Is antiskid operational when using the park/emergency brake?

The correct answer is that antiskid is not operational when using the park or emergency brake. The primary function of the antiskid system is to prevent wheel lock-up during braking when the main hydraulic brakes are engaged. This is particularly important during normal landing conditions where maintaining control and traction is crucial.

When the parking or emergency brake is applied, it typically locks the wheel in place rather than modulating brake pressure. Since the antiskid system relies on detecting wheel speed and adjusting brake pressure to prevent skidding, it becomes inactive under conditions where the wheels are not turning or are fully locked, such as when the parking or emergency brake is engaged. The design of these braking systems is focused on holding the aircraft stationary rather than controlling its deceleration on a runway.

Understanding this distinction is vital for ensuring proper aircraft handling and safety protocols. In normal operations, the antiskid system is engaged during routine braking procedures with main hydraulic brakes, allowing for effective management of braking forces.