Danger at 40,000 Feet

"Explosive decompression" is what happens to passengers and crew members of a pressurized airliner when a window blows out at high altitude. Announcing that it had made some experiments on the subject, the Civil Aeronautics Administration said soothingly last week that such disasters are no great peril just now, because airliners do not fly high enough. But cruising altitudes are increasing. In an effort to make airplane manufacturers fully conscious of future dangers, the CAA made a movie which chilled the blood of hard-boiled air designers who saw it.

At the CAA's aeromedical laboratory at Oklahoma City, CAA man John J. Swearingen built a pressure chamber like an airliner's cabin, with seats and a window of thin plastic. He made dummies with the weight, center of gravity and articulated joints of an average human being. He seated a dummy next to the window and pumped air into the chamber to simulate conditions in a pressurized airplane flying at 30,000 ft.* Then he focused his movie cameras and broke the window.

Out Like Toothpaste. As the air rushed out of the cabin, the doomed dummy rose from its seat, shot toward the window and was forced through it like toothpaste extruded from a tube. When the pressure simulated an altitude of 40,000 ft., the dummy shot clear across the room, its legs and its arms detached.

After repeating the experiment many times, Swearingen decided that if a passenger is sitting less than 7 1/2 inches from the window (i.e., in the window seat) he will be "captured" by the outrushing air. Farther away (i.e., in the aisle seat), a passenger would be safer.

To test this conclusion, Swearingen himself sat in the aisle seat. When the window blew out, the inner seat rose in the air, spun around and tried to ram itself through the window. Swearingen's body jerked slightly as the air clawed at it. He insisted that he was in no danger, but other CAA men testified that "he couldn't light a cigarette for five minutes afterward."

Saved by Curves. Present-day windows, says the CAA, are strong enough to carry present-day pressures, and at the comparatively low altitudes (18,000 to 20,000 ft.) now flown by airliners, a passenger is unlikely to be captured by a rush of air to a broken window. There has been one such accident, but it did not turn out too badly. An airline hostess was sucked to a window, but her hips were wide enough to stick in the frame and save her from being popped like a cork into the empty air.* The pressure difference (only 2 1/2 lbs. per sq. in.) was not great enough to extrude her completely. ("Still," said one CAA official, "whenever I see a child banging on the plane window with a toy, I get up and tell him to stop it.")

Another danger of high-altitude flying is "anoxia" (lack of oxygen). If a pressurized plane should suddenly lose its air at 40,000 ft., the passengers, according to Swearingen, would lose consciousness in seven seconds, die in 45 seconds. Loss of pressure at 40,000 ft., said a CAA man, "is a complete catastrophe--like a wing falling off."

The time will come, thinks the CAA, when "explosive decompression" must be faced squarely. Jet airliners will have to fly at 40,000 ft. to economize fuel. The best way to make them decompression-proof, think some CAA men, would be to build cabins with no windows at all. A television eye in the plane's nose could show the passengers the country passing below--or movies could amuse them.

*At that altitude, the atmospheric pressure is 30% of that at sea level.

*There have been several cases of navigators blown out of broken observation domes and lost.

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