When flying at cruise altitude, the pressure inside the aircraft is higher than outside and that means a lot of air is pushing the door outwards. So how does the door stay in place and not open?

I'm not asking if a passenger could open a door, because that's almost impossible. I'm asking how does the door not open if there is a lot of air pushing it outwards?

  • $\begingroup$ I don't understand the question. Obviously doors can be opened, because people go in and out of them on the ground. If it's impossible for a passenger to open a door, what do you think is going to open the door? Most airliner doors (cargo doors generally excepted) open inwards (plug doors). Since there's a lot of force pushing the door outwards while the aircraft is pressurized, as you note, it requires a lot of force to pull the door inwards. $\endgroup$ – Zach Lipton Apr 2 '16 at 0:13
  • 4
    $\begingroup$ aviation.stackexchange.com/questions/15011/… $\endgroup$ – SMS von der Tann Apr 2 '16 at 0:17
  • 1
    $\begingroup$ @ZachLipton My question is: in-flight, when the cabin pressure is higher than outside, how does the door stay in place and not open? Because there is a lot of air pushing the door outwards $\endgroup$ – kepler22b Apr 2 '16 at 0:17
  • 3
    $\begingroup$ What stops anything breaking when it's used? The fact that it's been designed to be used in the way that it's designed to be used. $\endgroup$ – David Richerby Apr 2 '16 at 4:35

Most of the airline doors are plug type- i.e. they are wedge shaped, so that the pressure differential pushes it against the fuselage and prevents opening. For example, the following image shows the Boeing 737 door.

B737 door

Image from airteamimages.com

Note that the door is bigger on the inside, so that when it is locked in position, the pressure will push it against the fusealge, preventing it from opening. For opening the door, it has to be swung inwards before moving out.

  • 4
    $\begingroup$ Most of the airline doors are plug type - not for long. Most of the current generation don't use plug doors. $\endgroup$ – Simon Apr 2 '16 at 6:40
  • $\begingroup$ @Simon Am I right in assuming that the door still latches into the frame under force from seal face? Can they be cycled to another position whilst the door is under the pressure differential at cruise? $\endgroup$ – jCisco Dec 4 '17 at 8:21

Not the answer you're looking for? Browse other questions tagged or ask your own question.