Four more bodies found from Air France disaster

Four more bodies from Air France Flight 447 were recovered today, and helicopters began ferrying other remains to shore.

Air France rushed to replace instruments suspected of feeding false information to the doomed jet's computers, while Brazil announced it was doing the same on the president's plane.

The four bodies found this morning raises the total recovered to 28, meaning 200 others have yet to be found. Soldiers and medical personnel in surgical gowns carried off the remains in body bags at the island of Fernando de Noronha. They will be taken by plane to the coastal city of Recife, where experts will try to identify them using DNA and photos.

Identifying the bodies — knowing just where they were seated in the plane and studying their injuries — could provide clues to causes of the 31 May disaster, according to Peter Goelz, a former managing director of the National Transportation Safety Board.

With the plane's data recorders still apparently deep in the ocean, investigators have been focusing on the possibility that external speed monitors — called Pitot tubes — iced over and gave dangerously false readings to the plane's computers in a thunderstorm.

The L-shaped metal Pitot tubes jut from the wing or fuselage of a plane, and are heated to prevent icing. The pressure of air entering the tubes lets sensors measure the speed and angle of flight. A malfunctioning Pitot tube could mislead computer controlling the plane to accelerate or decelerate in a potentially dangerous fashion.

Air France said it began replacing the Pitot tubes on the Airbus A330 model on 27 April after an improved version became available, and said it will finish the work in the "coming weeks."

The monitors had not yet been replaced on the plane that crashed while on a flight from Rio de Janeiro to Paris.

Brazil's air force, meanwhile, said that was replacing the Pitot tubes on an Airbus A319 used by President Luiz In?o Lula da Silva because of a recommendation of the jet's manufacturer more than a month before the Air France crash. It did not say when the change was made.

All Air France jets taking off today will be equipped with at least two of the new Pitot sensors, Eric Derivry, a spokesman for the SNPL union, the main union for Air France pilots, told France-Info radio.

A memo sent to Air France pilots by the smaller Alter union yesterday 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, citing a "strong presumption" among its pilot members that a Pitot problem precipitated the crash.

The memo says the airline should have grounded all A330 and A340 jets pending the replacement, and warns of a "real risk of loss of control" due to Pitot problems.

Brazil's air force said search crews had recovered the vertical stabilizer from the tail section of Flight 447 — which also could provide key clues as to why the airliner went down in the Atlantic and where best to search for the black boxes.

The tail section includes the vertical stabilizer — which keeps the plane's nose from swinging back and forth — and the rudder, which controls the side-to-side motion. The data and voice recorders are also located in the fuselage near the tail.

From images of the recovered tail section, the damage looks like a lateral fracture, said William Waldock, who teaches air crash investigation at Embry-Riddle Aeronautical University in Prescott, Arizona.

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

Goelz said the faulty airspeed readings and the fact the vertical stabilizer was sheared from the jet could be related.