Originally Posted by
mbstone
There are lots of NTSB reports involving small plane crashes in which a door came unlatched inflight and the pilot became so obsessed with solving the problem of a partially open door, a relatively minor problem in a Cessna, that he forgot to fly the airplane.
Early on in my flight training my flight instructor deliberately left the door of the airplane (Piper Warrior) unlatched so that it would open up in flight and I could experience firsthand that a small plane flies just fine with a door open.
Prior to this, I also experienced an unintentional door opening from the left rear seat of a Cessna 172 being flown by a friend. CFI flying right seat took the controls while my friend got the door closed and latched. Must have closed the door stoutly because the closing of the door caused the big hinged window that takes up most of the door to fly open. Then my job as the left rear passenger became to reach out into the slipstream and pull the window shut. The joys of light general aviation!
As to an airline cockpit door opening on takeoff, I have only experienced it once. AA ex-TW 757 departing MCO for DFW late at night after a long delay. Flight attendant seated on the jumpseat at door 1L leapt up quickly and slammed the door shut. Takeoff continued uneventfully. Pilots probably never even knew the cockpit door flew open until after the F/A shut it.