RECIFE, Brazil - Brazilian helicopters began ferrying bodies of Air France crash victims to shore for identification Tuesday while a pilots' union said the airline was rapidly replacing speed sensors like those suspected of feeding false information to the doomed jet's computers.
Soldiers and medical personnel in surgical gowns carried body bags on stretchers off of helicopters that flew the first recovered bodies from ships at sea to the island of Fernando de Noronha on Tuesday. Officials said they would then be taken by plane to the northeastern coastal city of Recife, where experts will try to identify them.
Brazilian officials said searchers had found 24 bodies by Tuesday morning.
Peter Goelz, a former managing director of the National Transportation Safety Board, said that identifying the bodies, knowing where people were sitting and studying their injuries could give clues to causes of the May 31 crash that killed 228 people.
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 April 27 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.
Eric Derivry, a spokesman for the SNPL union, the main union for Air France pilots, told France-Info radio that all jets taking off on Tuesday would be equipped with two of the new Pitot sensors.
A memo sent to Air France pilots by the Alter union 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.
An official with the Alter union said there is 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.
At an industry conference in Kuala Lumpur, Emirates Airlines President Tim Clark said the Dubai-based company's 29 A330-200 planes have been flying since 1998 "and there is absolutely no reason why there should be any question over this plane. It is one of the best flying today," he said.
In a video posted Monday on a Web site, Brazil's air force revealed that 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.
William Waldock, who teaches air crash investigation at Embry-Riddle Aeronautical University in Prescott, Arizona, 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."
Goelz 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" which constricts how much the rudder can move at high speeds. If it were to move too far while traveling fast, it could shear off and take the vertical stabilizer with it.
"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.
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."
The discoveries of debris and the bodies also are helping searchers narrow their hunt for the cockpit voice and flight data recorders, commonly known as the "black boxes," perhaps investigators' best hope of learning what happened to the flight.
The wreckage and the bodies were found roughly 400 miles (640 kilometers) northeast of the Fernando de Noronha islands off Brazil's northern coast, and about 45 miles (70 kilometers) from where the jet was last heard from.
Searchers must move quickly to find the recorders because acoustic beacons, or "pingers" on the boxes begin to fade 30 days after crashes.
Some high-tech help is on the way for investigators: two U.S. Navy devices capable of picking up the pingers to a depth of 20,000 feet (6,100 meters).
The listening devices are 5 feet (1.5 meters) long and weigh 70 pounds (32 kilos). One will be towed by a Brazilian ship, the other by a French vessel, slowly trawling in a grid pattern across the search area. The devices will be dropped into the ocean near the debris field by Thursday, Berges said.
The French nuclear attack submarine Emeraude, arriving later this week, also will try to find the acoustic pings, military spokesman Christophe Prazuck said.
France's defense minister and the Pentagon have said there were no signs that terrorism was involved in the crash.
David Epstein, Qantas Airways General Manager for Government and Corporate Affairs, said two companies manufacture the Pitot monitors for the A330 planes - France's Thales Group and Charlotte, North Carolina-based Goodrich Corp.
The Air France plane uses sensors made by Thales while Qantas uses those by Goodrich for its 28 A330 planes, he said.