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Monday, Jul. 12, 1937

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What TWA has learned is being used in the Boeing plant in Seattle where six four-motored TWA transports are now being built (TIME, March 1). These will have supercharged cabins* to maintain normal air for crew and passengers, will fly at around 30,000 ft., are scheduled for service next year. Pan American Airways has two similar ships abuilding minus the super-chargers, which will be installed if TWA's are successful. The problem is a hard one, for the fuselage must be able to withstand the tremendous difference in pressure between the thin air outside and the supercharged air within. Last week the roof of Lieutenant Adam's cabin split with a resounding crack due to pressure strain as he reached his world record height. No such trouble was experienced, however, last week when the world's first supercharged-cabin plane flew from Burbank, Calif, to Mexico and back at 28,000 ft. The plane was a special Lockheed Electra, built in great secrecy for the U. S. Army, which looks to the substratosphere to take bombers out of range of guns and enemy planes without supercharged cabins.

TWA is not the only line to carry on high-flying research. United sent Dr. Edmund Henry Padden aloft with four human "guinea pigs" who tried various mental tests with and without oxygen. Without oxygen at 17,000 ft. none of the four obtained the same answer to simple problems, all answers were wrong and reactions were slow. Given oxygen, the four reverted to normal. When TWA and American Airlines pilots come down for a ticklish landing after long hours at 10,000 ft., they take sips of oxygen from tubes. Tasteless, it clears their fatigued minds, gives them a sudden freshness. Pan American-Grace offers passengers the same facilities in its transandean flights in South America at heights of 15,000 ft.

Just what are the effects of frequent insufficiency of oxygen are still largely unknown. Pilots often have sinus and ear trouble from changes in air pressure. Many have complained of a tendency for teeth to fall out after years of flying. Passengers making only occasional hops apparently need fear no such woes at present normal levels (5,000-12,000 ft.) though they may notice higher heartbeat, heartier appetites, lassitude (passengers who play ping-pong in Pan American's Pacific Clippers find they tire faster than usual). Three weeks ago Dr. Allan L. Barach of New York sounded off to the American Medical Association, calling it dangerous for those with angina pectoris to fly at 15,000 ft. without extra oxygen. This is a matter of little moment since future planes will be supercharged, and airline officials point out that passenger deaths from natural causes are no greater on planes than on other transport means. In 286,000,000 passenger-miles, TWA has had only one passenger die in the air—an 80-year-old man who had a preliminary heart attack on the way to the airport.

^{*Supercharged means charged with extra oxygen. This can be
done 1) by releasing oxygen from pressure tanks or 2) by compressing
thin air taken in from outside. The latter method is being built into
TWA's ships.}