Which statement about fuel pumps in small aircraft is true?

Which statement about fuel pumps in small aircraft is true?

• A. The electric boost pump is mounted on the engine
• B. There are no electric pumps in small aircraft
• C. Pumps are only used during maintenance
• D. The engine-driven pump is mounted on the engine and the electric boost pump is in the fuel system

Answer: (D)

In small aircraft, the fuel system usually has two pumps: an engine-driven pump mounted on the engine that provides continuous fuel pressure during normal operation, and an electric boost pump located in the fuel system (in the fuel lines or near the tanks) that serves as a backup, for starting, priming, and to ensure fuel pressurization if the engine-driven pump drops pressure. This setup explains why the true statement is that the engine-driven pump is mounted on the engine and the electric boost pump is in the fuel system. The other ideas don’t fit typical configurations: the electric boost pump isn’t mounted on the engine, many small aircraft do have electric pumps, and pumps are used during normal operation—not only during maintenance.

In small aircraft, the fuel system usually has two pumps: an engine-driven pump mounted on the engine that provides continuous fuel pressure during normal operation, and an electric boost pump located in the fuel system (in the fuel lines or near the tanks) that serves as a backup, for starting, priming, and to ensure fuel pressurization if the engine-driven pump drops pressure. This setup explains why the true statement is that the engine-driven pump is mounted on the engine and the electric boost pump is in the fuel system.

The other ideas don’t fit typical configurations: the electric boost pump isn’t mounted on the engine, many small aircraft do have electric pumps, and pumps are used during normal operation—not only during maintenance.