What is the least serious category of runway incursions?

Answer: A — Category D

The least serious category of runway incursions is Category D. This classification encompasses situations where there is no immediate safety risk but where aircraft or vehicles enter a runway without proper clearance or authorization, resulting in a potential conflict. Examples may include minor deviations that do not pose an imminent threat to operations, such as a vehicle crossing a runway while an aircraft is in a safe distance or during an idle phase. Understanding this categorization is important for recognizing how different types of incursions can affect airport safety and operations. Category D incursions are typically monitored and may involve follow-up procedures to ensure that the operators receive the necessary training or awareness to prevent similar occurrences in the future.