dump valve

dump valve

[′dəmp ‚valv] (engineering) A large valve located at the bottom of a tank or container used in emergency situations to empty the tank quickly; for example, to jettison fuel from an airplane fuel tank.

dump valve

i. The valve that allows the fuel in a tank to be dumped in flight quickly for emergency or operational reasons but mainly to bring the aircraft's weight to the maximum landing weight.
ii. An automatic valve that rapidly drains the fuel manifold when fuel pressure is below a predetermined level (e.g., at the time the engine is switched off). Also called a drain valve.