With one pilot locked out of cockpit, events point to the suicide or sudden illness of remaining pilot, with latter theory unlikely say experts.
Black box audio tape said to reveal that one pilot was locked outside cockpit and tried to smash down door as jet descended towards the Alps.
The airman - the ninth member of the French Air Force to die in the tragedy - suffered serious burns and died at a Madrid hospital.
Bernard Mengin is recovering in hospital after rescuers eventually located his motor glider in a tree in mountains across the Spanish border.
Philippe Jernnard from La Rochelle was on a US Airways plane bound for Florida when the flight crew found him in the jump seat behind the pilot.
Moroccan passengers to take airline to court after pilot joked that 'His Majesty the King of Morocco' was delaying their flight from Casablanca.