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I have never sat on the emergency seats near the wings, with the emergency exit. I have seen cabin crew instruct the passengers seated near the door on how to operate the door.

My question, what prevents a 'rogue' passenger from opening them mid-flight?

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    $\begingroup$ The answer should start with "if a passenger wants to open a door mid-flight, and if we freeze time to stop the other passengers running in his direction to beat the s**t out of him, then ... pressure differential ... etc." $\endgroup$ – WoJ May 23 '15 at 18:36
  • $\begingroup$ Well, it actually happen: skift.com/2015/05/12/… $\endgroup$ – Antzi May 24 '15 at 6:57
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    $\begingroup$ "planes that were taxiing or at a standstill" < not quite in mid-flight, though $\endgroup$ – user1804 May 25 '15 at 4:35
  • $\begingroup$ @HorusKol I imagine this could happen just after take-off roll (not yet mid-flight, but already in the air) $\endgroup$ – Manu H May 26 '15 at 14:29
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At cruising altitude there is between 4 and 8 tons of pressure acting on the inside of the door. There aren't too many passengers capable of exerting that much force on the handle (and even fewer handles that won't just snap off). Latch type doors have interlocks or over-center latches that prevent operation with a pressurized cabin.

It's theoretically possible to open the over-wing exits at approach altitudes when there is no pressure differential. Other than being windy/noisy it would not affect the flight in any way. Cabin doors usually open forward, good luck pushing them open against the airflow. If the person who pulled the window plug wants out, it's their (and only their) funeral. I've sat in the open doors of light aircraft in flight hundreds of times, legs in the breeze, no seatbelt, while the plane makes fairly steep turns toward the open door side. It's not a problem.

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    $\begingroup$ I've done it too, usually just before jumping out :) $\endgroup$ – rbp May 23 '15 at 14:15
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    $\begingroup$ @rbp I usually had to ride the plane down to pick up the next load. $\endgroup$ – paul May 24 '15 at 0:40
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    $\begingroup$ "Legs in the breeze" not on the rudder pedals? Also every jump pilot I saw wore a chute. $\endgroup$ – rbp May 24 '15 at 16:22
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    $\begingroup$ @rbp a) never said I was flying it, b) never said I wasn't wearing one $\endgroup$ – paul May 25 '15 at 0:51
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    $\begingroup$ @Aron no. Just because the door swings outward doesn't mean it opens outward. youtube.com/watch?v=C9_BUR8rGtE Watch carefully - the door is released, moves IN, then rotates and swings out. Yes, the hinge mechanism is rather complex. $\endgroup$ – paul May 26 '15 at 12:04
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In addition to the pressure differential, some aircraft also have mechanical locks. Here's the logic diagram for a 737 NG. This will be similar to all of Boeing's exit doors that are hinged at the top.

Door lock logic diagram

These conditions cause the emergency exit doors to lock:

  • Three or more of the entry/service doors are closed, and
  • Either left or right engine is running, and
  • Air ground logic is in the AIR MODE, or
  • The left and right thrust levers are advanced more than 53 degrees
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  • $\begingroup$ Could you add some clarifying text for those of us that can't read a logic diagram and/or aren't familiar with the terms used? $\endgroup$ – Nzall May 24 '15 at 16:55
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    $\begingroup$ So if 3 or more doors are entry/service doors are closed, no emergency door can open? So even on the ground with the engines off, if no one can open a non-emergency door for some reason, the emergency doors won't open either? $\endgroup$ – Dronz May 26 '15 at 0:25
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    $\begingroup$ @Dronz No, the rightmost logic gate is an AND. If 3 or more entry/service doors are closed; AND at least one engine has N2 >=50%; AND BOTH thrust levers are advanced more than 53 degrees OR the air/ground logic is in "air mode", THEN the doors lock. If at most 2 entry/service doors are closed, OR both engines are under 50% N2, OR at least one thrust lever has been advanced less than 53 degrees AND the air/ground logic is in "ground" mode, then the doors are not locked. $\endgroup$ – cpast May 26 '15 at 0:36
  • $\begingroup$ Hmm really interesting. Shows how far the aircraft engineers go to take care of security. $\endgroup$ – Dragonborn May 26 '15 at 6:37
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    $\begingroup$ Could you indicate the source from which you took this diagram? $\endgroup$ – Manu H May 26 '15 at 12:52
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At $10,680 m$ cruising altitude air pressure is $23.8 kPa$ / $3.45psi$ / $23,800 N/m²$; compared to $101kPa$ / $14.7psi$ / $101,000 N/m^2$ at sea level.

Now a 747 for example has a pressurization altitude of $2,440m$ which equates to an internal pressure of $75kPa$ / $10.9psi$ and a force of $75,000 N/m^2$.

So the internal pressure of $75,000 N/m^2 - 23,800 N/m^2 = 51,200 N/m^2$

Door dimensions are $1.93m (H) \times 1.07m (W) = 2.07m^2$

Or in feet & inches: $6'4" (H) \times 3'6" (W) = 22.17 sqft$

So $51,200 N/m^2 \times 2.0651m^2 = 105,733.12 N$

Which equates to roughly 11.88 Metric Tonnes of force on the inside of the door! The door being larger than outside portal of the door. It is forced into the frame with considerable pressure. It would be impossible for a human to operate the door under that force.

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  • $\begingroup$ Depends on their tools--you could develop that force with a block and tackle. (That doesn't mean you'll get it open, though--I'm sure you'll just bust the handle instead.) $\endgroup$ – Loren Pechtel May 26 '15 at 4:25
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The pressure differential will stop you.

In flight the airplane is pressurized to keep you conscious at high altitude. The doors plug doors with flanges and must be pulled inwards to open them; those flanges make them impossible to move even after you release the latches.

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  • $\begingroup$ But pressurization in the cabin will create a grater pressure inside the plane and with a smaller pressure outside the door should be pushed out ... $\endgroup$ – Davide May 23 '15 at 11:29
  • $\begingroup$ @Davide check my edit $\endgroup$ – ratchet freak May 23 '15 at 11:41
  • $\begingroup$ Oh right I did not know about that system ! $\endgroup$ – Davide May 23 '15 at 11:46
  • $\begingroup$ What about when the aircraft is not pressurized (beginning of climb and approach)? $\endgroup$ – Manu H May 23 '15 at 12:41
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A young man jumped from a plane :

The Globe and Mail

"The Beechcraft King Air 200 turpoprop aircraft was flying at about 23,000 feet at the time of the incident."

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    $\begingroup$ I wonder if this could have something to do with it being a turboprop or lower altitude? $\endgroup$ – Zizouz212 May 26 '15 at 1:50
  • $\begingroup$ Or a different style of door. Without looking, I would suspect that a King Air 200 has slightly different certification requirements than a Part 121 transport. $\endgroup$ – Sports Racer May 26 '15 at 16:13
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    $\begingroup$ For those truly interested Google 14 CFR 25.783 Fuselage Doors for Transport Category aircraft and 14 CFR 23.783 Doors for Normal Category aircraft which is what the King Air is. $\endgroup$ – Sports Racer May 26 '15 at 16:51

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