Submarine at air crash scene to hunt black boxes

A French nuclear submarine reached the crash zone of Air France Flight 447 today to comb the Atlantic depths for black boxes which should help determine what brought the Airbus down in the sea off Brazil with 228 people on board.

The slow-moving attack sub Emeraude will be able to trawl patches of about 13 square miles a day trying to pick up the boxes’ acoustic beacons or “pingers”, which are expected to start to fade 30 days after the crash, French armed forces spokesman Christophe Prazuck said today.

Brazilian searchers said they had now recovered 41 bodies from the scene. The remains are expected to be flown to Recife, Brazil, where investigators hope to identify them and find clues into the crash based on the victims’ injuries.

Without key information from the Airbus 330’s missing data recorders, investigators have focused on the possibility that external speed monitors - Pitot tubes – iced over and gave false readings to the plane’s computers as it flew into thunderstorms on May 31.

Airlines around the world have begun replacing Pitot tubes on their aircraft. And the European Aviation Safety Agency, responsible for certification of Airbus planes, said it was “analysing data with a view to issuing mandatory corrective action” following reports about the possible malfunctioning of the Pitot tubes.

It said this action should not prejudge the outcome of the investigation into the Air France crash and that the causes of the accident were still unknown. It said the A330 and other Airbus aircraft were safe to operate.

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.

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