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Aviation History
1976
1976 - 0573.PDF
fUGHT International, 10 April 1976 Blackhawk: no mechanical failure S IKORSKY'S Blackhawk prototype crashed xm the opening day of the 1974 SBAC display at Farn borough because of an error of judge ment by its pilot, according to the report* by the British Department of Trade's Chief Inspector of Accidents. The Blackhawk had been rolled fre quently, always to the right, and its display sequence, which was in con junction with a GH-53, was approved by the show Flying Control Commit tee. An observed routine was flown on August 29, when the two aircraft arrived at Farnborough after a work up at BAF Woodbridge. The principal difference between the accident roll and previous rolls analysed during the flight-test pro gramme was that the pitch attitude at the start of the roll was only 6° nose-up. According to company pilots, somewhere between 15°-20° was nor mal and recorded data showed entry attitudes of between 19°-23° nose-up. During tests the pitch attitude had been stabilised before the start of the roll but pitch was still increasing at about 9°/sec when the final roll began. At Farnborough, the Blackhawk diverged markedly in pitch as the roll progressed; it did not do this nor mally. By the time it had rolled through 100° the pitch rate had stabilised at 10°/sec but it increased rapidly as the helicopter approached the inverted position. At this point the nose was about 15° below the horizon whereas it was normally some 9° above. From the inverted position the rate - Lewis to study • advanced engine r materials < A FIVEYEAR government / industry f\ programme to develop better i materials for turbine engines, known as Mate (Materials for Advanced Tur- v bine Engines), has begun at Nasa's T Lewis Research Centre. The centre hopes to accelerate the application of t at least five examples of advanced- material technology from laboratory * to airframe. To launch the effort it r has awarded contracts worth about $2-3 million to AiResearch, P&W and * GE. t AiResearch will develop new materials to seal the tips of small- < engine compressors and turbines. Tip losses are proportionately more serious in small engines than in larger t units, and better seals to reduce hot- gas leakage in the TFE731 engine, for > example, could reduce specific fuel consumption by 1*2 per cent. The com pany is also to develop an economic - process, using directional solidification methods, for the manufacture of small-engine turbine blades. The use of superalloy turbine blades could re- of roll decreased rapidly and the air craft was pulled through the second part of a loop. This manoeuvre was complete when the Blackhawk struck the ground, level but with a high rate of descent. Bulb-filament analysis showed that no system warning lights had been illuminated at impact and films of the fatal roll gave no evidence of any failure before impact. The report details the safety pre cautions adopted for the SBAC flying displays, among which is that all dis play manoeuvres should be completed above 200ft. Sikorsky had specified 300-400ft as the minimum entry height for the Blackhawk roll and the evi dence is that the helicopter entered its final roll within these limits. The report goes on: "Thus although the commander started the last manoeuvre at a height above the mini mum display height specified by both the SBAC and the company, the entry height was insufficient to allow this very experienced display pilot to re cover from the consequences of an error of judgement at the beginning of the final roll. "The question must be asked," con tinues the report, "whether the height allowed an adequate safety margin in the event of a divergence from the normal flightpath such as might be caused by pilot misjudgement or dis traction." The recommendation is made that the height limitation for aerobatic manoeuvres at displays should be reviewed. The Chief Inspec tor considers that special considera tion should be given to the height that a pilot might require to recover from an imperfect manoeuvre. * Aircraft accident report 1/76. HMSO. price 80p duce s.f.c. by a further V2 per cent. P&W also is to investigate super- alloy processes, this time for JT8D turbine discs, with a potential cost re duction of about 20 per cent. GE, again, is to develop a low-cost process to manufacture superalloy compressor discs and turbine shafts. The cost re duction here is expected to be as high as 50 per cent and among applications are components for the F101 engine of the- Bockwell B-l and the CF6-50 for large commercial transports. The Mate programme is aimed at introducing these technologies into air craft powerplants by 1980. • The US Navy has awarded a $12-5 million contract to AiResearch for a 1,000 s.h.p. technology-demonstrator engine in which ceramic materials will replace a number of metal compo nents. The project is financed by Darpa (the Defence Advanced Re search Projects Agency), which, in association with the Ford Motor Com pany, has been investigating the appli cation of ceramics to marine gas tur bine engines. AiResearch will modify a standard T76 turboprop engine (powerplant of the twin-engined Rockwell OV-10A Bronco light armed reconnaissance air- 871 SENSOR The first executives of the future British Aerospace Corporation are likely to be named shortly. There will be four senior executives of Hawker Siddeley and BAC, a non- aviation industrialist, and a trade- union member. They will serve under Lord Beswick, chairman, on the Organising Committee; all will be appointed to British Aerospace on its formation. Some functions, including technical and production, may be fully covered by further appointments. Chief executives for each main division, aircraft and GW, can be anticipated, though there will probably not be a group chief executive. Hawker Siddeley is formally pro posing to the Department of In dustry two civil aviation projects: support for the A300B10, with RB.211-524 engines; and manufac ture of components at Hatfield for five HS.146s to maintain the design team and the workforce as Trident work (16 aircraft to deliver) runs out. The HS.146 is still based on the ALFS02; but now more than a poli tically strong contender—and the subject of current design studies— is the bigger-fan RB.401-20B of 6,200lb. The trijet HS.146 project with M45Hs remains ruled out. At least 85 per cent of Concorde take-offs from Heathrow since scheduled services started have met existing noise limitations. The highest noise recorded since ser vices began has been 115EPNdB and there have been occasions when, under similar conditions, sub sonic jets have recorded higher noise measurements than Concorde. British Airways Concorde pilots have adopted a constant-attitude initial climb in place of the earlier constant-airspeed technique. British Airways is likely to make an operating loss of less than £10 million in the year just ending— about the same as the previous year. About half the loss is due to the cost of dollar loans increasing as a result of the falling value of sterling. Load factor has remained about the same, and revenue-rate has not quite kept up with inflation. The operating account remains steady, mainly as a result of what British Airways will claim to be improved productivity. The carrier will end the year with 1,300 fewer staff, mainly as a result of "natural wastage." About £90 million, of which £20 million is from engineer ing, is now earned from third- party contract work and services by the engineering, traffic, flight, operations and computer depart ments. Braniff, Viasa and Singapore Air lines have all approached Air France or British Airways concern ing possible Concorde wet-leases, but both operators plan to utilise their entire fleets themselves if the right routes can be opened up.
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