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Aviation History
1960
1960 - 0241.PDF
FLIGHT, 19 February 1960 SYSTEM 241 SURVEY. BOAC AND AUTOMATIC LANDING VC10: Pt f —The Operator's Viewpoint LIKE many other operators, BOAC have always considered thatautomatic landing would be developed for airline use. Since the late 1940s the departments concerned with flight opera- tions and development have been carefully watching any activity which gave promise of achieving such performance. They had followed BLEU work at Martlesham Heath, Woodbridge, and later at Bedford, but for many reasons it was not until the later 1950s that automatic landing looked like becoming a practical possibility. Information about the Bell Automatic Landing System was first published early in 1957 and, in mid-1958, BLEU were able to release details of the single-channel system which has been called Autoland and to offer it as a basis for civil equipment. One significant retarding factor was the slow implementation, in early post-war years, of ILS. Now taken for granted, ILS is still the basis of the first stage of automation; without it, progress towards that goal was unthinkable. In 1950 and 1951, BOAC needed ILS for their first Comet operations, but London Airport was almost the only airfield on the African and Far Eastern routes which was so equipped. Even now, ten years later, imple- mentation of this ICAO standard is by no means complete and the best of installations does not yet provide for 100 per cent operation —a condition which is obligatory when a full automatic landing is being conducted and which is not met by the normal standby equipment. The provision of known equipment continued in parallel with the development of the new automatic techniques; and commer- cial operators at the same time were beginning to use ILS couplers in their autopilot systems to provide automatic approaches down to about 200ft. At the time when the second automatic step of auto-flare looked as if it could be introduced into service in a measurable number of years, BOAC were considering the Vickers VC10, an aircraft which would enter service in 1963-1964 and, more important still, would subsequently remain in service for ten years. Because of the time scale it was important to consider whether auto-flare should be taken into account in specifying the equipment for this aircraft. There were in fact two major considerations for BOAC to take into account when they began to specify VC10 equipment shortly after the contract was signed late in 1958. Firstly, BOAC decided that the autopilot should be considered essential in the en route case and the likelihood of any unserviceability removed. At 40,000ft, an airliner must be flown on instruments, but the pilot's energy should not be taxed at this stage when his full ability must be available during the more critical descent and landing phase. An autopilot can in any case control the aircraft better. In order to ensure the highest degree of autopilot service throughout the flight a duplicated installation appeared to have great advantages. Secondly, it was clear that a duplicated autopilot would give much greater scope for development of the auto-flare role with progress towards full automatic landing. For these dual reasons BOAC decided to accept the very considerable expense of fleet-wide auto- pilot duplication. The equipment is being made by Elliott and is similar to the Bendix PB-20 installation in the BOAC Boeing 707s. It is interesting to note that the reasoning outlined above does not include the hope that auto-flare will immediately improvere ^« ^ °* oneration- BOAC consider that it is extremely difficult to define this f actor in terms of economics and that no really appre- ciable profit could be shown until the full automatic landing has oecome so established that a reduction in the diversion fuel allow- ances can be made. It will be some time before a pilot could be persuaded to leave behind all or part of his fuel reserve and count on a certain arrival at destination using automatic equipment regardless of visibility. Crew psychology is indeed a major factor in almost any stage of automation, either during approach or landing. BOAC's first operational experience of approach couplers was in the Strato- cruiser in 1950 and all their aircraft are now so equipped. But, even now, automatic approaches are by no means regarded by the pilots as completely routine, even though the equipment performs according to specification. Pilots frequenly prefer to maks an instrument approach, manually in order to maintain their pro- ficiency—not necessarily because they dislike automatics. BLEU had clearly demonstrated that auto-flare and automatic landing techniques were sufficiently established to justify civil operators in planning on such equipment. The dual autopilot was decided upon for the reasons outlined above, but BOAC then set its sights at a practical level and decided to implement first the auto-flare stage which they expect to be achieved without any additional ground equipment. Auto-flare was in any case a most important first step towards automatic landing and that part of the operation had to be proved in service at an early stage. It was reasonable to suppose that if the autopilot could fly an aircraft better than a human pilot in the cruising condition, it could also better control the flare-out. As far as full automatic landing is concerned BOAC appear to have gone no further than to take a front-row seat in order to watch developments. They point out that although auto-flare is extremely expensive it can provide some immediate benefits. Any operator who equipped his aircraft for automatic landing now would be unable to derive due profit from the equipment until the necessary ground installations had been provided and all the pre- liminary trials and familiarization completed. A major factor is that of international standards since there is no guarantee that, when ICAO comes to consider this point, as it inevitably will, an American system will not be chosen in prefer- ence to equipment developed in Britain. Such a choice might more directly affect BOAC than, for example, BEA, because of its world- wide operations and its consequent dependence on a great number of foreign governments for infrastructure. BOAC feel that to solve the auto-flare problem would be a real advance in itself. It is also a simpler proposition from the certi- fication and reliability point of view. Auto-flare is not likely to allow any great decrease in weather minima, but it could improve landing accuracy to a point where the aircraft manufacturer or the operator would benefit from shorter landing field-lengths. Being in effect an extension of the- coupled ILS approach, it would pre- sent fewer difficulties from the human point of view and could be used or not for any particular landing. For monitoring, the pilots will need only the director instrumentation already destined for the aircraft and will in any case be able to verify performance by visual reference to the ground. BOAC point out that automatic landing in zero zero weather would be of limited value unless all the supporting ground facilities could operate under these conditions and the aircraft could also take off again. This is something of an illusory benefit and may not in fact become important for some time and perhaps not until supersonic airliners are introduced. In the meantime, they hope that auto-flare will prove adaptable to modification to automatic landing in whatever form it is internationally agreed.
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