What constitutes a "runway incursion"?

A "runway incursion" refers specifically to an unauthorized presence on a runway or taxiway, making this the defining characteristic of the term. This situation can occur when an aircraft, vehicle, or person mistakenly enters a runway where an aircraft is landing or taking off. Such incursions pose significant safety risks, as they can lead to near misses or collisions between aircraft and ground traffic.

Understanding runway incursions is critical for maintaining safety in aviation operations. The presence of an unauthorized entity on the runway disrupts the controlled environment in which aircraft operate, highlighting the importance of effective communication and adherence to protocols to prevent such occurrences.

Other options listed do not fit the definition of a runway incursion; for instance, emergency landing procedures relate to how pilots manage unexpected landings rather than unauthorized entries onto runways. Similarly, inaccuracies in distance measurements and timing discrepancies regarding takeoffs and landings concern operational metrics and scheduling, not the presence of unauthorized entities on the runway itself.