Two passenger jets nearly collided while flying over Australia on Thursday afternoon.
The Jetstar A320 and Singapore Airlines A330 aircraft had their near miss as they went over the Northern Territory.
Air-traffic control cleared the Jetstar flight from Darwin to Brisbane to climb through the Singapore’s jet’s altitude en route from Brisbane to Singapore.
The incident, called a “loss of separation”, occurred 75km southeast of the RAAF Base Tindal, near Katherine.
A “loss of separation” is when the risk of collision is increased when planes fly within 305 metres vertically and 9.26 kilometres horizontally of each other.
Australian Transport Safety Bureau (ATSB) Team Manager Mark Walker said they were investigating what caused the incident.
“At this stage we don’t have any further information. We’re in the process of working out what happened,” he said.
“We’ve requested the radar information and we’ll be interviewing the controllers next week.
Until we do all that it’s a bit hard for us to comment.”
There are over 100 ‘loss of separation’ incidents a year in Australia occurring on average once every three days.
“It can be a range of things, actions of controller, actions of flight crew, sometimes it can happen in civil airspace or in military airspace,” Mr Walker said.
“Some of them obviously get closer than others; some even though they’re close things are still under control.”
The ATBS declined to say how close the aircraft came to each other.
A Jetstar spokesman said no passengers were injured during the incident.
“Jetstar is aware of a loss of separation incident occurring near the top of flight JQ 673’s climb out of
Darwin,” he said.
“While following air traffic control directions our pilots became aware of the issue and immediately followed appropriate procedures to re-establish the required separation distance.
“There was no impact to passengers and the aircraft landed safely and without incident at Brisbane Airport as scheduled.”
The ATSB in October last year released a publication into loss of separation incidents between 2008 and 2012.
The report said there had been an increase in LOS incidents reported to the ATSB in the two years to June 2012.
However that number represented fewer incidents than between 2005 and 2008 despite “traffic levels have generally increased during the same period.”
It said there are on average six occurrences every year with an elevated risk of collision with the majority having no or minimal risk.
The report said aircraft separation has many levels of defences to avoid “errors that will inevitably be made from time to time by air traffic controllers and pilots.
“The defences ensure that even if a LOS does occur, the chance of an aircraft collision is still very remote.”
The ATSB report into the incident is expected to be completed in November.