The master switch controls the ______ shut off valve.

The master switch controls the ______ shut off valve.

• A. High pressure
• B. Fuel
• C. Low pressure
• D. Bleed air

Answer: (C)

Fuel supply to the engine is cut off by the low-pressure shut-off valve, which is commanded by the engine master switch. When the engine master is ON, the valve is energised and fuel can flow from the wing tanks to the engine’s fuel control unit. Switching the master OFF de-energises and closes the valve, stopping fuel flow and ensuring a safe engine shutdown. The high-pressure shut-off valve sits on the high-pressure side and isn’t directly controlled by the engine master switch in normal operation, and bleed air is a separate system unrelated to this fuel shut-off function.

Fuel supply to the engine is cut off by the low-pressure shut-off valve, which is commanded by the engine master switch. When the engine master is ON, the valve is energised and fuel can flow from the wing tanks to the engine’s fuel control unit. Switching the master OFF de-energises and closes the valve, stopping fuel flow and ensuring a safe engine shutdown. The high-pressure shut-off valve sits on the high-pressure side and isn’t directly controlled by the engine master switch in normal operation, and bleed air is a separate system unrelated to this fuel shut-off function.