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Flaming Spin. The first small crack was enough; air pressure (more than half a ton per square foot) did the rest. The cabin exploded like a bursting balloon; its top flew off; its tail and nose broke away. The wings broke in two, releasing floods of fuel, which ignited. Then the gutted fuselage with its two stub wings dived flaming to the sea in an inverted spin.
To check this theory, Farnborough built 100 small wooden models of the Comet, with parts designed to come apart. They were dropped from balloons or from the top of a hangar. At last one of them broke up in just the way that Yoke Peter did. Its center section spun down to the ground, where its fragments were distributed on the ground in the same pattern that the fragments of Yoke Peter had made on the bottom of the Mediterranean.
Still not satisfied, the Farnborough men constructed a large model of a Comet's cabin in transparent plastic. They filled it with model seats and model passengers. They pumped it full of air at 8¼ lbs. Then they deliberately fractured the skin near the direction-finder window and took a motion picture of what happened.
In one-thirtieth of a second three of the forward seats, one of them with a passenger, moved upward toward the break in the roof. The next row of seats followed close behind. As the "suction wave" raced down the cabin, passengers and seats flew out into space. In two seconds, the scientists figured, the cabin of Yoke Peter must have been empty.
This checked gruesomely with the autopsies performed on the bodies recovered from the sea. Most of them had skull fractures and external wounds. "Explosive decompression" (from pressurized to thin air) had burst all their lungs and hearts.
The De Havilland Aircraft Co., builders of the Comets, could not have been happy to hear the results of the inquiry, which placed the blame for the crashes on faulty design and manufacturing methods. But Britain's aircraft industry might well be proud of the inquiry's utter frankness. Its designers are already using the Farnborough testing methods to make sure that such disasters will not happen again.
* Failure of a metal after repeated straining. Small cracks, which sometimes start at tool marks, sharp indentations or other "stress raisers," spread through metal until it breaks. Sufficient strength, correct design and careful fabrication can prevent such failures.