A fuel shut off valve is typically incorporated with which component?

• A. Vent line
• B. Engine control unit
• C. Tank selector
• D. Fuel pump

Answer: (C)

In aircraft fuel systems, the ability to stop fuel flow quickly is built into the tank selector assembly. The tank selector not only chooses which tank feeds the engine but also houses a shut-off valve that can isolate the fuel line from the selected tank (or all tanks) when needed. This makes it the practical point to shut off fuel in an emergency or during maintenance, without needing to chase the pump or vent lines.

The vent line mainly serves to vent fuel tank pressure and vapor, not to control flow to the engine. The engine control unit (where present) manages fuel delivery but isn’t typically the primary shut-off point. The fuel pump delivers fuel, but shutting it off alone doesn’t guarantee complete isolation of fuel flow from the tanks unless the valve in the selector is also closed.