Hydraulic systems 1 and 2 are each powered by which combination?

• A. One electric and one engine driven hydraulic pump
• B. Two electric pumps
• C. Two engine driven pumps
• D. One electric and one pneumatic pump

Answer: (A)

Redundancy and flexible power sources are what keeps hydraulic systems reliable in all phases of flight. For each hydraulic system, you want both a primary source and a backup that can operate independently of the engine. The engine-driven pump supplies hydraulic pressure during normal engine operation, while an electric motor-driven pump can provide hydraulic power when engines are not running or if the engine-driven pump fails. This combination—one electric pump and one engine-driven pump for each system—ensures continuous availability of hydraulic pressure for critical actuators, whether on the ground or in flight. Two electric pumps or two engine-driven pumps either over- or under-allocate power sources and do not provide the same level of operational versatility. A pneumatic pump isn’t used for aircraft hydraulic systems, which is why that option isn’t appropriate.