A runway incursion is defined by the FAA as, "Any occurrence at an aerodrome involving the incorrect presence of an aircraft, vehicle or person on the protected area of a surface designated for the landing and takeoff of aircraft." There are four categories of runway incursions, Categories A-D. Category A being the most severe and Category D being the least severe. Category A is classified as an "incident in which separation decreases and participants take extreme action to narrowly avoid a collision." An accident can be the result of a runway incursion, and therefore exceeds the categories described.
The FAA estimates that approximately three runway incursions happen every day at towered airports in the United States. Thus, the number of unreported incursions at non towered airports must be much larger. Although a runway incursion is by definition a near miss at the worst, they are often a contributing cause in serious aircraft accidents. An accident that perfectly illustrates the dangers of runway incursions is the 1996 collision of United Express flight 5925 and a Beechcraft King Air 90A in Quincy, Illinois. A miscommunication between the landing Beechcraft, the departing King Air, and a third taxing aircraft turned deadly when the King Air failed to look for traffic and the Beechcraft wrongly assumed a radio transmission confirmed they were okay to land. Although the airport was not towered, the presence of both aircraft on intersecting runways was extremely dangerous and lead to a collision at the intersection. A total of 12 people lost their lives in that accident that could have been easily avoided.
Another infamous accident involving a runway incursion is the Russian Aeroflot Flight 3352 that took place in 1984. In short, the ground Air Traffic Controller fell asleep after he authorized several maintenance vehicles to enter the runway. A commercial aircraft carrying 170 passengers came to land at the airport, and the approach controller, oblivious to the maintenance crew on the runway, cleared them to land. To make matters worse, visibility was extremely low and the maintenance trucks did not have their rotating beacons illuminated. The commercial aircraft collided with the vehicles, resulting in 178 fatalities. In this example, the accident investigators placed the majority of the blame on the Air Traffic Controller, but there were mistakes made by all parties involved.
The airport environment is a complex operation with hundreds of moving parts. Pilots, air traffic controllers, and airport designers have to understand the hazards that come with miscommunications and poorly designed airport layouts. It only takes one moment of confusion for a runway incursion to happen, which could be deadly.
The FAA has a record of 1747 total runway incursions happening in the Fiscal Year 2017. There are several reasons that runway incursions occur. One of the most prevalent ones is miscommunication or a total lack of any communication. Many times, pilots and air traffic controllers get "stepped on" or, talked over on the radio frequency. It is highly critical that pilots repeat back their instructions to confirm with the controllers that they heard them correctly and that the directions were for their aircraft and not another. As in the above case study, although there was not a tower at the airport, the landing aircraft assumed that the aircraft announcing they would be holding short was the only one holding short. There was a misunderstanding in this case because one pilot’s radio transmission got covered up by the other aircraft holding short making the pilot of the landing aircraft assume that there was only one aircraft and they were holding short. Other common types of runway incursions include incorrect entry or vacating of an aircraft or vehicle onto the runway protection area, incorrect runway/taxiway crossing, incorrect spacing between departing and arriving aircraft, and landing or taking off without air traffic control clearance.
According the the FAA, approximately 65 percent of all runway incursions are caused by pilots. Detailed investigations of runway incursions over the past 10 years have identified three major areas contributing to these events including failure to comply with air traffic control instructions, lack of airport familiarity, nonconformance with standard operating procedures. Clear, concise, and effective pilot/controller communication is paramount to safe airport surface operations. This is something that is often stressed during initial and recurrent pilot training, but evidently the information does not always stick in the pilots’ minds.
Air traffic control instructions must be fully understood and complied with. Air traffic controllers are in place to assist pilots and want to help when there is confusion but many pilots don’t ask for the help. They are caught up in other tasks such as checklists, taxi directions, and non-essential chatter with the copilot. Pilots are to taxi with their heads-up and eyes outside to ensure they are aware of all aircraft and airport vehicles.
Major factors that increase the risk of runway confusion and can lead to a wrong runway departure include airport complexity, close proximity of runway thresholds, joint use of a runway as a taxiway (FAA, 2017). During the summer construction time, many airports will close runways or taxiways to resurface them or replace them. If a taxiway is closed, this can force aircraft to use runways as a means of getting to another open taxiway. It can also force the aircraft to back taxi on the runway they are departing from.
Thorough planning is essential for safe taxi operations. Aircraft accidents are more likely to happen on the ground than in the air because there are so many moving parts on the airfield. Pilots need to utilize the following services/tools in order to ensure safe airport surface movement: Notices to Airmen (NOTAMS), Automated Terminal Information Service (ATIS), Airport/Facility Directory (A/FD), and recognizing Hot Spots. Although using these pilot tools will not end all runway incursions, they will lower the risks if all pilots are equipped with the proper and current information.