Note to Piper owners:
When closing the doors, observe that the top latch does not ride up over
the top of the vertical latching"pin".
If you grasp the door mounted "hooked" latch, check to see if it is
loose and moves vertically or is firmly attached.
If it is loose, it can ride up over the top of the latching pin and give
a false indication of the tap latch being secure.
The door can then "pop open" in flight as the lower latch may not be
strong enough to withstand the air pressure differential between the
cabin and the slipstream.
The solution to assuring the latch is secure is to hook a finger over
the top of the latch and gently pull it downward and guide it so that
the latch hook centers around the latch pin as the door is pulled closed
and engage the top latch lever before depressing the lower latch lever.