A runway incursion is an incident where an unauthorized aircraft, vehicle or person is on a runway. This adversely affects runway safety, as it creates the risk that an airplane taking off or landing will collide with the object. It is defined by the International Civil Aviation Organization (ICAO) on April 27, 2006, 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 take-off of aircraft.
In October 2007, the Federal Aviation Administration dropped its own definition of "runway incursion" and adopted the above. The difference between the two was "that ICAO defines a runway incursion as any unauthorized intrusion onto a runway, regardless of whether or not an aircraft presents a potential conflict. For the FAA, an incident without an aircraft in potential conflict– such as an unauthorized aircraft crossing an empty runway– was defined as a 'surface incident' and not a runway incursion."
The 1977 Tenerife airport disaster happened when one of the aircraft involved, KLM Flight 4805 (a Boeing 747) initiated takeoff before it was supposed to and collided with another aircraft, Pan Am Flight 1736 (another Boeing 747). A total of 583 people lost their lives in the disaster - more deaths than in any other accident in aviation history.
On 11 October 1984, Aeroflot Flight 3352, a Tupolev Tu-154B-1 hit maintenance vehicles on the runway attempting to land in Omsk, Russia. The ground controller allowed the workers to dry the runway during heavy rain and fell asleep on the job. 174 people aboard the aircraft were killed, along 4 people in the wrecked maintenance vehicles.
On 1 February 1991, USAir Flight 1493 collided with the waiting SkyWest Airlines Flight 5569 on the runway, killing 34 people. An Air traffic controller mistakenly assigned the inbound Flight 1493 to a runway where Flight 5569 was waiting to take off.
On 16 November 1996, United Express Flight 5925 was landing at Quincy Regional Airport when the pilot of a Beechcraft King Air started to take off on an intersecting runway. As the field was uncontrolled, the United Express pilots inquired whether the King Air was clear of the runways. They received no response except for a call from a Piper Cherokee saying they were holding short. The King Air and United Express collided at the intersection of the two runways killing all 12 on board Flight 5925 and the pilot and passenger of the Beechcraft King Air.
On 1 April 1999, an Air China Boeing 747, Flight 9018, taxied onto an active runway at Chicago's O'Hare International Airport during the takeoff of Korean Air Flight 36, another 747. Flight 36 averted a collision by taking off early, missing the Air China aircraft by 75 feet. There were 8 people on the Air China jet, and 379 on the Korean flight.
1999 T. F. Green Airport runway incursion, 6 December 1999: In low visibility at night, a United Airlines 757 turned down the wrong taxiway and taxied onto the active runway just as a FedEx Express 727 took off. No collision occurred.
Linate Airport disaster, 8 October 2001: Scandinavian flight 686 collided on takeoff with a Cessna Citation registered D-IEVX that had turned onto the wrong taxiway, causing it to enter the runway.