A witness saw the left main cabin door open during flight, and an examination of the door showed the interior handle was not in the locked position.

Authorities believe that plane door may have been open before the small jet ended up crashing into a Fullerton warehouse, killing the pilot and his daughter.

An amateur-built plane that slammed into a furniture warehouse near Fullerton Airport, killing the pilot and his teenage daughter and injuring 19 victims on the ground, had defects in a door that appears to have contributed to the collision.