Italian investigators have found an Alitalia Airbus A320 departed Bologna while the runway was occupied by two ground vehicles, after an oversight during handover between tower controllers.
The two vehicles - one for bird control and the other for runway safety inspection - had been intermittently cleared on to the 2,800m (9,180ft) runway between aircraft movements in the space of 30min before the incident.
Weather data shows mist had reduced visibility to 1,800-2,000m along the runway axis. Just before the A320 was cleared to taxi to a holding point for runway 30, the safety vehicle was permitted to enter the runway from the opposite end and travel down. The bird-control vehicle was also cleared to drive along the runway, but in the opposite direction. Despite clearing the vehicles the controller did not activate a tower indicator warning that the runway was occupied. He "quickly" handed over to his successor, says investigation authority ANSV, mentioning the taxiing A320 but not the presence of the vehicles. As the incoming controller noted the A320, the two vehicles were in the vicinity of the runway's intersection with taxiway E. He released the holding-point stop-bar and cleared the aircraft, bound for Catania, to line up and take off from runway 30.
The A320 began its take-off roll about 75s later but, within a few seconds, the previous controller - who had remained in the tower - alerted that the runway was occupied. Ground control reacted to the alarm by instructing the safety vehicle immediately to vacate, but the bird-control vehicle instead responded and left the runway.
While the safety vehicle - still heading for the runway 30 threshold - did not reply, its driver saw oncoming aircraft lights and pulled the vehicle over to the right shoulder between taxiways F and E. ANSV says the aircraft, with 97 occupants, passed the vehicle 4s later at a speed of 120kt (222km/h). The vehicle was 10m from the A320's left wing-tip. The A320's crew, after rotation, reported seeing the vehicle: "There was a 'Panda' on the left side of the runway."
No passengers or crew were injured in the incident, on 20 November 2011. ANSV says the "unpunctual" handover resulted in the omission of "fundamental information" regarding the presence of the vehicles, which should have been relayed between the two controllers.