At what wheel speed is locked wheel protection active on the ground?

Locked wheel protection is a critical feature of the anti-lock braking system in the Embraer Regional Jets. It is primarily designed to prevent the wheels from locking up during braking, which can lead to loss of control during ground operations. This protection is active under specific conditions, particularly at higher speeds.

When the aircraft is on the ground and the wheel speed exceeds 30 knots, the locked wheel protection activates. This ensures that as the aircraft begins to accelerate, the brakes can be applied without the risk of any wheel becoming stationary while the others are still moving, which could create a dangerous skidding event. Therefore, once the wheel speed goes above 30 knots, the system is engaged to maintain optimal braking performance and control.

In contrast, the other conditions mentioned, such as being below specified speeds, are either under the activation threshold for locked wheel protection or pertain to different operational parameters. Hence, the choice indicating that locked wheel protection is active above 30 knots correctly aligns with the system's operational logic and safety measures in ground handling.