How bomb-proof is an airliner?

Dan, Huh??? My idea made sense and the “we” is everyone who has not declared war against the west.

Don’t get your other points, burning an NRA card would not end their membership or guns they own and the NRA has not declared one of these jihad things on the rest of us, have they?

As far as abortion, again no threat to the rest of us, they are not at war against us either, but as far as I am concerned if putting a bible there would make some not go in one, hell it ought to be tried, I think God would approve of a creative use of his Word like that. I doubt it would work, remember stepping on something is no big deal to anyone but these jihad nut cases, that is why the idea would work FOR THAT and is easy to implement.

It would not work on other groups at all, I agree. We are not afraid of feet, I can stand on my bible if I like, but they can’t theirs. It is an easy way to detect middle eastern values, and those are just the values most likely to have bombs in them, see?

Joe- OK, agree, just saw your post. I am done anyway. Just wanted to answer.

See pit.

Back on topic, I am not sure there is much probability for a small bomb to detonate the fuel tanks in an aircraft. The fuel tanks are fairly well protected, and the fuel is not really that easy to ignite, especially with all of the stuff between a passenger and a fuel tank. Vapor is a different story, but modern designs minimize vapor. Also keep in mind that it doesn’t appear that any bombings have resulted in a fuel explosion.

The real problem with a bomb is going to be fuselage failure. Depending on where the fuse is breached, you could get a catastrophic structural failure due to pressurization differences, wind, unbalanced loads, etc. This is much easier than trying to detonate fuel.

The other problems mentioned in this thread are the sorts of things that are going to take a blast that’s more than big enough to do fuse damage already. The control systems (and pretty much every other system, including engines) are multiply redundant. Structural components is sort of a misnomer, but it would be unlikely that a smallish explosion on the passenger deck is going to do significant structural damage independent of a fuselage breach. As far as loss of pressurization, pilots are trained to descend immediately and have oxygen masks.

So it’s pretty much about location and size of a breach. The other scenarios are less likely, if for no other reason than anything big enough to cause those sorts of problems has already made a sizable fuselage breach.

Is that so?

Actually, truly pure nitroglycerin isn’t that sensitive. You’d never get a licence to transport it, and you wouldn’t want to drop a filled metal-or-glass container of it onto a hard surface, but you could transport it in a flexible plastic container with a reasonable chance of getting away with it.

Contaminated nitroglycerin on the other hand can be hideously sensitive, and can explode for no apparent reason at all. Acidic contamination is the worst, but simple water contamination causes a self-catalysing acidification reaction that can make the stuff set itself off, given enough time.

Dynamite formulations typically contained a neutralising carbonate such as powdered limestone to prevent self-acidification, in addition to a nitroglycerin absorber. Ideally a nitroglycerin/nitroglycerol mixture was used rather than straight nitroglycerin, since they act as mutual antifreezes. Frozen dynamite is a whole lot less safe.

And yet a plane that lands safely is itself a footnote when compared with the effect of a plane that doesn’t.

Bomb goes off on plane, plane lands safely: news networks get in a tizzy, President apologizes, new ineffective screening processes implemented, minor drop in airline ticket sales.

Bomb goes off on plane, plane crashes: NTSB grounds all aircraft of same type pending investigation into cause, news networks get in a tizzy, new ineffective screening processes implemented, massive drop in airline ticket sales.

I question some of your assumptions here. Unbalanced loads cause cause issues with controlling flight, but structural failure? Highly unlikely. I also doubt “pressurization differences” are going to cause structural failures either - much of a pressurized airplane is actually UNpressurized, you really only need the “life support” for where the humans (and potentially live cargo) are. Depressurizing the “pressure vessel” causes problems for the humans, but not the airplane. Now, a large enough hole combined with turbulent wind effects, that can cause further structural damage, but not always.

However, on some designs these multiple redundancies go through “choke points” where a small amount of damage can destroy all use of the flight controls. One such model is the DC-10, and one such accident was the UAL Flight 232 Sioux City, Iowa crash. Crashes due to loss of flight controls have also occurred in B-747’s (Japan, 1985 and US, 1971), L-1011’s, and an Airbus 300 (Iraq, 2003). While it is unlikely an in flight bomb small enough to be smuggled on board could do such a thing I would not say it is “impossible”.

I think a better way to put this is any in-cabin explosion sufficient to cause fatal structural damage will almost certainly damage the pressure vessel and depressurize the airplane. Although the pressure vessel does take up a majority of the fuselage it is not the whole of the fuselage. Airliners are quite capable of flying while depressurized, the really critical thing is that the wings/control surfaces remain attached and the pilots have some way to control the direction of flight. There are a LOT of places you can poke a hole in the fuselage that will have little or no effect on the airplane, so “fuselage breach” isn’t really the critical issue here it’s where the breach occurs.