Raining aviation fuel?

[Golem]

Exactly how does an aircraft 'dump fuel' when in trouble and where can it off-load it all?

[Clanad]

Usually, only very large aircraft such as Boeing 747 and McDonald/Douglas DC-10 (and others) have the ability to dump fuel, although it can be an option on almost any transport aircraft.  It is pumped out through pipes in each wing tip.  The device through which the fuel passes atomizes it into very small droplets, so most of it will evaporate before getting to the surface.  In an emergency, the fuel can be dumped anywhere, but most larger airports have procedures and special areas denoted for this purpose.

[WaldoMcFroog]

As I understand it, many planes have the ability to dump fuel simply by flicking a switch and opening a valve to the outside world. It's probably a little more complicated than that, with presure equalisation involved, but that's what it amounts to.

Most often, fuel dumping occurs not because of the need to try and reduce explosion risks on a troubled flight, but because airlines are actually fined if they land with too much fuel on board! I know that about ten years ago, people from Hownslow in West London often complained of a tiny greenish film on their windows - it was aviation fuel that has been dumped into the atmosphere as the planes approach Heathrow. I know because I did a survey of residents under the Heathrow flightpaths as part of a Terminal Five consultation. Maybe this practice has changed since, however.

[Clanad]

My guess, Waldo, is that the substance was not jet fuel, since it's clear in color and has a distinctive odor, obviously.  The color, being described as greenish, is more than likely. "blue ice".  This is the blue sanitation water used in the lavatories.  It often freezes on the outside of the aircraft where is is flushed (no solids, by the way) and begins thawing as the aircraft descends into warmer air, especially near the ground on landing.  It, too, usually evaporates into the air, but sometimes it collects in a thin sheet aft of the exit point and. In the worst case, it can form a solid lump of ice of considerable dimensions and break off, falling through some hapless person's livingroom ceiling... This too has a distinctive odor...

[WaldoMcFroog]

Perhaps you're right. I know *they* all said it was dumped fuel!

[KebabMeister]

Military jets in the UK tend to fly out to sea to dump fuel considering it's relatively close to the majority of RAF bases.  They'll only dump inland if it's a complete emergency.