Can the parking brake be used to stop the aircraft if you lose hydraulic systems 1 and 2?

Can the parking brake be used to stop the aircraft if you lose hydraulic systems 1 and 2?

• A. Yes
• B. No
• C. Only with a special override
• D. Only on the ground

Answer: (A)

The key idea is that the parking brake is designed to work even when the main hydraulic systems you’re losing are 1 and 2. It’s fed by a separate hydraulic source or an accumulator, or it uses a dedicated path that isn’t affected by the failure of those two systems. When you apply the parking brake, pressure is trapped in the wheel brake lines, allowing the brakes to clench and hold, which lets the aircraft decelerate and stop on the ground even with those main systems out. This function is intended for ground use, so it won’t help you stop in the air, but it provides a reliable ground-stop capability when the primary hydraulics are lost.

The key idea is that the parking brake is designed to work even when the main hydraulic systems you’re losing are 1 and 2. It’s fed by a separate hydraulic source or an accumulator, or it uses a dedicated path that isn’t affected by the failure of those two systems. When you apply the parking brake, pressure is trapped in the wheel brake lines, allowing the brakes to clench and hold, which lets the aircraft decelerate and stop on the ground even with those main systems out. This function is intended for ground use, so it won’t help you stop in the air, but it provides a reliable ground-stop capability when the primary hydraulics are lost.