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.

You cannot de-pressurize an aircraft below the outside pressure for a departure. There is no mechanism for sucking air out of the cabin. The only thing you can do is blow air into the cabin and let air leave the cabin on its own.

The cabin air pressure depends on the rate at which air is being pushed into the cabin and the rate at which air is allowed to leave the cabin through the outflow valves. More air coming in than going out means increasing air pressure, and less air coming in than going out means decreasing air pressure.

I believe you could have lower cabin pressure than outside pressure when landing, if you close the outflow valves when descending. It shouldn't be a big difference -- maybe 0.25 psi.

I suspect that if pressurization begins before take-off, the pressure differential is very small. Maybe it has something to do with conserving engine power during take-off.


About a year or so ago, an AA (A300?) landed at MIA. The FA opened the door too soon, and the plane suddenly depressurized. He was thrown out of the plane onto the ground, and I think he was killed.

[This message has been edited by JS (edited 07-04-2002).]

Copied from this link:
http://news.airwise.com/stories/2000/03/952626592.html


Jet's Door Opened At 12000 Feet
Mar 9, 2000

A flight engineer opened a door to pull in a loose strap on board an American Airlines jet flying at 12,000 feet. Passengers on the Miami to New York, Newark flight did not know what was happening until there was a sudden change in cabin pressure.

They felt their ears pop and air rushed through the cabin about 1.30 p.m. Wednesday when a rear door was opened

The pilot later explained that the strap had to be retrieved because of the possibility its buckle could break loose and get sucked into an engine, passenger Cora Diaz told The Star-Ledger of Newark in a story for today's editions.

Diaz said she was sitting at the back of the airplane and saw a flight engineer and two crew members open the door.

``Everybody picked up their heads and said, 'What's going on? What's going on?''' Diaz said.

After closing and locking the door seconds later, the flight engineer returned to the cockpit and the pilot explained the procedure. The pilot said the strap was inadvertently left behind by food service workers.

He told passengers he slowed the plane and remained at 12,000 feet during the maneuver, Diaz said.

The Federal Aviation Administration is reviewing the incident, and a spokesman declined to say whether the pilot had acted properly.

No, they pressurize to slightly below field elevation. The purpose is to minimize the rate of pressure change immediately after takeoff. The newer airplanes do this, the older ones do not.

It was a B727.

D.B. Cooper had the crew descend to an appropriate altitude and then depressurize the airplane. Also, the rear stairs on a B727 is not a plug-type door so that wouldn't have been an issue.