Which hydraulic pump is activated during an EDP 1 failure?

In the event of an Engine Driven Pump (EDP) 1 failure, the system utilizes the ACMP 3A (Alternate Electric Hydraulic Pump 3A) to maintain hydraulic pressure and functionality. When EDP 1 fails, the aircraft's hydraulic system relies on alternate means to ensure continued operation and safety. ACMP 3A serves as the designated backup for the hydraulic system associated with EDP 1, providing the necessary hydraulic power for critical systems like landing gear operation and flight control surfaces.

In contrast, EDP 2, while operational, remains unaffected in this scenario and does not automatically activate in response to an EDP 1 failure. The other options, ACMP 3B and only back-up hydraulic pumps, do not play a direct role in compensating for EDP 1's failure as ACMP 3A is specifically designed to ensure hydraulic pressure continuity when EDP 1 is not available. Thus, the activation of ACMP 3A during an EDP 1 failure is crucial for maintaining safe aircraft operations.