Which device can provide emergency hydraulic power in addition to electrical power during an electrical emergency?

Which device can provide emergency hydraulic power in addition to electrical power during an electrical emergency?

• A. Engine-driven hydraulic system
• B. Ground power unit
• C. APU generator
• D. RAM Air Turbine

Answer: (D)

The RAM Air Turbine is designed to come to the rescue when normal power sources fail. It automatically deploys into the airstream, and the rush of air drives a small turbine that powers a hydraulic pump. That hydraulic pressure keeps key systems, especially flight controls, functioning even if electrical power is gone. Some RAT units can also drive a generator to supply electrical power to essential systems, but the important point is that this device provides hydraulic power independently of the airplane’s engines and main electrical system, exactly what’s needed in an electrical emergency. Engine-driven hydraulic pumps rely on operating engines, and ground power units or APU generators supply electrical power only (not hydraulic), so they can’t guarantee hydraulic pressure when power is lost.

The RAM Air Turbine is designed to come to the rescue when normal power sources fail. It automatically deploys into the airstream, and the rush of air drives a small turbine that powers a hydraulic pump. That hydraulic pressure keeps key systems, especially flight controls, functioning even if electrical power is gone. Some RAT units can also drive a generator to supply electrical power to essential systems, but the important point is that this device provides hydraulic power independently of the airplane’s engines and main electrical system, exactly what’s needed in an electrical emergency. Engine-driven hydraulic pumps rely on operating engines, and ground power units or APU generators supply electrical power only (not hydraulic), so they can’t guarantee hydraulic pressure when power is lost.