THE AIR Accident Investigation Unit has published its final report into a serious incident in which the wingtip of an aircraft with more than 200 people on board passed over a ride-on lawnmower on a runway at Dublin airport in May last year.
Directly before the incident, which occurred at 1.53am on May 29th, 2009, a member of the crew of the Boeing 757-28A reported to the control tower: “Could have sworn I saw a man riding a lawnmower.”
After the aircraft passed the vehicle on the runway, the crew reported: “Check . . . we saw ground equipment right at the runway lights at the edge lighting here,” to which the air movements controller responded: “I don’t believe it. They guaranteed me that they were clear of the runway.”
In the week before the incident, the Dublin Airport Authority had received reports from pilots that precision approach path indicators at the end of runway 10 had become obscured by long grass. However, there had been difficulties cutting the grass because of wet weather.
It was considered a priority to have the grass cut in that particular area. Just after 1.47am, the air movements controller instructed the driver’s supervisor to halt the grass-cutting due to low visibility.
The driver’s supervisor told the investigation that he had instructed him to clear the field using a hand-held maintenance radio.
However, the driver did not vacate the runway but remained on it for approximately five minutes, as he believed he was vacating the field due to low visibility as a result of fog, and thought he had “an extra few minutes to vacate the runway”. He was unaware that an aircraft was arriving until he heard it on the runway behind him.
At 1.53am the aircraft, which originated in Sharm-el-Sheikh in Egypt, passed the ride-on mower on the runway.
The report found that the probable cause of the incident was the failure of the lawnmower driver to vacate the runway after he had been instructed to do so, and cited six contributory causes.
The report found that the DAA should review its training programmes, including the frequency of refresher training, for all operatives who are required to drive on the manoeuvring area.
A risk assessment of grass-cutting has since been carried out at the airport, and new control measures introduced.