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Aviation History
1961
1961 - 1636.PDF
740 FLIGHT, 9 November 1961 SURVET ON Tuesday of last week, at Hounslow, Middx, the BritishAirline Pilots' Association held a forum on automaticlanding. Several of the principal manufacturers concerned gave explanatory lectures and the pilots expressed some forcefulopinions on the subject. Introductory remarks by Capt W. D. Wellwood. chairman of BALPA. and Capt M. W. Broom, forumsub-committee chairman, showed that the pilots were determined to make their requirements known at the planning stage. Pilots,said Capt Broom, were consumers but not customers; they had to use the equipment, but the operators who paid for it had not BALPA Discusses Automatic Landing necessarily a knowledge of pilotage. Moreover, there was a strongfeeling that teething troubles and insufficient training discouraged pilots from making use of such automatic devices as approachcouplers. These were still not used in the great majority of poor- weather approaches. It was necessary to launch a publicity pro-gramme for pilots about automatic landing; and this was one of the main objects of the forum. Capt Bressey Opens the Attack While the manufacturers set a soothing and informative tone in their speeches, Capt P. E. Bressey, on behalf of BALPA, deliber- ately launched a rather provocative attack on automatic landing. Pilots were fairly happy about the progress with automatic landing itself, he said, but not at all happy about the overall way in which the problem was being tackled. They had had unhappy experiences with certain new equipment introduced in recent years. There were four main reasons for lack of enthusiasm for automatic landing:— (1) Pilots tended to view with suspicion the introduction of any newdevice or procedure tending to undermine their powers of command —though once it has been proved successful in everyday operationson a world-wide basis they were willing to accept it. Past examples were GCA and automatic approach. (2) Again, with recent history very much in mind, pilots found thatsuch devices tended to be introduced into service before initial teething troubles were overcome, and it was usually the pilot who suffered duringthis 'running-in"' period. Piecemeal introduction of autolanding might mean that the full system would never materialize. (3) From pilot participation in various working parties and committeesat present dealing with autolanding problems, it appeared that insuf- ficient attention was being given to the overall problem. (4) Even if answers to the above three questions could be found, itstill appeared that automatic landings were going to be possible only with some aircraft on some runways at some airfields under someweather conditions. Capt Bressey then enlarged on these four points, as follows. Delegation of Command The pilot was held ultimately respon-sible for a very valuable capital investment, the personal safety of his passengers, and was not unmindful of the fact that if anythingdid go wrong he was at the end which hit first. When GCA was going through its initial teething troubles a pilot could always havesome check as to what the controller was doing with him by cross- reference to some other navaid. He could set his own limits, andif he was not happy at the way things were going, he could break off the approach and divert. Similarly with approach couplers—the pilot monitored the performance by his instruments and in many cases his critical height was higher with an automatic couplerthan with manual flying. "So far," continued Capt Bressey, " a pilot has never allowedany aid or device to get his aeroplane into such a dangerous position that he was unable to extricate it from this situation by taking overmanual control. Now for the first time he will be asked to allow a series of black boxes to manoeuvre his aeroplane right down tothe runway surface. Unless he has full visual reference to the ground at his critical height he will from then on have little or nomonitoring information; and in the event of a malfunction of the equipment below this height his chances of completing a successfulovershoot will probably be slim. This means a complete reversal of his basic approach to fundamental matters of safety which has beendrilled into him for 20, 25 or 30 years. Habit dies hard. Could a monitor help if something went wrong at 100ft? How could pilotskeep in practice for manual landings? What would happen if automatics were the only means of landing ?" Teething Troubles The more complicated the device, the longerthis period seemed to be, and this new device was nothing if not complicated. Equipment which worked perfectly in the laboratory,or under the carefully controlled environment of a test station, failed lamentably when it had to "rough it on the line," in anaeroplane which might be flying some 15 hours a day in and out of extremely varied climatic conditions (when standing on theground at transit stops), and subject to maintenance by personnel new to the equipment. ••Admittedly," continued the speaker, "there is little or nodanger involved during this running-in period, but if the service- ability rate is low, and the period prolonged, pilots tend to losefaith in the equipment, and will refuse to use it when it does work. 1 can think of at least two expensive pieces of equipment nowcarried on some British aircraft to which the above remarks apply." The Overall Problem Much thought had been given to the air-borne equipment proposed. " We hear talk,'" said Capt Bressey. "of failure rates of 1 in 10", triplicated systems, triplex systems—and even of duplicate ground equipment. All this will, we hope, bring the aircraft safely to rest on the runway. Unless it can besafely removed from the runway fairly quickly, it is now just an obstruction preventing the next aircraft from landing. "At many major airports, this "removal from the runway" in-volves some pretty complicated taxi routing, and some even more involved manoeuvring when reaching what is known as the "mar-shalling area." How this is to be done under conditions of zero- zero visibility, no one has yet explained. "How passengers are to be removed from the aircraft withoutgetting lost in the fog, and how all the servicing vehicles are to do their work, is not really a pilot's worry. But unless the aircraft isto sit on the tarmac until the weather improves, all these necessary functions must be performed, and then presumably the pilot willbe asked to tax iout to the right end of the correct runway and get it airborne—or will all this too be performed on Autotaxi andAutotake-off? We should like to know." 100 per cent Utilization This was obviously the ultimate aim.said Capt Bressey—to land the passenger safely at the right airport at (approximately) the right time, every trip. He continued:— "BLEU has amassed an impressive record of over 2,000 [8,000!—Ed] successful autolandings—some of them in almost zero-zero conditions. But 1 believe that all of these have been made in smallor medium-sized straight-wing aircraft of fairly low wing-loading, and under only moderate cross-wind conditions. "For world-wide application, autolanding will have to copewith large, heavy swept-wing jets, with high wing-loading, some- times under strong gusty cross-wind conditions, perhaps even on anicy runway. "Autolanding is based primarily on ILS, which has been thestandard ICAO bad-weather approach aid for more than ten years. Yet in the whole Eumed region—and this takes in a lot of airfields—there are not yet a dozen airports which have more than one ILS at the end of one runway. Many have no glide-path, or one whichis promulgated as 'unreliable.' Many more have no ILS at all and, because of terrain problems, little hope of ever having one.At those airports which are equipped with ILS. the serviceability rate often leaves much to be desired. "Duplication of equipment, if the money can be found to pay forit, may help this problem to some degree in some locations, but we have a long way to go yet before we reach our 100 per cent goal." Capt Bressey went on to quote Murphy's Law—"If it is possibleto install something the wrong way, somebody sooner or later will do it that way." He quoted an instance of a British airliner whichwas longitudinally slightly unsuitable and had two autopilot controllers. On one flight it was put into level cruise at the top ofthe climb and the steward was called forward to the flight deck. The nose went down, and the co-pilot trimmed aft on the auto-pilot. The nose went further down; the co-pilot trimmed further aft; and a dive developed from which the captain recovered athigh speed in a flight level reserved for traffic moving in the opposite direction. It was then discovered that the co-pilot's pitch controlwas connected in reverse. Now, the two controllers looked iden- tical—same shape, same plugs, no indexing marks except for thelast of a string of digits in the part number. But the captain's unit contained an override, so that the captain ultimately hadcontrol of the autopilot; and it so happened that if the captain's unit was mounted in the co-pilot's controller it worked in tra
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