Jet's tail stabilizer found, could offer clues

 

updated 9:04 p.m. ET June 8, 2009

RECIFE, Brazil - Search crews recovered the vertical stabilizer from the tail section of an Air France jetliner that went down in the Atlantic, Brazil's air force said Monday — a key item in finding the cause of the crash.

Eight more bodies also were found, bringing the total recovered to 24 since Air France Flight 447 disappeared with 228 people on board, according to Air Force Col. Henry Munhoz.

The discoveries of debris and the bodies are all helping searchers narrow their hunt for the jet's black boxes, perhaps investigators' best hope of learning what happened to the flight. The data and voice recorders are located in the fuselage near the tail section of the jet.

William Waldock, who teaches air crash investigation at Embry-Riddle Aeronautical University in Prescott, Ariz., said that does not mean the black boxes will necessarily be located near where the debris was recovered, "but finding the tail narrows down the area even further."

Brazilian military officials have refused to detail the large pieces of the plane they have found. But a video on the Brazilian air force Web site entitled "Vertical Stabilizer Found" shows video of the piece — which keeps the plane's nose from swinging from side to side — being located and tethered to a ship.

The part had Air France's blue-and-red stripes, was still in its original triangular shape and was not visibly burned. 

Speed monitors probed
Waldock — who examined the photos and video of the stabilizer and rudder — said the damage he saw looks like a lateral fracture.

"That would reinforce the idea that the plane broke up in flight," he said. "If it hits intact, everything shatters in tiny pieces."

No signs of burn marks on the stabilizer offered scant clues: Any explosion or fire in the fuselage would likely not make its way back to the tail section, according to Waldock.

Examining the fracture surfaces will also be key, Waldock said, since it will indicate from what direction the force came that snapped the piece.

Investigators are looking at the possibility that external speed monitors — called Pitot tubes — iced over and gave dangerously false readings to cockpit computers in a thunderstorm.

Peter Goelz, a former managing director of the National Transportation Safety Board, said the faulty airspeed readings and the fact the vertical stabilizer was sheared from the jet could be related.

The Airbus A330-200 has a "rudder limiter" that constricts how much the rudder can move at high speeds — if it were to move to far while traveling fast, it could shear off, and take the vertical stabilizer with it as they are attached.

"If you had a wrong speed being fed to the computer by the Pitot tube, it might allow the rudder to over travel," Goelz said. "The limiter limits the travel of the rudder at high speeds and prevents it from being torn off."

Asked if the rudder or stabilizer being sheared off could have brought the jet down, Goelz said: "Absolutely. You need a rudder. And you need the (rudder) limiter on there to make sure the rudder doesn't get torn off or cause havoc with the plane's aerodynamics."

Goelz also said the bodies recovered will play a role in the investigation. If investigators can determine the identity of a body and know where that person was sitting in the plane, the types of injuries sustained could offer clues into the crash.

The investigation into TWA Flight 800 that crashed off the coast of Long Island, New York, in 1996, found that victims sitting in front of row 30 sustained flash burns. Goelz said that helped investigators confirm that the nose broke off and fire blew back from the fuel tank onto those passengers.

The wreckage and the bodies were found roughly 400 miles northeast of the Fernando de Noronha islands off Brazil's northern coast, and about 45 miles from where the jet was last heard from on May 31.

High tech help on the way
Some high-tech help is on the way — two U.S. Navy devices capable of picking up the flight recorders' emergency beacons far below on the ocean floor. What caused the plane to plunge into the middle of the ocean on May 31 might not be known until those black boxes are found.

Slideshow   Grim search Two nations mourn as searchers look for more debris. more photos

An internal memo sent to Air France pilots Monday and obtained by The Associated Press urges them to refuse to fly unless at least two of the three Pitot sensors on each planes have been replaced.

The leader of another pilots' union, however, said Monday that Pitot troubles probably didn't cause the Flight 447 disaster.

Searchers must move quickly to find answers in the cockpit voice and data recorders, because acoustic pingers on the boxes begin to fade 30 days after crashes.

While large pieces of plane debris — along with 24 bodies — has helped narrow the search, it remains a daunting task in waters up to 1.5 miles deep and an ocean floor marked by rugged mountains.

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