How does a displaced threshold affect landing distance?

How does a displaced threshold affect landing distance?

• A. It shortens the available landing distance.
• B. It lengthens the available landing distance.
• C. It has no effect on landing distance.
• D. It changes the required landing technique.

Answer: (A)

A displaced threshold reduces the part of the runway available for landing by moving the touchdown point forward from the very start of the runway. The area before the displaced threshold can still be used for takeoff and for rollout when landing from the opposite direction, but it cannot be used for landing in this direction. So the distance you can actually land on—the landing distance available—is shortened by the length of the displaced portion. This is why the correct choice states that the available landing distance shortens. It doesn’t lengthen the distance, it doesn’t have no effect, and the fundamental landing technique isn’t changed—you simply land farther down the runway.

A displaced threshold reduces the part of the runway available for landing by moving the touchdown point forward from the very start of the runway. The area before the displaced threshold can still be used for takeoff and for rollout when landing from the opposite direction, but it cannot be used for landing in this direction. So the distance you can actually land on—the landing distance available—is shortened by the length of the displaced portion. This is why the correct choice states that the available landing distance shortens. It doesn’t lengthen the distance, it doesn’t have no effect, and the fundamental landing technique isn’t changed—you simply land farther down the runway.