Engines of Our Ingenuity

No. 112:
THE COMET FAILURES

by John H. Lienhard

Click here for audio of Episode 112.

Today a novel anticipates a real disaster. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

The redoubtable Boeing 707 jetliner went into service in 1958. The English got a big jump on us with their de Havilland Comet. It was put into service six years earlier, in 1952. But disaster struck the Comet after one year of service.

A Comet leaving Calcutta disintegrated in a thunderstorm. When investigators couldn't find any other cause, they blamed the storm. Eight months later, a second Comet blew up in clear sky, 27,000 feet over the Island of Elba, off the coast of Italy. It was hard to recover much from the ocean, so that crash went undiagnosed. Then a third Comet exploded over the Mediterranean, three months later, and the whole fleet was grounded.

A more intense search finally yielded some wreckage, and it showed the failure had occurred in the cabin area. So the engineers did a huge fatigue test of an actual airplane. They varied the cabin pressure hydraulically while they flexed the wings. After 3000 pulsations a crack appeared near a cabin window and quickly spread. It turned out that the Comet's designers had overlooked stress concentrations at rivet holes near the windows.

The windows were redesigned, and a new safe Comet went into service in 1958 -- only five months ahead of the Boeing 707.

Now the oddest thing about all this is that a former de Havilland engineer wrote a best-selling book called No Highway in 1948 -- while the Comet was in the final design stage. We talk in another episode about the author Nevil Shute. A distinguished writer, he also wrote On the Beach and A Town Like Alice.

No Highway is about a new airplane called the Reindeer that's mysteriously crashed in Canada. Our ears prick up -- Dasher, Prancer, and so forth -- Comet was also one of the Reindeer. An engineer, a structural theoretician named Theodore Honey, is sent to investigate the crash. Honey has his own theory that Reindeers should suffer a fatigue failure after about 1400 hours in the air, but no one takes him seriously.

Halfway across the Atlantic, Honey, who's pretty oblivious to his surroundings, discovers he's riding in a Reindeer. A few questions reveal that this particular plane has been in service just about 1400 hours. Honey suddenly has to assume responsibility for saving 200 people who feel no need of being saved from anything. I leave you to find a video of the movie version of No Highway to see what Honey did. (Its title is No Highway in the Sky. It stars Jimmy Stewart as Honey, and Marlene Dietrich.)

How did Nevil Shute anticipate the Reindeer disaster? Author Henry Petroski's idea isn't dramatic, but it's convincing. He thinks Shute followed his engineering instinct, which was very good, and it took him where real life had eventually taken the Comet.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Shute, N., No Highway. New York: William Morrow, 1948.

Petroski, H., To Engineer is Human: The Role of Failure in Successful Design. New York: St. Martin's Press, 1985, Chapter 14.

For more information about Nevil Shute, see Episodes 110 and 1159 and the following website:

This episode has been greatly rewritten as Episode 1773.

http://www.nevilshute.org/



The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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