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Does Airbus Have a Rudder Problem???
EFL...Hat tip InstapunditAt 35 000 feet above the Caribbean, Air Transat flight 961 was heading home to Quebec with 270 passengers and crew. At 3.45pm last Sunday, the pilot noticed something very unusual. His Airbus A310's rudder -- a structure over 8m high -- had fallen off and tumbled into the sea. In the world of aviation, the shock waves have yet to subside. Mercifully, the crew was able to turn the plane around, and by steering it with their wing and tail flaps managed to land at their point of departure in Varadero, Cuba, without loss of life. But as Canadian investigators try to discover what caused this near catastrophe, the specialist internet bulletin boards used by pilots, accident investigators and engineers are buzzing. One former Airbus pilot, who now flies Boeings for a major United States airline, told The Observer: "This just isn't supposed to happen. No one I know has ever seen an airliner's rudder disintegrate like that. It raises worrying questions about the materials and build of the aircraft, and about its maintenance and inspection regime. We have to ask as things stand, would evidence of this type of deterioration ever be noticed before an incident like this in the air?" He and his colleagues also believe that what happened may shed new light on a previous disaster. In November 2001, 265 people died when American Airlines flight 587, an Airbus A300 model which is almost identical to the A310, crashed shortly after take-off from JFK airport in New York. According to the official report into the crash, the immediate cause was the loss of the plane's rudder and tailfin, though this was blamed on an error by the pilots. There have been other non-fatal incidents. One came in 2002 when a FedEx A300 freight pilot complained about strange "uncommanded inputs" -- rudder movements which the plane was making without his moving his control pedals. In FedEx's own test on the rudder on the ground, engineers claimed its "acuators" -- the hydraulic system which causes the rudder to move -- tore a large hole around its hinges, in exactly the spot where the rudders of both flight 961 and flight 587 parted company from the rest of the aircraft. On Sunday night Ted Lopatkiewicz, spokesperson for the US National Transportation Safety Board (NTSB), which conducted the flight 587 investigation, said that the board was "closely monitoring" the Canadian inquiry for its possible bearing on the New York crash. "We need to know why the rudder separated from the aircraft before knowing whether maintenance is an issue," he added. Airbus -- Europe's biggest manufacturing company, to which British factories contribute major components, including aircraft wings -- has now overtaken Boeing to command the biggest share of the global airliner market. In sales literature to operators, it described the A300 series as a "regional The firm recently launched its superjumbo, the two-storey A380, which is due in service next year. Like earlier Airbus models, this relies heavily on "composite" synthetic materials which are both lighter -- and, in theory, stronger -- than aluminium or steel. Fins, flaps and rudders are made of a similar composite on the A300 and A310, of which there are about 800 in service all over the world. Composites are made of hundreds of layers of carbon fibre sheeting stuck together with epoxy resin. Each layer is only strong along the grain of the fibre. Aircraft engineers need to work out from which directions loads will come, then lay the sheets in a complex, criss-cross pattern. If they get this wrong, a big or unexpected load might cause a plane part to fail. It is vital there are no kinks or folds as the layers are laid, and no gaps in their resin coating. Holes between the layers can rapidly cause extensive "delamination" and a loss of stiffness and strength. Airbus, together with aviation authorities on both sides of the Atlantic, insists that any deterioration of a composite part can be detected by external, visual inspection, a regular feature of Airbus maintenance programmes, but other experts disagree. In an article published after the flight 587 crash, Professor James Williams of the Massachusetts Institute of Technology, one of the world's leading authorities in this field, said that to rely on visual inspection was "a lamentably naive policy. It is analogous to assessing whether a woman has breast cancer by simply looking at her family portrait." More at the article. I know there's a lot of pilots on RB...what do you ladies & gents make of this? Posted by: Desert Blondie 2005-03-14 |
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