When a hydraulic pump switch is set to AUTO, the pump will automatically start when an AC generator is online and ___.

• A. Nose gear is down
• B. Antiskid is engaged
• C. Flaps are out of the zero degree detent
• D. Hydraulic reservoir is full

Answer: (C)

In AUTO, the hydraulic pump only comes on when there’s real demand for hydraulic pressure and electrical power is available. Once the AC generator is online, the system has power, and if the flaps are commanded to move away from the fully retracted position (out of the zero-degree detent), there’s a hydraulic demand to extend or adjust the flaps. Starting the pump at that moment ensures the actuators have the pressure they need.

If the flaps remain at zero, there’s no immediate hydraulic work being requested, so the pump doesn’t start automatically. The other conditions—nose gear position, antiskid status, or whether the reservoir is full—don’t create a hydraulic demand and thus aren’t triggers for auto-start.