What must occur for the hydraulic transfer unit to supply fluid at a normal rate?

• A. The landing gear is down and locked
• B. The System A engine-driven pump must be operational
• C. System A engine-driven pump volume must be lost
• D. The backup hydraulic pressure must increase

Answer: (C)

For a hydraulic transfer unit to effectively supply fluid at a normal rate, it's essential for the engine-driven pump in System A to be operational. This is because the engine-driven pump is responsible for generating the pressure necessary to move the hydraulic fluid throughout the system. If the engine-driven pump is functioning correctly, it can maintain the required pressure and flow rate for the system, allowing the hydraulic transfer unit to operate efficiently.

When the volume from the engine-driven pump is present, it ensures that hydraulic pressure is available, which is crucial for various operations such as landing gear deployment and other flight control surfaces. The backup hydraulic pressure does not contribute directly to the normal operation of the hydraulic transfer unit for supplying fluid, and having the landing gear down and locked doesn't influence the hydraulic supply rate. The focus is on the proper functioning of the primary hydraulic source, which aligns with the understanding that a lack of fluid volume from the engine-driven pump would hinder the system's ability to perform correctly.