What is the function of the engine-driven fuel pump in a typical narrowbody fuel system?

• A. To deliver pressurized fuel to the engine fuel control unit for combustion.
• B. To circulate fuel within the wing tank.
• C. To vent fuel to prevent vapor lock.
• D. To heat the fuel for improved atomization.

Answer: (A)

The engine-driven fuel pump exists to deliver fuel at the high pressure required by the engine’s fuel control unit so the engine can meter and burn fuel properly. In a typical narrowbody system, fuel is taken from the wing tanks by boost/boosted pumps to a lower-pressure line, then the engine-driven pump on the accessory gearbox boosts it to the pressure the fuel metering unit needs during all power settings. This high-pressure supply enables accurate fuel delivery and reliable starting and operation. Other tasks—such as circulating fuel within the wing tank, venting to prevent vapor lock, or heating fuel for atomization—are handled by different parts of the system, not the engine-driven pump.