Ask the pilot

What if my seatmate tries to open the cabin door at 37,000 feet?

By Patrick Smith

Read more: Technology & Business, Business, P. Smith, Ask the Pilot

May 5, 2006 | Last Friday we focused on the plight of Harraj Mann, the Clash fan whose run-in with a hypervigilant cab driver was covered by the Sun, a U.K. newspaper. For the record, the British tabloids aren't normally on my reading list -- unless it's to sarcastically scrutinize a paper's shameful aviation reportage. The Sun, in particular, is notorious for overcooked air travel stories.

Then again, who needs Europe when there's the American media to kick around, with its own never ending supply of off-kilter articles? Behold the latest frightening incident in the skies above the American heartland, as brought to us by our old friends the Associated Press.

In summary: Two weeks ago, a disturbed man aboard a United Airlines flight out of Chicago had to be subdued after claiming to have a bomb and attempting to open a cabin door during flight. Passengers, along with three Secret Service agents en route to join President Bush's entourage in California, wrestled Jose Manuel Pelayo-Ortega to the floor of the Sacramento-bound Airbus A320. The jet was diverted to Denver, where Pelayo-Ortega was taken into custody.

A few things are wrong with the AP's rendering. First off, there's no such thing as an Airbus "A-320." Lose the hyphen; it's an A320. This may strike the average reader as an eminently excusable infraction, but it's one newspapers and wire services make repeatedly.

But getting to the meat of the issue: Despite the reporter's every attempt -- intentional or not -- to suggest otherwise, there was virtually no way for Pelayo-Ortega to open a cabin door while aloft. The facts and fallacies of airplane doors are a topic addressed in my book, and I touched on it in a column many months ago. (Judging from the mail I receive, this is a surprisingly common concern among airline passengers.) Now that the press has gotten hold of an incident and made mush out of the facts, it's worth revisiting.

Essentially there are two types of cabin doors: the larger kind, like the ones that passengers use to board and deplane, and the simpler, hatch-type emergency exits, normally found over the wing. All commercial airliners have the former. Others -- generally smaller types like the 737, A320 and various regional jets -- have both.

During flight none of these doors can be opened, for the simple reason that cabin pressure won't allow it. Think of an aircraft door as a drain plug, fixed in place by the interior pressure. With very few exceptions, aircraft doors open inward. Some retract upward into the ceiling; others swing outward or downward against the fuselage; but they all open inward first, and not even the most musclebound human will overcome the hundreds of pounds of pressure holding them shut. At a typical cruising altitude, as many as 8 pounds of pressure are pushing against every square inch of interior fuselage. That's 1,152 pounds of weight against each square foot of door. Flying at low altitudes, where cabin-pressure levels are lower, even a differential of 2 pounds per square inch is still more than anyone can displace -- even after six cups of coffee and the frustration that comes with sitting behind a shrieking infant for five hours.

For good measure, cabin doors are held secure by a series of electrical or mechanical latches, or both. So, while I wouldn't recommend it unless you enjoy being pummeled and placed in a chokehold by panicked passengers who don't know better, a person could conceivably sit there all day tugging on a door handle to his or her heart's content. The door is not going to open -- though you might get a red light flashing in the cockpit, causing the captain to spill his Diet Coke.

(If you're wondering about the infamous D.B. Cooper, he ordered the crew to depressurize the cabin, then parachuted out the rear tail-cone exit, which on the old Boeing 727 did not include an in-flight lock.)

On the ground -- and as one would hope with the possibility of an evacuation -- the situation changes. In most cases, opening a door on the ground -- while taxiing, for example -- will also activate a door's emergency escape slide. As an aircraft approaches the gate, you will sometimes hear the cabin crew calling out "doors to manual" or "disarm doors." This varies somewhat, depending on the type of plane, but it has to do with overriding the automatic deployment function of the escape slides. Parked at the terminal, you don't want the slides billowing into the Jetway corridor or onto a catering truck.

But, you ask, What if in the very first (or last) moments of flight, screaming down the runway at 150 knots, when pressurization is minimal or at zero, a man leaps up and grabs for the door? Will it open?

It might, yes. But unless he then hurls himself through the opening and directly into the path of a rear stabilizer, damaging it severely, nothing catastrophic is going to happen. Even if he's ingested by an engine, the plane will still fly.

Now, let's assume the worst. Say Mr. Pelayo-Ortega has a hydraulic jack hidden in his luggage and is able to pop the exit of that United A320, fully pressurized at 37,000 feet. At the very least, depending on exactly how fast the door opens, it's going to be excessively noisy and confusing, with oxygen masks dropping from the ceiling and people's belongings flying around. The aircraft might be damaged if debris strikes the wings, engines or tail. But there's a decent chance that the only person ejected from the jet will be Pelayo-Ortega himself, and possibly any occupants who aren't wearing their seat belts. (When the fuselage of an Aloha Airlines 737 ruptured during flight in 1988, only one occupant -- a flight attendant -- was pulled overboard.)

Next page: Even a minor in-flight disruption is liable to result in a pair of supersonic fighters hanging outside your window