Jet sent message on rudder problem

June 14, 2009 12:01:02 PM PDT
A burst of last-minute automatic messages sent by Air France Flight 447 includes one about a problem with a rudder safety device but that does not explain what sent the jet plunging into the Atlantic Ocean, an aviation expert said. Meanwhile, the head of the parent company of the jet's manufacturer said in comments for release Sunday that the plane likely crashed for a variety of reasons.

The aviation industry official, who has knowledge of the Air France investigation, told The Associated Press on Saturday that a transcript of the messages posted on the Web site EuroCockpit is authentic but inconclusive.

The flight was carrying 228 people from Rio de Janeiro to Paris on May 31 when it ran into fierce thunderstorms.

One of the 24 automatic messages sent from the plane minutes before it disappeared points to a problem in the "rudder limiter," a mechanism that limits how far the plane's rudder can move. The nearly intact vertical stabilizer - which includes the rudder - was fished out of the water by Brazilian searchers.

"There is a lot of information, but not many clues," the official said, speaking on condition of anonymity because he is not authorized to discuss the matter.

The official said jets like the Airbus A330 automatically send such maintenance messages about once a minute during a plane's flight. They are used by the ground crew to make repairs once a plane lands.

Martine del Bono, spokeswoman for the French investigative agency BEA, which is in charge of the crash probe, and Airbus spokesman Stefan Schaffrath declined to comment on the transcript.

If the rudder were to move too far while traveling fast, it could shear off and take the vertical stabilizer with it, which some experts theorize may have happened based on the relatively limited damage to the stabilizer.

The industry official, however, said the error message pertaining to the rudder limiter did not indicate it malfunctioned, but rather that it had locked itself in place because of conflicting speed readings.

Investigators have focused on the possibility that external speed monitors - called Pitot tubes - iced over and gave false readings to the plane's computers.

"The message tells us that the rudder limiter was inoperative," said Jack Casey, an aviation safety consultant in Washington, D.C. "It does not give you any reason why it is not working or what caused it, or what came afterward."

Unless the plane's flight data and cockpit voice recorders - the black boxes - are found, the exact cause of the accident may never be known.

In Paris, the head of Airbus' parent company said there is probably more than one reason for the crash of Flight 447.

"In such an accident, there is not one cause," EADS CEO Louis Gallois said. "It's the convergence of different causes creating such an accident."

He added: "It's essential for everybody to know what happened and we know that it's not easy. I hope we will find the black box."

Gallois spoke Saturday at a media day hosted by European Aeronautics Defense and Space Co. ahead of the Paris air show, which starts Monday. His comments were embargoed for release until Sunday.

A French nuclear submarine is scouring the search area in the hopes of hearing audio pings from the black boxes' emergency beacons and the first of two U.S. locator listening devices is scheduled to arrive Sunday.

But the search area includes a wide grid and some of the deepest waters of the Atlantic - and searchers have only two more weeks before the signals from the black boxes begin to fade.

So far, there is no evidence of an explosion or terrorist act, just clues that point to systemic failures on the plane. Experts have said the evidence uncovered so far points to at least a partial midair breakup of the Airbus A330.

Military ships and planes had to suspend the search for bodies and debris Saturday afternoon because of bad weather. No more bodies were recovered, but a "medium-size" piece of plane debris was discovered Saturday, according to Brazilian air force Gen. Ramon Cardoso.

Coroners also said dental records of the victims and DNA samples from relatives will be necessary to confirm the identities the 16 bodies examined thus far.

Brazilian authorities Sunday revised the number of bodies they have retrieved downward, from 44 to 43, after a recount. Another six have been pulled from the Atlantic by French ships.

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