What role does parking brake play in an aircraft braking system and how is it secured?

• A. The parking brake maintains wheel lock when on ground; typically uses hydraulic pressure held by a locked valve or mechanical pawl to prevent unwinding.
• B. The parking brake powers steering lock during ground operations.
• C. The parking brake provides additional braking force to nose wheels during takeoff.
• D. The parking brake serves as an emergency brake that releases automatically upon liftoff.

Answer: (A)