What condition triggers the standby rudder PCU to take over control?

• A. Main PCU Force Fight Monitor trips
• B. System A fails completely
• C. Flaps are fully extended
• D. Pressure loss in hydraulic System B

Answer: (A)

The standby rudder Power Control Unit (PCU) is designed to take over control in specific scenarios to ensure continued functionality and safety of flight operations. In this case, the condition that triggers the standby rudder PCU to take over is when the main PCU's Force Fight Monitor detects an abnormality, commonly referred to as a trip.

This trip signifies that there is a discrepancy in the forces being applied to the rudder by the primary system, indicating a potential failure that could compromise the control of the aircraft. As a safeguard, the standby rudder PCU automatically assumes control, allowing the pilots to maintain effective steering and stability of the aircraft.

Other conditions listed may signal issues in the hydraulic systems or other unrelated factors, but they do not specifically relate to the operation of the standby rudder PCU in the context of a Force Fight Monitor malfunction. The focus is on the importance of redundancy and fail-safety measures within hydraulic systems, ensuring that critical controls, like the rudder, remain operational even in the event of a malfunction in the primary control unit.