What effect will the loss of either the #2 or #3 hydraulic system have on braking capability?

• A. Anti-skid braking will be available from the remaining system, with a 50% loss of stopping capability.
• B. Brakes fail completely.
• C. Braking is unaffected.
• D. Anti-skid will be enhanced.

Answer: (A)

Redundancy in hydraulic braking systems means the brakes can be powered by more than one independent circuit. If one hydraulic system is lost, the other system still supplies pressure to the brakes, so braking doesn’t disappear. Anti-skid braking will still work because the surviving system can operate the anti-skid control. However, with only one system available, the total braking capacity is reduced by about half, giving a 50% loss of stopping capability. Brakes don’t fail completely, braking isn’t unaffected, and anti-skid isn’t enhanced just by losing one system.