Finding myself with a lousy fuel calculation I was set to land with waaay too much on board, and as my ´craft had a Jettison feature I started dumping.Which got me to thinking: bearing the cost of fuel and airlines desperate desire to save/make money, do they dump for "overweight landing" reasons or just in emergencies?Are there any rules as to max/min height for dumping, over land or sea etc?And what happens to the fuel in mid-air? Does it all evaporate? And what effect does that have on our Mother, Earth? Talking of cost-saving/passenger-fleecing:I know that Ryan plans to charge for prime seat reservations but is it true that they are going to start charging for hygenic paper in the toilets, like they still do in some Euroland public Wcs, with a little old lady sat at the entrance begrudgingly handing out a cupla sheets of old newspaper.Hahahaha - now I know what NewsCorp can do with all the old copies of that disgusting shitrag the NOTW - give them to Ryan!

Fuel dump is for emergencies only. All aircraft can land above max landing weight if they have to, the main issue is a high Vref or Vapp due to the heavy weight. If you are departing very heavy you need to calculate the amount or runway distance available to stop, take the MD11F for example, it has a high Vapp at most weights, if you need to land in an emergency at the max take off weight you are probably going to get into trouble and over run, that’s why the Swiss MD11 crew still had to dump fuel despite being on fire. The fuel will disperse as a mist but ideally you want to dump over the sea or over a unpopulated area, obviously you would only think about doing that if you had a problem that doesn’t require a land ASAP in the QRH.

Thanks.

Also: a/c designed to fly shorter distances, typically have no dump capability- the lang gear is strong enough to landle landings at T.O. weights in order to prevent having to take on fuel at every stop- wasting time. Long distance a/c T.O. heavy, burn fuel, and are much lighter at the destination, requiring a landing gear that will handle less sress- much cheaper. Therefore, they require a means to lower weight in an emergency.