Airline Doors

A couple of recent news articles made me think of Cecil’s column on opening airplane doors in flight. (Cecil’s column at http://www.straightdope.com/classics/a2_390.html))

From: http://www.cnn.com/2000/TRAVEL/NEWS/03/09/airliner.opendoor.ap/index.html

The followup article was: http://www.cnn.com/2000/TRAVEL/NEWS/03/10/airliner.opendoor.ap/index.html

I am curious about the “The strap was pulled through the door seal” quote. I can’t pull a seatbelt through my car door when it’s closed and I bet a aircraft door seals a lot tighter than my car door. If it’s that loose, wouldn’t it leak air?

The second article goes on to say:

And, of course, the snaps would make it that much harder to pull through a “closed” door.

There is also the mention of lowering the cabin pressure, but if you are just going to “pull the strap through the seals” why would you need to lower the pressure?

My usually reliable sources are being very quiet and/or unhelpful on this one. Anyone here got any ideas on this one?


“Sometimes I think the web is just a big plot to keep people like me away from normal society.” — Dilbert

This is why the airplane was depressurized, so that the inside cabin pressure wouldn’t go rushing out through the door. Also, notice that American Airline claims the door wasn’t opened, but they didn’t claim it wasn’t unsealed or loosened. Maybe you can’t pull a seatbeat though your car door when it is closed tight, but if it were ajar it might be possible. I am guessing that the door was unsealed enough for the door seals to be in a relaxed state so the strap could be pulled in.


“The truth does not make a good story; that’s why we have art.”

The real link to Cecil’s column:
http://www.straightdope.com/classics/a2_390.html

Tanstaafl, be careful with punctuation.

It really sounds like you could be on to something. I know plenty of media sources would just as soon not arouse the anger of a potential major sponsor like Boing. I’d like to see some pilots say whether pulling a snapped strap though is even remotely possible.

Maybe you should post this to GQ - more people read that one.

Your Quadell

I don’t think that’s even possible. Aircraft doors have to open inwards first, and even a small pressure difference would prevent that.
Besides, if a plane is in flight, cruising at around 500 mph, the wind pressure would keep the door firmly closed. Even if some refugee from Krypton were to force it open, the wind would promptly tear it off!
And the plane can’t slow down without stalling, either. If THAT happens, the crew must worry about more pressing issues such as imminent impact with the ground…

Well they were at the altitiude of 12,000ft. Now if they were higher up at let’s say 32,000ft. (which is the cruising altitude for those big planes like the boeing we are talking about) Now when they reach that higher altitude they can also reach higher speeds, therefore raising the pressure on the exterior of the planes surface. Now suppose the airline attendants knew the seal would leak at the higher altitudes they probably did open the door to pull in the strap at 12,000ft.

Door seals in an aircraft are not seals like on your car door. Without knowing the exact mechanism, it’s possible that air pressure differential pushes the seal closed around the door frame, and that the seal may be made of rigid material like metal with a rubber covering or something. So if the air pressure differential is removed, the seal may be quite loose even if the door is latched shut. That’s my educated WAG.

Whether wind pressure would either make it impossible to open a door or rip it off its hinges depends totally on where the door is in relation to the aerodynamic characteristics of the airplane. If the door is on the side of the airplane, in an area of laminar flow, you may be able to open it easily and not move much air into the cabin at all. Think about a well-designed convertible, which can be travelling 100 mph with almost no wind in the passenger compartment. Same thing. Parachute jumpers open and close doors in flight all the time, or fly without any doors at all. If the jet is slowed to minimum safe speeds (say 1.3 times the stalling speed), it will be going maybe twice as fast as a jump plane, but not much more than that.

In my Grumman AA1 you could roll the canopy back at 135 MPH, easily. It would get louder in the cockpit, but with no wind blast at all.

Nicklz: Actually, the indicated airspeed (proportional to the wind resistance the aircraft is feeling) goes DOWN at higher altitudes. The airplane is travelling faster through the air, but the air is much less dense. So, the air exerts less force on the airplane.

The simple reason to do it at 12,000 ft is because that’s the highest altitude at which you can safely depressurize an aircraft. Above 12,500 ft, people will suffer hypoxia and other physical problems. If you depressurize the airplane at 32000 ft, everyone would be unconscious in a minute or two, and dead soon after that.

Finally getting back to following up on this…

Maybe, but there isn’t much difference between “ajar” and “open” in my mind. “Open a little bit” and “open a lot” are both “open”. YMMV

Oops! Closing parenthesis got me. Thanks.

As for airline doors, they open inward so they wouldn’t be “ripped off” by the wind. (It might get a bit breezy in the cabin though.) Opening inward causes them to be held shut by air pressure. If you have never seen an aircraft door open, they slide inward out of their frame for a few inches then pivot to one side on the hinge.

There is a rubberized gasket which seals the opening but the door itself fits fairly close within its frame.

I can accept that they 1) lowered the cabin pressure, 2) slid the door inward from the frame and 3) pulled the strap through. I still think that sliding the door inward counts as opening it though (even if it was never swung “open”).

Cecil’s column also mentioned that Boeing was changing their door design to prevent them from being opened in flight after the D.B. Cooper incident. OTOH, the article says that the aircraft in question was a 727 which is an older design, so it may not have had the new doors installed.


“Sometimes I think the web is just a big plot to keep people like me away from normal society.” — Dilbert

I was just using the word “ajar” for lack of a better term, but I was trying to say what others have now said better, which is that somehow the door could be unsealed enough for the strap to be pulled out without the door actually being opened and caught by the airflow around the airplane and being ripped off its hinges.


“The truth does not make a good story; that’s why we have art.”

Before we get too far down this “ripped off its hinges” path, have we decided which door it was? I know that the 727 has a door in the very back of the plane, which opens downwards to become its own staircase. In reading the news reports, they mentioned that the passengers in the back of the plane heard a noise, etc., so it makes me think that this is the one used. In which case, the airflow would tend to push the door closed again, but not rip it away.