The parking brake consists of which mechanism?

• A. Mechanical linkage to hold brake in applied position
• B. Electronic actuator controlling brake pressure
• C. Hydraulic pump for brake system
• D. Pneumatic release valve for parking brake

Answer: (A)

Holding the brakes in the applied position when the aircraft is parked relies on a mechanical linkage that physically locks the brake mechanism in place. This design ensures the brakes stay engaged without needing continuous hydraulic pressure, power, or electronic control. In this setup, a pawl or latch connected to the brake assembly secures the applied state once the parking brake is engaged, providing a simple, robust means to prevent creeping or movement of the aircraft.

Other options rely on active systems: an electronic actuator would require power to maintain brake pressure, a hydraulic pump handles regular braking rather than locking the parked state, and a pneumatic release valve would deal with releasing pressure rather than holding the brakes applied.