What additional conditions are necessary to initiate automatic operation of the standby hydraulic system?

• A. Loss of both Systems A and B while airborne
• B. Flaps must be retracted and System A functioning
• C. All systems must be operational
• D. Flaps extended and FLT CONTROL switch ON

Answer: (D)

The correct choice highlights the necessary conditions for the standby hydraulic system to automatically initiate its operation. In most hydraulic systems, specific inputs are required to transition to standby mode, ensuring reliable operation and safety.

When the flaps are extended, it indicates that the aircraft is in a configuration where additional hydraulic power may be needed to control other flight systems effectively. Coupled with the FLIGHT CONTROL switch being in the ON position, this setup confirms that the aircraft's primary hydraulic systems are not able to provide sufficient pressure or volume to maintain proper flight control. These conditions signal the system that automatic engagement of the standby hydraulic system is essential for continued safety and operational capability.

The other choices imply scenarios where the standby system would not necessarily need to activate or would indicate a malfunction, thus emphasizing that flaps extended and the FLT CONTROL switch ON are critical for engaging the standby system automatically.