Page 1

ISSN 0010-8073




4th QUARTER 198 7




SFrs 5 .-

27th ANNUAL IFATCA CONFERENCE April26-29 1988 International Federation


DE JANEIRO of Air Traffic Controllers' Associations BRAZIL

Conference Theme:

Efficiency in Air Safety in South America


Convention Center of Hotel Nacional Rio

Main Hotel:

Hotel Nacional Rio


Fee: US$ 90 In order to allow an estimate of the number of participants, please confirm registration before 15th January.

Air Transport:

VARIG is the main conference carrier and has agreed to grant to conference participants and accompanying persons 50% rebate on all-year normal fare.

Organising Committee

Rua Visconde de lnhauma, 58 - sala 411 20091 - Rio de Janeiro - RJ - Brazil Tel. (021) 233-803 7 Telex 21 30297 FCIR BR



THE CONTROLLER Geneva, Switzerland, December, 1987

Publisher International Federation of Air Traffic Controllers· Associations. P.O. Box 196. CH-1215 Geneva 15 Airport. Switzerland Officers of IFATCA E.F. Sermijn. President-and Chief Executive Officer. U. Windt. Executive Vice-President Administration. T. Gustavsson. Executive Vice-President Finance. W. Rooseman. Executive Vice-President Professional. R.W. Randall. Executive Vice-President Technical. P. O'Doherty. Executive Secretary Editor H. Harri Henschler 1998 Glenmore Avenue. Sherwood Park. Alberta. Canada. TBA OXB Telephone (403) 467-6826 Management and Advertising Sales Office The Controller. P.O. Box 196. CH-1215 Geneva 15 Airport. Switzerland H.U. Heim. Subscriptions and Publicity. Tel. (022) 82 26 79 M. Henchoz. Accounting. Tel. (022) 92 56 82 B. laydevant. Sales Promotion. Tel. (022) 82 79 83 Printing House 'Der Bund'. Verlag und Druckerei AG Effingerstrasse 1. CH-3001 Bern. Telephone (031) 25 12 11 Su~scriptions and Advertising Payments to: Union Bank of Switzerland. Airport Branch CH-1215 Geneva 15 Airport. Switzerland Account: IFATCA/The Controller No. 602 254.MD L Subscription Rate: SFrs. 20.- per annum (4 issues). plus postage and package : Surfacemail: Europe and Mediterranean countries SFrs. 4.20. other countries SFrs. 5.40. Airmail: Europe and Mediterranean countries SFrs. 6.20. other countries SFrs. 10.60. Special subscription rate for Air Traffic Controllers. ~ontributors are expressing their personal points of vi~w and opinions. which may not necessarily coincide with those of the International Federation of Air Traffic Controllers· Associations (IFATCA). IFATCAdoes not assume responsibility for statements made _an~opinions expressed. it does only accept respons1b1lityfor publishing these contributions. C_ontributionsare welcome as are comments and critici~m. No payment can be made for manuscripts submitted for publication in 'The Controller'. The Editor reserves _the right to make any editorial changes in manu~cnp)s. which he believes will improve the material without altering the intended meaning. Wri~e~ permission by the Editor is necessary for repnntmg any part of this Journal.

Advertisers in this issue Philips, Marconi, Thomson-CSF, Selenia Photos H. Tade, Ferranti, Beach Airport, Boeing, CYATCA,Danzas, hhh Cartoon Randall THE CONTROLLER/DECEMBER 1987

Volume 26 · No. 4

In this issue Technical Panel at IFATCA '87


Status of Aircraft (Civil or State)

page 11

Air Traffic Flow Management

page 14

Air Industry Seeks Technical KO over Wind Shear

page 17

'The Guardian Angels'

page 19

Speed Control of Aircraft by ATC

page 21

Meeting of the IFATCA Executive Council

page 26

Airlines of the World: Qantas


Editorial H. Harri Henschler

In 1962, the first year of IFATCA's life, three Corporate Members joined the Federation. The number of Corporate Members has since steadily increased to, now, thirty-three. IFATCA's Corporate Members cover all aspects of air traffic control requirements, from communications, navigation, radar, recording and related equipment through computers and software to aeronautical charts and consultation and research. Corporate membership in the Federation ensures the vital two-way communication between the users the air traffic controllers - and the manufacturers, consultants and researchers - the Corporate Members. This link, throughout the year but in particular at the annual conference, encourages the exchange of views on requirements and desired features of equipment, enhancements to computer capabilities, layout of sector control consoles, and the feasibility, inherent restrictions and cost-effectiveness ratio which the Corporate Members face. Additionally, at the annual confer-


ence, Corporate Members avail themselves of the Technical Exhibit to provide information on new and improved equipment, to show videos, films. scale models, mock-ups or the real thing. and to establish and renew personal contacts with the Member Association representatives and representatives of various governments and civil aviation authorities - the eventual purchasers. The Technical Panel, the feature in this issue of 'The Controller'. has become a traditional component of the annual conference. Presentations and papers of high quality are offered during the Panel, and the animated question-and-answer period which follows the presentations is proof of the mutually beneficial relationship between the Corporate Members, air traffic controllers. and the representatives of the governments and aviation authorities. Corporate Members. directly and through their elected Corporate Members Coordinator. perform a valuable and appreciated function within IFATCA. It is incumbent upcm all. Member Associations and Corporate Members. to take full advantage of the possibilities whiGh increased understanding and involvement offer.

When Singapore 's Changi International Airport was co111pleted in 1981, it featured many unique solutions to the operational and organizational problems of a busy airport -a commitment to innovation that will be repeated in the construction of the new Terminal 2. Due for completion in 1989 , Terminal 2 features a computerized Flight Information Display System (FIDS II), employing new-technolog y displa y techniques. FIDSII will integrate the flow ofinformation among the public , ad111inistration and operational areas to display the right information , in the right format , at the right place, at the right time. TheS$19 .5 millioncontractforthedesign,supplyandinstallationofthishighly innovative system was wo n by Philips in the face of strong international competition. Yet Philips' associa tion with Singapore Civil Aviation goes far beyond FIDS II. We supplied Changi's long-range (ATC) and airport surface detection radars , outdoor lighting and public address and sound systems. And a Philips AEROPPmessage switching system enables Singapore to pla y a key role as a Regional node in the worldwide Aeronautical Fixed Telecom111unications Network, AFTN.

In The Netherlands, the Civil Aviation Authority has developed an ambitious U.S.$750 million expansion project for Amsterd am Airport, Schiphol. And by the mid-90 s the airport will be capable of an annual traffic throughput of up to 18 million passengers and over 900 OOOtonnes of cargo. Philips is helping with energy-efficient termin al lighting, new -generation SNF-llasy111metricnon-glareapronfloodlighting ,and 1nan yo thertechnicalaspectsof this massive airport development project. We have also been co1nn1issioned to implement the first international CIDIN (Common ICAO Data Interchange Network ) node as a 1nodernization rJWt:11:;il,;:i&I of the existing AEROP~syste1n for AFfN. . . ..


'::.. :



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Q ~ has the co~~°o';1a:~~~~f,f ;s::so~:f~ ~~~~~~t~~~: ,t~h!~:t i ~ ~ specific needs of airport authoriti es the world over. Philips. The sure sign of expertise wor ld wide .




The Technical Panel at I FATCA '87, Nairobi As in past years IFATCA '87 again offered the Corporate Members of the Federation a platform to directly address the conference participants. A large audience of delegates and observers attended the Panel, under the chairmanship of outg oing Executive Vice-President, Technical, A.F. W (Lex) Hendriks, and listened appreciatively to the presentations. The general discussion which followed the presentations was proof of the interest generated by the speakers and of the involvement of conference delegates and observers in the subject matters presented. At the head table, in addition to Lex Hendriks, were Ron Mahendran of Ferranti, the Corporate Members' Coordinator , Harry Cole of Marconi, Jim Pawson of Ferranti and Roger Kahane of Thomson-CSF. The first paper, presented by Roger Kahane, was 'The New Kenya Integrated Air Traffic Control Radar System '. Readers will recall that this paper was published in issue 2 1 8 7 of, The Controller' in the context of the Annual Conference in Nairobi. Henry W Cole of Marconi Radar Systems was the next speaker . Harry presented an intriguing concept:

Electronically Scanned Antennas (ESA) for Secondary Surveillance Radar (SSR) Introduction For once it is appropriate to start with the question 'What is an ESA?' and give the question 'Why?' second place. Curren t ly. surveillance radars use beams formed by an array which itself is mechanically rotated at a regular rate: so the beams it makes rotate. The data rate is tied to this. At 15 rpm rotation, new data on targets is called out every 4 s - whether needed or not, and never faster.

An Electronically Scanned Antenna (ESA) is a static non-rotating array producing beams which can be pointed in any direction at will . Changes of direction can be made almost instantaneously - in microseconds using modern fast switching microwave devices . ESAs are not new but until recently have been very expensive, being used in high power primary radars for defense purposes . The use of ESAs in SSR, with its much lower

(I to r) R. Kahane, L. Hendriks, J. Pawson, R. Mahendran. H. Cole


output powers, holds the promise of greatly reduced costs .

Why Have Them? Independently mounted rotating SSR antennas usually have about 5 to 10 hp motive power . Gene.rally, in still air, only about 2 or 3 kW of power is dissipated in turning the antenna. Even for 24 hours continuous operation the electricity bill is quite low about £5 (7 to 8 US dollars) a day at UK rates . Stresses both electrical and mechanical are relatively low and the likelihood of massive and expensive mechanical failure is very low indeed. Even though ESA operation requires less prime power, there's not much economic sense in replacing mechanical antenna rotation by static systems on this score. The need rests much more in making best use of time to gather target data at varying rates as the ATC situation warrants it . This becomes more important when Mode ·s· - particularly the Data Link facility with its Extended Length Messages (ELMs), are used . They last for 56 µs. ELMs are sometimes required to be transmitted as a train of 16 , separated by about 50 µs and thus can grow to 1440 µsin duration; at 15 rpm and beamwidth of 2 . 5 degrees the dwell-time on a particular aircraft will be 27 µs- enough for 10 ELMs

Opening of Technical Exhibit {I tor). R. Mahendran. Erik Sermijn , H. Cole, Kenya dignitaries.


and their replies . However. to give service on transponders not Mode ·s· equipped . normal SSR interrogations on Modes 'A' and ·c· also have to be repeated (3 times in one beamwidth for the highest data integrity) . To get the necessary unamb iguous range correlation . these have to be issued at about 250 per second . Thus in a rotating antenna system these repetit ions will take 6 x 4 µs = 24 µs leaving only time for 2 of the hyperELMs . It is easy to see then that an antenna system permitting variable dwell-time on nominated bearings is going to be much more efficient. Another point worth noting (See Fig. 1) is that even in a relatively busy area . with the interrogator continually illuminating the sky. only 50% of the time is real data being gathered. The other 50% is spent regularly and continuously looking for new targets. In periods of quiet . the data gather ing efficiency is even less.

How Can ESAs Work? Look at a typical modern large vertical aperture array (see Fig. 2) . It produces a narrow beam in azimuth by arranging output power to be divided among its 35 identical radiators as



Interrogation arcs


Areas over which



Interrogation ~ be made

__. ..... __,,...: ';', r--/



Note: Active time is 5 0%









SSR responses

Centre of response

Fig. 1. Typical example of actual SSR responses in the South-East of England.


Fig . 2. Marcon i Radar's LVA Antenna Type S 7095 co-moun ted with primary radar S57 7.


indicated in Fig. 3. Because the Linear Set of phase ofthe energy is equal for all. and Radiators all the radiators are in line. the radiation is a plane wave and forms the required narrow beam. The larger the number of radiators. the narrower the beam becomes. Imagine now that the LVA was made much longer - say 4 times as long (140 elements) ana it Power In was wrapped back on itself to form a cylinder (see Fig. 4). It is possible to select any contiguous set of 35 and form an LVA from it. The beam from such a set would be spoiled because the radiators are no longer in a straight line. It is restored to its proper form by introducing phase delays to each radiator to compensate for the curvature introduced by the cylinder as Phase shown in Fig. 5. The radiated beam would be in the direction at right angles to the tangent of the cylinder at Fig. 3. Amplitude taper and uniform phase of power fed to the radiators in the array creates a narrow the mid-point of the chosen set of 35 beam with low sidelobes. elements. In such an array there will be 140 Switching Network azimuths to choose from i.e. at 2.5 degree intervals. This would be sufficient to ensure all aircraft anywhere ....... in the 360 degree azimuth range / could be interrogated. for the 35 / I elements give a beamwidth of about \ 2.5 degrees. By using the monopulse I TO INTERROGATOR / J direction finding technique. the airRESPONSER ' , / l craft's precise bearing within the 2.5 I 1,,, II .. ' /\ I degree beam can be measured to within a few minutes of arc. / ~ These days it is possible to operate \ very fast r.f. switching devices. By / Total of 140 Radiators their use it will be possible to connect / any set of 35 from the 140 elements to the SSR interrogator/ responser in microseconds and to leave them so connected for as long as desired. An A POSSIBLE ELECTRONICALLY SCANNED ARRAY elegant by-product of this form of ESA CONRGURATION is the possibility of mounting it round a tubular building. Fig. 4. The switching network connects any set of 35 radiators to the interrogator-responser through a splitter as in Fig. 3. ESAs in Operation With such an arrangement it is easy to see the ESA can be stepResultant scanned. one element at a time. to PlaneWave execute a 360 degree surveillance Propogated regime in increments of 2.5 degrees at whatever rate desired. Obviously any •surveillance· system must do this. But it need not do it at a regular rate. or continuously. Consider as b(I>= Phasedelay to example. a certain traffic pattern concentrated in two wide sectors and very equal that of few aircraft in the rest of the cover. An \ end radiators ESA could be made to serve them all \ in the manner shown in Fig. 6. It will It)< Set of contiguous be possible to optimize the ·pointing/ / \ radiators scanning· program to make best use of available time. Obviously to retain the complete surveillance program.






-1\ ,,,.,,,.






-- '






\1, \

Fig. 5. Showing the need for graded phase delay to restore true plane wave radiation.




Controllingthe increasinglycrowded airspace around airports demands clear, accurate radar coverage throughout the approac h right down to touchdown. The MarconiS-511Approach Control Radar has proved its abilityto provide this service, not only to AirTrafficControllers with the UK-CAA, but to many other aviation authorities throughout the world. Clear - no matter how difficult the clutter conditions. Clear- because the S-511weathe r channel allows the AirTrafficController to direct aircraft around the wo rst weathe r conditions. Clear- so he knows he is seeing the aircraft, not false alarms. Our approach - is to provide a high techno logy system at an affordable price with increased reliabilityand low through-life costs. Maintenance is straightforward, with built-in remote control and monitoring as standard, plus a support service second to none - Good news for engineers and controllers alike! Find out more about the S-511today, by writing to:

Marconi Radar Systems


ÂŤ88> I 9 8 8

Ma rconi Radar Systems Limited, Writtl e Road, Chelmsford, Essex CMl 3BN, England. Tel: 0245 267111Telex : 99108 Facsimile: 0245 357927


th e tim e to cover the 360 degrees will increase by the sum of the ' pointing ' and 'dwell -times· executed . However , w e have seen that one ELM takes approxim ate ly 1.4 µs . Therefore, even 100 of these can be made in ½ s so th e surveillance time under these busy circumstances would only grow to 4.1 4 s instead of the assumed 4 s. The exampl e in Fig . 6 exaggerates the ' directi ng· mode , giving half a second increase to t he assumed 4 s. Even so, it w ould be entirely tolerab le to a surveillanc e SSR. Such scanning programs would be part of th e ' radar management' function necessary to be added to an SSR wh en it is raised to the Mode standards. M ost modern SSRs have antic ipated thi s need , wh ich should reduce th e up-date costs . The UK CAA have recently placed a contract with M arconi Radar t o study t he design possibiliti es fo r ESA's .


Sector 1 Sector 2






-I J:ts f--












Explored 90








~ = Beam steered anywhere in 0°to 360°






It s =Surveillance Scan time increase by beam directing




l/ 2


Tme - Seconds

4 (16rpm)




Fig. 6. Hypothetical 'scanning and pointing' program . The 360 degree scan time is only slightl y increased by the 'pointing' periods .

To conclude another most successful and stimulating Techni cal Panel, before the general discussion Bernard Lucat of Thomson-CSF addressed the audience on New Pedagogical Concepts for ATC. This presentation will be printed in a future issue of 'The Controller '.

The third present ation was by J.B . Pawson of Ferranti Computer Systems. Jim offered a paper on

Microwave Landing Syst ems (MLS)

The Instrument Land ing System (ILS) has served as the stand ard precision approach and landing aid for the last 40 years. During t his time it has undergone a number of improve ments to increase its performance and reliability. However, in relati on to future aviation requireme nts the ILS has a number of basic limitations: It is site critica l and expensive to inst all. Because it uses the ground in front of the glide slope antenna to form t he beam a large area in front of th e antenna must be cleared. The cost of site preparat ion sometimes exceeds the cost of equipment. Secondly , the g lide slope is sensit ive to nearby reflections. This can reduce airport capacity at locations where departing aircraft must be held at a great distance from take-off thres hold in order to stay clear of the critical reflection area when instrume nt approach is in progress. Third ly, only 40 ILS channels are available and frequency congestion is becoming a problem in many countr ies . 8

I LS lacks the flexibility needed for future aircraft operations because it provides only a single glide path and is not easily adaptable to high angle approaches by STOL aircraft and helicopters . Moreover , it provides azimut h guidan ce to a single approach pat h over a very narrow sector. This prec lud es its use for segment or cu rved approach paths. Finally , signal reflect ions limit the use of ILS in rough terrain and mountaino us reg ions . During the last 30 years these limitat ions in ILS have stimulated a search for a bett er system . In 196 7 ICAO reco gni zed the need and took acti on to establish an international stan dard based on microwave techno logy . Two types of MLS were con sidered : one using t he Doppler effect and the ot her using a time reference scann ing beam , and aft er a great debate in t he aviat ion community finally in 19 7 8 it w as decided t o standardize on the scanning beam MLS as the replaceme nt for ILS. ICAO has intro duced a tra nsit ion

Jim Pawson plan which began in 1986 and aims to have MLS in general use in civil aviation from 1995 onwards . The plan ma kes provision fo r MLS to be phased in while existing ILS services are maintained and it is expect ed th at ILS and M LS will coe xist fo r some tim e aft er 1990 unt il t he maj orit y of aerodromes and aircraft are eq uipped. THE CONTROLLER / DECEMBER 1987




In special cases a BAZ ca n be installed solely to prov ide depa rtur e and missed approach guidance . For example where terrain or rest rict ed airspace dictate a very accura t e instrument departure and these rest rictions prevent the est ablishmen t of an instrument approach from th e opposite direction . In these cases t he DME/ P and EL stat ion would not be required. The antenna conf igurat ion can be varied to meet the coverage needs of each site. The azimut h cove rage can be as low as ± 10° or as high as ±60° from the runway cen ter lin e . It can also be different on eithe r sid e. For example , at Valdez, Alas ka t he cove rage extends 40 ° to the south of th e runway centerline but only 10 ° t o th e north because of nearby mo unt ains. M LS siting configura ti ons ca n be varied to meet operati onal requirements . For example , an M LS has been installed at Jasper, Alberta, Canada, with the OM E elemen t co lloca t ed with the EL instead of the AZ element in order to reduce the shadow ing eff ects of a nearby moun t ain. ML S instal lations for heliports may have th eir AZ , EL and DM E elemen ts co lloca t ed to save space .


M icrow ave La nding System

M LS System Elements MLS includes the following major elements :


Signa l Format The M LS can operat e on any one of 200 channe ls from 50 31 MHz to 5991 M Hz inclusive . This is expect ed to be suffi cien t to fulfil all future needs for MLS channels. In any MLS the AZ, BAZ and EL stati ons all tr ansmit on the same freque ncy. Basic and auxiliary data are tr ansm itted in th e sequence and t he DM E/ P transmits on a paired freque ncy in L-band. The M LS signal format is a very flexible struc t ure wit hin wh ich lies the potential to transmit the signals from various stat ions in any desired order. A pream ble at the beginning of each ti me slot tell s the airborne processor wh ich fu nction will be transmitted next. As soon as the processor decodes t he message in the time slot it w aits for the preamble for the next tim e slot.

the stations passage indications provided by the marker transmitter of the ILS. The DME/ P has an accuracy of ± 100 ft in the final approach mode as • Azimuth (AZ) compared to the ±600 ft accuracy of • Elevation (EL) the standard DME system. • Precision Distance Measuring Finally the Back Azimuth Stat ion is Equipment (DME/ P) identical to AZ. The BAZ can be com• Back Azimuth (BAZ) pared to the back course of an ILS The azimuth station (AZ) can be localizer. Its purpose is to provide likened to an ILS localizer but it has a guidance for departures and missed much wider proportional guidance approaches . ICAO has specified 7 nm coverage. as the minimum range of BAZ comConsequently it sometimes will be pared to 20 nm of the AZ. possible for a single AZ to provide In general installations wit h BAZ Data approach guidance to additional runwill be those with a need for opposite ways or helipads on the airport. ML S facilities transmit 2 categor direction approaches . In such cases ies of data, basic and auxiliary . The The elevation station is similar to the glide slope facility of the ILS the installations will have separate format is flexible; the data are in digital except that the MLS elevation pro- DME/P and EL stations for each or alphanumeric form and consist of a vides for a wide selection of glide path approach direction . Only one DM El P number of data words which can be angles by the pilot up to 15 degrees . and EL station will be switc hed on at modified to suit operational require ments. Basic data include station The signal coverage of the EL extends any t ime . The AZ and BAZ stations will inter- identification which is transmitted at t hrough the area covered by the AZ. The Precision DME (DME/ P) Tran- change fun ctions w hen t he approach least once per second. Only a small sponder is compatible with standard system for the opposite direction is in portion of the auxiliary data has yet DME avionics and is colloca t ed with use. To provide t his bi-direct ional been defined but possible uses could the AZ . The DM E/ P provides con- capability the BAZ will have a 20 nm include met information and land ing condi t ions. t inuous range information in place of coverage. THE CONTROLLER/ DECEMBER 1987


Angular Measurement The ftZ. antenna generates a narrow vertical fan shaped beam and sweeps it to and fro across the coverage area. At the beginning of the ftZ.time slot the ftZ. preamble is transmitted. then the TO scan starts. At the end of this scan there is a pause before the FRO scan starts. During the scan cycle the aircraft receives a TO pulse and a FRO pulse. The time between these 2 pulses is measured giving angular location of the aircraft. A long interval indicates the aircraft is to the right of the center while a short interval indicates the aircraft is to the left. The same angular measurement principle is used for determining the elevation angle. The EL antenna generates a narrow horizontal beam and sweeps it through the coverage area. The TO and FRO pulses are measured in the vertical plane giving an elevation angle measurement and thus its displacement from the glide path angle selected by the pilot. Because aircraft flight control systems are considerably more responsive to changes in elevation than to changes in azimuth the elevation scan cycle is repeated 39 times per second compared to 13 times per second for the azimuth cycle. Hardware Most of the objectives of the ML$ design required the use of a wavelength much shorter than that used for ILS consequently antennas are much smaller. Let us now turn briefly to airborne equipment. Whilst existing controls and displays can be used, some additional special airborne equipment is required and aircraft manufacturers are working with administrations and airlines towards implementing M LS in time for introduction of MLS as the next generation standard approach aid. Conclusion Finally I think it is worth summarizing those advantages that will result from the introduction of MLS.









-* -¡-...----~--

--- -- - -----

Installation Installation costs will in all cases be less than ILS but in some cases the saving will be very significant. Moreover. installation periods will be dramatically reduced. There are already examples of MLS being fully installed in days rather than the months it can take to complete an ILS installation. Interference At the frequency used by M LS the narrow beam is much less susceptible 10


to multipath which makes ILS useless close to mountains and in areas of heavy snow or rain. Moreover, multipath often degrades the signal in less severe terrain and weather conditions and it requires flat and obstructionfree ground in front of ILS antennas. In some cases, airport departure capacity can be increased by replacing ILS with MLS where the ILS siting dictates holding positions at long distances from the runway.

Beam Coverage The considerably greater coverage of M LS offers: Greater flexibility in ATC procedure design and thus: • Increases handling capacity in congested areas; • Minimizes approach path lengths resulting in fuel saving; • Improves noise abatement procedures; • Reduces instrument approach criteria in areas of difficult terrain; • Increases the glide path angles available. Greater flexibility in ATC system design: For example, • MLS, in addition to being a precision approach and landing aid, could create redundancy in existing nav. aids thus saving in replacement cost. • Or, on the other hand, implementing MLS into a new system design could result in the need for less sophisticated approach and nav. aids to support the over-all plan. Frequency Congestion The increased number of frequencies available brought about by the introduction of MLS will solve the congestion problem which is becoming serious in many parts of the world. Navigation Unlike ILS, MLS provides, through the Precision Distance Measuring equipment, continuous distance to go information.

It Pays to Advertisein 'TheController' THE CONTROLLER/DECEMBER1987

Status of Aircraft (Civil or State) £Jat£q~(;7®,' (Editor's Note: Our readership, controllers and pilots, will have pondered interceptions by military aircraft of civil aircraft in international airspace and the legal aspects and implications of such actions. Other aspects addressed in the article below are incidents and accidents involving civil aircraft transporting military personnel. 'Status of Aircraft' is reprinted with permission of the IFALPA Quarterly Review's Editor. hhh.) ·

This paper presents the comments of the International Federation of Air Line Pilots Associations (IFALPA) as presented to the Legal Commission at the !CAO 26th Assembly, and includes a description of some of the practical problems which have arisen in the recent past, together with IFALPA's views on how the subject can best be progressed. Problem At present there does not appear to be an internationally accepted interpretation of the provisions of Article 3 of the (Chicago) Convention on International Civil Aviation which defines the status of aircraft flying internationally:

Article 3 Civil and state aircraft a) This Convention shall be applicable only to civil aircraft, and shall not be applicable to State aircraft. b) Aircraft used in military, customs and police services shall be deemed to be State aircraft. c) No State aircraft of a contracting State shall fly over the territory of another State or land thereon without authorization by special agreement or otherwise. and in accordance with the terms thereof. d) The contr~cting Stat~s undertak~. when issuing regulations for their State aircraft. that they will have due regard for the safety of navigation of civil aircraft. Background The key to Article 3 (b) seems to be contained in the word 'used' and it seems to follow that the status of the flight crew is thus determined by aircraft usage rather than by other factors such as aircraft registration. markings or the flight plan identification used. The potential for difficulty seems to arise in the instance of a civil air transport type aircraft which may

be interpreted as being used for one of the purposes put forward in Article 3 (b). For example, an operator may contract with a State to carry out services for one of the defined purposes and the persons on board may be unaware of the fact that the provisions of the Convention and other international legal instruments are no longer applicable. The three uses put forth in Article 3 (b) do not include other common uses applicable to State aircraft in international services. For example, the transportation of remote station supplies, emergency assistance and humanitarian missions or the transport of State diplomatic and foreign service personnel aboard aircraft chartered by a State. Past occurrences known to the Fe.deration wherein the status of the aircraft involved was or could have been in question include the following: a) On 10th October 1985 Egyptair flight MS 2843 was en route from Cairo to Tunis. It was the understanding of the flight crew that the aircraft was operating as a 'VIP Charter to the Egyptian Government' and was being used to transport the alleged hijackers of the Italian cruise ship ·Achille Lauro'. The individuals were travelling under armed guard. While en route on its filed ICAO flight plan, the aircraft was intercepted by armed aircraft of the US navy and forced to land at an aerodrome in Sicily where the individuals were removed and detained while the aircraft was permitted to depart. There was no subsequent action taken by ICAO or any other international body, apparently because no State made a formal complaint and it is believed that an informal decision had been taken that the aircraft was being used in police services at the time of the occurrence. 11

b) On 4th February 1986. a Grumman G2 aircraft registered to Libyan Arab Air Lines departed Tripoli en route to Damascus with the purpose of the flight believed to have been the transportation of Syrian diplomatic personnel home following a conference. The flight was subsequently intercepted by aircraft of the Israeli Air Force while over international waters and forced to land at one of their aerodromes where the passengers were reportedly removed from the aircraft and searched. before being released to continue their journey. A formal complaint was made to ICAO and in the course of the Council examination Libya presented copies of the Certificate of Airworthiness ar:idthe flight crew· s licences as evidence that the aircraft status was civil. The Council accepted the documents offered as evidence. c) On 12th December 1985 a DC-8 type aircraft operated by Arrow Airways (a USA operator) crashed shortly after take-off from Gander. Canada. The aircraft was under charter to the US Department of Defense for the sole purpose of transporting US Army personnel returning from peace-keeping duties in the Middle East. While the sole usage of the aircraft was 'military·. the accident was subsequently classified as a 'fatal-accident - non-scheduled passenger flight' and investigated under the national provisions related to ICAO Annex 13. d) On 29th September 1984. a USregistered 8-707 operated by South Pacific Airways was en route to a Middle Eastern destination with 120 Fijian military personnel on board. During the polar transit from Alaska to Europe the flight crew became lost and inadvertently penetrated the sovereign airspace of Norway. The aircraft is understood to have been under charter to the UN Middle East peace-keeping team but again the incident was investigated and corrective measures were initiated by the State of the Operator using civil procedures. In both this case and the occurrence cited above an additional complication would appear to arise from the fact that. in addition to the fact that the aircraft usage was solely military. they were both in the service of an international organization.

little uniformity in the application of Article 3 by national or international authorities with regard to whether the aircraft was being used as a civil or State aircraft. The current tendency seems to have been driven more by political convenience than by uniform application of the Article. The potential difficulties for the flight crew engaged in flying State aircraft in international civil air transport type operations involving military. police or customs services seem to include: a) The non-applicability of international air law conventions and their safeguards to flights operating as State aircraft. b) The application of national civil laws. rules and regulations to civil flight crews operating 'State' aircraft. i.e. would the civil or military investigative and judicial process be applied in the event of an accident or incident? The question of the status of the aircraft can be very clear in the instance where the State charters the entire aircraft for well-defined transport purposes. In cases where the State or International Organization charters only a portion of the seats available and the operator offers the remainder of them for sale to the general public the situation becomes less clear. For example: i) Within some States it is a common practice for the military to provide partial funding for the acquisition of new aircraft by an operator on the understanding that the aircraft will be released for military service in the event of a national need.

Agreements also exist for the operator to provide flight crews. maintenance and servicing. In this instance it seems clear that the flight crews would be placed in a rather tenuous legal position. ii) There are instances wherein persons under custody and deportees have been transported by aircraft chartered by the State for that purpose. In an international case a strict interpretation of Article 3 would seem to place the aircraft in the status of a State aircraft being used for 'police· purposes. In other cases it is common to accommodate both persons travelling in custody and the general public on the same flight. Would such an aircraft be considered as being used in police services and therefore accorded the status of a State aircraft? Recommendations The matter of civil versus State status of civil air transport type aircraft is one of concern to the international airline pilot since there are clear indications of a lack of uniform application of the existing provisions of Article 3 of the Convention on International Civil Aviation. The matter is believed to be one that fully warrants careful consideration by the ICAO Legal Committee through inclusion in its Work Programme as a high priority item. It is also believed that the subject should be studied by the Air Navigation Commission with the goal of determining whether the existing provision of the ICAO Annexes to the Convention adequately reflect and support the intent of Article 3.

Concl1U1sio1111s As can be seen from the above examples there has apparently been 12

"Snowbirds. tower. low pass cancelled. push down and go around . .. THE CONTROLLER/DECEMBER 1987


Starship A New Era in Business Aviation

A futuristic-looking aircraft garnered attention at this year ' s Paris Air Show: the Beech Starship - the world's first tandem-wing configured all-composite business turboprop. Starship is the product Beech Aircraft has developed to follow its highly-successful King Air line, which has achieved a 50-percent share of the business turboprop market since its introduction in 1964 . The King Air's 1986 share of that market exceeded 70 percent . Starship was engineered to improve the King Air in every way possible: speed, comfort, cabin space, accoustics, handling and flight characteristics, and greater operating efficiency . Starship achieves all of these goals. To make Starship faster and more efficient, Beech chose to use composite materials rather than traditional aluminum. Composites can be formed much more smoothly than aluminum,

creating less drag and therefore achieving greater speed and efficiency. Composites can also be more easily manufactured into today's complex aerodynamic shapes , permitting Starship ' s beautiful but functionally efficient lines. For example , Starship' s wing consists of four distinctly different airfoils between the fuselage and the wing. These separate airfoil shapes optimize performance throughout Starsh ip' s speed range, a~d provide the most efficient local airflow over each section of the wing . Such a variety of aerodynamic shapes could not be economically produced in volume on a single wing using traditional aluminum construction techniques. Starship is made primarily of graphite carbon epoxy sheets sandwiched around a Nomexâ&#x201E;˘ honeycomb core . Kevlarâ&#x201E;˘ is also used in some areas, with titanium employed at high-stress points .

Starship ' s eng ines are mounted aft to put the passenger compartment far ahead of propellers and engines . This configuration offers two advantages : it reduces cabin noise substantia lly below the levels of any existing tur boprop, and it positions passengers ahead of the wing to enjoy an unrestricted view and a ride quality avai lable previously only in medium and large-sized business jets. To reduce sound levels further, Starsh ip does not use a convent ion al tail, which would act as a large sounding board to transmit engine and propeller noise into the cabin. Instead, tipsails are used as vertical stabilizers and in rudder contro l. The tipsails also increase the effect ive wing span by nearly 10 percent and take advantage of natural wingtip vortices to slightly increase forward thrust. Starsh ip's tandem wing design makes it naturally stall resistan t. and thus safer than conventional aerodynamic configurations . Its main wings are equipped with Fowler flaps, which increase wing area for low-speed operat ion without adding substantially to drag . The flaps are interconnected with Starship' s variable-geometry forward wing. which extends for low speed operation to balance the pitching moment created by flap extension . and sweeps back to reduce drag in high speed cruise . Starsh ip' s cabin is larger than that of Beech ' s Super King Air by nine inches (23 cm) in height, a foot (30 cm) in width and by nearly four -anda-half feet ( 1.35 m) in length. It will be pressurized to 8 .5 psi (0.6 kg/ cm 2 ) to provide an 8.000-ft cabin altitude at 41,000 ft . In keeping with its advanced aerodynamic design. Starship 's cockpit is equipped with the most advanced integrated avionics system in business aviation. A 14-tube Collins Electron ic Flight Instrumentation System (EFIS) designed specifically for Starship offers increased information management and reduced crew workload unavailable in any comparable aircraft. Starship will be certified to operate at 41.000 ft and cruise at 400 miles per hour - 6 .000 ft higher and 40 miles per hour (64 km/h) faster than the most recent King Air model. Starship is scheduled to receive Federal Aviation Administration certi fication by the end of 1987. Deliveries wil l begin during the second quarter of 1988. First European deliveries will occur in 1989 .

Beech Starship



Air Traffic Flow Management Gianfranco Russo, Head of ATFMU Rome

Introduction Air Traffic Flow Management is a subject with which most controllers outside of Europe and the United States of America are not too familiar, at least as yet. While adequately equipped, staffed, and managed air traffic control systems might alleviate to a great extent the requirement to restrict the free movement of air traffic. limited airport acceptance rates due to runway and taxiway configuration, parking and handling problems will in turn increase the necessity to limit access. Europe. with its great variety of air traffic control systems and capacities. its seasonal travel patterns to various, but defined. vacation areas was the natural candidate for an international flow management system to help overcome such shortcomings. For readers of 'The Controller' and participants in the annual conferences who have. over the years. puzzled over acronyms ATMG. ATFM. FLO-W. FLO-E. etc .. the article below offers many answers as well as a reasoned explanation why controlled restriction of air traffic flow is considered a necessity. The article was first published in ·Assistenza al Volo'. ANACNA' s. the Italian Association's. outstanding March 1986 issue celebrating the IFATCA Silver Jubilee. H. Harri Henschler

Historical Background By the early 1970s the traffic density in certain parts of Europe had reached a point where the ATS System was no longer able to cope with the traffic demand. As a consequence. serious delays were experienced. particularly as a result of an imbalance between air traffic demand versus traffic handling capacity of different parts of the ATC system. Measures taken at local level to correct the situation were effective only at that level. but had consequences with the ATC system of the other States. therefore heavy penalties and disruptions to air traffic occurred in those parts of Europe where traffic density is high. An urgent need for international cooperation had arisen in order to 14

solve the air traffic services problems in Europe and to permit the regularity. economy and safety of air transport in general. It had become clear that any permanent solution could only be sought on a regional scale and required concerted and concentrated efforts by all States and users concerned. within the framework of ICAO. In June 1980 a Special European Regional Air Navigation Meeting (EUR-RAN) was held in Paris. The meeting. when looking for possible solutions to the various problems encountered, found that improvement of the ATC system and provision of an air traffic flow management could eliminate most of the difficulties. It was also recognized that for many reasons (firstly an economic reason). the capacity of the ATC system could not be expanded indefinitely. The EUR-RAN therefore agreed that air traffic flow management would be necessary to avoid an overload of the ATC system by ensuring the maximum use of available capacity and by reducing penalties arising from situations where this was not possible.


The meeting also agreed to encourage the development of a common reference base on expected air traffic demand as a basis for the formulation of coordinated air traffic flow management measures. To achieve this. the EUR-RAN recommended that a single. integrated ATFM service be established for the EUR Region and the EANPG (European Air Navigation Planning Group) was requested to undertake as a matter of priority. work aimed at the earliest possible implementation of the ATFM service. At the same time a Central Data Bank (COB) would be implemented for ATFM purposes and Eurocontrol Organization was invited to develop detailed proposals for the establishment and operation of a Central Data Bank in Brussels. The ATFM Service in the EUR Region is being activated under the general supervision of EANPG. with ATMG (Air Traffic Management Group). the Informal Flow Control Meetings - Europe East/West. the meeting of the heads of ATFM units and Eurocontrol's FMPG. acting as main recommending/ coordinating organs. Present Stage in Implementation of European ATFM Service The ATFM Area (a defined area throughout which ATFM is provided. see Chart) is actually delineated by the following FIRs/UIRs: Stavanger. Oslo. Stockholm. Tampere. Malmo. Warsaw. Bratislava. Budapest. Bucarest. Sofia. Istanbul. Ankara. Nicosia. Athens. Rome. Mar-




seille. Barcelona. Seville. Lisbon. Canary(TMA). Madrid. Brest. London. Shannon. Scottish. The European ATFM Area is served by 11 ATFM units geographically located within the area. while one unit is located outside this area: the 12 are as follows: Athens - Benelux - Beograd Copenhagen - Frankfurt - Istanbul London - Madrid - Paris - Prague Rome - Moscow (outside the ATFM Area). The overall traffic situation in the Eastern part of the Region had developed to an extent that made the provision of flow management service a widespread requirement. The expansion of the ATFM area as defined in 1980. had become a necessity and to that end an ATFM unit had been established. In that enlarged area. plans are under way in the interested COMECON States to create a data bank within the national canter of the USSR ATC Joint System in Moscow. Under discussion is the possibility to extend the ATFM area to include the whole EUR region. except for the Asian Part of the USSR. Objectives of the ATFM Service The Flow Management Service is designed to ensure an optimum flow of air traffic to or through areas within which traffic demand exceeds the available capacity of the ATC system. This optimum flow is achieved by the ATFM service maintaining. in continuous cooperation with related ATC Units and operators. a balance between the traffic demand and the capability of ATC to accommodate that demand. The operation of an integrated European ATFM Service. while respecting the intention of the operators to the maximum extent possible should ensure: full exploitation of available ATC capacity;. maximum flexibility in handling traffic flow; orderliness in traffic flow. The ATFM service is based on the following basic principles: 1. Prevent expected overloads of the ATC system with minimum adverse effects upon aircraft operators. 2. Uniform procedures applied by all units in the ATFM area. 3. The closest possible coordination maintained between ATFM units. ACCs and aircraft operators.

achieved by ATFM activities in two stages. as follows. Strategic ATFM activities (from several months until 24 hours before execution of flight operation): a) early identification of expected bottlenecks within the ATCsystem: b) corrective actions (e.g. capacity increase. alternative routings. and other measures taken in cooperation with ACC and aircraft operators) Tactical ATFM activities: a) rerouting of traffic; b) time slot allocation to individual flights. The Organization of Strategic ATFM Plan The efficient operation of ATFM service depends on the timely receipt of reliable information on planned flight operations and revisions. as well






















ACC parrtycter,endmg on trafficflows

ACC co-operatingin ATFMacrrvrties.

ATFM Activities The necessary balance between air traffic demand and ATC capacity is

as data on ad hoe flight operations (the first data on planned flight become available following the summer timetable conference of the aircraft operators. in December or January each year. It also depends on the availability of information on the air navigation infrastructures (ATS route network. ATC sectorization) as well as on data resulting from load threshold values of the ATC system. In order to obtain an appreciation of the total expected demand during tactical activities. data processing is made by using relevant RPL/ FPL data in addition to COB output (when COB will be full operational). The processing for a relevant day of operation should cover the following: a) expected hourly ATC sectors loading: b) expected traffic flows over specific points or into specific areas;





c} expected arrival and departure traffic flows at selected aerodromes. Air traffic demand data. infrastructure data and load threshold values are necessary to: i} identify location and time periods where the demand is expected to approach or exceed the load threshold values; ii} prepare alternative solutions. if possible. to solve such problems.

Practical ATFM Activities 1. Rerouting: rerouting of particular flights is done by offering:

Book Review Human Factors in Flight, Frank H. Hawkins. Gower Technical Press Ltd.. Gower House. Croft Road, Aldershot, Hants. GU7 7 3 HR. UK, 360 pages, US$ 26. 95 paperback (ISBN 0-291-39 739-5) or US$ 59. 50 hardcover (ISBN 0-291-39 738-7)

· Human Factors in Flight' is a challenging book. a book well read by representatives of air traffic controllers and controllers themselves. a} alternative route; While much of the book seems b) off-load route (specific route prodirected towards flying operations. the posed by an ATFM unit when the underlying principles are equally preferred route is subject to delay}; applicable to the field of air traffic c} any routes where capacity is availcontrol and many of the subjects able. 2. Time slot allocation (Slap pro- covered indeed overlap the flying and control functions. cedure} The author. Captain Frank HawIn the ATFM concept two prinkins. offers impressive credentials in ciples are basic: aviation and human/technical/ergoa} The application of ATFM measures nomic endeavors. The subjects in the form of delays is limited to covered are wide-ranging. situations when other efforts to · Human Factors· defines interresolve a demand/ capacity probrelationships of software. hardware. lem have failed: is therefore the last environment. lifeware (human); resource. 'Human Error' examines causes and b} Air Traffic Flow measures have to contributing factors; other chapters be applied to aircraft on the explore · Fatigue. Body Rhythms and ground. wherever possible. Sleep' as well as 'Fitness and The slot allocation procedure is a Performance· - all equally applicable method for streamlining traffic flow by to shift-working. non-physically-active acting on individual flights in such a controllers 'Vision and Visual way that available capacities or appli- Illusions· examines factors which cable acceptance rates are fully contribute to mistakes in properly utilized. assessing a given situation. A slot is defined as a given time at A chapter 'Motivation and Leaderwhich an aircraft is expected to arrive ship' delves into the psychology and at a given point (slot reference point}. the theories of human needs. motivOn the basis of traffic demand ation and its maintenance. A particuinformation (primarily from FPL and larly interesting chapter is ·communiRPL}. the ATFM unit prearranges the cation: Language and Speech'. Here. slot sequence over the slot reference Hawkins defines the types of compoint for individual flights concerned munication. looks at verbal and body in accordance with two principles: language. describes the vocal and 'first planned - first served' or 'first to auditory systems. explores speech, call. first to be served'. redundancy, masking and noise. The slot sequence over the slot ref- errors. and intelligibility, and looks at erence point is based on ETD and the the tragic Tenerife and other accielapsed time between the airport of dents. departure and the slot reference point. Other chapters of interest to conIn conclusion we can say that the trollers are· Attitudes and Persuasion·. integrated ATFM service is intended to 'Training and Training Devices·. assist ATC by establishing and main- 'Documentation· which gives examtaining an expeditious flow of traffic in ples of poorly worded and phrased the ATC system. and to assist aircraft documents. in particular where a operators by providing a cost effective language other than one's mother utilization of the available capacity. tongue is used. as well as examples as The ATFM service should ensure that to how these could be improved. the traffic flow in the ATC system does There is a practical application here to not exceed a level manageable by the composing of ATC Manuals of ATC. Operation. and directives to pilots. 16

'Display and Controls' and 'Space and Layout' address the ergonomic factors in designing equipment. Again, the principles are equally applicable to designing or determining air traffic control equipment. an activity more and more Member Associations are becoming involved in. Obviously, equipment designed for a population where the average height is 1.80 m will not be comfortable in a country where the average height is 1.60 m and vice-versa. Finally. there is a chapter 'Education and Application' which could be used as a blueprint for establishing a 'Human Factors Training System'. Such a system. so far. appears to exist. and in a limited form. only in the airline industry. There may be, in the future. a need to establish and offer a 'Human Factors Training System· within air traffic control. If this need arises. · Human Factors in Flight' will have offered a valuable contribution. If it never does. the book will. at the very least. have offered insights of great value on a large number of factors of intimate and direct interest and within the experience of many. if not all. air traffic controllers. H. Harri Henschler


Traffic in the US rose 12.2% in revenue passenger-miles for Air Transport Association members. ATA said. Domestic RPMs were up only 7 .2%. but international traffic soared 33%. In both markets traffic outstripped capacity increases. boosting domestic load factors 3.2 points to 67.1 % and international load factors 10.4 points to 74.1 %. Total RPMs for the first seven months increased 13.5%. ATA said. ('Air Transport World' 1018 7) THE CONTROLLER/DECEMBER 1987

Air Industry Seeks Technical KO over Wind Shear William Rahr, Supervisor of Product Development Avionic Systems Division , Sundstrand Data Control, Inc.

Air safety organizations, governing agencies and private industry have joined forces in a concerted effort to overcome the dangers of wind shear and microburst phenomena. New knowledge is inspiring new solutions and a decisive technical knockout of this menace to air safety may be within our capabilities in just a few short years . While aviation in the 1980s is safer than ever before , we now have the opportunity to make it even safer . This article describes the work that is being done to minimize and perhaps ultimately even to neutralize the dangers of wind shear. It looks at some of the more promising approaches for future solutions as well as today's best defenses against severe wind shear conditions . It describes in particular the practical Mark V GPWS/wind shear computer from Sundstrand Data Control and how that system offers immediate , low-cost wind shear detection and alert for nearly all currently operating commercial aircraft, as well as for new aircraft.

United Airlines and Aviation Weather Associates, the training aid allows pilots to experience wind shear conditions through training videos and flight simulations based on FAAdeveloped wind shear models . Throughout its development, the training program has been reviewed by manufacturers and operators of a wide range of aircraft types to ensure that it will be applicable to all members of the aviation community . Ground-based Detection Networks Ground-based wind shear detection networks hold promise for the futu ~e because of the ir ability to help pilots avoid wind shear rather than react to it. Existing ground systems , however, are unable to detect and adequately communicate all wind shear and microburst conditions, and significant help is at least five years away. The National Weather Service radar networ k and its radar tech-

nicians can identify rapidl y developing atmospheric changes but do not presently have the means to ensure timely and meaningfu l communication to air traffic cont rollers . The termina l-based Low-Level Wind Shear Al ert System (LLWAS) does com municate its data immed iately, but it does not have the ability to detect all microburst situa t ions . The FAA is working on improvements to both of these systems, including an expansion of the LLWAS systems from six to eleven sensors , planned for com pletion within the next five years . One prom ising new method of microburst detection is Doppler radar , which was used in the NIMROD study that first identified and described a microburst . Two advanced Dopp ler weather radar networks are now under development : The Next Generation Radar, or NEXRAD, is a long-ra nge Dopp ler system being jointly developed by the National Weather Service and the US Air Force for weather mon itoring outside the terminal area. Initial installations are targeted for comp letion in 1993 . The Terminal Doppler Weather Radar (TDWR) is a similar system designed to function within t he air termina l environment. TDWR w ill provide microbur st det ecti on and information on a variety of atmospheric conditions , as we ll as predict wind shifts and sto rm movement. Deliver ies are sc heduled to begin in 199 1.

Developing Winning Strategies There are several viab le approaches to reducing the danger_of wind shear encounter , including spec ial pilot training, ground_-based detection networks , and airborne detect ion and recovery guid ance systems . Each of these approaches is current ly being explored and promises a sig nificant contribution to effect_1ve protection from the dangers of wind shear. Pilot Training All pilots now receive spec ial training in how to react to severe wind shear conditions. In late 1985 the Federal Aviation Ag ency awarded a contrac t to the Boeing Company to develop a wind shear sim ulation training aid. Developed In cooperation w ith McDonnel Douglas. Lockheed, THE CONTROLLER/ DECEMBER1987

Sundstrand Data Control's Mark V GPWS/ wind shear comp uter has been specified to provide wind shear detection and alert functions for all new Boeing 737 , 757 , 767 and 747-400 aircraft .


While ground-based detection networks are well worth pursuing because of their ability to provide advance warning of dangerous wind shear conditions, their full development and implementation will be costly and is still several years away. Immediate protection is needed, and that will come in the form of airborne detection and guidance systems. Airborne Detection Systems Two types of airborne systems are being developed: those using forwardlooking sensors to provide the flight crew with the ability to avoid wind shear conditions, and those using present-position sensors to warn the crew that the aircraft is entering a wind shear condition. The 'lookahead' capability, like the Doppler radar ground-based networks, has shown promise for future applications. Tests using radar. laser, acoustic and infrared sensors indicate that some combination of these technologies may eventually produce an effective wind shear avoidance capability. At this point. however, it does not appear that a practical version of such a system can be ready for several years to come. Today's best protection from wind shear, then, and the only viable response to an imminent wind shear rulemaking, is an airborne system

using present-position sensors. Sev- hardware or of the use of additional eral present-position or 'reactive¡ wind cockpit space. It is extremely valuable shear detectors have already received for timely retrofit applications. The FAA certification. Some of these pro- Mark V is directly compatible with its vide only a detection capability, while predecessors and can replace them others add a guidance feature to assist one-for-one to provide not only an the flight crew in escape procedures. enhanced GPWS but wind shear A few of the more advanced systems warning as well. go beyond a strictly reactive mode to This flexible approach to wind provide flight crews with some warn- shear safety offers significant benefits ing to prepare for wind shear encoun- in terms of schedule and cost of ownter, though not enough to avoid the ership. Not surprisingly, this Mark V Computer has been very well received encounter. in the industry.

An Early Advantage with the Sundstrand Mark V

Technology Winning Out

The most practical and successful of these certified systems, and the system that Boeing has selected for wind shear alerting on all of its new aircraft, is Sundstrand Data Control's Mark V GPWS/wind shear computer. The Mark V provides wind shear detection by processing information about longitudinal acceleration, normal acceleration, vertical speed, angle of attack, radio height and flap position. The basic algorithm does not require inertial grade flight path accelerations or earth-referenced accelerations. What makes the Mark V so practical is the fact that it offers today's most advanced capabilities without requiring the installation of additional

The air transportation industry and its regulatory agencies are building the foundation for a clearcut victory over the dangers of wind shear. Improved ground-based sensor systems and forward-looking airborne detectors hold promise for future applications. There are answers for today as well, with pilot training programs and Sundstrand' s retrofittable Mark V GPWS/wind shear computer leading the way. The threat of wind shear is still with us, but it is on the ropes; judging from the industry's initial responses and co~tinued dedication to air transportation_ safety, we can anticipate a technical knockout of wind shearrelated accidents in the near future.


















t>.o a 0




o o o'bo EADI The Mark V GPWS/wind shear computer provides efficient wind shear capabilities in both retrofit and new applications. Shown here is the Boeing 731300 1mplementat1on.





Editor's note: The article below first appeared in vol. 5 no. 2 of 'Sunjet', the Cyprus Airways in-flight magazine. The article, it must be remembered, was written for the general travelling public, in an understandable language. Cyprus Airways' efforts to bring air traffic control and the controllers closer to the understanding of its passengers are commendable and it is hoped that other airlines will follow its example. The article is reprinted with the kind permission of Cyprus Airways. hhh While you are eating your lunch, reading this magazine or just gazing out at the fleecy horizon. every inch of your progress is being monitored on the ground with the utmost care and concentration . Several pairs of eyes are tracking your course as you wing your way, and they know exactly where you are, how fast your aircraft is travelling , its height. direction and the time at which you will be landing. Over a large section of the Eastern Mediterranean. your ' guardians' are the men in the Cyprus Air Traffic Control Centre in Nicosia. and without them you wouldn 't get off the ground at all - nor would your pilot take you. Their job is to guide and control all aircraft flying in the Nicosia Flight Information Region. . The Nicosia Flight Information Region (F.I.R .) covers a large chunk of the Eastern Mediterranean. an area of some 175,000 square kilometres. which stretches from the west coast of Israel then along the coast of Lebanon and Syria to a boundary along the south coast of Turkey, to 150 kilometres west of Rhodes, before it hands over any westbound traffic to the Athens Centre. A 'map' of the skies shows it divided into motorways or ¡corridors¡ of its own, with reference points at regular intervals . Ea_ch of these points is named with a five letter , two syllable word like 'Ledra ' , ' Dasni ' and 'Aplon' , which would not easily be misunderstood over the radio. Until this year the Nicosia Air Traffic Controllers monitored and guided the traffic in their region by the ' procedural' method , which meant that they were alerted to the movements and whereabouts of aircraft through radio contact and by telephone and telex messages . The preceding conTHE CONTROLLER/ DECEMBER 1987

trol centre on the aircraft's route would verbally 'hand over' a flight, whose Captain then communicated to Nicosia his height, position, heading and speed. and remained in direct radio contact with Nicosia until handed over to the next area control centre, or Control Tower . All that has changed this year with the arrival of radar control. The sophisticated equipment was installed earlier in the year on the Kionia Peak near Macheras , and the job of the air controllers has changed radically now that they can. literally , see the whole picture . At each of the three radar 'sets' there is a team of three men: a Radar Controller, a Planning Controller and Nicosia Area Control Centre

an assistant . They work in shifts, and a six hour shift consists of two hours on duty, one off, and a repeat of this sequence. The Centre is manned 24 hours a day, seven days a week because, unlike London's Heath row and many of the European airports , Cyprus has aircraft flying in its airspace and landing at its airports at all hours of the day and night . The controllers are a dedicated team . That these men belong t o a special breed is apparent from the degree of alertness and concent ration required , coupled with the right mental aptitude that is essentia l for thi s demanding job . The Air Traffic Controller would usually be a university graduate who is also fluent in English . He must have flying experience. at least to PPL level (private pilot's licence). He will undergo rigourous training, during which he will be sharply scrutinised as to his abi liti es and reactions , and will even under go psychological tests. He must be able to endure stress and remain calm with a steady voice at all times. He will have medical check ups once or twi ce a year . And above all he must observe a strict lifestyle , which means no socialising on the nights before he goes on duty . But clearly these men find their work totally absorbing . It is common to turn up for duty an hour early , few spend that hour of relaxation with their feet up behind a newspaper. Some excuse is usually found to slip back into the room and observe proceedings . All communicat ions are in English, which is one of the international languages of the skies.


Basic words and phrases have been standardised, but the different nationalities present a variety of accents to get used to, some more bewildering than others . If in doubt the controller can revert to the phonetic alphabet for precise communications. i.e . 'b' for bravo, 'f for foxtrot, 't' for tango. But due to its posit ion between East and West, Cyprus airspace is used by a large number of overflying aircraft and Nicosia is, of course, in contact with them . In ¡ the summer months Nicosia A.O .C., handles an average of 360 flight s during a 24 hour period. During period s of heavier traffic the radar screen can be conveniently 'split', which reduce s the load by 50 %, with one team working on half the region, and a second team on the other half concurrently . In wintertime there are about 25% less movements , with more aircraft overfly ing the island than landing on it. These movements are not all neces sarily comme rcial passenger flights. There are cargo fli ghts and a number of military aircraft. Of the military flight s that Nicosia handles, which does not include spy planes who never contact anybody, some behave like normal f lights, while others carry out exercises and formation s locally . Indeed it might be the Red Arrows themselves requesting a training period . Nicosia gives them an area to themselves 'to play around in for an hour of two' . So what happens when your flight approaches the island? Firstly , the Nicosia Control Centre will have had plenty of advance notice of its arrival. This will have been organised by your Captain who, well before you have flashed your passport at Immigration and stocked up with duty frees, has checked on the weather and filed his flight plan . This goes to all the cen tres on the route, and is sent in th e form of a telex. When this is received at the Nicosia Centre it is given to the computer programmer, who enters it into his movements plan . The computer progr ammer advises the radar operators of your f light and the call sign that he has designated to it . Meanwhile , as you wing your way towards the island your flight will be ' handed on ' from one centre to the next. If you are flying in from the East you will be on an even-numbered altitud e, such as 26 ,000 or 28 ,000 feet while eastbound aircraft are given odd-numbered altitudes like 27,000 or 29 ,000 feet. Your arrival in Cyprus airspace will be immediately apparent . The radar sends out a pulse which is received by 20

Larnaca Control Tower

your aircraft, converted and reflected back to the station . So you appear as a blip on the radar screen, but as yet an unidentified one . The pilot will be contacted by the centre and requested to 'squawk' his identity and flight details . (In controllers' jargon aircraft are birds, whose language is 'squawking '. ) The pilot will respond by turning on something called a transponder, which alters the signal seen on the radar, identifying the aircraft and giving various details

to the Controller . Or he will advise his altitude , heading and speed verbally to the Centre. At this time Nicosia will inform the Captain of the code he is to use in Cyprus airspace. As the controllers monitor its course they will be issuing their descent instructions . By the time you have uprighted your seat, stowed your table and found your shoes they will have handed the flight over to the Control Tower and you will have touched down on the tarmac .

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Speed Control of Aircraft by ATC The emphasis on the higher flight levels Michael Bloodworth, The Institute of Navigation, reprinted with permission of the Editor of 'Transmit'

ATC is faced with two main situations which can benefit from the use of speed control at the higher flight levels. First. aircraft in the cruise require to be as near their optimum height and speed as possible. and air traffic controllers have to juggle the two parameters to suit the majority: secondly. radar controlled descents (and climbs) operate on a tactical basis. and in this situation speed control is a valuable ATC option. The radar controllers. rather obviously. see the aircraft on their radar displays moving at their true airspeed and use this speed together with the disposition of the aircraft to plan the tactical flow. However. it is a fact of life that the True Airspeed (TAS) of an aircraft varies with its height. as the following theory shows. whilst the pilot is operating an airframe that is kept flying by reference to a different speed known as the Equivalent Airspeed (EAS). At about 40.000ft the EAS is roughly half the TAS. whilst down at the lower levels. with airfield approach control. the difference is only about 20kt: the TAS has reduced towards the EAS as the aircraft descended. The ATC problem is therefore how best to deal with several aircraft all at different heights and therefore closing up. or perhaps moving apart. relative to each other.




HEIGHT (ft) x 1000 30







Fig. 1

two significant air speeds: one is TAS required for navigation (and for certain aspects of design). the other is EAS. This EAS is easily measured by the difference in dynamic and static pressure sensed at the aircraft Pitotstatic head. However. it is subject to various errors such as the local airflow and. in particular. the progressive rise in temperature due to local compression of the air as the speed of the Basic Theory of Flight aircraft increases. These errors are corrected as far as If you can answer the following question you may wish to skip this possible. and the speed presented to section on theory. Boeing 74 7s have the pilot as an Indicated Airspeed (IAS): his flight manual presents most been test flown to at least Mach 0.92 (M 0.92) and are tested to an airspeed of his flight data to him in IAS thus of 4 10 kt at which speed the over- giving him a direct correlation bespeed warning sounds. Since the 74 7 tween the airspeed indicator and the cruises at 500kt. why do they not all 'book' speeds required for flight. Therefore ATC must use IAS. and forget break up in the cruise? There is a very basic formula for lift about EAS. Another major factor affecting (and a similar one for drag) which flight (i.e. apart from EAS) is the speed states: lift= ½pV 2 SCL where p=density of the air (at that height); V = TAS; of sound. represented at whatever S=wing area; CL=coefficient of lift. ~f speed it occurs by Mach 1 (M 1). Once one considers p and V. then as the a,r you start moving you are up against a density decreases (with height) the changing characteristic of air flow. but aircraft has to fly faster to generate the it is not until about M 0.5 that it begins same lift. The combined value of the to have any real effect. By M 0.8 it is two digits. pV2 can therefore be con- having considerable effect. the centre sidered as an EAS. We therefore have of lift is moving rearwards. drag is THE CONTROLLER/DECEMBER1987

300 TASlltt)

increasing. and even the low speed buffet boundary is beginning to rise. i.e. increase in speed. If the speed is increased then high speed buffet will be experienced. and probably even a shock stall if the critical speed for the wing is reached. This illustrates that it is the approach to the speed of sound that can be critical. and not just M 1 itself. The speed of sound in air is mainly dependent on the temperature of the air; under International Standard Atmosphere (ISA) conditions it has a speed at sea level of 661 kt. and at 36.000ft a speed of 573 kt; the speed then remains constant up to 60.000ft where it begins to increase again. Thus a climbing aircraft will climb at its optimum IAS until reaching the altitude at which its TAS has increased to its Mach number limiting speed; from then on it will be Mach limited and will reduce its TAS as it follows the reducing speed of sound. After passing 36.000ft (IAS). and if still climbing. the TAS will remain constant for a given Mach number; however. drag is still reducing. as the density falls. and the aircraft will continue higher for overall economy. Pilots therefore think Mach number in the cruise. and to a certain extent 21

ground speed for navigational aspects: and IAS in the descent and climb phase. The relationship between height. TAS. density. temperature. Mach number and IAS is shown in Fig. 1. The airframe flight limiting parameters discussed so far enable a simple Flight Performance Envelope (FPE)tobedrawnasshowninFig. 2. This envelope and its optimum operating point only apply for a particular set of flight conditions. The area around the operating point contains the safety margins: they comprise speed reserves (increase in speed towards high speed buffet; reduction in speed towards stall buffet) and a 'G' reserve or buffet margin, for maneuvering forces and/or air gusts with vertical components. (The effect of the latter is proportional to TAS. which we have shown to be high in the cruise.) Not only does such a gust increase the loading on the wing, but the ·resultant velocity' of the airflow takes the wing nearer to its critical Mach number, which in turn further reduces the margins. If an aircraft experiences turbulence it has to adopt a speed that reduces the potential forces. whilst still leaving sufficient margins to deal with the buffeting. The rough-air speed is usually around 280klAS (knots IAS). or a Mach number of perhaps M 0. 7 (M 0.82 for the faster big jets). The above theory therefore shows that the pilot is in an airframe kept airborne by reference to IAS (EAS) and his whole world is largely governed by this. i.e. his airframe stalls at an IAS.

and it overspeeds at an IAS (which at the higher flight levels and/ or speeds is itself largely supplanted by compressibility limitations referenced to the speed of sound). As already mentioned, the radar controller's display is a true airspeed picture: it is the controller who has to bring the effect of the two speeds (TAS and IAS) together in his brain. and he/she eventually acquires the knack by experience, mainly · on the job'.

aircraft is behaving normally and flying at a constant IAS, the TAS will begin to fall. (Since the speed of sound is still increasing. the Mach number will continue to fall.) Finally, TAS will reduce to the same figure as IAS at sea level (for practical ATC purposes anyway). The changeover point. or more precisely. the· changeover flight level'. between Mach limitation and IAS limitation is subject to many variables. However. some sort of changeover reference is necessary for ATC The Technicalities of Speed mental effort and generally FL245 can Control be taken as a suitable point. This Descending aircraft close up on changeover point (flight level) tends to each other (the leading one is lower vary with the cruise speed: e.g. 8737, and therefore slower): climbing air- M 0.72, changeover FL245; 767, craft move apart. This assumes similar 757. Tristar. 747. M 0.8. FL300, flight profiles and speeds (rare in real BAe 146, M 0.6, FL210. life), and starting from similar heights. Generally 250/ 290 klAS is flown This is why the following paragraphs for descent. and 2801330 klAS in the concentrate on the descending en route climb after departure due to phase; everything is coming together the extra weight. Most modern jets both horizontally and vertically! can be pushed to descent at 350 klAS Consider an aircraft arriving in the but this gives unnecessarily high rates controller's airspace and ready for of descent and also wastes fuel. descent. It will be flying to a Mach The practical aspect of achieving number. and will start its descent any necessary speed control is made more or less at the same Mach num- easier with the aid of one or two rules ber; as the aircraft descends the TAS of thumb. Consider two aircraft, may increase slightly as the speed of descending line astern. 6 nm apart. sound increases (this is of no practical and both descending at the same significance): at the same time the air optimum speed (IAS): then. since the density is increasing and thus the IAS leading aircraft is bound to be lower will be increasing until at a particular than the succeeding one, probably by flight level (say around FL2 70) it 4000ft, the TAS of the leading aircraft reaches the required IAS operating will be less; therefore the two aircraft value. are closing up. ATC must therefore From this point onwards the air- apply a speed differential (IAS) to craft will be IAS limited instead of these aircraft. The rule of thumb for Mach limited. and assuming that the this (at these higher levels and speeds)







~ SEA LEVEL------,-6..,.5-kt

Vs ______

3_1_0.._k_t ____

4....,20._k_t _______



Fig. 2 Note: Vmo/Mmo Maximum Operating Speed (k!AS and Mach number)



is to use 6 or 7 kt (IAS) per 1000ft difference in height. For example, if our leading aircraft is passing FL200 at 285 klAS, the TAS will be 380 kt. The following aircraft will then be passing FL240, and if ATC apply a speed differential between the two aircraft of 24klAS (i.e. 6X4 or 6 klAS X 4000ft height difference) then an IAS of 260klAS (285klAS less 24klAS) applied to the second aircraft will also be found to equate to a TAS of 380kt (at that height of FL240). Therefore these two aircraft will hold station. both at 380 kt (TAS). instead of closing up. In the above example separation already existed and was held constant. If longitudinal separation does not exist say one aircraft is on top of another. the simplest way is to split them left and right onto two separate tracks for descent. If. however. ATC require 5nm between them for subsequent handover. then the aircraft must have their relative speeds adjusted by two factors. As already discussed. one is an allowance for the difference in height; the other is for a speed differential that will produce 5 nm separation during the time taken for descending. This allowance is based on the fact that if you fly for 10min at 30kt (TAS) you will cover 5 nm. If our descent phase is to last 10 min (say to the top of the landing stacks). we need only apply a 30 kt TAS differential and we have 5 nm separation. Converting the 30kt TAS into klAS is very much into the world of variables. but as a guide line use 22klAS. Therefore if the initial height difference is 4000ft and the descent time 10min (70nm). then a differential of 24+22klAS (6X4+22)=46klAS will produce 5 nm separation. The~e rule of thumb figures are based on aircraft flying similar profiles: in practice they rarely do so. ATC will therefore need to apply trimming changes of speed: some aircraft will gain; some will lose. Hopefully it will have all happened more smoothly, though someone might wonder if you took the 45 klAS off the lower aircraft in our example: I leave you to think about this. The En Route Situation In the en route situation the emphasis shifts away from trying to keep aircraft apart. towards the need to get as many aircraft as possible to their optimum flight level and speed. Modern big jets tend to fall into three speed groups in the cruise: M 0. 72. M 0. 78 to 0. 8. and a few M 0.82 to 0. 85. Some of the newer aircraft are flying at slightly higher levels. but within each flight level there are always differing THE CONTROLLER/DECEMBER 1987

speed requirements. The only way to optimize this permutation is for ATC to find out what variations the pilots are ?.ble to ~ccept. and by changing the Jigsaw picture around to their mutual benefit. At the higher levels M 0.01 equates to approximately 6 kt TAS, and a useful rule of thumb is: 30 kt TAS speed differential = M 0.05 = 5 nm in 10 min (or in 75 nm distance flown at 450 kt TAS). The cautionary note here is that if the aircraft are both high and heavy they are not going to be able to slow down or speed up by very much: if heavy. the maximum acceptable change in Mach number will be about M 0.02. A typical problem is when one aircraft is catching up another: if the leading one is at M 0.72 and the other at M 0.76. this gives a TAS differential of roughly 24 kt. If they are 20 nm apart now they will be able to fly for 30 min before reducing to 8 nm separation. i.e. 'absorb' 12 nm at 24 kt = 0.5 hour. The Changing Pattern of General Speed Limits As aircraft descend from their cruising levels they move into the wider part of their flight performance envelope (with a general minimum of 250klAS) where. very roughly. a 40 klAS variation gives a TAS variation of 55 kt. Below 10,000ft the IAS variation normally becomes restricted on the high speed side (probably to 250 klAS) by terminal area speed restrictions. and also by good airmanship (there is a lot of traffic around). At 5000ft a variation of 30klAS will produce a TAS change of 35 kt. This reduction in readily available TAS changes at the low levels is largely offset by the lower airspeeds. i.e. 30 kt (TAS) will gain or lose 5nm in 10min at any height but at the low levels it is accomplished in less distance. e.g. 45 nm instead of the 65 nm at FL220 (or 75 nm in the cruise). The other main point concerns the allowance for relative height difference in that, at the low levels. the rule of thumb allowance becomes 4 to 5 klAS per 1OOOft (in place of 6 I 7 klAS per 1000ft). Descent Without ATC Intervention The intention of this paragraph is to show what can be done without ATC intervention. and shows that a stream of aircraft arriving at 2min intervals could fly to Top of Descent (TOD) at 420kt (TAS). all descend on similar profiles and at similar speeds. and then turn off the runway at 20 kt (TAS!), all without ATC (or computer) involvement. The speed differential

absorbed is 400 kt; sounds impossible on that basis. You might call this an extreme case of ATC Doppler, i.e. a Doppler in which the frequency remains constant, but the wavelength changes. Einstein's theory of relativity will not provide the clue to how this descent works, but the Doppler comment will. When Applying Speed Control, Remember ... 1. As aircraft level off at the same or similar levels that your speed restrictions will require changing: tell aircraft what to do before they level off. 2. If in doubt and in particular above FL280, ensure that the pilot concurs. Do not use speeds less than 250 klAS on aircraft descending from FL280 unless the pilot really does concur; remember that aircraft climbing to this level in a maximum weight en route climb will require minimum speeds nearer 290klAS. When descending below FL140 speeds down to 220klAS may be freely used: 210klAS may also be used, but only on certain types of aircraft: with these speeds the aircraft can be kept 'clean'. 3. Bear in mind TMA speed restrictions when operating the TMAs (terminal areas). 4. Make sure to add the word knots to any speed instruction (to avoid confusion with flight levels). 5. ¡only control. and especially only restrict. when you have to: this also applies to flow control.


A third Tokyo airport is in the plans of the Ministry of Transport. Although both Tokyo lnt'I Airport at Haneda and the New Tokyo lnt' I Airport at Narita are being expanded, MOT believes their capacity will be outstripped by the rapidly increasing traffic. Construction is forecast to begin in '97 in order for the airport to open by '07. As presently planned, the airport will be built on reclaimed land in the Sagami Bay in the southern part of Kanagawa Prefecture, in the top of the Boso Peninsula or in the Sea of Kashima. ('Air Transport World' 10187)


Accident and Incident Investigation The Directors at IFATCA '87 accepted the following to be the Federation's Policy on Investigation of Accidents and Incidents: • When an accident or incident is alleged to have occurred where the actions of an air traffic controller may have had a bearing. the controller is to be immediately removed from control duties pending the results of a preliminary investigation. The removal is mandatory. without prejudice. and is non-disciplinary. • Written controller statements are to be used only to assist in the investigation. and are not to be used for disciplinary purposes.

• An Investigative Board is convened. normally within seven days of the occurrence. The proceedings of the Board should be comprised of individuals who have operational experience in air traffic control. • The controller has the right to be accompanied by a representative of his choice at any hearing. inquiry. or investigation into any air traffic control incident or accident. • The controller and his representative have the right. prior to appearing before any Investigative Board. to review all relevant video and audio recordings and computer readouts of air traffic control operations where available. In addition. the controller and his representative shall be provided with copies of transcripts of all relevant audio recordings prior to appearing before any Investigative Board. • The circumstances prompting the investigation and the perceived operational situation immediately prior to the alleged incident/ accident shall be made available to the controller and his representative prior to any questions being put to the controller. • The controller and his representative have the right to make representations and direct questions to the official in charge of the investigation. •

No controller involved in an incident or accident enquiry shall suffer loss of pay during all aspects of an investigation.

• Audio and/ or visual recordings and transcripts of air traffic control communications are intended to provide a record of such communications for use in the monitoring of air traffic control operations. and the investigation of incidents and accidents. Such recordings are not to be used to provide direct evidence as such in disciplinary cases. or be used to determine controller incompetency. •

Reports regarding air traffic control incidents or accidents issued by any Investigative Board shall not determine or apportion any blame or liability.

• The controller and his representative shall be provided with the opportunity to review and comment on the Report. If the controller disagrees with any portion of the Board's Report. he can request in writing that a review be conducted. This review should be conducted by a Senior Air Traffic Control official who was not a member of the Investigative Board. • Any air traffic controller involved in an air traffic control incident or accident shall receive full psychological counselling services. if the controller so chooses.


INMARSAT Transmits Test SATNAV Signals INMARSAT began transmitting position determination and navigation signals in November 1987 as part of an on-going trial aimed at the eventual implementation of an INMARSAT radiodetermination satellite system (ROSS) capability. INMARSAT is the 50 membercountry cooperative that operates 9 geostationary satellites to provide maritime. aeronautical and other mobile communications services worldwide. The scheduled transmissions consist of spread spectrum signals to be generated by direct modulation with a pseudonoise (PN) sequence at 1.023 megabits per second. A comparison of such signals from several sources enables the precise position of a receiver to be determined. The PN sequences are similar to those employed by the Global Positioning System (GPS). the US Government navigation scheme which depends on polar orbiting satellites. That similarity offers two advantages. One is that those particip~t(ng in the trials will be able to use mod1f1ed existing GPS receivers to receive the signals. The other is that. if the trials are successful. manufacturers of satellite communications terminals would be able to combine or integrate navigation signal reception capability from both GPS and INMARSAT satellites into their designs. By carrying PN signals on a regular basis. INMARSAT could improve the coverage of GPS as well as provide integrated navigation services with its two-way communications capabilities. including the provision of integrity information and differential correction data. Test transmissions will be at a variety of power levels in order to determine the minimum power which provides effective performance and to demonstrate that such signals can coexist with communications signals in the same band. Initial transmissions will be in the INMARSAT Atlantic Ocean Region. The PN spread spectrum signal is one example of a general category of wideband signals which could form the basis for a geostationary satellite navigation system. Another such category. called coherent narrowband carriers. will be tested over the INMARSAT system in future.


4 th Joint European Meeting Lisbon, 10/11 October 1987

European Skies in Trouble Problem Area No. 1: United Kingdom The 23 European Member Associations of the International Federation of Air Traffic Controllers' Associations (IFATCA) in their meeting in Lisbon 10- 11 October 8 7 expressed concern regarding the current situation within the British air traffic control system. For many years the UK was considered to have one of the best equipped air traffic control systems in Europe. The continual failure of major computer equipment in the oceanic

Crash ¡Accidents do not happen, they are caused .. .' Nothing new, of course, but still worth mentioning from time to time. The Swiss Pool for Aviation Insurance do just that in their new film presented to the public in June 1987. Based on the evaluation of some 350 accident investigation reports six ¡ model' cases were reconstructed from the pilot's point of view. In a mountainous area, such as Switzerland. proper flight planning which includes detailed weather briefing - is of paramount importance for every VFR pilot. Accepting advice from local pilots or aerodrome chiefs/ ATC is another item a pilot not familiar with the topographical layout or the rapidly changing weather conditions in the mountains should never consider unnecessary. All accidents shown in this film were avoidable by sticking to some of the basic rules: Plotting the flight path with tracks and times (which in the example shown would have prevented the pilot flying into a valley without exit); Getting up-to-date weather information from all available sources (which would have led the pilot to choose another route of flight or to THE CONTROLLER/DECEMBER1987

and London areas combined with a large increase in overall traffic is resulting in the reduction in the efficiency of the British air traffic control system and a lowering of the morale of the air traffic controllers. The European Member Associations of IFATCA support the Guild of Air Traffic Control Officers in calling for an independent inquiry into the UK air traffic control system.

Problem Area No. 2: Greece The present air traffic control system in Greece is out of date and quite inadequate for the amount of traffic that has to be handled. The status of the air traffic controllers is continuously decreasing.

The pressure on the controllers to work under civil mobilization. that is still in force, has an adverse effect on the provision of air traffic control. Promises of the Greek Government to stop civil mobilization were not fulfilled. The European Member Associations of the International Federation of Air Traffic Controllers' Associations feel that the situation is too critical and that drastic measures have to be taken by the Greek Government in order to raise the level of the air traffic control system and controllers' status in Greece. This is required to achieve the efficiency level of comparable European air traffic control systems.

abstain from taking off at all in The new Ferranti Aeronet national some other cases shown); switching center will replace the Keeping two-way communication existing Ferranti Argus 500 AFTN with ATS and immediately report- Message Switch currently in opering when getting into a difficult ation at London Heathrow Airport. situation (e.g. finding oneself on "The United Kingdom center is one top of a solid cover of clouds with of the busiest AFTN message switches no possibility of descending VMC. in the world and has a significant role and getting low on fuel. as shown within the international civil aviation in another case). network as the main intercontinental The film addresses itself mainly to link between Europe and North private pilots and flying clubs but is America. with European links to Poralso of interest to controllers - who tugal. France, Holland, Belgium, Iceland, Ireland and other links to very often are a last resort for help. The film is available in French and Iceland and Canada. The new switch will support the German, also as video tape in most new 'Common ICAO Data Interstandards, from Swiss Pool for Aviation Insurance, P.O. Box 357, CH- change Network' (CIDIN) procedures which allow higher transmission 8401 Winterthur, Switzerland. speeds to be used and a much wider Bernhard Ruthy range of aeronautical data to be carried over a common network. The canter will also support telex facilities via the British Telecom telex network and also provide a comprehensive range of meteorological Ferranti Wins Heathrow facilities including automatic bulletin preparation and broadcast. AFTN Contract Ferranti Computer Systems Limited has been awarded the contract by the Civil Aviation Authority for the United Kingdom's new Aeronautical Fixed Telecommunications Network (AFTN) Message Handling System.

The begiinning ef wisden:u is calling a thing by nts right name. (Old Chinese proverb)


Meeting o th Executive OU



H. Harri Henschler , Editor

The last weeke nd of September 19 87 saw all membe rs of the Exec utive Council and the Editor assembled in Lisse - a pleasant town some thirty minutes drive from Sch iphol Airport for the 1987 Council Meeting. The venue for the gathering, w hich was preceded by a meeting of the Executive Board, was the · Congrescentrum De Nachtegaal Van Lisse·, an ideal location since it allows flexible meeting hours. Thus, t he first day's discussions carried on we ll into the evening and the meeting did not w rap up until after 18 00 on the final day. The participants did, however, have an appreciated extra hour of sleep, or after-hours discussion, due to the return in The Nethe rlands to Standard Time from Summer Time. At the formal openi ng of the Council Meeting Erik Serm ijn , Presiden t and Chief Executive Officer , greeted and welcomed the participa nts and expressed satisfaction that, again, all members of the Council wou ld be able to attend this , the 6th Council Meeting of IFATCA.

Erik Sermijn stated that the emphasis of discussion would be, as in the past, on Report s of the Regional VicePresidents (RVPs) Developments in relations with other organizations The Future of the Federation The Meeting began with report s and updates on all activities of the Executive Board and the Editor since the previou s Council Meeting. All required actions , attendance at meeting s of the IFATCA Standing Committee s, meetings with representatives of other international organizations, and liaison visits, had taken place and the affairs of IFATCA, in all aspect s, are in order and in hand .

Reports from the I FATCA Regions Africa East (AFE) The RVP, Steve Mworia, reflected w ith satisfaction on the recent and successful Annual Conference rn

Nairobi. There was. however , some disappointment that the flurry of activity and interest in IFATCA and the profession. expected after I FATCA ' 87 , had not yet mate rialized in this area of the world where improvements are still required . Steve is planning a number of visits to member and non-member associations (MAs and non-MAs) in the Region, and he will continue his efforts to organize a Regional Meeting .

Africa North (AFN) Abou Y. EI-Karimy , RVP AFN , touched on some of the problems air traffic controller s are facing in some countries in the area where national law does not permit the formation of professional associations. Member associations· previou s problem s have been , or should soo n be. solved and the 4th Regional Meeting was scheduled for Casablanca, Morocco , during Novembe r 1987 . Contacts had been established with controllers in a number of countries where no associations yet exist and will be followed up. A program of exchange visits of repre sentati ves and member s of th e AFN MA s is in the process of being finalized . Africa West (AFW) Thi s w as the fir st regular Council Me eting for Emperor 0 . On asanya. RVPAFW . Even so. IFATCA matter s in AFW are in hand . contacts wit h member and non -member associations are being furthered. and a Region al Me eting is planned for 1988 in Nigeria. Relation s with other organization s. in particular the reg ion al ICAO repr esent ation , cont inu e to impro ve .

/FATCA President and Executive Vice-President, Administration 26

Asia (ASI) RVP Eddy Chu reports good contacts and ongoing comm uni cat ion s wit h MAs and non-MAs in t he region as we ll as w ith ot her organ izations , part icu larly the RVP Asia East of the Internat iona l Federation of Air Line THE CONTROL LER/ DECEMBER 1987


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Pilots' Associations (IFALPA). This is a region where civil aviation activities are increasing at an accelerated rate and which deserves special attention. A joint Regional Meeting Asia/ Pacific is being organized by the Japanese Member Association in December 1987.

Pacific (PAC) The RVP, Neil Vidler, detailed changes and possible upheavals within two countries ' air traffic control systems , Australia and New Zealand, brought about by pending or ongoing privatization of the systems . These developments must be closely monit ored to ensure continued and future adherence to the ILO (International Labour Office) Recommendations regarding air traffic controllers. Major problems are also envisaged to confront a number of very small nations in the Pacific area where, as in As ia, civil aviation is expanding rapidly, and lessthan-adequ ate levels of equipment technol ogy and controller expertise are faced. The RVP will closely mon itor all aspects of these developments, as possible, through liaison visits and personal contacts. Caribbean (CAR) Vivian Hanenberg, RVP CAR, expressed sati sfaction with the state of affairs in the region and with the liaison visit on behalf of the Executive Board, of the Executive Vice-President, Finance , Tord Gustavsson, in May 1987 . There is satisfactory involvement and contact with MAs , non-MAs , and administrations . However, problems of lack of full appreciation and recognition of the profession by some governments still exist and must be overcome, working conditions and equipment need to be improved . The 4th Regional Meeting is scheduled for December in Barbados. Europe Central (EUC) For Kurt Kihr, RVP EUC, the Lisse meeting also meant his fi rst part icipation in a Council Mee ting. He outlined his regiona l activities and emphasized the need to continue to improve communications at all levels. There had been a number of meetings with and between MAs in the region, contacts with non-MAs are being established or deepened . Of particular concern was the long-standing prob lem of civil mobi lization of air traffic contro llers and pilots in Greece , it is hoped a solution will occur in the near future , and the fact finding miss ion by the Executive Vice-President, Professiona I, Wim Rooseman, to Athens was successful and appreciated . 28

Regional Vice-Presidents (I to r) CAR, NCA, AFW, PAC, EUW, EUC, SAM, AS!

A joint Regional Meeting of Europe West/Central was scheduled to be held in Lisbon in October 1987.

Europe West (EUW) The RVP, Philippe Domogala, reported on numerous problems MAs in his region are facing. Most of these are caused by signif icant traffic increases, a shortage of staff , equipment shortcomings and non-responsive administrations . Controllers in France and Spain, neither of which are affiliated to IFATCA, felt they had to resort to strike action . Cooperation with other organizations, particularly the ICAO Regional Office in Paris, is most satisfactory and t he Portuguese MA is hosting, as stated above, the 4th Joint Regional Meeting in Lisbon. North and Central America (NCA) Hugo Esquivel A., RVP NCA, reported to the Council Meeting, his first, that IFATCA matters are proceeding satisfactorily in the region . Contacts with the Member Associations are being maintained , many MAs are engaged in ongoing efforts to improve working, staffing and equipment conditions using the relevant I LO Recommendations . The RVP has conduc ted and is planning liaison visits to MAs , and a Regional Meeting is planned for the near future . South America (SAM) As he did at previous meetings, the RVP SAM , Mario Salazar, reflected on the many probl ems MAs in his region continue to face, to the extent even, th at a negative impact on the functioning of the MAs themselves can be reported. In a number of countries in the region conditions for con-

trailers are so unsatisfactory that association work and involvement must take second place to ensuring one's livelihood, a regrettable circumstance which does not contribute to the enhancing of safety in aviation . There is a lack of firm information on details of preparation for the 1988 Annual Conference in Rio de Janeiro, and the RVP SAM was charged with conducting a fact-finding mission. As in the past, some Member Associations are faced with severe financial problems caused by devaluation and inflation, and avenues to overcome these problems are being explored.

Summary There were common threads throughout the reports from the IFATCA regions, varied as they are . The great majority face now, or will face in the very foreseeable future, a shortage of qualified controllers brought about either by insufficient training, inability to retain qualified controllers or failure to properly prepare for the tremendous increase in air traffic, and pending retirements . Another obvious problem, either now or before too long , is the absence of adequate equipment, where the definition for 'adequate ' can range from basic communications to the requirement to replace and modernize aging computerized systems .

Relations with Other Organizations The lengthy and detailed discussion on this important item can best be summarized by stating that, on the whole , good and growing relations THE CONTROLLER / DECEMBER 1987

Executive Secretary , Executive Vice-Presidents Technical and Finance, RVP NCA (I to r)

exist with other organizations of interest to IFATCA. In some regions such relations are of long and proven standing, in others they are only now being established or firmed , but with very few exceptio~s which will be followed up, they exist. A number of recent developments are worth special mention: The ICAO Study Group on the Manual Concerning Interception of Civil Aircraft (MICA) has begun its work . The IFATCA nominee to the group which consists of representatives of six states and nominees from IFATCA. IFALPA and IATA (International Air Transport Association) is Harri Henschler. IATA convened, in late September 19 8 7, a conference on System Demand and System Capacity in Montreal. IFATCA was represented by its Liaison Officer, T~chnical and Operational, Jack Pinsent . A_n article on this conference 1s planned for inclusion i_n a future issue of 'The Controller . The ILO continued, on invitation, to conduct studies into working conditions of air traffic controllers in a number of countries . These studies provide valuable information and assist in detecting possible problem areas . The Principal Officers of IFALPA and the Executive Board of IFATCA had scheduled a joint meeting for October 1987 where items of common concern and mutual interest were to be discussed .


RVP AFE and Executive Vice-President , Professional (I to r)

Future of IFATCA


As one may have expected , this item caused a great variety of concerns , suggestions and ideas to be brought forward and be discussed . There was extensive examination of the responsibilities of the Executive Council and its role in the Federation , and its members renewed their commitment to keeping the flow of information open; a joint approach to problem-solving, and adherence to the Federation's Constitution and ByLaws as the integral part of IFATCA's functioning. The wide-ranging discussion eventually identified three areas of major future concern to the air traff ic control profession and the Federation . Considerable effort , time and resources may be required to adequately prepare to face the challenges wh ich these major items may pose : Future technology ; Legal liability of the air traffic controller; Improving the conditions in all aspects of air traffic controllers in developing countries . It is obvious that, after years of discussion of the future of IFATCA w ithin the Executive Board and at IFATCA '87 , three items of considerable complexity and great impact on controllers and aviation were singled out for special attention . This does not ind icate, of course , that other areas of concern would be neglected . It means , however , t hat all components of IFATCA will be called upon to contribute to facing the challenges posed by future technology, controllers' legal liabili ty, and the continuing struggle to achieve acceptable standard s and the recognition of the profession in developing countr ies.

The participants expressed to the Executive Vice-Pres iden t, Professional, Wim Rooseman , who had prepared and organ ized the Exec utive Council Meeting , their gratitude for his many efforts. It was dec ided that, if possible, the next Counci l Meeting should again be held at De Nac htegaal Van Lisse on 24 and 25 September 1988 . Special than ks were also conveyed to the Vereniging Het Nederlandse Luchtverkeers leide rsgilde, the Netherlands Guild of Air Traffic Contro llers, whose hospitality and efforts greatly contr ibute d to a very success ful meet ing . The part1c1pants left Lisse thoroughly briefed on developments, updated on present and future activities and with a renewed commi tment to further enhance the profile and involvemen t of the Federation in their areas of respon sibility and the IFATCA Regions.


Gatwick airport, London, has overtaken Kennedy Airport, New York, in interna tional passenger numbers to become the world ' s second-busiest international airport , BAA claimed in London . BAA said that in the 12 months ended April this year , Gatwick handled 15.85 7 ,000 international passengers. almost 100,000 more than JFK. ('Air Transport World ' 101 87 )


Airlines of the World: Qanta Qantas Airways was registered as a compan y on November 16th . 1920. making it the wo rld 's second oldest commercial air line. In those days it was known by its f ull name. Queensland and Northern Territo ry Aerial Service. after the area of the vast Australian outback that the airline intended to service. Those beginnings bred the exemplary safet y record and the long flight sec t ors that remain the norm today . Qan t as continues to serve Australia, carrying its populat ion along the lon g ha uls to foreign countries and ea rnin g valuable fore ign exchange by bringin g in increas ing numbers of touri sts, servicing engines and airc raft fo r air forces and airlines and sel ling exper tis e and computer software. In Novem ber 1922 . w hen the airline ' s f irst regu lar service between Clonc urry and Charle ville in Western

Queensland took to the · air. the fleet consi sted of two ·wood and wire · biplanes . an Avro 504K and a BE 2E . Now the airline operates a fleet of 30 aircraft, including 24 Boeing B 7 4 7 Jumbos in four different versions and six tw in-engined Boeing B 767s. In 1922 the BE 2E took almost 30 hour s t o fly 5 7 7 miles from Charleville to Cloncurry , including an overnight st op at Longreach . In little more than 20 hour s toda y, the late st Qantas Boe ing B 7 4 7-3 00 Exten ded Upp er Deck aircraft can fly from Sydney to London , stopping only at Bombay . Qanta s' experience on these long fl ight sectors began to develop in 193 1. w hen the airline st arted carrying mail as far as Darw in on a joint ope rat ion w ith Briti sh-own ed Imperial Airways. In 1934 . Qantas fle w the Brisbane-Darwin sector of the regular services to London. taking over the

Darwin-Singapore sector in the following year . Qantas ' headquarters moved from Brisbane to Sydney in 1938 when the airline introduced the famous Short 'Empire' flying boats. connecting Sidney with Singapore until the Japanese advance in World War II cut the link in 1942 . It was then that Qant as' real reputation as a long distance carrier developed as the airline flew Catalina flying boats , and later Liberator and Lancaster bombers between Perth and Ceylon . The Catalina Service crews awarded themselve s the · Order of the Doub le Sunrise ' because crew and passengers saw the sun rise twice during tho se monumental over-water flight s. The Australian Government bought a half- share in Qanta s in 1946 , purchasing t he airline's outstanding shares in the following year. The Government then named Qant as as Au st ralia 's overseas airline. Although the Government owns all Qantas· share s, Qanta s is still struc tured as a company, incorporat ed under the Companies Code of the St ate of Queensland. Qanta s is not a statutory authority or a Government Department.



One of Oantas ·s first aircraft . A vro 504 K



······· ··

Qantas Boeing 74 7-300,

Extended Upper Deck

One of Qantas ·s first offices, Long reach, Central Queensland, late 792 7 THE CONTROL LER/ DECEMBER 1987


To the Editor Dear Sir, Your 3 / 87 issue describes a midair collision near Hamilton Ont. in June 1984 . The article twice points out that the relativ e bearing of the two aircraft was unchanging during a period prior to the collision, and attributes this effect to the similarity of the two airspeeds . In fact whatever the airspeeds, two aircraft in straight line flight on a collision course at constant speeds will have an unchanging relative bearing . In theory , given these straight-line , constant speed conditions, this constancy of bearing is a necessary condition which can be used to test for collision risk. In practice, even in some situations where the miss-distance is appreciable, the rate of rotation of the sightline is undetectably small until shortly before closest approach . It should be noted that if one or other of the aircraft is changing airspeed or departing from straight-line flight chang ing relative bearing does not guarantee that there is no collision risk. Yours faithfully, Stanley Ratcliffe BSc, FRIN, FRAeS, Malvern, Worcs. UK (The Controller ' welcomes letters from readers wishing to share their comments, observations and concerns . The Controller ' reserves the right to edit letters for length. hhh) Qantas Headquarte rs 7986.

The Qantas In ternat ional Center. Sydne y.

Lockheed Constell ations , Supe r Constellation s and Douglas DC4 Skymasters were used t o start services across the Pacific , and in 1958 a Round-the -Wor ld service fr om Au stralia was comme nced . Qant as began a long and co ntinuing associa ti on with Boeing wh en the fi rst Boeing 70 7 jetliner entered service in 1959 . The Boeing B74 7 'Ju mb o' entere d service in 19 71 and until t he rece nt introduction of Boeing 7 67 Extended Range jets , w as th e only aircraft type operated by Qant as. Qantas has become imp ortant to the Australian econom y . The airline's foreign exchange earnings contribute more than $4 billion. The airline competes against more than thirty other international carriers, winning the lion's share of traff ic to and from Austra lia. There are now Qantas services to Southern Africa , India, Singapore, Bangkok , Hong Kong, Japan, Kuala Lumpur, the Pacific nations, New Zealand, China . 32

the Philippines, the United States, Canada, Europe and the United Kingdom . Qantas services all of Australia ' s eight international airports , including t he new north Queensland gateways of Cairns and Townsville . These two airports give excellent access to the Great Barrier Reef and resort islands, wi t h good connections to the Aust ralian inland and capital cities. Qantas eng ineers maintain aircraft, aviation systems and engines for t he Indonesian Air Force, Saudia, CAAC, Boeing, The Royal Australian A ir Force and Varig. Computer systems developed by Qant as like QUADS and ASPIC are now sold internationally and have been bought by many airlines including Brit ish Airways , Aer Lingus, Varig, Ansett, Japan Airlines , Thai Internat ional , Kuw ait Canadian Airline s Int ernati onal and Air New Zealand , to hand le t heir passenger bookings and flight cater ing.

In coming issues of -'The Controller' - Report on the ICAO Future Air Navigation Systems Group - Global Air Traffic Control System Voice Driven ATC Simulator - High Blood Pressure


Corporate Members of IFATCA AEG Aktiengesellschaft, Ulm, FRG Ansafone Electronic s.p.a., Pomezia, Italy Cardion Electronics, Woodbury, USA CAE Electronics Ltd., Saint-Laurent, Canada Cecsa Systemas Electronicos SA, Madrid, Spain CISET S.p.A., Rome, Italy Cossor Electronics Ltd., Harlow, UK Dictaphone Corporation, Rye, USA Eaton Corporation, AIL Division, Farmingdale, USA Engineering and Economics Research Technologies, Ottawa, Canada Ericsson Radio SystemsAB, Stockholm, Sweden Ferranti Computer Systems Ltd., Cwmbran, UK Hollandse Signaalapparaten B.V., Hengelo, Netherlands EB TeleCom, Nesbru, Norway Jeppesen & Co. GmbH, Frankfurt, FRG Jerry Thompson &Associates Inc., Kensington, USA Litton Communications Switching Systems, Frei burg i. Br., FRG Marconi Radar Systems Ltd., Chelmsford, UK McDonnell Douglas Electronics, St. Charles, USA Mitre Corporation, Mclean, USA PhilipsTelecommunicatie en Data Systemen Nederland B.V., Hilversum, Netherlands Plessey Displays Ltd., Weybridge, UK Racal Avionics Ltd., New Malden, UK Raytheon Canada Ltd., Waterloo, Canada Schmid Telecommunication, Zurich, Switzerland SCICON Ltd., London, UK Selenia lndustrie Elettroniche, Rome, Italy SEL-Standard Elektrik Lorenz, Stuttgart, FRG Societe d'Etude et d'Entreprises electriques, lssy-les-Moulineaux, France Sofreavia, Paris, France Software Sciences Ltd., Farnborough, UK Thomson-CSF, Meudon, France Westinghouse Electric Corp., Baltimore, USA

The International Federation of Air Traffic Controllers¡ Associations would like to invite all corporations. organizations. and institutions interested in and concerned with the maintenance and promotion of safety in air traffic to join their organization as Corporate Members. Corporate 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 Controller' is offered as a platform for the discussion of technical and procedural developments in the field of air traffic control.

IFATCA - The Controller - 4th Quarter 1987  
IFATCA - The Controller - 4th Quarter 1987