Can the cabin door be opened in flight?
 

Yet another incdent, this time in CHina, of a crazy passenger trying to open the cabin door in flight. Does anyone know if this is really possible? Especiallly on a pressurized aircraft.

Is this a threat we must take very, very seriously?

It depends on the aircraft.

Most of the command airliners have plug-type doors which can not be opened when the aircraft is pressurized. Other airliners don't have plug-type doors so opening would be possible, though difficult, when the airplane is pressurized.

Under 9,000 ft isn't air pressure equalized between cabin and outside? Does that mean that at low altitudes nothing keeps someone from opening the doors?

Fortunately, many people with such inclinations don't know one usually has to pull emergency exit doors inward. For those that open outward, except at the rear, there would be significant air flow pressure to overcome.

The sergeants who open doors for military parachutists are always tethered in themselves.

I often sit in exit row seats and have thought about this myself. On the 737 I was on last Friday the exit doors over the wings hinged at the top and very definitely opened outwards - so the higher cabin pressure compared to outside would aid opening the door at altitude. What is there to stop some lunatic opening these doors in flight?

Look closer at the design. The doors are hinged such that they have to go inward before they can go outward. Probably the best place to witness this on any sort of plane is sitting at the exit row right next to door two on the 757 (row nine on UA, not sure about other airlines).

Isn't it interesting, that everything you need to know can be learned right here on the BBS to be a troublemaker?!

No. The airplane begins to pressurize either during taxi, or immediately after takeoff, depending on the aircraft.

The idea is to keep the rate of change and maximum cabin altitude both as low as possible to minimize discomfort.

The door can be opened inflight, in order to evacuate smoke in the cabin.

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When one considers the surface area of a door or window exit multiplied by the air pressure pushing against it, you'd need to be able to move several thousand pounds in order to force open a door or window.

Cabin air pressure at cruising altitude is lower than air pressure at sea level. At a typical cruising altitude of 11 000 metres (37 000 feet), air pressure in the cabin is equivalent to that at an altitude of 1500–2500 metres (5000–8000 feet) above sea level. Which explains why my ears don't pop nearly as much flying in and out of the mile high city of Denver!

Let's say a window exit measures 3 feet by 5 feet. Sea level air pressure is 14.7 pounds per square inch. (Cabin air pressure would be less, but we'll use 14.7 psi for this exercise). Hence the weight of the air pushing against that window exit would be nearly 32,000 pounds or 16 tons (2160 square inches of exit multiplied by 14.7 pounds per square inch).

To those who provide reasons why it's not possible to open a cabin door, i offer 1 word: D. B. Cooper

(OK, 1 word and 2 initials.)

Yes, but D.B. Cooper opened the door in the tail of an airplane.(I am sure someone here can cite the mfg and model, if not the actual aircraft number!) Those doors are been disabled on that model of plane...and IIFC on all tail section doors. At a rear facing door it would make sense that outside airpressure from forward motion would not be an issue. But then again, I am not an engineer, pilot, or skydiver. I did though live a few years with a retired US Army Airborne colonel.

Lik people say, it would depends on the door. Obviously, on some airplanes, doors will open easily. Like planes used for skydiving. (that is, if then even have a door or keep a door closed).

I've never been on an airliner where the door opened up in flight. But I have on small single engine airplanes. No big deal, really.

Just keep the seatebelt on, like they tell you to. http://www.flyertalk.com/travel/fttr...orum/smile.gif

So during taxi, this would mean that they depressurize the interior to equate to a higher altitude? This would minimize the change in pressure as the plane rises. But then shortly after takeoff, the pressure outside would be greater, thus making it very easy to open an inwards-opening door.

I believe DB Cooper depressurized the cabin pressure and was at a relatively low altitude.