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Why do airplanes dump fuel?

Updated: Jun 8, 2023

When an aircraft needs to make an emergency landing, it needs to dump fuel urgently. What is this process, and what happens to the fuel?

Many people know that fuel can be dumped from a ship during a flight. However, not many people know what it is for and where the dropped gasoline goes afterwards. Does it really just fall on people's heads? Today we will tell you about the causes and nuances of this process.

Why do airplanes dump fuel
emergency landing

Under what conditions is fuel dumped?

This procedure for dumping fuel is used very rarely, but it still takes place. The fact is that there is only one reason for performing it: an emergency on board requiring the vessel to land.

The whole process has to do with the specific design of the aircraft itself. There is a simple rule that states that when an airliner lands, its weight must necessarily be lower than it was when it took off. That is, by the end of the flight, each aircraft weighs less than it did at the beginning.

This is due to the combustion of fuel. The volume of the fuel tanks in the Boeing 747 is almost 200 tons. During an hour in the air, only about 10 tons of this volume are used up. When the aircraft has already landed, its weight is lower as some of the fuel has simply burned off.

Why is the fuel dumped?

This technique is only used if the aircraft requires an emergency landing. Of course, a lot can go wrong on board during a flight, from technical faults to the sudden deterioration of the health of one of the crew members.

At the time of landing, it may turn out that the airplane has not yet used the required amount of fuel, and the pilot may dump some of the fuel to bring the weight of the aircraft down to the landing weight limit. If it is left in the tanks, the landing can turn into a disaster.

Where does the fuel go afterwards?

Fuel, which is used for aircraft, is a volatile and fairly light type of fuel that can evaporate extremely quickly, especially once atomized.

When an aircraft decides to dump fuel at altitude, the pilots flick a switch in the cockpit, and pumps push the fuel out of nozzles in the wings. The fuel disperses over a wide enough area that the particles evaporate into a fine mist. Essentially, evaporating into a gaseous form and then fading into the background gases of the atmosphere

Naturally, it will not disappear on its own, but it will not fall on people's heads either. It will still be in the air for a while before it falls to the ground with precipitation or settles in some other way. Don't worry about fuel snow, as the concentration will be very low. Pilots never dump fuel over populated areas, so leave your fears behind.

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