PARIS — The Air France Airbus 330 that crashed into the Atlantic on June 1, killing all 228 people aboard, did not break up in the air but rather hit the water intact, French investigators said on Thursday.
But at a news conference at their headquarters at Le Bourget airport near Paris, officials from the French Office of Investigation and Analyses acknowledged that they still had no clear notion of the reason for the crash.
Analysis of autopsies and debris patterns in the weeks after the crash had seemed to bolster speculation that the plane had broken up in flight. But the investigators said that their examination of floating debris indicated that the plane hit the surface of the ocean on its belly, at very high speed and facing in the direction of its intended flight.
The plane,Air France Flight 447, was flying through an area of strong thunderstorms near the equator on its planned route from Rio to Paris when it sent a series of automated messages to a maintenance base. The messages were the last communications from the plane, and with the flight data recorders still being sought, remain the only direct information about what might have caused the crash.
One of the maintenance messages indicated a rapid change in cabin pressure, which might have meant depressurization. But depressurization could occur without breakup, experts said.
Alain Bouillard, who is leading the French investigation, said that “visual examination of the debris shows that the plane hit with the bottom of its fuselage with very strong vertical acceleration.” Shelves in the galley had compressed to the bottom, he said, among other evidence.
But investigators said that knowing how the plane hit the water did not tell them why. They are continuing an extensive search for signals from the “black boxes,” the cockpit voice recorder and the flight data recorder, which they believe would give them enough evidence to draw a conclusion.
Those boxes are equipped with “pingers,” battery-driven speakers that emit a sharp acoustic tone. The investigators said they would continue searching for the boxes until July 10, when the batteries that drive the pingers are expected to be exhausted. After that, they will continue the search with diving equipment and towed sonar.
The plane went down more than 600 miles off the coast of northern Brazil, in an area where the sea bottom is rugged and deep. Investigators hope to use sonar to locate the debris field, and then would try to zero in on the black boxes.
Outside experts said they expected that investigators would press forward with the search for months, if necessary. “If there’s any chance of efficacy of sonar, I’d keep going,” said William Voss, president and Chief Executive of the Flight Safety Foundation, an international group based in Virginia. The plane and the airline are under “a big cloud,” he said. “Airbus is in the worst imaginable position; any blogger with a theory is condemning them, and there’s no way to disprove it.”
Illustrating how little is known, investigators said that Flight 447 had flown for its final 39 minutes without radio contact with Brazilian air traffic control, leaving unclear whether it radioed a distress call.
Since the crash, much attention has been paid to another of the maintenance messages, one that indicated the plane’s speed-sensing mechanism had malfunctioned. Airbus, the manufacturer, had recommended replacement of a component of that system, called the Pitot tube, and Air France had replaced the tubes on some of its airplanes, but not the one that crashed. After the crash, they rapidly replaced all the tubes.
“The Pitot tubes are something strongly suspected” in the malfunctioning speed indicators, Mr. Bouillard said. “It is an element but not the cause,” he said.
In the United States, the National Transportation Safety Board is gathering information on two recent A330 flights in which the speed-sensing mechanism failed. But Mr. Bouillard said that without more information about the Air France flight, the relevance of the other planes’ malfunctions would not be clear.
Thus far, aviation regulators in the United States and Europe, who commonly take manufacturers’ recommendations and make them mandatory, have not done so for the Pitot tube replacement, because their role here is unclear.
The lack of a strong theory to explain the crash one month into the investigation has left open the door to a great deal of speculation about the cause and, more broadly, the safety of Airbus planes and the fleet of Air France-KLM, Europe’s largest airline. The fanning of safety concerns, analysts said, are particularly unwelcome heading into the peak of the summer travel season at a time when the global economic downturn is already eating into air traffic volumes.
No comments:
Post a Comment