What is inhibited while FUEL DUMP is selected?

When the FUEL DUMP function is selected, certain systems are inhibited to ensure that the fuel dumping process occurs without interference or complications. In this scenario, chaff and flare dispensing is inhibited. This is crucial because while performing a fuel dump, the aircraft may need to focus on reducing its weight rapidly, which involves the potential for critical handling and safety considerations. If chaff or flares were dispensed at the same time as fuel dumping, it could create complications, such as affecting aircraft control or safety during a critical phase of operation.

The chaff and flare systems are typically used for countermeasures, and their inhibiting during the fuel dump allows pilots to concentrate on the act of reducing the aircraft’s weight without additional distractions or risks. The other functions, like fuel transfer, engine start, and hydraulic flow, are not as directly related to the immediate safety needs while conducting a fuel dump and are typically allowed to operate as necessary. This ensures that vital systems remain functional and ready for operation when needed most.