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Aviation History
1978
1978 - 0264.PDF
450 FLIGHT Internationa/, 18 February I97B Letters Leave traffic sequencing to the controllers SIR—While supporting the general idea of Flightwatch, I must take issue with Capt Proctor's suggestion (February 4) that aircraft so' equipped "could sequence themselves near air ports." The problems of allowing for changing courses, airspeeds and heights would impose an intolerable workload on the crew, whose attention should be directed towards the safe operation of the aircraft, adherence to the published instrument approach, and compliance with ATC orders. Sequencing can only be performed safely by experienced personnel equipped with a fixed-base radar, working in a calm environment, and with no other prime duties. Experi ence with seaborne radar has proven that the task of manoeuvring relative to another moving target is not as easy as it might at first seem. I doubt that Flightwatch would be SIR—Having just finished a partic ularly unusual night shift as a radar controller at London ATC Centre, I was perusing the February 4 Letters pages before getting my head down. Imagine my surprise when I read Capt Proctor's letter about self- sequencing. At 0655 that morning there were about 25 jet aircraft inside the Lon don Flight Information Region bound aries and heading for the four Heathrow stacks (i.e. all within about 15-20min flying time of the OCK, BIG, LAM and BNN beacons). On my sec tor (Lydd on 127 1MHZ) there were between 0655 and 0710 four Gatwick, four Heathrow and one Southend in- bounds; one departure each from Gatwick, Heathrow and Mildenhall, all climbing eastbound to Dover; two eastbound overflights for Dover; and a Learjet climbing from Boulogne to Brookmans Park for Glasgow. This traffic presented a fairly normal load which any radar controller at LATCC could have handled, provided that he was doing the controlling. Imagine the radar picture if Capt Proctor and his airborne colleagues had been "sequencing themselves near the airports" or "safety separat ing themselves closer than ATC permits." 109 Blagrove Drive, JOHN NEWMAN Wokingham, Berks Correspondence for these pages should be addressed to the Editor, Flight International, Dorset House, Stamford Street, London SE1 9LU, and marked "For Publication." Letters should preferably be no more than 300 words long. We reserve the right to edit all correspondence. of very much value in congested terminal areas unless fitted with an auto-alarm. Crews are too small and too busy these days to be able to monitor such a system thoroughly. Filters would be needed to prevent unnecessary conflict alerts of depart ing and arriving aircraft On the other hand, after cutting down the height, range and direction of the conflicts considered, the warning time before a genuine potential collision might then be too small to allow avoiding action. Flightwatch might be of more value as an ATC monitor en route, but for the following reason I doubt that worthwhile savings could be made, as suggested by Capt Proctor. Flight watch is only workable through ground-based radar. With no differ ence between the accuracy of the ground and Flightwatch displays, therefore, what could possibly be done SIR—We were amused, not to say amazed, by Capt J. D. Proctor's letter about the use of Flightwatch for self- sequencing. Shouldn't it have appeared in Straight and Level instead? His suggestion does however merit con sideration, provided of course that throttles, rudder pedals and a variety of other aircraft controls are fitted SIR—Sensor for January 21 said that in the CFM56 engine the French already had 30 per cent of a new 160-seat European aircraft. We find it difficult to understand how this figure has been arrived at, and are con cerned that it makes the CFM56 look very expensive. There are many ways of looking at the engine percentage of the value of an aircraft. Although, as far as I am aware, the price of the European aircraft has not been fixed, we can find no way that the engines could be more than 20 per cent of an airline's initial investment in this aircraft, even assuming ultra-conservative initial spares purchases. Snecma contributes half of the CFM56, so at less than 10 per cent of the aircraft and spares, its share is obviously a long way below 30 per cent. Further, we believe that it is quite wrong to include the engines in any discussion of sharing arrangements by partners planning to develop an aircraft. Development of the CFM56, taking place quite separate from any to reduce separation standards? Either we accept a minimum radar separation or we don't. If you haven't got radar control, then you haven't got Flightwatch. So for the routes on which fuel savings would be worthwhile, such as the oceans and long-distance non-radar sectors, you would be back to pro cedural separation anyway. How about a Flightwatch able to display other aircraft through interro- gator/responder equipment, independ ent of ground-based radar? More ex pensive no doubt, but it would have the advantage of monitoring the situation anywhere, and might reduce longitudinal separation from the 15min prevailing on many routes. Even with frequent position-reporting points, it would allow more aircraft up into the more economic levels. 22 Martin's Drive, CAPT I. H. SHEPHERD Wokingham, Berks to the radar controllers' consoles. If he considers ATC separations ex cessive, perhaps he should discuss the matter with that stalwart body the Airmiss Working Group. Air Traffic Control, B. J. MCCARTNEY Heathrow Airport R. E. DAWSON P. WILSON P. J. BISH European airframe programme, is over halfway to completion. We ex pect the engine to be used in many applications apart form the new Euro pean twin 160-seater. There is only one reason for using the CFM56 on this aircraft: it is the best for the job. History shows that as soon as competing engines are available, air craft manufacturers waste as little time as possible in offering their cus tomers a choice of powerplant. Thus, what starts as a 20 per cent share of income from sales for the airframe company can very soon fall to a half or a third of that if it has to count the engine. In summary, CFM International will sell to any aircraft programme and essentially has the same rights and obligations as any other vendor, regardless of where its product is made. Our prime obligation is to pro vide value for money, which the CFM56 does. CFM International, B. I. GORDON 160 Avenue de Versailles, (Marketing Paris manager) How the engine-makers share in the collaborative cake
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