Is it true that if you shoot a bullet through the skin of an airliner in flight, everyone would get sucked out the little hole? If not, Hollywood has a lot of explaining to do.
Adam and Jamie from Mythbusters on the Discovery Channel set out the other night to find out if this was true. The myth is based on the fact that an airliner at 35,000 feet is like a ballon flying through the air — the air pressure on the inside (pushing out against the inside of the plane) is much higher than the ambient air pressue at that altitude.
When you pierce the skin of a ballon with a pin, the whole thing pops. The pressurized air inside the ballon rushes out with such force that it “grabs” the edges of the hole as it leaves and tears the ballon apart in an instant. The same should be true for an airliner, right? And everything in the plane should go rushing out the hole, right?
No. Mythbusters proved this wasn’t the case, thus proving wrong several dozen action movies and at least one James Bond film. And, true to Mythbuster’s style, they proved this point with a veritable tidal wave of geekiness.
They went to an airline graveyard in the Mohave Desert and found an old Hawaiian Airlines 737. They sealed it up, then brought in a massive air compressor and pumped the plane full of air until the difference between the interior of the plane and the air at sea level was the same as it would be if the plane was flying at 35,000 feet.
Now the cool part — inside the plane, they had parked their crash-test dummy, Buster, in a window seat. In the aisle, they rigged up a Glock 9mm to a firing mechanism and pointed it at the hull of the plane. Then, with the plane fully pressurized, they fired the gun remotely.
What happened? Nothing. Sure, the air rushed out, but even styrofoam peanuts they had placed in the aisle didn’t move, much less Buster. They did the test a second time, this time firing through the window right next to Buster. Same result — nothing.
Not satisfied (I love it when they’re not satisfied…), they rigged explosive cord around the window to simulate the window blowing out due to structural failure. They pressurized the plane again and blew the window.
The results were much more satisying — Buster got his arm yanked out the window. Crash test dummies aren’t designed to come apart, but if he were a human, I think he would have lost his arm. However, the rest of his body just wasn’t going through the window, no matter what the myth said.
Still not satisifed, Adam and Jamie put a “shaped charge” (whatever that is) against the hull next to Buster’s knee. Plane pressurized once again, they blew the charge.
Now, I don’t know how much damage was from the charge and how much was from the air rushing out, but the entire roof came off the plane. Buster, believe it or not, was still belted in his chair, but there was a 20-foot section of the roof missing. That plane was toast, and it looked eerily similar to Aloha Airlines flight 243 that lost its roof in mid-flight back in 1988.
So, myth busted. However, they didn’t address one thing: the drop in air pressure caused by the velocity of the air outside the plane. You see, the entire concept of flight is based on the fact that air pressure goes down as the speed of the air goes up.
So when a hole gets blown in the side of the plane, even after all the air rushes out and the pressue of the plane is equal to the ambient air pressure at that altitude, you now have 600 m.p.h. air rushing past the hole, which would have a much lower air pressure than the stationary air inside the plane. Does this make sense to anyone else?