Square Windows Caused this Plane to Crash - de Havilland Comet

On July 17, 1949, renowned British aircraft company de Havilland introduced the world's first commercial jet airliner: the de Havilland Comet.

Equipped with four Ghost turbojet engines, large square windows, luxurious interiors for the passengers, a pressurized cabin, and a unique-looking fuselage, the Comet appeared to be coming straight from the future.

Still, despite all of its innovations, the Comet had faults that turned into terrible consequences. Fatal crashes within a year of service grounded the aircraft several times to examine its malfunctions and redesign it.

But although the company never fully recovered, the military did find a use for the Comet. Under code name Nimrod, the British Air Force heavily modified the aircraft, and it then began a new career as a submarine hunter.

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[hawk]

Further research and study into the problem with the comet turns out they had nothing to do with the Square Windows it had to do with the metal they were using for the entire fuselage of the plane was flexible to keep it from cracking but flexibility allows it to actually work Harden and crack quickly.
The square window frames were rounded at the corners and were more than reinforced enough to not be the start of a problem. They were probably the most tested portion of the pressurized portion of the aircraft. The reason it worked as a military craft is because the military aircraft was not fully pressurized like the passenger version was.

[j.thomas]

Not at all a failure. It paved the way for all future jet commercial air travel. First flight in 1949 and finally retired in 1997 gave it a long life. When pioneering and breaking new ground, there will always be difficulties. The Comet taught airframe designers and metallurgists to better understand and study the concept of metal fatigue, window shape, flight cycles, and even the effects of pressurization on soft metals. The Comet wasn't a failure, but it did show us how much more we needed to learn.

[ibbylancaster]

My grandpa was a mechanic with the now defunct Eastern Airlines and when going through some stuff after my mom passed, I ran across a toy airplane that turns out to be a British Airways Comet. I was offered $100 for it, but I just couldn’t see myself selling it. I don’t know where he got it, but I know where it’s staying 😎. Much love to you Mr Dark and to all those that love these videos. May you all have a wonderful day.

[JamesLaserpimpWalsh]

The old De Havilland factory was knocked down recently in Christchurch (UK). It was of course another company's property now but it was still sad to see the old building go. Cheers for the vid

[jeremytravis]

When I went to engineering college they quoted this case. 
Similar mistakes had been made in the first Liberty Ships that cracked around the square deck hatches.
Corners = Stress raisers.

[Steve-GMHUU]

Still think this aircraft looks far better than any modern airliner. The first commercial jet airliner and still the most stunning looking? Though, I would have to say the term "failure" is debatable. Given the groundbreaking concept and design, there was a high risk of significant, previously unknown, problems being presented.

[glendanison]

I love the engines faired directly into the wing. Very aesthetic and still futuristic looking even today.

[adamdubin]

Beautiful Aircraft, when I was but a wee lad studying engineering the Comet was the example used to talk about metal fatigue and stress concentrations.

[greateraviationgl]

Finally, a commercial airline video by Dark Skies ✈️

[jcarne]

Threeparots1 nailed the reason for the structural failures below. Punching rivet holes in the corner reinforcement of the windows, instead of drilling and reaming, led to cracks.

[stuart]

Excellent video. I appreciate how difficult it must be to get continuous footage of the subjects... so I get that substitution images are necessary. Great work, mate.

[davidyoung]

I always love Dark Footage Inc. Just clear concise information. No bullshit, no dancing around a point for 30 minutes, just a synapses then right into the story.

[ianmacfarlane]

The De Havilland Comet is still a beautiful aircraft.
It's such a tragedy that the problem with the square windows wasn't picked up sooner - not only could lives have been saved in these awful accidents, but it might have saved the British aircraft industry.

[andrewtaylor]

The square windows were an element to the fatigue cracking, as they provided an easy starting point for it. But the root of the problem really lay in that new special ultra thin aluminum alloy that they used for the skin. It fatigued in ways and directions that didn’t show up in their tests. While Boeing and Douglas were watching the Comet crashes and findings with interest, their passenger jets were mainly past the point of major modification by the time the Comet crashes occurred. Boeing had already learned many of the lessons regarding large pressurized airplanes and fatigue cracking, in developing (and crashing) the B-29.

[Sacto]

It was more than just the square windows. It was the too-thin aircraft skin and the riveting process in putting in the windows. that made the metal fatigue problem worse.

[gijsv]

You forget to tell they put a Comet in a watertank, and put it under pressure. There the flaw was discovered.

[tonykennedy]

Spent the best years of my RAF life flying /working on the nimrods ❤️

[ronalddevine]

I believe I flew in a Comet in the early 70s. If I remember correctly it was British European Airways from Athens, Greece to Geneva Switzerland. Very comfortable plane. They pioneered every one else's success.

[onionhead]

I always thought the Comet engine intakes were so cool looking. Overly modern for that era.

[jumpjetcaptain]

I wouldn't call it a failure, they fixed the weakness in the windows in the later versions. But by then, the 707 came and won over most of the customers.