Apol's if this is old news, but searching for "Air Ambulance EC135 door falls off in flght" didn't bring back any results....
Apparantly when you operate the front cockpit door jettison lever,
deliberately or otherwise, it pulls the retaining pins out from the door hinges.
If you then pull the lever back up it DOESN'T push the pins back in again, and if you keep flying the door falls off !
- Anyone know more about this one ?
( A fairly recent occurrence I'm led to believe )