"For the moment, we can't explain the accident," the head of the BEA air accident investigation agency, Paul-Louis Arslanian, admitted at a breakfast for aviation journalists. "We still don't know what caused the AF447 accident."

Air France flight AF447 from Rio de Janeiro to Paris crashed into the ocean on June 1 and was ripped apart. Just before dropping off radar screens it had emitted a series of automatic warning signals indicating systems failures.

The wreckage of the jet and the bodies of some of the passengers and crew were recovered in deep water 1000 kilometres off Brazil's coast, but the black box flight recorders remain lost.

Analysis of the error messages indicated a problem with the Airbus A330 twin-engined jet's "Pitot probes" — air speed monitors — but the BEA has so far said only that this was a "factor, not the cause" of the crash.

Nevertheless, since the crash both the European air safety agency and planemaker Airbus advised airlines to replace the Pitot probes used on the doomed jet with a later and more reliable model made by a US firm.

Relatives of the dead have angrily demanded that Air France and Airbus take responsibility for the crash and French prosecutors have opened a preliminary manslaughter investigation that could lead to negligence charges.

Arslanian said the hunt for the plane's black boxes would resume "in autumn" after two previous sweeps, one of them seeking a locator signal emitted by the boxes and another using sonar, failed to find them.

"When in autumn? I don't know," he added.

AFP

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