Parking brake operation on the A320 is provided by which hydraulic system?

Parking brake operation on the A320 is provided by which hydraulic system?

• A. Blue
• B. Green
• C. Yellow
• D. Orange

Answer: (C)

The thing this question tests is how the A320 keeps the brakes engaged when the aircraft is parked. That requires a dedicated hydraulic path that can hold brake pressure even when other systems may be offline. On the A320, the parking brake is supplied by the Yellow hydraulic system. The three hydraulic systems—Green, Yellow, and Blue—are independent, and the Yellow circuit is arranged to drive the parking brake valves and the associated brake actuators on the main landing gear. When you set the parking brake, pressure from the Yellow system is trapped in the brake lines, applying and holding the brakes. Releasing it allows that pressure to vent and the brakes to release. This setup keeps parking brake function reliable even if other hydraulic systems are unavailable, which is why the Yellow system is the correct choice for parking brake operation.

The thing this question tests is how the A320 keeps the brakes engaged when the aircraft is parked. That requires a dedicated hydraulic path that can hold brake pressure even when other systems may be offline. On the A320, the parking brake is supplied by the Yellow hydraulic system.

The three hydraulic systems—Green, Yellow, and Blue—are independent, and the Yellow circuit is arranged to drive the parking brake valves and the associated brake actuators on the main landing gear. When you set the parking brake, pressure from the Yellow system is trapped in the brake lines, applying and holding the brakes. Releasing it allows that pressure to vent and the brakes to release.

This setup keeps parking brake function reliable even if other hydraulic systems are unavailable, which is why the Yellow system is the correct choice for parking brake operation.