Why was a pilot locked out of the cockpit?

[Time]

One of the pilots on Germanwings Flight 9525 was locked out of the cockpit when the plane crashed Tuesday, a senior military official told The New York Times, citing evidence from the cockpit voice recorder.

http://www.cnn.com/2015/03/25/europe...ain/index.html

[Lazie]

All pilot affi start wear pampers to prevent a wacko from have complete control of the cockpit.

[Jangle]

Protocol says that if one of the pilots want to leave the cockpit, then a flight attendant needs to sit in while one is out.

[Za]

Protocol says that if one of the pilots want to leave the cockpit, then a flight attendant needs to sit in while one is out.

US protocols not European

[Islandman]

Co-pilot appears to have deliberately crashed plane

http://www.marketwatch.com/story/ger...ane-2015-03-26

[MdmeX]

Co-pilot appears to have deliberately crashed plane

http://www.marketwatch.com/story/ger...ane-2015-03-26

See also

http://www.bbc.com/news/world-europe-32063587

[Willi]

U sure about that?

[Time]

Co-pilot appears to have deliberately crashed plane

http://www.marketwatch.com/story/ger...ane-2015-03-26

Hold on. We should really wait for the data recorder before reaching a conclusion. It looks like a deliberate crash but;

1- Pilots can go to sleep. The remaining co-pilot could have been sleeping or had a heart attack. If he was sleeping he could disable the auto pilot by mistake.

http://www.dailymail.co.uk/news/arti...150-miles.html

2- You can disable the auto pilot by accident. For example, you can do it by bumping the engine control that is between the two pilots or by turning the control column. However the control must feel the pressure for at least 30 seconds before it disable the auto pilot.

http://timesofindia.indiatimes.com/i...w/19860300.cms

http://en.wikipedia.org/wiki/Aeroflot_Flight_593

3- The cockpit door can malfunction and jam. But the co-pilot should have declared an emergency, unless he was asleep.

http://abcnews.go.com/US/delta-plane...ry?id=28590807

4- The A32X series has an airworthy directive for a problem that can cause the jet to nose down lose height and crash.

http://www.mirror.co.uk/news/world-n...-crash-5392290

5 - The jet was serviced just before the flight because it had issues.

http://www.dailymail.co.uk/news/arti...ed-faults.html