Standard operating procedure at airports around the world have established certain protocols to determine what type of incident occurs on a runway when an accident happens. Each definition makes reporting, incident management and investigation easier for officials. These incidents are officially referred to as runway events.
A runway incursion happens when a second plane somehow enters the runway safety area. This can occur if a plane enters the runway on the ground or from the air. Usually this involves pilot or air traffic controller error. In the event a single aircraft uses the wrong runway or taxiway, the incident is considered runway confusion.
A runway excursion is an event in which a single aircraft exits the runway in an unwanted fashion. Sometimes, a pilot may take off too early or the aircraft may exit the runway on the ground from malfunction or poor weather conditions. Overruns, in which the aircraft does not take off in time before the end of the runway is reached, is also an example of a runway excursion. These are the most common types of runway accidents, accounting for 96 percent of accidents between 1995 and 2007 according to the Flight Safety Foundation.