Which of the following best defines a displaced threshold?

• A. Shortening of a runway due to obstructions, noise abatement, or safety area dimensions.
• B. A new runway alignment.
• C. A temporary runway closure.
• D. A marking indicating the end of the runway.

Answer: (A)

Displaced threshold means the landing threshold is moved inward from the physical end of the runway to provide clearance from obstacles, noise considerations, or safety area requirements. Because the threshold is shifted, the available landing distance in that direction is shortened. The portion of runway before the displaced threshold can still be used for takeoffs (in that direction) and for rollout when landing from the opposite direction, but it cannot be used for touchdown in that direction. This is why the description that emphasizes shortening the landing distance due to obstructions, noise abatement, or safety area dimensions is the best fit. The other options describe different runway concepts (new alignment, temporary closure, or a marker for the end of the runway) and do not define a displaced threshold.