What is defined as a "runway incursion"?

A "runway incursion" is specifically defined as an incident involving the incorrect presence of an aircraft, vehicle, or person on the protected area of a runway. This situation can lead to dangerous conflicts during takeoff or landing, as it poses a significant risk to safety by potentially leading to collisions or other accidents.

The protected area of a runway is crucial for maintaining safe operations, and any breach of this area by unauthorized entities can result in severe consequences. This definition helps clarify that the issue at hand involves unauthorized access or incorrect positioning on the runway, which can disrupt normal airport operations.

Other options do not accurately encapsulate the definition of a runway incursion. For instance, simply having an aircraft on the taxiway or a collision between two aircraft does not pertain to the established parameters of runway incursion. A malfunction of landing gear while it can impact safety, does not concern itself with the specific aspect of unauthorized presence on a runway. Thus, the correct definition revolves around the unsafe presence of aircraft or vehicles in restricted runway areas.