Fuel Jettison System
The fuel jettison system moves fuel overboard to decrease the landing weight. The system only operates in the air.
To operate the system, you set the ARM switch to ARM and the nozzle switches to ON. This opens the isolation valves, puts on the jettison pumps, and opens the jettison nozzles.
The jettison pumps put main tank fuel into the refuel/jettison manifold. The override/jettison pumps put center tank fuel into the fuel feed manifolds, through the isolation valve, and into the refuel/jettison manifold. The fuel goes overboard through the jettison nozzles.
Fuel quantity and jettison time show on EICAS and the fuel synoptic. The jettison system automatically goes off at the maximum landing weight (MLW). You can set the MLW up or down with the FUEL TO REMAIN switch.
The override/jettison and boost pumps put fuel into the engine feed manifold. You open the defuel valve from the refuel panel. Fuel goes through the defuel valve, the refuel/jettison manifold, and the
refuel panel adapters into a ground container.
You use the boost pumps and the defuel, crossfeed, and refuel valves for a tank-to-tank transfer on the ground.
Aircraft Fuel Dumping