Emergency landing fuel dump

[Helo]

Was returning from San Francisco on VS20 last Thursday when a passenger became sufficiently ill that we had to land a couple of hours into the flight in Winnipeg.

My questions about this are:

1. Why do you dump fuel - to reduce weight or minimise explosive possibilities landing with all that flammable material?
2. What happens to the fuel - does it vaporise or rain down? Are you limited to where you can jettison it?
3. How do you only jettison a particular volume of fuel - is there any risk of dumping too much? Is it a nervous time for pilots?
3. Are airlines insured for the cost of fuel, if they have to land because a passenger is ill? What's the value of full fuel on a 747-400?

Apologies for all the questions, but I'm fascinated!!

Thanks

Helo

Ooops - here I am, replying to myself. :-)

Having now used the search button (apologies, should have done that before), I have answers to questions 1 thru 3!! Can anyone advise on question 4 though?

Thanks

[PAXboy]

No idea!!! I think that you wil find the best place to ask these are in "Questions" or "Tech".

If you do so, you will need to delete this thread as the moderators do not like to have two threads going simultaneously in different forums.

Cheers.

[mutt]

1: The B747-468 can land at its Maximum Takeoff Weight, but it requires a maintenance inspection afterwards. It is therefore more prudent to dump the fuel to bring the aircraft down to a more realistic landing weight.
2: It vaporises, there are limitations on dumping in a non-emergency situation.
3: 747-468 probably has a fully automated system, crew can select the amount of fuel that they want dumped, previous 747's use that wonderful "tool" called the Flight Engineer to monitor the dumping.
4: Nope. Cost of fuel depends on where you buy it and what sort of deals your airline can get from the fuel company, but generally you are probably looking at around a dollar a gallon, so full tanks are around $55000.

Now if i had actually read the end of your message i would have realized that you had found the topic on fuel dumping thats in the Tech Forum......... So i guess that i should just retire to bed!!

Mutt.

[Helo]

Thanks guys, informative as ever!