FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1982
1982 - 0238.PDF
king has caused the loss of a Britannia, a Nord 262 and possibly a 737 in recent times. De-icing is ultimately the responsibility of the operator's maintenance department has not been fully accepted; inspec tion and maintenance procedures have been tightened, putting the onus particularly heavily upon the 748 maintenance department and crews. 747 ENGINE POD In December 1979 No 4 engine pod separated from a 747 wing in a heavy landing at Heathrow. There was a severe fire, but the air craft and its occupants were saved. It was found that the forward pylon bulkhead had failed from a crack which may have been started three years before at Chicago Airport in a collision with a baggage container. A similar crack previously discovered by another 747 operator came to light during the investigation, the report of which concluded that "deficiencies in the approved maintenance inspection procedures" had allowed the crack to develop to the point of failure. LUSAKA 707 In May 1977 a 47,600hr 707-320C approaching to land at Lusaka on a cargo flight lost its port tailplane, crashing with the loss of all six on board. The accident was caused by tailplane-spar fatigue. It was a day when the safe bit of a failsafe structure failed hard. The airline maintenance engineer might reason ably describe the crack as having been in an uninspectable area. The aircraft had made 16,700 nights, of which most had been in the hands of its only previous owner. After the accident similar cracks were found (with difficulty) in the tailplanes of 26 other high-time 707s and, with hindsight, reports of loose fasteners came to light. This was more of a design than a maintenance problem; but maintenance departments have found—as British Airways did in the case of Trident wing cracks—similar problems in hard-to-inspect areas of high-time structures. CONCORDE TYRE BURSTS An Air France Concorde taking off from Washington in June 1979 suffered a tyre burst on take-off which caused wheel failure. Fragments punctured the wing fuel tanks. The aircraft re turned with fuel streaming. In August 1981 a British Airways Concorde tak ing off from New York also suffered a tyre burst. This damaged a debris- deflector, which in turn burst the other tyre on the same axle. The result was wheel failure and a rejected take-off at 165kt and heavy weight. Titanium pipes were found to have melted in the subsequent fire, although the carbon brakes survived so well that some pads were later returned to ser vice. Three engines were so badly damaged that British Airways was £2J2 million out of pocket—.all the result of soft tyres. Concorde tyre inspections Since then Concorde tyres have been "preflighted" even more care fully than usual and the fusible plugs —which have given looseness trouble —especially carefully checked. In ad dition Concorde's wheels have been made stronger (and incidentally heavier). No tyres get more of a bashing or heating than those of Concorde, an aircraft which demands the highest runway velocities. The Dunlop carbon brakes have worked so well that this material will certainly replace tradi tional steel on new subsonic aircraft. Delta, for example, has called for bids to carbon-brake its 757s and British Airways will probably have carbon brakes on its 757s as retrofits and eventually as new. Carbon brakes will be making fewer visits to the main tenance department than steel brakes do. Carbon brakes cost three times more per landing but the cost is coming down as better ways of pro ducing the carbon pads are devel oped, and the 3,000-landing carbon brake is in sight. How or why those Concorde tyres became soft during or before take off is not clear, but maintenance de partments everywhere are taking all tyres very seriously. Although Con corde's tyres, wheels, and brakes are the industry's hottest, they are by no means the only ones which seem to be giving trouble—even more trouble than in the past. The probable reason is that all air lines are being forced by economic and commercial squeezes to operate at higher weights and hence higher tyre pressures—pressures which come out in the maintenance depart ment budget as a higher rate of rolling-stock defects. Tyre pressures are up around all the fleets as operat ing weights increase in response to the demands of the commercial de partment. WASHINGTON 737 The Air Florida 737 crash earlier this month in Washington DC could have been caused by airframe icing, the re moval of which may be a subcon tracted task; but responsibility rests with—or must be of concern to—the airline's maintenance department. The aircraft had been de-iced by groundcrew with water/ethylene- glycol solution. But, as happened fatally to an Allegheny 262 in Febru ary 1979 and to a Redcoat Britannia at Boston in February 1980, the wetted ice may have refrozen during a traffic delay. The above are some of the serious accidents and incidents in the last few years which, if not "mechanic error," have been of concern to the maintenance department. The length of the list is quite surprising. We are conditioned now to think of the modern aeroplane as a highly reliable machine, the maintenance of which has become a smooth routine. The list makes us aware that this is not en tirely justified, and it measures the responsibility which we place on the airline industry's maintenance depart ments, rj This separation of a 747 engine pod in a heavy landing was investigated by the UK Accidents Investigation Branch, which found that it had been caused by "deficiences in the approved maintenance procedures". The pylon bulkhead failed from a crack started three years before in a ground collision with a baggage truck 232 FLIGHT International, 30 January 1982
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
