What is a reason that the HYD pump 3B operates regardless of switch position?

The reason that the HYD pump 3B operates regardless of switch position is due to the Automatic Deployed Generator (ADG) being deployed. When the ADG is activated, it can trigger the hydraulic systems to ensure essential functions are maintained even if the manual switches are not in the "on" position. This is a safety feature designed to maintain power and hydraulic capability during critical situations, such as when the aircraft is in an emergency or powered by backup systems.

In normal circumstances, hydraulic pumps operate based on their respective switches, allowing pilots to control hydraulic flow as needed. However, the design of the system ensures that the deployment of the ADG takes precedence, enabling HYD pump 3B to function without the necessity for switch activation, thereby securing hydraulic pressure when it's most critical.