During preflight checks, what is run to pressurize the fuel system so that internal leaks in the fuel manifold can be detected?

• A. Boost pump
• B. Fuel pump
• C. Vent valve
• D. Pressure regulator

Answer: (A)

During preflight you want to push fuel pressure into the system while the engine isn’t running so you can see any leaks around the fuel manifold. The boost pump is designed to create that pressurization in the fuel lines for priming and system checks, making leaks visible as fuel seeping from joints or fittings.

The other options don’t fit this purpose. The engine-driven fuel pump isn’t active until the engine runs, so it wouldn’t be used for a ground leak check. The vent valve would only release pressure, not create it for testing. A pressure regulator maintains a set pressure but doesn’t provide the initial pressurization needed to reveal leaks.