Air France Flight 447 may have stalled after pilots slowed down too much after encountering turbulence, according to new information leaked to the French press.
Airbus is sending advice on flying in storms to operators of its A330 jets, according to Le Monde newspaper. The report reminds crews to maintain adequate speed and the correct attitude, or angle of flight, when entering heavy turbulence.
Pilots usually slow down aircraft when entering stormy zones to counter its effects
However the aircraft risks stalling if speed is reduced too much.
Experts argue that Airbus issuing the new advice suggests that investigators have evidence that the aircraft slowed down too much, causing a high-altitude aerodynamic stall. This would also explain why the aircraft broke up at altitude.
A company official said: “Each time there is an accident, it is imperative for the manufacturer to inform all operators of the type of aircraft concerned of any specific procedures to put in place or any checks to carry out.” However Airbus declined to comment on the report.
Accident investigators have data of the last four minutes of Flight 447, transmitted automatically by satellite to Air France’s base at Paris Charles de Gaulle airport.
A stall would also be consistent with the sequence of events that have leaked to the media from the Air France data. At 35,000ft - the altitude at which Flight 447 was cruising - is hard to recover from stalling in still air, but in the midst of a tropical storm, it would be virtually impossible.
Accident investigators believe the chances of recovering the black box would be virtually zero as it would be 3,000 metres under water - a depth at which no black boxes have previous been recovered. The search would be made even tougher as the ocean floor in the region is mountainous.
However a French deep-sea research vessel and robot submarine will begin their search to track and retrieve the recorders, which should be transmitting homing signals.
Even with the recorders, investigators might never be able to solve the mystery of Flight 447, said Mr Arslanian. He said: “I cannot rule out the possibility that we might end up with a finding that is relatively unsatisfactory in terms of certainty.”
Meanwhile the navy along with French spotter aircraft are scouring an area about 745 miles (1,200km) northeast of the coastal city of Recife. They have so far found seats, plastic and sections of aluminium on the surface from the Airbus A330 that came down early on Monday while flying through severe storms from Rio de Janerio to Paris. The discovery dashed hopes that passengers could have survived.