What happens to the switching valves if primary hydraulic pressure is restored?

• A. They remain in backup position.
• B. They switch to maximum pressure position.
• C. They switch to normal operating position.
• D. They vent to the reservoir.

Answer: (C)

When the primary hydraulic pressure comes back, these switching valves move back to the normal operating position, reestablishing the primary flow path to the actuators. The valves are designed to hold in a backup position only when the primary pressure is lost; once pressure is restored, the hydraulic control recognizes that primary supply is available again and shifts the valves accordingly to restore full, normal operation of the system. This automatic return ensures the flight controls and other hydraulic-actuated components receive the intended, primary-system pressure without manual intervention. Venting to the reservoir or driving the valves to a max-pressure state isn’t how they operate in this recovery scenario, and remaining in backup would delay or prevent normal function.