If an anti-skid sensor fails, how might the braking system behave?

• A. It will lock the wheels to prevent skidding.
• B. It may revert to non-ABS braking or operate with reduced functionality; pilots rely on normal braking with degraded protection and fault indication.
• C. It continues to function normally without any impact.
• D. It automatically activates manual braking as a backup.

Answer: (D)

When the anti-skid system loses its wheel-speed input, it can no longer modulate brake pressure to prevent wheel lock. The usual outcome is a degraded or non-ABS braking mode: the brakes work, but the anti-skid protection is unavailable, and a fault indication will alert the crew. You then rely on normal braking technique, knowing the wheels may skid if you brake aggressively, especially on slippery surfaces. There isn’t an automatic switch to manual braking; pilot input still controls braking, but without the ABS protection.