I would imagine this would be standard procedure to keep the cabin door locked sort security purposes. I'm a bit surprised the captain would not have a key. Can the door only be opened from inside?
If the copilot can be heard breathing, but nothing else, is it possible the copilot passed out or had a stroke?
A locked cockpit door can normally be unlocked from outside, apparently. Here the co-pilot deliberately locked him out. That’s not something done after having a stroke or whatever
A commentator on CNBC reporting on the German press conference characterized the breathing as calm and normal and not indicative of a health issue. No words were spoken by the co-pilot.
Probably not. The French prosecutor said it looks like he deliberately set the instruments to descend into the mountainside.
The French news conference had this question. The response is that the plane was on auto pilot. To begin the descent you would have to turn and turn and turn the wheel, not just a little eg if you passed out and you nudged the wheel.
The man is breathing normally.
Secondly, the pilot can unlock or lock the door from within. If he puts it on “lock” you cannot enter with the pass code.
In the USA someone must be in the seat if a pilot leaves. This is not the case in Europe.
The Captain has an emergency access code to gain entry when the cockpit door is locked. It can be intentionally disabled from within the cockpit.