Definition 1 of 2
Plain English Meaning
A switch-like valve that lets you choose where fluid goes or which source it comes from. In a fuel system, it picks which tank feeds the engine. In a hydraulic system, it routes pressure to the component you want to move.
Full Definition
A valve used in aircraft fluid systems (fuel, hydraulic, or pneumatic) that allows the pilot or system to direct flow from a source to one of several possible destinations, or to choose between several possible sources feeding a single line. Common examples include the fuel selector valve, which chooses which tank feeds the engine, and hydraulic selector valves, which route pressure to operate , , or .