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How Do Airliners Safely Store Fuel?

Fuel management is the most complex and important part of the logistics of flight, as the weight and centre of gravity of that fuel can have a considerable effect on the airliner’s ability to fly in a controlled and safe way.

As well as this, due to aircraft flying where the outside air temperature is extremely cold, this temperature variation affects the pressure the fuel tank is put under, making a pressure relief valve an essential part of any aircraft.

Large aircraft primarily store their fuel in the wings, the central part of the body and the horizontal stabiliser at the back of the plane, and will use fuel in a specific order to ensure that the centre of gravity of the plane is not at any point compromised.

Central tanks tend to be used first, as the fuel in the wings helps to provide ballast to protect the wing from external forces that can cause them to bend and buckle.

In many cases, the wing tanks are separated into inner and outer tanks as well, which help to relieve stresses further, and there is a surge tank system present throughout that serves to collect any fuel that falls out of any of the tanks during particularly sudden flight manoeuvrers.

This also provides another function of helping to relieve pressure in case of fuel overflows and avoids a vacuum developing in the tanks as a plane climbs higher.

The fuel is pumped into the engines by a series of electrically driven pumps that can be controlled by the pilot, although this is only typically used in the event of a vapour lock event, where fuel cannot enter the pump properly.

 Typically the left-hand tank fuels the left engine and vice versa, but in the event of an engine failure or flame out, a cross-feed valve allows fuel to be pumped from the tanks on the other side, and can also be used to balance the fuel being used once the wing tanks start being employed.