A view from Dave Trott

The Comet's tale

The UK had the world’s first jet airliner.

It was called the de Havilland Comet.

It was built in 1949, and went into service in 1952.

As a jet, it was smooth, quiet and fast.

But jet engines used more fuel.

De Havilland solved that by having the Comet fly much higher: 30,000 feet.

Thinner air meant less resistance, so the engines used less fuel.

But no-one had ever flown passengers at that height.

The entire aircraft interior would have to be pressurised.

It involved entirely new levels of technology.

But once the technological problems were solved, the Comet became the world’s first scheduled jet airliner.

In the first year, Comets flew 105 million miles and carried 28,000 passengers.

But then they started to fall out of the sky.

The first one was near Calcutta.

Witnesses said it just seemed to explode in mid-air.

The next one was between Rome and Cairo.

Again, witnesses said it just seemed to blow apart.

All the Comets were grounded until the wreckage could be examined.

And they found something they’d never experienced before: metal fatigue.

It came from the constant pressurisation and depressurisation.

And the cause wasn’t any of the technologies they’d developed.

Not the electronics, not the hydraulic systems, not the avionics, not the jet engines.

It was the one thing they hadn’t even thought about.

The windows.

The Comet had square windows.

Every aircraft until that point had square windows.

There had never been any reason not to have square windows.

But no passenger aircraft had been pressurised before.

Pressurisation causes the fuselage to expand slightly, like a balloon.

The problem with square windows is the pressure isn’t distributed evenly – it’s concentrated in the corners.

Just the way a lady’s stiletto heel makes a mark on a wooden floor, because all her weight is concentrated on to that one point.

So in the Comet, all the pressure was at the corners of the windows.

A corner cracked, the crack went around the fuselage, and the aircraft blew apart.

It took ages to find the problem because everyone was looking for a much more complicated answer.

It never occurred to them that the answer could be so simple.

So basic.

But that’s why, when you get on any airliner now, you’ll see the windows don’t have any corners.

The corners are rounded.

So the pressure is evenly distributed and there aren’t any weak points to develop cracks.

A tiny little insignificant detail like the corner of a window.

They concentrated on the technology, but they didn’t think of that.

Concentrating on technology and ignoring simple basic answers?

Does that sound familiar?

Can we think of another industry where that might be the reason things aren’t working?

Worrying about technology and ignoring the basics.

Dave Trott is the author of Creative Mischief, Predatory Thinking and One Plus One Equals Three