Rkmcswain From United States of America, joined Dec 2000, 222 posts, RR: 0 Posted (11 years 3 months 1 week 6 days 14 hours ago) and read 640 times:
Every so often, you read about an airplane that loses engine power or has an engine failure during takeoff and it must return to the airport. Usually, it mentions something about the aircraft having to dump fuel prior to the emergency landing.
Questions:
1) What are the reasons for dumping the fuel? I assume it is so that there is a minimum amount of fuel in case of a "crash landing"...
2) Isn't this a great hazard itself, due to a large amount of jet fuel deposited in the atmosphere?
3) What happens to this fuel? Does any liquid fuel actually reach the ground?
UAL Bagsmasher From United States of America, joined Sep 1999, 2116 posts, RR: 12 Reply 1, posted (11 years 3 months 1 week 6 days 13 hours ago) and read 607 times:
The fuel is dumped to lighten the aircraft for landing. Most aircraft have a much higher allowable takeoff weight than they have a landing weight. Structural damage is a very real possibility should an aircraft land seriously overweight. While it may not be good for the environment, most if not all the fuel dumped will vaporize beofre it reaches the ground. This depends on the altitude at which it is dumped. Fire hazard is also reduced by dumping fuel, but weight is the main reason fuel is dumped in an emergency.
ILUV767 From United States of America, joined May 2000, 3140 posts, RR: 10 Reply 2, posted (11 years 3 months 1 week 6 days 13 hours ago) and read 607 times:
THe big reason is so the landing gear does not colapse updon the landing, because the plane is always lighter when it lands than when it takes off.
When fuel is dumped, it comes out as a fine mist. It evaporates. There is no real harm done to the atmosphere and the earth.
FDXmech From United States of America, joined Mar 2000, 3251 posts, RR: 44 Reply 7, posted (11 years 3 months 1 week 4 days 23 hours ago) and read 540 times:
Thats right, at least for the MD11. The restriction for the MD11 (and others I'm sure) is its certified to land at max take-off weight, but the landing must done with the autopilot OFF. Autoland is not acceptable at this weight. Yet an overweight landing inspection must be accomplished.
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