On our F100's we had two different types of door.
I seem to recall that if an integral airstair was fitted, then the door was held by bolts, but if not then it was a plug type door. Also something about it was a derivative of the older F28, and a locating bar was needed to help the door line up properley for latching. Either way door unsafe indicators were fitted if the pins weren't fully home.
Or maybe I've forgotten it all already. Either way a scary experience.
