SINGAPORE - Their job is to pick up debris on airport runways: Rags, dead birds - any foreign object that should not be there, so planes can land safely.
But last week, two airport maintenance personnel were in a van parked on the runway when a Singapore Airlines plane landed, said Changi Airport Group (CAG).
The plane's wing tip narrowly missed the van.
The runway incursion is being investigated by the Air Accident Investigation Bureau (AAIB) at the Ministry of Transport.
Last Thursday, just after 11am, SQ001 was approaching Changi Airport.
An SIA spokesman said the Boeing 777- 300ER plane with 194 passengers and 15 crew members on board was landing after flying from Hong Kong.
At that point, a yellow maintenance van had entered the runway, with two people inside.
The van was taking personnel to the runways to clear debris.
As part of operating procedure when entering the runway area, the vans' occupants are supposed to contact the control tower, which then gives them permission to enter, The New Paper understands.
Once in, the vehicle is supposed to wait at a holding area for permission to approach the runway.
But that morning, the van apparently approached the runway without heading to the waiting area. It is understood its occupants believed they had the goahead to do so.
Their van was stationary as the plane landed and barrelled towards them. The plane's wing tip narrowly missed the van.
They then drove out of the area. The SIA spokesman said yesterday there were no injuries and no damage to the aircraft.
TNP understands both men who were in the van have been suspended. An AAIB spokesman said it had been informed of the incident and is currently investigating.
A CAG spokesman said it takes the matter seriously and is also conducting its own investigation.
MP Ang Hin Kee, a member of the Government Parliamentary Committee for Transport, said that while the incident should not be taken lightly, people should not be quick to assign blame.
"We need to investigate how there was a breakdown in operating procedures, whether the training and drills given to the staff are adequate and then establish where the gaps are and plug them," he said.
Mr Gary Ho, a senior lecturer in Temasek Polytechnic's Aviation Management and Services diploma course, said such incidents are rare as there are many checks in place to prevent them.
Had the two vehicles collided, depending on the speed and location of the aircraft, it could have resulted in fatalities, he said.
Mr Andrew Belshaw, a registered aviation consultant with the British Association of Aviation Consultants, said that nine out of 10 runway incursions are caused by human error, such as inexperienced airfield drivers, miscommunication between control tower and the driver, language issues and when a pilot fails to understand the instructions given.
The most important thing is that such incidents are dutifully reported and investigated, he said. "It's the only way lessons can be learnt and we can prevent such mistakes from happening again."
According to a report published by the US' National Aeronautics and Space Administration (Nasa), a runway incursion occurs whenever there is an event that creates a possible collision between an aircraft and another vehicle, or object on the runway.
Passengers on board a Go Air flight to Mumbai from Delhi's Indira Gandhi International Airport had a narrow escape when the aircraft aborted its take-off at the last moment to avert a collision with an Indian Air Force plane which was crossing the runway at the same time.
Two people were injured when a Lion Airoperated Boeing 737-800 hit one of three cows on a runway in Gorontalo, Indonesia.
An Air Canada flight arriving at Toronto's Pearson International Airport ignored orders to abort its landing as a driverless van rolled onto the runway. The plane missed the van and landed safely. The pilots claimed they did not get the warning. The van had been left with the motor running.
A drunk man drove his car onto two runways after crashing through the Philadelphia International Airport perimeter fence in the US, forcing an air traffic controller to order a passenger plane to abort its landing.
A woman, who was high on drugs, rammed her car through a security gate and drove onto the runway at Phoenix Sky Harbor International Airport in the US. No one was hurt.
A Cessna 172 was at the northern end of Runway 03/21 at Singapore Seletar Airport while waiting for clearance from the control tower to take off on Runway 21.
At the same time, a Piper 28A plane was moving towards the holding area to wait for clearance from the control tower to enter Runway 03/21.
The Piper mistook a take-off clearance that was meant for the Cessna and taxied onto the runway. However, the Cessna had also started its take-off roll.
The tower controller noticed and cancelled the Cessna's take-off clearance. The two aircraft stopped about 100m from each other.
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