Engines of Our Ingenuity

No. 1773:
THE COMET FAILURES

by John H. Lienhard

Today, we fall from the sky. 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.

This Saturday morning, the first of February, 2003, finds me recording in the newsroom of our radio station. The story of the returning shuttle Columbia, disintegrating over Texas, is just breaking. All around me, reporters, in shock over the loss of people they've known, struggle to clear their heads and shape the terrible story.

And I hear a fifty-year-old echo of another such incident. When the Boeing 707 jetliner went into service in 1958, the British had long since gotten the jump on us with the de Havilland Comet. They'd put it into service six years earlier.

But disaster struck a year later. A Comet leaving Calcutta came apart in a thunderstorm. When investigators could find no other cause, they blamed the storm. Eight months later, a second Comet blew up in a clear sky, 27,000 feet over the island of Elba, off Italy's coast. It was hard to recover much from the ocean, so it went undiagnosed. Three months later, a third Comet exploded over the Mediterranean, and the whole fleet was grounded.

The de Havilland D.H.106, Comet
The de Havilland DH106, Comet

A more intense search finally yielded some wreckage. Since the failure had occurred in the cabin area, engineers did a huge fatigue test of an actual airplane. They varied the cabin pressure hydraulically while they flexed the wings. After three thousand pulsations, a crack appeared near a cabin window and quickly spread.

The Comet's designers had overlooked stress concentrations at rivet holes near the windows. The problem was fixed, and a new Comet went into service only five months ahead of the Boeing 707.

The oddest thing about all this is that a former de Havilland engineer wrote the best-selling book No Highway in 1948 -- while the Comet was in its final design stage. He was Nevil Shute, who also wrote On the Beach and A Town Like Alice.

No Highway is about a new airplane called the Reindeer, mysteriously crashed in Canada. Our ears prick up -- Dasher, Prancer, and so forth -- Comet was also one of the Reindeer. A structural engineer, 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. No one takes him seriously.

Halfway across the Atlantic, Honey, who's pretty oblivious to his surroundings, finds he's 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 two hundred people who feel no need of being saved. Read the book, or find a video of the movie version, No Highway in the Sky, to see what Honey did. (It stars Jimmy Stewart and Marlene Dietrich.)

But how did Nevil Shute anticipate the Reindeer disaster? Historian Henry Petroski's idea isn't dramatic, but it's convincing. He thinks Shute followed his solid engineering instincts, and they led him where real life eventually took the Comet.

Now we have more grief and another mystery. Another fatigue failure? We don't know. I can only hope we find out quickly.

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: http://www.changeover.com/shute/

This is a greatly revised version of Episode 112.



The crew of STS-107

The Crew of Columbia flight STS-107 (Courtesy of NASA)


The Engines of Our Ingenuity is Copyright © 1988-2003 by John H. Lienhard.