If the ADG deploys, what will happen to hydraulic system 3?

When the Alternate (or Backup) ADG (Auto Deployable Generator) deploys, it triggers specific actions in the aircraft's hydraulic systems to ensure continued operation and safety. The correct answer indicates that Pump 3B will automatically operate, regardless of the switch position.

This automatic operation is essential because, in the event of a deployment of the ADG, the system needs to maintain hydraulic pressure for critical flight controls and systems. The automatic activation of Pump 3B allows for a seamless transition to backup power and ensures that the necessary hydraulic functions remain operational, which is vital for the aircraft's performance and safety during emergency situations.

The other choices do not accurately reflect the system's behavior during ADG deployment. For instance, stating that hydraulic system 3 will become inoperable contradicts the design intent to maintain functionality. Similarly, suggesting that Pump 3A would take over does not align with how the system redistributes power since it's specifically Pump 3B that is designed to operate under these conditions. Lastly, requiring manual activation of Pump 3B would delay the response in an emergency scenario, which is not how the system is intended to function when rapidly addressing hydraulic needs after ADG deployment.