What is Hydraulic System 2 (HS2) and what does it supply?

• A. Provides hydraulic pressure to non-flight systems only.
• B. Provides electrical power to hydraulic components.
• C. Provides hydraulic pressure only to the primary flight controls.
• D. Provides hydraulic fluid pressure to the primary flight controls either as a primary or backup source, and also supplies pressure to all other non-flight control systems.

Answer: (D)

HS2 is the secondary hydraulic source that can power the flight-control surfaces as needed and also feed the rest of the aircraft’s hydraulic systems. It provides hydraulic pressure to the primary flight controls either as the main source or as a backup if the primary system is unavailable, ensuring you can still move the control surfaces. At the same time, it supplies hydraulic pressure to all non-flight-control systems, so other actuators and hydraulic circuits on the aircraft receive power from HS2. This dual role—supporting primary flight-control actuation and supplying non-flight-control hydraulics—captures why this system is described as both a primary/backup source for the flight controls and a provider for all other hydraulic needs.