Which hydraulic systems provide brake pressure?

• A. Hydraulic System 1 powers outboard brakes
• B. Hydraulic System 2 powers inboard brakes
• C. Hydraulic Systems 1 and 2 power the Parking/Emergency brake
• D. Hydraulic System 1 powers all brakes

Answer: (C)

Aircraft braking relies on redundancy: two independent hydraulic systems supply the pressure so that brakes work even if one system has a fault. The parking or emergency brake is specifically designed to be supplied from both hydraulic systems. This ensures the parking brake can be applied and held, and the aircraft can be brought to a stop or restrained on the ground, even if one system is unavailable. The other statements imply a single system powering all brakes or split duties for main brakes, which would reduce redundancy and reliability. So the parking/emergency brake drawing pressure from both System 1 and System 2 is the design that matches how these brakes are kept functional in an abnormal or parked state.