I read this story on CNN.com, which is about a crazy airplane passenger who tried to operate the lever of an exit door while the plane was in mid-flight.
And that got me wondering. There *is * a mechanism to prevent an exit door from opening while the plane is in flight, isn’t there? (Please, *please * let the answer be yes…)
On a side note, I was struck by the passage in the article that said that air marshalls eventually subdued the dude. Air marshalls? More than one? I thought we only had enough air marshalls to put one on every 30 or so flights, and there were two or more on this one?
The doors need to come inward slightly before they can be opened outward. Pressurisation dictates that you’d need to be superman to be able to bring the door in.
Still, I dunno what would happen if you tried at 800ft.
I don’t think it’s possible; apart from any safety interlocks that might exist, my understanding is that, although the doors on most commercial planes open outwards, they are hinged in such a way that they must be pulled inside the plane first, turned, then pushed back out through the doorway. I think the pressure holds them in place. Could be wrong about that though.
I think the design is called a ‘plug’ door - it is a safety requirement to prevent the door blowing out if it is improperly fastened or something breaks.
This makes me wonder about D.B. Cooper who parachuted out of a commercial airliner with a backpack of money. He must have jumped out at an elevation low enough that the air pressure inside the plane was low enough that he was able to overcome the pressure and open the door anyway.
I can’t see Xema’s site linked above, as work thinks it’s inappropriate. But I’ll walk you through my own rough calculation:
According to this page, airlines typically pressurize their cabins to an equivalent of 6000-8000 ft altitude. Using a value of 7000 ft corresponds to a pressure of 1632 lb/ft[sup]2[/sup]. The pressure outside at 30000 ft is 628 lb/ft[sup]2[/sup].
So the outward pressure on the door at altitude is 1000 lb/ft[sup]2[/sup]. I don’t know exactly how big an airline emergency door is, but let’s say it’s only 4 ft x 3 ft. That’s 12 ft[sup]2[/sup], which figures to 12,000 pounds of force required to move the door.
Suffice it to say that door isn’t budging in flight. Get down to 8000 feet or below and it’s a different story.
Please note that DB Cooper jumped from the rear of a 727; this was not a typical “side of the plane” emergency exit; some (if not all) older models of the 727 had a rear exit that folded down with a staircase (under the tail section). I once boarded such a plane that way in Munich. I believe it could be lowered in mid flight; enough for a maniac to jump with a 'chute.
Thousands of skydivers who have attended the World Freefall Convention can attest to this, for many years they’ve had a 727 cargo jet as a special attraction. 160 people to 14,000ft, we exited via the rear airstair.
Yes, and DC-9’s, too. After the “DB Cooper” incident, they were retrofitted with spring-loaded vanes that rotate across the door edge when air flows over them, to prevent in-flight openings. The part’s name? The DBC Vane.
Most definitely. Dunno about more recent years but when I went nobody was doing big formations out of the jet. 120mph exit speed, single file. We’d drop half the plane, then turn around and do the other half.
Result is 160 skydivers in a great big line spread all over the countryside.
You could certainly do formations, there’d just be an awful lot of distance to close. For the big record attempts it always seems to be something like a half-dozen C-130s where you can get everyone out the door very close together.
Amusing note, the first time that they ever did it back in the 1990s people started getting out before the pilot throttled back the engines and they were hitting the air at 160mph. Lots of amusing video of helmets and shoes being knocked off when people entered the airstream.
Right, it doesn’t open, but someone futzing about with the mechanisms while in flight can damage something that may cause trouble later on, e.g. render the door inoperable or damage the emergency chute.
