Which components are powered by hydraulic systems in the 737?

• A. Avionics.
• B. Primary flight controls, landing gear, brakes, and other actuators.
• C. Cabin lighting.
• D. Water system.

Answer: (B)

Hydraulic power is used to move components that require a lot of force and precise control. In the 737, the primary flight controls (the surfaces that actually steer the airplane), the landing gear, wheel brakes, and many other actuators are driven by hydraulic actuators. This setup provides the high force and reliable actuation needed for safe, responsive control of the aircraft.

Avionics and cabin lighting are electrically powered, not hydraulic, and the water system uses pumps and plumbing for potable water, also not hydraulic. So the components that are powered by hydraulic systems are the primary flight controls, landing gear, brakes, and other actuators.