Touchdown wheel protection inhibits brake application for how many seconds after the main gear weight on wheels signal indicates on ground?

Touchdown wheel protection inhibits brake application for how many seconds after the main gear weight on wheels signal indicates on ground?

• A. 1 second
• B. 2 seconds
• C. 3 seconds
• D. 4 seconds

Answer: (C)

Touchdown wheel protection is built to prevent braking from engaging too soon as the aircraft settles onto the runway. When the main gear weight-on-wheels signal shows ground contact, braking is inhibited for a brief period to allow the tires and landing gear to stabilize and to avoid skidding or tire damage from the high touchdown forces. The duration of this protection is three seconds. This window is long enough to cover the initial settling and any minor bounce, but short enough to let braking begin soon after the airplane is clearly on the ground. If the delay were only one or two seconds, premature brake application could still occur during a hard or unsettled touchdown; four seconds would unnecessarily delay deceleration after touchdown and could complicate situations requiring prompt braking, such as a rejected landing.

Touchdown wheel protection is built to prevent braking from engaging too soon as the aircraft settles onto the runway. When the main gear weight-on-wheels signal shows ground contact, braking is inhibited for a brief period to allow the tires and landing gear to stabilize and to avoid skidding or tire damage from the high touchdown forces. The duration of this protection is three seconds. This window is long enough to cover the initial settling and any minor bounce, but short enough to let braking begin soon after the airplane is clearly on the ground. If the delay were only one or two seconds, premature brake application could still occur during a hard or unsettled touchdown; four seconds would unnecessarily delay deceleration after touchdown and could complicate situations requiring prompt braking, such as a rejected landing.