but that pilot could not get back in. the official says the cockpit voice recorder indicates quoting, "the guy outside is knocking lightly on the door and then he hits the door stronger and no answer. there is never an answer." he goes onto say, quoting "you can hear he's trying to smash the door down." so at this point there are two possibilities. the pilot inside the cockpit was either incapacitated though there's no sound of distress, or he deliberately kept the other pilot out. the cockpit door automatically locks. in the united states you must have two people in the cockpit. so if a pilot leaves, a flight attendant is require today go in. it's unclear what the rules are in germany, but this would explain why during the ten-minute descent there is no mayday or any conversation at the ground. take a look at the cockpit of the a320. there's no center yoke or control column. instead airbus uses a side stick controller.