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Aviation History
1974
1974 - 1900.PDF
730-731 BOAC engineering costs, in cents per available tonne-km, from Icao statistics BRITISH AIRWAYS ENGINEERING the USA and the acceptable deferred deficiency list by the Overseas Division). BEA's work on automatic landing led to a Civil Aviation Authority (CAA) requirement that the airline should demonstrate a certain level of system integrity in routine line service. This level should be at least as high as that demonstrated in manufacturers' testing, and over many more landings. The requirement resulted in the expansion of the flight data recorder (FDR) carried in each aircraft. About 40 measurements, direct or derived, were agreed to be rele vant. Some 64 measurements are sampled each second, from 1 to 8 times for different parameters. The European Division has now demonstrated more than 5,000 automatic landings in good visibility, with the captain in a position to take over. On this experience the CAA has approved the automatic landing system for Category 3 weather, in which cloud base and visibility are too low for manual landings and the aircraft is under automatic control to touchdown. Four such touchdowns were in fact done in passenger service on one day in November 1973. Flight data recorders All recordings analysed in European Division for auto- landings are also simultaneously subjected to a flight operational analysis, which searches for non-standard events. Events without direct safety implications do not go to the flight manager, who is responsible for discipline as as well as for safety, but to a specialist air-safety pilot, a retired captain whose professional discretion is trusted by pilots and by the management. Aberrations are dealt with quietly and informally. Nobody knows who the erring pilot is, but every pilot knows that the fleet performance is being monitored by the FDR. The objective is safety, not discipline. Handled this way the flight data recorder—especially one recording so many parameters—may be regarded by the pilot as friend rather than snooper. Cost of the European Division's flight data analysis pro gramme is about 40p per aircraft flying hour—about £70,000 a year. Some of this money is recovered under a contract with the British Government to supply data for CAADRP (Civil Aircraft Airworthiness Data Requirements Programme) to check and update the British Civil Air worthiness Regulations (BCARs) and other operational standards. Would the European Division have fitted such compre hensive flight-data recording if the CAA had not required it? The chief engineer says that it would, for management as well as for safety reasons. In any case; as from January 1975 the CAA will require all airlines to increase the number of channels from six to 40-plus—enough to derive much more about the flightpath. The new CAA crash-recorder philosophy is to find out what the pilot was actually doing, rather than just deriving the flightpath. The overdue CAA requirement for cockpit voice recorders (CVRs) is already anticipated by the new aircraft; British Airways will install CVRs in all its fleet by January 1976. The European Division is putting particular emphasis on engine health monitoring (EHM), using readings from the flight-data recorder to do various analyses, one of which is plotting vibration against spool speeds and com paring each flight vibration level with "signature" levels. European Division claims that this method will detect a single broken turbine blade and that this, with other analyses which warn of impending engine trouble, can save one in five serious engine failures. Last year 32 very FLIGHT International, 21 November 1974 ll I L_ I I I 1960 1962 1964 1966 1968 1970 1972 expensive failures were avoided using the manually logged system of EHM alone. A small staff of five specially trained engineers in the division's Early Failure Detection Centre know by the shape, size, quantity, colour and texture of metallic par ticles on magnetic plugs and oil filters where mechanical failure is incipient. The Rolls-Royce Speys of the Trident and Super One-Eleven fleets feature two well designed and located magnetic plugs in each engine oil system, and these are removed for inspection every 50hr. The main oil pressure filters are also examined at intervals of 600hr and 750hr respectively on these fleets. In a typical year of European Division's operations nearly 25 per cent of all engine premature removals are predicted early. This represents 75 per cent of all possible detection, with a monetary saving amounting to approxi mately £300,000 net that would otherwise be expended on engine repairs. Engines as expensive as the RB.211 will have to do better than the Speys of the Trident 3, which have been suffering from blade-cooling problems, though these are now being overcome. The shutdown rate on this Spey engine type is currently 0-16/1,000 engine hours for basic engine problems compared with an airline industry "alert- level standard" generally accepted at around 0-3. Although rates of 0 16 and 0-3 are great improvements on the piston era's 0-7, they are still too high for the RB.211. The RB.211 of the TriStar has an elaborate Teledyne electronic engine monitoring system. Unlike the older turbine engines it is designed from the start for bore-scope and easy X-ray inspection. It also has improved design features for magnetic plug and oil filter metallic particle monitoring. Out of the high frequency of European Division opera tions has evolved the BeaTech system. All defects are notified inbound to London by the captain about 20min before landing. This gives the Engineering Division time to arrange for the appropriate specialists and spares. Even before the passengers have disembarked a senior engineer is on the flight deck for a discussion with the captain. Overseas Division Overseas Division has a quarter of the European Divi sion's despatch rate. But its aircraft are often up to 80hr away from base, while those of the European Division come home to roost every night. The Overseas Division has 17 Boeing 747s; 11 Boeing 707-320Cs and nine -436s (with maintenance responsibility for those of AirTours); 11 Standard VClOs, of which four have been sold to Gulf Air and two more to executive owners in the Middle East, the rest being up for sale; and 16 Super VClOs. Total engineering staff of the Overseas Division is 6,300, of which just over 4,800 are maintenance engineers. Total cost of the engineering and maintenance department is now nearly £40 million a year, or about 14 per cent of the total divisional direct operating cost. While European Division subcontracts about 8 per cent of its engineering, Overseas subcontracts only 2-3 per cent. As the Gulf Air VClOs and Ghana 707s regularly to be seen
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