What does the Back Up pump pressurize?

What does the Back Up pump pressurize?

• A. 1st stage primary servos only
• B. Pilot assist module
• C. 1st or 2nd stage primary servos, 2nd stage tail rotor, and APU
• D. 2nd stage tail rotor only

Answer: (C)

The Back Up pump serves as a secondary hydraulic source to keep critical flight-control paths pressurized when the primary pumps aren’t supplying pressure. It pressurizes the components that directly affect control authority: the first-stage primary servos and the second-stage primary servos that move the flight controls, and the second-stage tail rotor servo that handles yaw. It also provides hydraulic pressure to the APU’s hydraulic circuit so the APU can start or operate as needed. This combination ensures you maintain control and system operation in a pump-failure scenario, which is why this is the best answer.

The Back Up pump serves as a secondary hydraulic source to keep critical flight-control paths pressurized when the primary pumps aren’t supplying pressure. It pressurizes the components that directly affect control authority: the first-stage primary servos and the second-stage primary servos that move the flight controls, and the second-stage tail rotor servo that handles yaw. It also provides hydraulic pressure to the APU’s hydraulic circuit so the APU can start or operate as needed. This combination ensures you maintain control and system operation in a pump-failure scenario, which is why this is the best answer.