Why may an electric boost pump be used in an APU?

Why may an electric boost pump be used in an APU?

• A. To supply fuel under pressure to the control
• B. To heat the fuel
• C. To vent fumes
• D. To remove air from fuel

Answer: (A)

In an APU fuel system, providing a steady, sufficient fuel pressure to the fuel control unit is essential for accurate metering and reliable starting. The electric boost pump delivers pressurized fuel from the storage tank to the fuel control, so the APU can begin and run even if the engine-driven pump isn’t yet supplying pressure or can’t maintain it during rapid changes in demand. This isn’t about heating the fuel, venting fumes, or removing air from the fuel—the boost pump’s job is to ensure the fuel control receives the required pressure for proper operation.

In an APU fuel system, providing a steady, sufficient fuel pressure to the fuel control unit is essential for accurate metering and reliable starting. The electric boost pump delivers pressurized fuel from the storage tank to the fuel control, so the APU can begin and run even if the engine-driven pump isn’t yet supplying pressure or can’t maintain it during rapid changes in demand. This isn’t about heating the fuel, venting fumes, or removing air from the fuel—the boost pump’s job is to ensure the fuel control receives the required pressure for proper operation.