Air France 447 - French Jet Hit Ocean Intact, Officials Say
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PARIS — The Air France Airbus A330 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 Thursday.
But at a news conference at their headquarters at Le Bourget airport near Paris, officials from the French Office of Investigations and Analyses acknowledged that they still had no clear understanding of the reason for the crash of Air France Flight 447. The plane was flying through an area of strong thunderstorms when it went down 600 miles off northern Brazil en route to Paris.
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 their examination of floating debris indicated that the plane plummeted on its belly onto the ocean surface, facing in the direction of its intended route.
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.” Among the evidence was that shelves in the galley had compressed to the bottom, he said.
But investigators said that knowing how the plane struck the ocean did not tell them why it went down. They said they would continue trying to detect signals from the “black boxes” — the cockpit voice recorder and the flight data recorder — until July 10, when the batteries powering the “pingers” are expected to be exhausted. After that, they will search using diving equipment and towed sonar.
Without the information from the flight recorders, the main source of information about what happened to the plane is a series of messages sent automatically from the plane to a maintenance base.
The investigators said that the flight had no radio contact with Brazilian air traffic control in its final 39 minutes, leaving the maintenance transmissions the plane’s last known communications. Airbus has said that the messages indicate that Flight 447’s problems may have begun with “unreliable air speed indication” and that other indicated failures could have been consequences.
A faulty air speed indicator could mislead pilots into flying faster or slower than the plane could handle. Some initial suspicions were that the plane had flown too fast, possibly into turbulence, causing it to break up.
But flying too fast or too slow could also disrupt the flow of air over the wing, causing the plane to lose lift and fall.
Also, in an area of thunderstorms, high-altitude temperatures can be unusually warm and the air thin, which experts say means reduced thrust and speed. That further narrows the range of speeds at which an aircraft can be controlled.
Airbus, the manufacturer, had recommended replacement of a component of the air speed indicators, called the Pitot tube, and Air France had replaced the tubes on some of its airplanes but not on the one that crashed. Afterward, it rapidly finished replacing its fleet’s tubes.
The French investigation continues to look closely at the component. “The Pitot tubes are something strongly suspected” in the malfunctioning speed indicators, Mr. Bouillard said. He said, however, “It is an element but not the cause.”
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 the component’s role here is unclear.
Another maintenance message indicated a rapid change in cabin pressure; if the plane had broken up, that might have indicated the moment of depressurization. But depressurization could have occurred without breakup, experts said.
Photos of a section of the tail floating at some distance from other debris had raised comparisons with the crash of an Airbus A300 in Queens in November 2001. In that case, the tail fin separated from the plane in flight because of pilot actions that put the plane into an unanticipated oscillation. But the French investigators said they had concluded that the Air France plane’s tail was still attached at impact.
The investigators’ report makes clear that air traffic controllers in Brazil and Senegal were slow to realize that the plane had been lost. Two hours and 45 minutes after it sent a final automated message, controllers were still asking the crew of a different Air France jet to try to contact it on their radios. Mr. Bouillard said there had been a “dysfunction” in communication between the controllers in coordinating their handling of the flight.
Reports have varied on how many bodies have been recovered; officials said Thursday it was 50.
The amount of information that remains unknown a month after the accident adds to the pressure to find the plane’s recorders and come up with a more definitive reconstruction.
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 R. Voss, president and chief executive of the Flight Safety Foundation, an international group based in Virginia.
The plane and Air France 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.”
Nicola Clark reported from Paris, and Matthew L. Wald from Washington.
