Air France jet sent message on rudder problem

June 13, 2009 10:31:08 PM PDT
A burst of automatic messages sent by Air France Flight 447 before it crashed includes one about a problem with a rudder safety device but lacks decisive clues as to what sent the jet plunging into the Atlantic Ocean two weeks ago, an aviation expert said Saturday. The industry official, who has knowledge of the Air France investigation, told The Associated Press that a transcript of the messages posted on the Web site EuroCockpit is authentic but inconclusive.

One of the 24 automatic messages sent from the plane minutes before it disappeared May 31 with 228 on board points to a problem in the "rudder limiter," a mechanism that limits how far the plane's rudder can move. The flight was headed from Rio de Janeiro to Paris through an area of fierce thunderstorms.

The nearly intact vertical stabilizer - which includes the rudder - was fished out of the water earlier this week 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 that crashed 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," Jack Casey, an aviation safety consultant in Washington, D.C., said last week when the existence of the automatic messages was first divulged. "It tells us that for some reason it was no longer functioning. That is all the message means."

"It does not give you any reason why it is not working or what caused it, or what came afterward," Casey said.

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

A French nuclear submarine is scouring the search area in the hopes of hearing audio pings from the black boxes' emergency beacons. The first of two U.S. locator listening devices won't arrive until Sunday.

So far, there is no evidence of an explosion or terrorist act, just a number of 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 resumed the search for bodies and debris on Saturday morning but suspended their efforts by mid-afternoon because of bad weather conditions, Brazilian air force Gen. Ramon Cardoso said at a news conference.

No bodies were recovered, but a "medium-sized" piece of plane debris was discovered inside the search area by the merchant ship Gammagas, flying the flag of Antigua and Barbuda, Cardoso said. Coroners said in a statement that dental records of the victims and DNA samples from relatives will be necessary to confirm the identities the 16 bodies examined thus far.

Authorities say they have retrieved 44 bodies. Another six have been pulled from the Atlantic by French ships but won't become part of the official death tally until they are counted by Brazilian officials.

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Bradley Brooks reported from Rio de Janeiro and Stan Lehman from Sao Paulo. Associated Press writers Alan Clendenning in Sao Paulo and Jenny Barchfield in Paris contributed to this report.


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