Why do planes explode when they crashed?

Question

Why don't they just get crushed or crack up?

Answer 1

Actually, it is very unusual for an airplane to explode in a crash. The only thing that airplanes carry that can result in an explosion is fuel (excluding military aircraft carrying munitions, of course); however, there must be a combination of conditions present which will result in an explosion, one or more of which are typically not present in an aircraft accident: 1) there must be an appropriate air/fuel mixture to allow an explosion (actually, it takes a large amount of air and fuel vapor to explode, "wet" fuel will only burn); 2) that fuel/air mixture must be contained inside a sealed container at a minimum pressure (in most crashes, fuel tanks rupture prior to any ignition of the air/fuel mixture inside, limiting the potential for an explosion); and 3) there must be a source of ignition (i.e., sparks, flame, etc.). There are few, if any, electrical components near enough fuel tanks to cause sparks which would result in an explosion, and, once the fuel tanks lose integrity (typically immediately at impact), the lack of containment of fuel vapors limits the potential for an explosion.

I am not saying that there is sometimes a fire after a crash, typically resulting from ignition of spilled fuel, be it from contact with an electrically "hot" wire or with a hot engine part (exhaust pipe, etc.). This does not happen in every instance, either.

I presume the "explosion on crashing" you are asking about was prompted by watching movies/TV, etc. The reason they "explode" on crashing in the movies or on TV is the same reason cars always explode as they sail through the air after running off a cliff-side road - the FX people installed a "bomb" in the car (or airplane) and triggered it by a radio signal to make a dramatic effect. Do you really believe that if a car leaves the road over a cliff that it will spontaneously explode in mid-air? That's just not terribly likely, and is certainly not accounted for in the laws of physics. It is just a lot more visually exciting on film than watching it crunch against the ground below. BTW, if you watch, you will find that almost all of the "aircraft explosions" shown in films or on TV take place when the plane "crashes" on the other side of a hill or tall trees (out of sight of the camera), with a fireball erupting over the visual obstruction at the supposed site of the crash. What really happened is that a pilot flew the aircraft below the sight plane of the camera behind the obstruction, pulled into a normal attitude, and flew out of camera range at low level, and the FX people exploded a fireball charge behind the obstruction to simulate a gigantic explosion. The only exception to this is when the filmmakers are using computer generated images, or if they insert film of actual crashes and explosions of military aircraft taken during wartime (with explosions typically resulting from ordnance still on the aircraft, such as bombs).

Answer 2

The speed which the plane is flying, plus the amount of fuel on board. Add to that the fact that planes carry oxygen canisters, which will explode but not burn. Commercial carriers are limited to how much hazardous material they can carry. Cargo planes are not limited as to how much hazardous material they can carry.

Some hazardous materials are extremely explosive or flammable, especially when combined. Sometimes, if a pilot is aware there is a problem, they will try to dump fuel so as to limit the amount of fire.

Remembering that the fumes from the fuel would still remain, even if the tanks were empty, the impact would provide the spark needed to ignite the fumes, which would cause an explosion.

Answer 3

Airplanes usually hit with tremendous force, and the aluminum shatters into many small pieces, grinding up occupants like a meat grinder in a fraction of a second. This also generates heat. Plus if the engines are running, there is a hot blast of flame in the combustion chamber of the turbine. The fuel at some point during impact will reach the perfect air fuel mixture and ignite from those sources of heat. I'd rather drive my car.

Answer 4

A suv can comprise approximately 23-27gallons of gas. a popular 747 can carry 63705 gallons of Jet A-a million gasoline. Jet gasoline is lots greater explosive than gas and as a airplane crashes, i could guess that each and all and sundry which twisted metallic creates some form of spark. additionally the gasoline is contained interior the wing and undersection of the airplane, in assessment to a vehicle which has the tank geared up on the backside of the vehicle. A airplane will crash with alot greater tension than a vehicle. basically seem on the aftermath of a airplane crash. The gasoline could be right away dispersed around the wreakage section.

Answer 5

Because they are literally flying fuel tanks - a 767-300ER on an intercontinental flight carries 300,000+ lbs of fuel on board. If you pay attention next time you fly, on take off - you may be able to perceive the sloshing ( IE swaying of the airplane ) on your takeoff roll.. Of course there is less chance of fire onlanding than there is on takeoff b/.c it has been burned off. A fully loaded DC 10 OR 767-300 OR 747 cannot return to land after takeoff untill it pumps fuel overboard because there is SO much fuel weight that the landing gear would otherwise be over stressed.

Answer 6

Are you talking about real planes or planes that you have seen explode in films. Real things tend to explode less easily than those in hollywood films. You can imagine a simple car park prang causing an explosion similar to that which flattened Hiroshima if the film model of explosions held true in real life.......

Answer 7

Because Aviation Fuel is highly explosive, and the wings are generally full of the stuff.

So you have the fuel ready to go - all you need is a spark.

So if you have that much metal, electrical circuitry etc, all hitting something hard, you can guarantee a spark - Et Voila - One Fireball

Answer 8

That is not a rule. If the tanks are full, probably It will have fire. If the tank is not full It will have a explosion. When a crash happens the friction between metallic parts cause Sparks that ignite the fuel or the gas inside the tanks causing fire or explosion.

Answer 9

Because in all the best films a huge explosion is a prerequisite.

Most planes do not explode when they crash in real life.

Answer 10

Because they have tons of fuel on board, and the impact at crash causes a massive explosion.