What is a displaced threshold?

• A. Shortening of a runway due to obstructions, noise abatement, or necessary to provide safety area dimensions.
• B. An alternate landing strip reserved for emergencies.
• C. A painted marker indicating the usable portion of the runway.
• D. The maximum takeoff weight limit of the runway.

Answer: (A)

A displaced threshold is when the landing threshold is moved down the runway from its physical starting point. The section before that displaced threshold cannot be used for landing, usually because of obstacles, noise abatement, or to provide the necessary safety area. Because of this shift, the available landing distance is shortened, even though that initial portion may still be used for takeoff or as a rollout area when landing from the opposite direction.

This is why the correct choice describes shortening the usable landing distance due to obstructions, noise considerations, or safety-area requirements. Other options describe an emergency landing strip, a simple painted marker, or a weight limit, none of which capture why a threshold would be displaced.