Audio recovered from the cockpit voice recorder indicates one pilot left the cockpit before the plane began its descent and was unable to get back in. A senior military investigator:
The guy outside is knocking lightly on the door and there is no answer. And then he hits the door stronger and no answer. … You can hear he is trying to smash the door down. We don’t know yet the reason why one of the guys went out. But what is sure is that at the very end of the flight, the other pilot is alone and does not open the door.