Are Liquid Explosives on a Plane Feasible?

permaculture writes "The Register describes the difficulty of mixing up a batch of liquid explosives on a plane. Further, it opines that such a plot might work in a Hollywood film, but not in the real world. Liquid explosives were used for the 7/7 London bombings in 2005, according to the official account — or not, as now seems more likely." This story selected and edited by LinuxWorld editor for the day Saied Pinto.

Comments

No need for an explosion

[andrewman327]

Here is another source on the issue.

I was shocked to hear the media talking about the possibility of bring nitroglycerin onto an airplane. The entire reason that dynamite was invented is because the liquid is horribly volitile. Some people have speculated that the terrorists were not attempting a large scale explosion as CNN and Fox News would have you believe. Instead they were waiting until the plane was in the middle of the Atlantic and starting a fairly large fire. There are many substances that can create a dangerous fire on an airplane in the middle of the ocean at 30,000 feet. There is no need for a Holywood style explosion at all. I am being intentionally vague in this post, but three men with drink containers full of certain substances starting three fires at three different parts of the plane would be extremely difficult to control, especially considering the lack of fire surpression systems in the passenger cabin. I am not a firefighter (rookie EMT and will be training to be a rescuer) but I cannot imagine trying to put out three fires with the 1-2 fire extingueshers available.

The first World Trade Center bombing and OK City show that everyday chamicals can be combined with horrific results. In those situations, however, there were truckloads of the two ingredients. I agree in part with TFA that it would be hard to perform an explosion the size of Pan-Am 103's with liquids, but that is not necesary.

Another chemist's view

[quitcherbitchen]

Bruce Schneier linked to another post which had an interesting take by a chemist in a graduate program. He describes details of the chemicals involved and what it would take to detonate them effectively onboard a plane.

The summary: improvised explosives involve pretty nasty stuff that you'd be hard pressed to mix in an airplane lavatory without killing yourself in the process.

An even better article

[jgs]

Perry Metzger wrote an excellent post to the interesting-people mailing list last Friday. He goes into more detail than the Register article does, offers first-hand information, and packs in more irony and sarcasm besides.

Re:Flight 505 to MacGyver City...

[deanpole]

You mean as Brainiac shows in this video.

That door is staying closed until you land

[jgs]

Not quite sure what your point was, but the idea of opening an airplane door in mid-flight has been thoroughly debunked. For example, see Patrick Smith's Salon Article on the subject (mind-bending advertisements or oppressive money-grubbing subscription may be required). In short, you can't open the door because there's a lot of air pressure holding it shut. From the cited article,
 

At a typical cruising altitude, as many as 8 pounds of pressure are pushing against every square inch of interior fuselage. That's 1,152 pounds of weight against each square foot of door. Flying at low altitudes, where cabin-pressure levels are lower, even a differential of 2 pounds per square inch is still more than anyone can displace -- even after six cups of coffee and the frustration that comes with sitting behind a shrieking infant for five hours.

Of course, if you don't believe him you can try it for yourself. Remember to pack a hydraulic jack in your carry-on.

Re:That door is staying closed until you land

[mrchaotica]

How come planes don't just implode like a sub that strays too deep?

Because the plane is designed to withstand it.

Also, the difference between 1 atmosphere of pressure (i.e. ground level) and some fraction of an atmosphere (at cruising altitude) is an order of magnitude or so smaller than the difference between ground level and the bottom of the ocean.

Also, not to be a wiseass, but how do skydivers get out of a plane?

Those planes have sliding doors instead of ones that open inward.

Re:That door is staying closed until you land

[Deadstick]

The door does not need wind to keep it shut. Its mating surfaces are tapered just like a bathtub stopper, and the internal pressure holds the door tightly against the frame.

The door also does not just "open out". It starts by moving inward a couple of inches, which it can only do when the pressurization has been turned off and the pressure allowed to equalize. Then the upper and lower ends of the door bend inward a few inches, which reduces the total height of the door. Then it rotates slightly outward on a complex double pivot, which moves the forward edge a little aft and the aft edge a little forward. Now it's able to fit through the door frame, and it swings out on the same double pivot.

As for shooting a hole in the fuselage, that would have very little effect. An airplane is not a sealed pressure vessel; if it were, you'd be feeling really rotten halfway to Europe. The pressurization supplies a constant flow of air, and a unit called the outflow valve lets it out of the airplane at an electronically controlled rate to keep the correct pressure inside. If you shot four or five holes in the airplane with a .45, the outflow valve would just close down maybe halfway.

Now it would be possible to get a much bigger hole by shooting out a window, and that would cause a rapid -- not "explosive", but rapid -- decompression. The people near the window would undoubtedly lose their magazines -- but they wouldn't notice that, because the pilot would be doing some rather attention-getting maneuvers to get the airplane down to a safe breathing level.

public education of science is obviously in BIG trouble

See, this is why engineers get annoyed when computer engineers call themselves engineers...;-)

rj

Craig Murray

[replicant108]

The article quoted is by Craig Murray - an ex-ambassador to Uzbekistan, who gained notoriety by blowing the whistle on the UK's support for Uzbekistan's torturers.

Needless to say, Mr Murray paid a heavy price for his candour.

Nitro on a plane

[toupsie]

The "Mark II" "microbombs" had Casio digital watches as the timers, stabilizers that looked like cotton wool balls, and an undetectable nitroglycerin as the explosive. Other ingredients included glycerin, nitrate, sulfuric acid, and minute concentrations of nitrobenzene, silver azide (silver trinitride), and liquid acetone. Two 9-volt batteries in each bomb were used as a power source. The batteries would be connected to light bulb filaments that would detonate the bomb. Murad and Yousef wired an SCR as the switch to trigger the filaments to detonate the bomb. There was an external socket hidden when the wires were pushed under the watch base as the bomber would wear it. The alteration was so small that the watch could still be worn in a normal manner.

Read up!