Which system provides pressure to the outboard brakes?

• A. Electrical system
• B. Pneumatic system
• C. Hydraulic system
• D. Fuel system

Answer: (C)

Brakes rely on a high, controllable pressure to clamp pads against rotors. The hydraulic system is designed to generate and deliver that pressure through brake fluid in sealed lines to the wheel brakes. When you press the pedal, the master cylinder converts your force into hydraulic pressure. That pressure moves to the outboard brakes, where pistons push the brake pads against the rotors, creating friction and slowing the aircraft or vehicle. The incompressible fluid gives a solid pedal feel and precise, predictable braking, and the system can be arranged with separate circuits for safety.

Pneumatic systems use compressed air, which is more compressible, leading to a softer, less immediate braking feel and less consistent performance for high-demand braking. The electrical and fuel systems don’t directly provide the braking actuation pressure, so the hydraulic system is the one that supplies the needed brake pressure.