Originally Posted by
MechEngr
0.4 psi on the door would keep it shut. 30 inches X 80 inches -> ~1000 pounds of force to pull in against to get it off the stops.
I’d want to know a lot more about the door mechanics before concurring with that.
Clearly, the stops prevent direct outward motion of the door (whether or not there is cabin pressure). The door therefore needs to move upwards in order to clear the stops before moving outwards and then forwards.
How much resistance the stops present to upward movement of the door is a function not just of the pressure on the door forcing it against the stops, but also the friction between the door and the stops. The countless videos of A32x door operation don’t appear to show any appreciable inward movement of the door prior to lifting, so I doubt there is any geometric interference. The mechanical advantage provided by the handle is another factor, bearing in mind that raising the handle by approximately a foot appears to only lift the door by the 3 cm or so necessary to clear the stops.