Details have emerged of a close shave between a corporate jet owned by James Packer's Crown Casino and a Virgin Australia passenger aircraft over the skies of Armidale late last year.
A report from air safety inspectors reveals that the Gulfstream IV, which is used to fly Asian high-rollers to Crown's Melbourne casino, and the Virgin 737-800 were flying towards each other on air routes which intersected about 35 nautical miles north-west of the city on October 8.
An air traffic controller identified the situation but the instructions issued to the pilot of the Gulfstream meant that the corporate jet was cleared for descent below the level at which the 737 was flying.
The progress towards what air inspectors term a "breakdown of separation" continued when the controller did not recognise the error during the Gulfstream pilot's read-back of the clearance, the report from the Australian Transport Safety Bureau states.
A breakdown of separation occurred about 3pm when the planes got within 4.8 nautical miles (8.9 kilometres) of each other.
The appropriate separation between planes is 5 nautical miles side by side, or 1000 feet vertically.
Fortunately, an automatic alarm was activated seconds later, and the controller issued an alert to the Virgin pilots advising them that the Gulfstream was at 1 o'clock in their line of vision at 4 nautical miles.
"The pilot of the 737 responded that the traffic was sighted and that a traffic alert and collision avoidance system ... traffic advisory alert ... had been received. This was reported to have assisted the pilot to visually sight the descending Gulfstream IV," the report states.
"Subsequently the controller acted correctly to recover from the ensuing breakdown of separation."
The ATSB's general manager of aviation safety investigation, Ian Sangston, said today that the report highlighted the various layers of defence in a complex air-safety system.
"In a complex situation there are a number of layers of defence ... and where there is an inadvertent slip up on the part of the controller, other layers in the system catch the slip," he said.
The report found no evidence the pilots of either aircraft were at fault.
The Virgin jet was flying from Brisbane to Sydney, while the Gulfstream was operating a flight from Melbourne to the Gold Coast Airport at Coolangatta.
The corporate jet is one of three Gulfstreams – two of which are V versions – the casino owns to fly high rollers to Melbourne from destinations throughout Asia.
In a VIP configuration, Crown's corporate jets can seat about 10 people.
Crown controls 80 per cent of the high-roller market in Australia.
- The Sydney Morning Herald