon as pos sible after take-off, where he can then wait for the transi tion to supersonic. This will also be desirable from a per formance point of view.

During climbs on subsonic aircraft, some of you, travel ling as passenger in the past, must have experienced what I will call "weightlessness" when your pilot has desperate27

ly complied with a late instruction by ATC to level out at a given altitude. This is nearly always caused by the ground controller having been caught by the unexpected

I hope that the difficulties will not be insurmountable, be

behaviour of another aircraft in your vicinity. If you have

the ground. In all cases where ground radar monitoring is feasible, pilots would like to see a meteorological radar operator sitting side by side with the ground controller, operating his own cloud detecting radar, so that he can

had this experience, I am sure that you will be right be hind me when I say that the SSI pilot will need about 5,000 ft. lead warning from ATC if he is going to be required to level out at an intermediate altitude. The SST will have a much higher rate of climb, and lead time in this respect, will be important.

I will now turn to the question of military traffic. There will have to be a much greater liaison than exists at pre sent between the civil and military over the U. K. and European airspaces. If politics will allow it, I would like to see one body controlling civil and military air traffic fly ing in the airspace of Western Europe and the British Isles. Military security is an obvious stumbling block to this, but as supersonic and faster subsonic aircraft appear on the scene, means will have to be found to increase the size of control areas and all traffic in those areas should, regard less of classification, be under one control. The Air Traffic Control authorities are not the only people who need to put their house in order, to prepare for the arrival of the supersonic and large numbers of new subsonic aircraft. Airlines and manufacturers will have to

take a long cool look at flight deck equipment and opera tional methods to see how best future operational effici ency can be improved. This, not only for economic benefits but also so that life will be made easier for the pilot and

ground controller, which in turn will moke for safer flying. One item of equipment which every pilot would like to see in a prominent position on his panel, is a pictorial navigation display. Some airlines seem to be lukewarm about ordering the pictorial display, other airlines, who are not so lukewarm, do not seem to know where to put it. We, the British Air Line Pilots Association, want a pic torial navigation display and we want it positioned on the flight deck so that both pilots, in their correct operating positions, will easily be able to interpret its information. When one considers the early need to evaluate equip ment and methods connected with supersonic flight, it seems incredible to me that there is no truly representative Concorde simulator available in the British Isles. All of us

who are in any way concerned with the Concorde project, must wish to see this serious omission speedily put right. Sonic boom and oceanic track selection are two ques

tions which will bedevil the planners and the airlines. The airlines and the manufacturers of supersonic aircraft ob viously hope that no sonic boom or track selection restric tions will be made. It is nevertheless necessary to look at sonic boom and track selection in order that we can soon devise methods to minimise the nuisance to residents of

populated areas, and also minimise the economic penal ties to operators.

As far as supersonic aircraft flying west from the British Isles are concerned, the acceleration to supersonic can, with a slight utilisation and fuel penalty, take place over

cause there seems to be a definite requirement for this phase of the flight to be adequately radar monitored from

easily advise the ground controller. This we would also

like to see set up in terminal areas. Last year I was radar vectored, on a climb out of Chicago, straight through a minor line squall over Lake Michigan. I am only too pleas ed to say that it was not as severe as the one which caught the BAG 1 â&#x20AC;&#x201D;11 a month or two later.

If the airlines are going to be allowed to fly on the

most favourable track of the day there will be new pro blems. On most occasions the best track is likely to be near the great circle, which will take the SST over the maritimes and possibly into sonic boom restrictions. It will

also take the SST over lower flying subsonic aircraft, they also favour the great circle, and then the problem of un

scheduled SST descents crops up. As far as lower flying traffic is concerned, on the rare occasion that the SST may need to descend due to a high level of radiation, the SSTs

descent problem does not look too serious. According to the prophets, she should be clear of damaging radiation at 42,000 ft. This would only just put her in the flight level bonds of subsonic traffic. If, however, the SST had to des cend due to an engine failure at cruising level, she will need to come down to a sufficiently low level to enable her to slow down to a speed which will allow the failed

engine to stop windmilling. Once the engine has stopped,

the next consideration will be the continuation of the flight on three engines. In the case of Concorde, and it

won't be very much different for other delta shaped SSTs, the optimum three engine cruise will be between 29,000 ft. and 33,000 ft. depending upon her weight at the end of the drift down. I think I am correct in saying that if, from a fuel consumption point of view, she is going to reach her intended destination on three engine cruise, she will have

to fly at these lower levels. Although we all know how remarkably reliable the modern turbo jet engine can be,

and I see no reason for the Olympus 593 or other super sonic engine to be any less reliable, the possibility of an engine failure can never be ruled out. It is for this reason

that track allocation for the supersonic aircraft, over

oceans, may be governed by the need to keep them away from the areas where subsonic aircraft are flying. This

would give the SST greater freedom of movement in the vertical plane.

On long sea crossings the Mach 2.0+ aircraft will need to have consistently accurate navigational and course

steering equipment. It will also be highly desirable for ATC radar coverage to extend well out over the ocean in

order to quickly detect any inadvertent departure by the supersonic from her intended track. Because of the speed, any inadvertent excursions from track will be highly signi ficant and will require early detection.

the sea. Some acceleration areas look more attractive than

others, for Instance, the area to the west of the Scilly Isles and south of Eire appears to lend itself ideally to the ope ration. However, weather and other considerations, on the day, may make it necessary to break the sound barrier in other than the ideal areas. This non static aspect of the operation may make the provision of ground based radar, to regularly monitor the transition, very difficult to achieve. 28

From what we have been told, it does seem likely that the supersonic aircraft will have very accurate and reli able navigational equipment. Nevertheless, we in BALPA would like to see such equipment well tested and route

flown on the Mach 2.0+ aeroplanes before there is any move to reduce the present lateral separation over the o c e a n s .

Later in the supersonic programme lateral space at

order to gather information from most VOR stations, it is

high altitudes is likely to be at a premium and it may well be that vertical space will have to be used more

necessary, even at close range, for one crew member to clamp his earphones with both hands to be able to hear

economically than is at present envisaged. Altimeters

the speech. Broadcasts giving landing information with sufficient range and clarity will be a must for the SST.

have to think in terms of large vertical separation. Has anybody thought of developing a high level radar alti meter? If it is feasible, it should indicate height very

sumption, Concorde will need to fly the initial approach and holding patterns at 300 knots. She will waste a lot of fuel if she has to fly these patterns at the present slower

accurately over the sea. The other reason for large ver tical separation is that, on most high speed aircraft, the

mandatory speeds. To allow for possible flight deck errors,

pilot's pitch information on his panel has been relatively

to be enlarged or repositioned further away from other holding, departure or approach areas.

which derive their information from pressure ore notori ously inaccurate high up and this is one reason that we

poor. We look for a decided improvement in this field,

for both the pilot's and Air Traffic Control's sake.

So that she will not be heavily penalised on fuel con

it may be that the present ICAO holding areas will have

Ladies and Gentlemen, most of you ore probably al

On the question of airborne equipment, the situation

exists today where numbers of aircraft are flying in the same areas with widely different equipment, e. g. the VCIO flying with precision altimeters, which derive their infor mation from pressure and an air data sensor, alongside other aircraft flying on the old fashioned "steam" jobs. As we introduce new aircraft, I think that it would be wise

for the licensing authorities to keep a much tighter rein on airborne equipment, especially with such items that can give you a different story, on each aircraft type, for the

some set of parameters. This should apply to private, mili tary and airline operators.

The supersonic pilot will need to know his position very accurately when he is approaching the point where he starts his descent to his destination. Long range DME will

help, but he will also need clearance from ATC to descend

ready well advanced in your thinking on the problems which I hove raised in this paper, you no doubt hove been aware of them as long as I have. My main purpose in the preparation of this paper was to try to highlight some areas which I am sure will be of concern to the supersonic pilot and Air Traffic Control. There ore more, but my time here is running out. From what I know of the thought, money and work

which has gone into the Concorde programme, and the amount of test flying which is planned for Concorde, I am sure that she is going to be a winner. Let us also not forget that she is well ahead of her rivals, at least, the ones that we know about. So that her introduction into passenger

service will not find us unprepared, I will end this paper again expressing the hope that urgent investigation of the problem areas will continue, and that no effort or expense

well in advance of his flight plan descent point. Before he leaves his cruising level he will need adequate landing information pertaining to his destination. Europe is fairly well covered in this respect by VHP for weather, but the landing information which we now receive from VOR/ voice is just not good enough. Colts Neck and Deer Park

will be spared to modify or change existing systems that may be found wanting. The penalties for an unnecessarily restrictive operation for the supersonic will be high, espe

in the New York terminal area, are prime examples. In

money spent in making ourselves prepared.

cially in terms of aircraft utilisation. The rewards for on unrestricted and successful operation will be economically

high, and should amply recompense us for the effort and

Electronic Scarecrow The hazard of bird strikes to aircraft has, for some

time, been a matter of concern to aircraft operators and airport authorities.

Various methods of scaring birds away from airfields

have been investigated, but there does not seem to be a simple solution to the problem. In most cases were acousti

cal means were applied, the birds got quickly accustomed

to whatever noise generator was used. The firm SABA has recently developed on electronic

scarecrow which con produce such a variety of natural and artificial callnotes and distress calls that the birds alleged

ly to not get accustomed to them. The sound spectrum of the colls is partly in the ultrasonic range. It has been com posed so as to cause particular discomfort to animals but m i n i m u m d i s t u r b a n c e t o t h e h u m a n e a r.

The scarecrow is of simple construction and virtually free from wear and tear. Its power consumption is suffi ciently low for battery operation over an extended period of time.

A pulse generator, multivibrators, power amplifier and loudspeaker are the main components of the system. The loudspeaker is matched to the acoustical impedance of the

atmosphere by means of a horn, for optimum sound radi ation.

SABA

The International Federation o f A i r Tr a f fi c C o n t r o l l e r s A s s o c i a t i o n s A d d r e s s e s a n d O f fi c e r s AUSTRIA

FRANCE

Verband Osterreichischer Flugverkehrsleiter

F r e n c h A i r Tr a f fi c C o n t r o l A s s o c i a t i o n

A 1300, WIen Flughafen, Austria, Postfoch 36

Association Professionnelle de la Circulation Aerienne B. P. 206, Paris Orly Airport 94

President

Vice-President

Nogy

Kihr

Secretary H. Bauer Deputy Secretary W. SeidI

Treasurer

Chrystoph

BELGIUM

Belgian Guild of Air Traffic Controllers Airport Brussels National Zaventem 1, Belgium President Vice-President

A. M.

van

Maziers der Straate

Secretary C. Scheers Secretary General A. Davister

Treasurer H. Editor J.

Campsteyn Meulenbergs

I F A T C A L i a i s o n O f fi c e r J . A e l b r e c h t

France

President Second Vice-President

M. Pinon

General Secretary

J.Lesueur

Treasurer

J. Bocard

Deputy Secretary Deputy Treasurer

M. Imbert

I FAT C A L i a i s o n O f fi c e r

A. Clerc

R. Philipeau

G E R M A N Y

G e r m a n A i r Tr a f fi c C o n t r o l l e r s A s s o c i a t i o n

Verband Deutscher Flugleiter e. V.

3 Hannover-Flughafen, Germany Postlagernd Chairman

Vice-Chairman

C A N A D A

Vice-Chairman Vice-Chairman

C a n a d i a n A i r T r a f fi c C o n t r o l A s s o c i a t i o n

Secretary

56, Sparks Street

Francis Zammith J. M. Lefranc

F i r s t Vi c e - P r e s i d e n t

Treasurer

Kassebohm H.

Guddat

E. H.

von V/.

Bismarck Kremer

H.J.KIinke K.

Piotrowski

Editor L. Goebbels I F A T C A L i a i s o n O f fi c e r W . G o e b e l

Ottawa 4, Canada Vice-President

J. D. Lyon J. C. Conway

GREECE

Managing Director

G. J. V^illiams

Air Traffic Controllers Association of Greece

Treasurer

A. Cockrem

Chairman IFATCA Comm. R. Roy

10, Agios Zonis Street, Athens 804, Greece President C. Theodoropoulos Vice-President N. Protopapas

DENMARK

General Secretary E. Petroulias Treasurer S. Sotiriades

President

D a n i s h A i r Tr a f fi c C o n t r o l l e r s A s s o c i a t i o n

Copenhagen Airport â&#x20AC;&#x201D; Kostrup Denmark V. F r e d e r i k s e n

Vice-Chairman

Secretary Treasurer Member

Aa.

Jaenicke

Christiansen

P. of

the

Board

Breddam M.

Jensen

HONGKONG

Hongkong Air Traffic Control Association Hongkong Airport President

Secretary

Treasurer

Allcock

Ayers R-Lo

ICELAND

Air Traffic Control Association of Iceland

FINLAND

A s s o c i a t i o n o f F i n n i s h A i r Tr a f fi c C o n t r o l O f fi c e r

Reykjavik Airport, Iceland

Suomen Lennonjohtojien Yhdistys r. y.

Chairman

A i r T r a f fi c C o n t r o l

Secretary

Treasurer

Helsinki Lento

G. K.

Kristinsson

S.Trampe

Sigurosson

Chairman

Fred. Lehto

IRAN

Vice-Chair

Vdino Pitkdnen

Secretary

Heikki Nevaste

Iranian Air Traffic Controllers Association Mehrobad International Airport

Treasurer

Aimo Happonen

Te h e r a n , I r a n

Deputy

Vilio Suhonen

Secretary General E. A. Rahimpou

IRELAND

RHODESIA

I r i s h A i r Tr a f fi c C o n t r o l O f fi c e r s A s s o c i a t i o n

R h o d e s i a n A i r Tr a f fi c C o n t r o l A s s o c i a t i o n

AT S S h a n n o n

Privote Bag 2, Salisbury Airport

Ireland

Rhodesia

President

Murphy

V i c e - P r e s i d e n t P. J . O ' H e r l i h y Gen. Secretary J. Kerin Treasurer

President

Secretary

Treasurer

Drake

Flavell

Va n d e w a a l

Lane

Asst. Gen. Secretary M. Durrack

SWEDEN

S w e d i s h A i r Tr a f fi c C o n t r o l l e r s A s s o c i a t i o n

Fack 22, Sistuna, Sweden

ISRAEL

Chairman

A i r Tr a f fi c C o n t r o l l e r s A s s o c i a t i o n o f I s r a e l

Secretary

P. O. B. 33

Treasurer

Lod Airport, Israel

Berkenstam

Karlahag

Starkman

I FAT C A R e p r e s e n t a t i v e G . A t t e r h o l m

Chairman

Jacob

Vice-Chairman Treasurer

Wachtel

Katz E.Medina

SWITZERLAND

S w i s s A i r Tr a f fi c C o n t r o l l e r s A s s o c i a t i o n

V. P. R. S., P. O. Box 271 CH 1215, Geneva Airport, Switzerland Associazione Nazionale Assistenti e Controllori

della Civil Navigazione Aerea Italia

Chairman

Secretary

Monin

Roulin

Via Cola di Rienzo 28 TURKEY

Rome, Italy President

Dr.

Secretary

Treasurer

Bertoldi,

Mercuri

Guidoni

Tu r k i s h A i r Tr a f fi c C o n t r o l A s s o c i a t i o n

Yesilkoy Airport, Istambul, Turkey President Alton Koseoglu UNITED

LUXEMBOURG

G u i l d o f A i r Tr a f fi c C o n t r o l O f fi c e r s

Luxembourg Guild of Air Traffic Controllers

Klein

14, South Street, Park Lane London W 1, England Master A. Field, QBE E x e c u t i v e S e c r e t a r y W. R i m m e r

Kimmes

Treasurer

Luxembourg Airport President

Alfred

Secretary

Andre

Treasurer

Feltes

P-

Brodshaw

URUGUAY

NETHERLANDS

N e t h e r l a n d G u i l d o f A i r Tr a f fi c C o n t r o l l e r s

Asociacion de Controladores

Aeropuerto Nacional de Carrasco

Postbox 7590

Schiphol Airport Central, Netherlands President

J. van Londen

Secretary

F. M. J. Mente

Tr e a s u r e r

P. K a l f f

Member, Publicity Member, IFATCA-affairs

T. M. van Gaalen B. H. van Ommen

To r r e d e C o n t r o l

Montevideo, Uruguay Chairman U.

Pallares

Secretary

Beder

Treasurer

Puchkoff

VENEZUELA

Asociacion Nacional de Tecnicos en

NEW ZEALAND

Tr a n s i t o A e r e o Ve n e z u e l a

Air Traffic Control Association

Dept. of Civil Aviation, 8th Floor, Dept. BIdas Stout Street

Wellington, New Zealand

President Secretary

KINGDOM

E.Meachen C. Latham

N O RWAY

Lufttrafikkledelsens Forening

Box 51, 1330 Oslo Lufthavn, Norway Chairman G. E. Nilsen ^'ce-Chalrmon K. Christiansen Secretary j. Kalvik Treasurer E. Feet

Avenida Andres Bello, Local 7 8129 Caracas, Venezuela President Manuel A. Rivera P. S e e r. G e n e r a l V. A l v a r e z . J i m e n e z Y U G O S L AV I A

Jugoslovensko Udruzenje Kontrolora Letenja Direkcija Za Civiinu Vazdusnu Plovidbu Novi Beograd, Lenjinov Bulevar 2 Yugoslavia President A. Vice-President

Secretary

Treasurer

Member

Stefanovic Veres

Zivkovic Zivkovic Budimirovic

Corporation Members of the International Federation of Air Traffic Controllers' Associations The Air Traffic Control Association, Washington D. C., U.S.A. The Air Transport Association, Washington D. C., U.S.A. Wolfgang Assmann GmbH., Bad Homburg v.d.H. Compagnie Generale de Telegraphie sans Fil Malakoff, Paris, France Cossor Radar and Electronics Limited,

Harlow, England

The Decca Navigator Company Limited, London ELLIOTT Brothers (London) Limited Borehamwood, Herts., England FERRANTI Limited

Bracknell, Berks., England Glen A. Gilbert & Associates,

Washington D. C., U.S.A. IBM World Trade Europe Corporation, Paris, France International Aeradio Limited,

Southall, Middlesex, England

ITT Europe Corporation, Brussels, Belgium

Jeppesen & Co. GmbH, Frankfurt, Germany The Marconi Company Limited Radar Division Chelmsford, Essex, England N.V. Hollandse Signaalapparaten

Hengelo, Netherlands

N.V. Philips Telecommunicatie Industrie Hilversum, Holland

The Plessey Company Limited Chessington, Surrey, England Selenia - Industrie Elettroniche Associate S.p.A. Rome, Italy The Solartron Electronic Group, Ltd.

Farnborough, Hants., England Telefunken AG, Ulm/Donau, Germany Texas Instruments Inc., Dallas 22, Texas, USA Whittaker Corporation,

North Hollywood, California, USA

The Internationa! Federation of Air Traffic Controllers' Associations would like to invite all corpora

tions, organizations, and institutions interested in and concerned with the maintenance and promo tion of safety in air traffic to join their organization as Corporation Members.

Corporation Members support the aims of the Federation by supplying the Federation with technical information and by means of an annual subscription. The Federation's international journal "The Con troller" is offered as a platform for the discussion of technical and procedural developments in the fi e l d o f a i r t r a f fi c c o n t r o l .

Schiphol.

First airport in Europe with an automatic air traffic control data-processing system;

Schiphol Amsterdam SATCO automatic air traffic control in full operation.

Main features of Signaal Main operational features

flight path calculation coordination

clearance processing

flight plan and radar data-processing systems. Computer features

Programming features modular design fl e x i b i l i t y

reconfiguration capabilities

correlation between radar data and

on-line real-time programming

flight plan data

multi-level programming

c o n fl i c t r i s k d e t e c t i o n c o n fl i c t r e s o l u t i o n

electronic data display

software and hardware controlled

microminiaturization techniques high operating speed 1 microsec. memory cycle mass memories

fiigh reliability

growth potential continuity of operation easy servicing.

synthetic dynamic display daylight large screen display flight progress board stripprinting automatic transfer of data via data

links to adjacent centres

. â&#x20AC;&#x17E; on ROX.12 Hengelo. The Nelherlands.

-ply to For further information please apply to N V. Htjilandse Signaalapparale ,

t rhi HÂŤfa handling and air traffic control systems

SIGNAAL

t.:;rOUANDSESG I NAALAPPARATENHENGELO

AIR TRAFFIC CONFUSION OR. ^'1' miLftgA'.

:>r.

DECCA HARCO The answer to increasing air traffic confusion is an accu rate, comprehensive, automafic and reliable Nav/ATC system incorporating a Data Link. Decca-Harco is the only system that can meet the navigation and ATC demands of both sub- and super sonic air traffic. And only Decca-Harco can provide the flexibility and accuracy that permits close lateral separa tion of aircraft throughout the route structure. At the control centre the Decca Data Link provides the controller with accurate displays of the identity, al titude and precise position of all co-operating aircraft,

using the common reference of a high accuracy, area coverage system. The necessity for R/T communication is reduced by the use of two-way Alpha-Numeric mes

On the flight-deck Decca Omnitrac—the world's most

advanced lightweight digital computer—provides the

pilot with undistorted pictorial presentation and auto matic chart changing. The 'ghost beacon facility gives

him bearing and distance to any point. Omnitrac also provides auto-pilot coupling and automatic altitude con

trol which maintain respectively any required flight

path and flight profile. The ETA meter indicates either time to destination or ETA.

It is only through an integrated system, operating from a

common reference, such as Decca-Harco, that a great many aircraft of different types flying at various speeds

sages and routine reports are eliminated, reducing the

and altitudes can be efficiently co-ordinated into a single

workload and increasing the reliability of the ATC system.

disciplined traffic pattern.

DECCA-HARCO The comprehensive Nav/ATC system The Decca Navigator Company Limited • London