Backgrounder: World's mysterious airplane crashes

Air France Flight 447, all 228 people on board killed

Brazil's Navy sailors recover debris from the missing Air France Flight 447 in the Atlantic Ocean in this June 8, 2009 file photo released by Brazil's Air Force. French aviation investigators said on Dec 17, 2009 that new airline safety standards may be required after the crash of Air France Flight 447 cast doubt on the reliability of speed-measuring equipment in difficult, stormy conditions. [Photo/IC]

On June 1, 2009, Air France Flight 447, an Airbus A330, went down over the Atlantic Ocean after leaving Rio de Janeiro for Paris, killing all 228 people on board.

The aircraft's black boxes were not recovered from the ocean floor until May 2011, nearly two years later.

A final report released by the French government in July 2012 stated that ice crystals obstructed pilot tubes in the aircraft, causing the autopilot to disconnect.

The crew reacted incorrectly and ultimately led the aircraft to an aerodynamic stall from which they did not recover, the report said.