A runway incursion is an aviation incident involving improper positioning of vehicles or people on any airport runway or its protected area. When an incursion involves an active runway being used by arriving or departing aircraft, the potential for a collision hazard or Instrument Landing System (ILS) interference can exist. At present, various runway safety technologies and processes are commonly employed to reduce the risk and potential consequences of such an event.
Definition
The internationally-accepted definition of a runway incursion is:[1]
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 take off of aircraft.
In the United States, the FAA classifies runway incursions into 3 types, with 5 levels of severity:[2]
Runway Incursion Type
Operational Incident
Action of an air traffic controller that results in less than required minimum separation between two or more aircraft, or between an aircraft and obstacles (vehicles, equipment, personnel) on runways or clearing an aircraft to takeoff or land on a closed runway.
Pilot Deviation
Action of a pilot that violates any Federal Aviation Regulation, example: a pilot crosses a runway without a clearance while en route to an airport gate.
Vehicle/Pedestrian Deviation
Pedestrians or vehicles entering any portion of the airport movement areas (runways/taxiways) without authorization from air traffic control.
A serious incident in which a collision was narrowly avoided.
Category B
An incident in which separation decreases and there is a significant potential for collision, which may result in a time critical corrective/evasive response to avoid a collision.
Category C
An incident characterized by ample time and/or distance to avoid a collision.
Category D
Incident that meets the definition of runway incursion such as incorrect presence of a single vehicle/person/aircraft on the protected area of a surface designated for the landing and takeoff of aircraft but with no immediate safety consequences.
Analysis
Audio of the 1 April 1999 runway incursion at Chicago O'Hare International Airport
Formal study of runway incursions began in the 1980s, following several high-profile near misses and fatal collisions of airliners operating on airport surfaces. One of the earliest reports on the topic was published in 1986 by the American National Transportation Safety Board (NTSB), titled Runway Incursions at Controlled Airports in the United States.[3] Citing examples like the Tenerife airport disaster and the 1972 Chicago–O'Hare runway collision, a special investigation was opened "to investigate selected runway incursions to determine their underlying causes and to recommend appropriate remedial actions."[3]: 1 After detailed examination of 26 incursion incidents occurring in 1985, investigators compiled a list of conclusions and safety recommendations. Among their findings were a need for clearer airport signage, improved controller supervision, and revised training procedures for aircrews and controllers. Despite the valuable data generated by the investigation, the NTSB conceded that, at the time, "the magnitude of the runway incursion problem could not be measured because of both incomplete reporting and follow-up investigations by the FAA."[3]: 33
Two years later in 1988, the Federal Aviation Administration issued its own report, Reducing Runway Incursions, with the purpose of establishing an integrated program for runway incursion reduction. Its general recommendations included:[4]: 44–45
Establish a steering committee on runway incursion reduction
Emphasize the analysis of pilot-related causal factors
In January 1991, the FAA published the first edition of its biennial Runway Incursion Plan (now known as the NationalRunway Safety Plan). The document introduced organizational and legislative reforms alongside new initiatives to leverage research on human factors, design, technological innovation, and professional development.[4]: 45–46 In August 1992, however, a US General Accounting Office (GAO) congressional testimony criticized the agency's budgeting, delayed implementation, and inadequate reporting of the initiatives, especially its rollout of ASDE-3 radar and Traffic Collision Avoidance System (TCAS) technologies.[5]
Despite newfound emphasis on runway incursion prevention, another fatal accident occurred on 3 December, 1990, when eight people were killed after two Northwest Airlines flights collided in fog at Detroit Metropolitan Airport.[4] The NTSB determined the accident's probable cause to be pilot error due to communication errors, inadequate crew resource management (CRM), and disorientation exacerbated by deficient airfield geometry.[4]: 79 Additionally, the NTSB recommended stricter airport certification requirements under 14 CFR Part 139 in the areas of lighting and conspicuous markings/signage. [4]: 80
In 2000, research into incursions at uncontrolled and non-towered airports was conducted by the Aviation Safety Reporting System based on data gathered by interviewing pilots who had experienced a runway incursion. Interviews lasted around 45 minutes to 1 hour, and the data was de-identified for FAA use in developing safety measures.[6]
In 2005, the FAA assisted ICAO in its creation of a formal, internationally-accepted definition of a runway incursion. The new verbiage was first added to the fourteenth edition of PANS-OPSDoc 4444, but it was not until 1 October 2007 that the FAA finally adopted the ICAO definition. Previously, the FAA had maintained that an incursion only included incidents in which a potential traffic conflict existed. An event without a potential conflict– such as an unauthorized aircraft crossing an empty runway– had been defined as a 'surface incident'.[7]
As of 2017, the last fatal runway incursion accident involving a U.S. Federal Aviation Regulations Part 121 air carrier was in 2006.[8]
Between 2011 and 2017, 12,857 runway incursions were reported in the United States. Between October 2016 and September 2017, 1,341 were reported. Of these, six were placed in the most serious categories A and B. Four of these were considered ATC incidents, and two were "pilot deviations". Of the 1,341 incidents, 66 percent were caused by pilot deviation, 17 percent were vehicle/pedestrian incidents, 16 percent were air traffic control (ATC) incidents, and 1 percent were "other".[8]
An FAA study of the year ending September 2016, found that of 361 runway incursions attributed to pilot deviation, 27 percent resulted from "pilot failed to hold short of runway as instructed", and 14.7 percent from "pilot failed to hold short of runway". 5 percent of pilot deviations were classified as the pilot failing to comply with an ATC clearance. In 3.4 percent of deviations, the pilot departed without a departure clearance.[8]
The NASA Aviation Safety Reporting Service (ASRS) received 11,168 reports of runway incursions between January 2012 to August 2017, at a rate of approximately 2000 per year. More than 40 percent of reports were filed by general aviation pilots, and 36 percent by air carrier pilots. Factors included situational awareness, communication breakdown, confusion, and distraction.[8]
