Two out of three pilots were sleeping minutes before the Air France plane plunged into the sea off Brazil in 2009, with the loss of all 228 people on board, media reported Monday.
Horrific details of the last moments of Flight 447 have emerged in a disturbing new investigation into the 2009 disaster involving an Airbus 330, Daily Mail online reported.
Recorded conversations between 37-year-old David Robert, Pierre-Cedric Bonin, 32, and Marc Dubois, the 58-year-old captain of the plane, reveal that two of them were asleep when the plane got into difficulty in a tropical storm, said the report.
It said the findings "raised terrifying questions about safety aboard civilian passenger jets", and the "culture" of the Air France pilots on board, the report said.
"If the captain had stayed in position through the Inter-tropical Convergence Zone, it would have delayed his sleep by no more than 15 minutes, and because of his experience, maybe the story would have ended differently," chief investigator Alain Bouillard was quoted as saying.
"But I do not believe it was fatigue that caused him to leave. It was more like customary behaviour, part of the piloting culture within Air France," he added.
Robert was also sleeping in the small cabin containing two berths just behind the cockpit when the disaster happened.
The plane was suffering from a loss of lift or a "stall" and its airspeed sensors had malfunctioned but the junior pilot, instead of lowering the plane's nose to deal with the stall, as they should have done according to normal procedures, raised it.
Dubois finally entered the cockpit one minute and 38 seconds after the pivot tubes malfunctioned, but by that time it was not possible to save the plane, according to the report.
Robert said: "F***, we're going to crash! It's not true! But what's happening?"
Soon after, either Robert or Bonin are heard to say, "F***, we're dead" before it crashes into the Atlantic.
It took two years to retrieve bodies and essential records such as the flight's voice recorder from the bottom of the sea, the report said.
Air France, however, denied that its pilots were incompetent.
Both Air France and Airbus are facing manslaughter charges.
