French officials on Friday unveiled a report about the last moments of Air France Flight 447 in June 1, 2009, releasing information generated from ‘black box’ flight data discovered in early May.
The plane was on autopilot, flying at 35,000 feet when it encountered turbulence. At this point, pitot tubes, instruments which tell how fast the plane is moving, have apparently frozen and not working.
The pilots then slow the plane by disengaging the auto pilot and the auto-thrust. However they are slowing it too much, putting the plane into a stall as the nose of the plane rises as high as 16 degrees and the plane begins to ascend but begins to lose speed. By the time it reaches 38,000 feet the plane begins to fall, dropping at some points at 10,000 feet per minute, which is about 130 miles per hour.
The entire fall took 3 ½ minutes. With the pitot tubes frozen, instruments on the plane were not giving them useful information.
The plane was on a flight from Rio de Janeiro to Paris. It was carrying 228 people.
The black box was discovered in early May in what appeared to be good physical condition. It was found by a submarine scouring the ocean floor 3,900 meters (12,800 feet) below the surface.
The report was released by the Bureau d’Enquetes et d’Analyses (Bureau of Investigation and Analysis).