What identifies an unusable portion of a runway that appears usable?

• A. Painted holding sign
• B. Blast pad markings
• C. Displaced threshold markings
• D. Chevron markings

Answer: (D)

Chevron markings are used to identify an unusable portion of a runway that may appear to be usable. These markings typically form a series of angled shapes, and their primary purpose is to indicate areas where aircraft should not land or take off. By using chevron markings, air traffic authorities clearly communicate that certain sections of the runway are either unsafe or designated for other uses, helping to prevent accidental incursions by aircraft.

The other markings mentioned serve different purposes. For example, painted holding signs provide guidance to pilots about where to hold before proceeding, while blast pad markings indicate a safety area at the end of a runway that is not meant for landing or takeoff. Displaced threshold markings denote a portion of the runway that is not available for landing but can be used for takeoff. Each type of marking plays an important role in enhancing safety on runways, but only chevron markings are specifically designed to highlight an unusable area that could otherwise be mistaken for usable runway.