The memory remains

New-generation flight data recorders will give full details of an air crash

Published: Sunday 28 February 1999

flight recorders for all civil aircraft built after 2004 will have back-up power supplies built in, air safety experts have decided. The move followed the crash of a Swissair jet off Halifax, Nova Scotia, in September 1998, in which two black boxes -- the flight data recorder and the cockpit voice recorder -- cut out six minutes before the impact. The investigation of the crash, in which 229 people perished, has been hampered by the absence of data on those final minutes.

At present, only the latest of the world's approximately 12,000 civil aircraft use tape-based recorders that are powered by the plane's generators, which, in turn, are driven by the engines. But the recorders have no built-in back-up power source.

Recently, the Filght Recorder Panel of the International Civil Aviation Organisation in Montreal, Canada, announced that it has decided to "support the need for an independent power source for flight recorders". The panel has to work out the technical details, but Peter Sheppard, head of the flight-recorder branch at uk' s Air Accident Investigation Branch, and a member of the panel, says the independent power supply will have to last at least 10 minutes after the loss of external power. This will require new-generation microchip-based flight recorders, says Sheppard. "Independent power supplies will only be applicable to aircraft with solid-state recorders, as they only need half the power of a tape recorder," he says. The new recorders will save two hours of cockpit activity, as against 30 minutes with conventional tapes.

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