article_snippet: When are pilots allowed to leave the cockpit?
article_snippet: Patrick Sonderheimer, the pilot of the plane, waited to reach cruising altitude  before stepping out of the cockpit, pictured .
article_snippet: Patrick Sonderheimer, the pilot of the Germanwings plane, waited to reach cruising altitude at 38,000ft before stepping out of the cockpit.
article_snippet: Why was co-pilot Andreas Lubitz allowed to remain on the flight deck on co-pilot Andreas Lubitz own?
article_snippet: Access to the cockpit door on the Germanwings
article_snippet: But, in line with German aviation authority requirements, Germanwings did not stipulate that a pilot could not be left alone in the cockpit.
article_snippet: Why was the pilot unable to get back into the cockpit?
article_snippet: But Lubitz was able to barricade Mr Sonderheimer inside the cockpit thanks to an armoured bullet-proof door designed to protect passengers by keeping out terrorists.
article_snippet: What screening did Lubitz undergo before being allowed to fly?