Underwear Bomber Couldn't Have Brought Down Flight 253, Simulation Suggests

By Andrew Moseman | March 10, 2010 4:20 pm

We gave the BBC a hard time this morning for going a little overboard in declaring the Large Hadron Collider a broken-down mess. But here’s something cool: In a new documentary, a team simulated the blast that “Underwear Bomber” Umar Farouk Abdulmutallab tried to create on Christmas Day last year. Their finding: Even if he had blown up the bomb successfully, it wouldn’t have been enough to take down flight 253 from Amsterdam to Detroit.

Dr John Wyatt, an international terrorism and explosives adviser to the UN, replicated the conditions on board the Detroit flight on a decommissioned Boeing 747 at an aircraft graveyard in Gloucestershire, England [BBC News]. Wyatt used the same amount of the explosive pentaerythritol that the bomber carried, about 80 grams, which packs about the punch of a hand grenade. They put it on the same seat and lit off a controlled explosion, which sent a shock wave through the aluminum exterior.

The metal was permanently bowed out, and a handful of rivets were punched out, but no gaping holes appeared. The pressurized air inside the cabin would have slowly leaked out [Discovery News]. Wyatt and his cohorts say that wouldn’t have been life-threatening, and it wouldn’t have brought down the plane. However, the blast would probably have killed the bomber and the person next to him. And things wouldn’t have been all sunshine and roses for the survivors, either. Team member Captain J. Joseph said the noise and the smoke would have been awful, “not to mention the parts of the bodies that were disintegrated as part of the explosion” [BBC News]. Their eardrums could have ruptured, too.

This wasn’t a perfect simulation: Wyatt tested a 747, while the actual bomber flew aboard an Airbus 330. And the conditions inside were normal atmospheric pressure, not the pressurized state of a plane in flight. But Wyatt argues that the Airbus’ stronger composite materials mean it would have fared even better than his test aircraft. As for the pressure? “It’s over so quickly that the difference in pressure wouldn’t make a difference,” said Wyatt. “By the time the shock wave got to the door the pressure would have normalized” [Discovery News].

In Britain, the documentary (called “How Safe Are Our Skies?”) aired on BBC Two. You can still see it on their iPlayer. For those of us here in the United States, the Discovery Channel broadcasts it tomorrow night (Thursday) at 10 PM EST.

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CATEGORIZED UNDER: Physics & Math, Technology
  • http://discovermagazine Don Baron

    Dear Sirs,
    Personally, I don’t think this was such a great idea to show terrorist and would be terrorist how not to detonate your underwear bomb. Perhaps you should show how a bomb should be made in order to take down an airliner. This would save the terrorist much time and money for research and development. Don Baron Wellington Fl

  • Reg Pinder

    Does it really matter? The simple fact that he tried to bring it down should be enough to lock him up for good. There really was no point to these tests.

  • Arthur Taylor

    Actually, I think it’s a darn good idea that these fool “jihadists” were de-scarified and exposed for the idiotic numpties they really are. Yes, sometimes they manage to do terrible things, but mostly they’re idiots and any success they have is more down to luck than planning.

    This movie should be required viewing: http://www.youtube.com/watch?v=Dwcj7o4pW_o

    We are in almost no danger at all, and prats like this entirely fail to scare me. This simulation supports that view, and to me that’s a very good thing, unless one enjoys being scared and demonising the admittedly violent, but entirely clueless.

  • Oliver

    What an absurd examination. That isn’t a simulation at all. The plane would have been pressurized, with closed doors, flying 30,000 feet up. The blast most certainly would have taken down the plane. Think about it. An already pressurized plane undergoes a drastic increase in pressure by a bomb. That would certainly be enough to penetrate 5mm thick airplane-grade aluminum. The people were thankfully lucky. It Is also naive for anyone to think that the so called jihadists are idiots. It should be taken more seriously than that. Our discerning governments know it.

  • Adam

    An explosive charge “the size of a hand grenade” does it’s damage by scattering shrapnel at high velocity and inflicting tissue damage. Pressurized or not makes little difference. Pressurized doesn’t mean the cabin is air-tight. It just means it’s regulated to maintain a certain pressure. A sudden increase in pressure results in the plane venting air to rebalance the system. Just like electricity or water, air follows the path of least resistance, and blasting through the hull or a sealed doorway, is not.

    The impact of the actual volume of expanding gas from such a small charge would be akin to sneezing in a car with doors closed.

  • Oliver

    What a silly person you are. You think I would state such a fact without having calcuable proof. I’m a physics professor, the math prooves my statement, not this lame excuse to make people feel safe.
    I’m not talking shrapnel dear sir, I’m speaking in terms of the shockwave created by the explosion. Math is my proof. I shall post it if you’d like.


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