French Sub Begins Black Box Crash Search

A French submarine began scouring the ocean for the flight data recorders belonging to the doomed Air France airliner that plunged into the Atlantic Ocean last week, the French military said today.

The nuclear-powered Emeraude submarine is equipped with advanced sonar and will begin patrolling different search zones each day beginning Wednesday in the search for the black boxes that hold the clues to how the jetliner carrying 228 people disappeared over the open ocean.

Seventeen more bodies were pulled from the sea Tuesday, bringing the number recovered to 41. Another 187 have yet to be found. The first remains were brought to land by helicopter and will be flown to this coastal city Wednesday for identification.

Federal police began visiting families in Rio de Janeiro to collect genetic material — hair, blood, a cheek swab — to help identify the corpses.

Figuring out where the victims were seated and studying their injuries might help explain what brought down Flight 447 as it flew into thunderstorms on May 31, according to Peter Goelz, a former managing director of the National Transportation Safety Board.

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

A key part of the investigation relies on a burst of 24 automatic messages the plane sent during the last minutes of the flight. The signals showed the plane's autopilot was not on, officials said, but it was not clear if the autopilot had been switched off by the pilots or had stopped working due to conflicting airspeed readings.

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

Air France said it began replacing the tubes on its A330 and A340 jets in May after pilots reported several incidents of icing leading to a loss of airspeed data, and that it had already replaced the Pitots in smaller A320 jets after similar problems were reported.

"What we know is that other planes that have experienced incorrect airspeed indications have had the same Pitots. And airplanes with the new Pitot tubes have never had such problems," said Air France pilot Eric Derivry, a spokesman for the SNPL pilots union.

An Airbus jet made an emergency landing after having engine trouble after takeoff from the Canary Islands Wednesday morning, but no one was hurt and the problem did not appear to be similar to the instrument issue that is being probed as a possible cause of the Air France crash, authorities said.

The plane was flying from Las Palmas, in the Canary Islands, to Oslo, and had been in the air 10 minutes when it landed. It was not immediately known what airline owned the plane.

Meanwhile, airlines around the world moved quickly to replace Airbus speed monitors like those suspected of feeding false information to the computers on Air France Flight 447 and possibly causing the plane to break up over the Atlantic Ocean.

While no cause has been established for the disaster, Derivry said the Pitot failures create "a web of presumptions, but only presumptions," that they could be a contributing factor.

The monitors had not yet been replaced on the A330 that was destroyed en route from Rio de Janeiro to Paris.

On Tuesday, the airline assured its pilots that none of its A330s or A340s would fly without at least two of the new instruments, and that all Air France A330s and A340s will have all three Pitots replaced by July. Brazil's air force said it is replacing them for the president's jet.

But some pilots said the planes should remain flyable even if Pitot tubes ice over in thunderstorms. And the European Aviation Safety Agency issued a precautionary safety bulletin Tuesday reminding operators about existing procedures to safely fly the aircraft even when air speed indicators malfunction.

"We are aware of issues with this in the past, but at no time were they classified as safety-critical," said Daniel Hoeltgen, the agency's spokesman.

About 70 airlines operate some 600 A330 planes similar to the doomed Air France jet, and two companies manufacture the Pitot monitors for them: France's Thales Group and Charlotte, N.C.-based Goodrich.

Thales made the Pitot tubes on the plane that crashed, company spokeswoman Caroline Philips confirmed. She did not say how many other planes use the devices.

Some major airlines — including US carriers United Airlines, Delta Air Lines, Delta's Northwest Airlines subsidiary and US Airways — said they are upgrading the devices on their Airbus planes, according to the manufacturer's recommendation, and warning pilots in the meantime.

"Until these installations are complete, we are communicating with our flight crews to reiterate the correct procedures to be used in the event of unreliable airspeed indications," Delta spokeswoman Betsy Talton said.

Some other major airlines said their Airbus jets use Pitots made by Goodrich and have had no problems related to icing or loss of data.

Airline industry officials also rallied to defend Airbus. 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."

The investigation was also examining the plane's vertical stabilizer from the tail section, which was found floating in the ocean. Damage that can be seen in images appear to reflect 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 that the vertical stabilizer was sheared from the jet could be related.

The Airbus A330-200 has a "rudder limiter" which restricts the movement of the rudder at high speeds. If it were to move too far while traveling too 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.

And could the loss of a rudder or stabilizer bring down a jet?

"Absolutely," Goelz said. "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."

France, Brazil and the Pentagon have said there are no signs that terrorism was involved in the crash.

Brazil's military is handling the search for passengers and wreckage, leaving the accident investigation to the French, who have not responded to questions about where the debris would be stored and examined. The cause of some other airline disasters — TWA Flight 800 off New York for one — have been discovered by meticulously laying out recovered wreckage in a warehouse.

Copyright AP - Associated Press
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