TWO air-traffic controllers were involved in a safety scare involving two passenger planes at Sydney airport and were then asked to continue their shifts, contrary to what their union says was accepted safety practice.
The air-traffic control union, Civil Air, has asked the government air-traffic control manager Airservices Australia for an explanation of the incident amid concern that the controllers were asked to stay at their posts to offset staff shortages and keep air traffic flowing smoothly.
A report of the incident, obtained by The Australian, shows that two aircraft, an Airlink Beech 1900 bound for Bathurst and a Rex SAAB 340 bound for Dubbo, came within 2.3 nautical miles (4.3km) of each other shortly after take-off from Sydney airport on August 1.
The required minimum separation is three nautical miles.
The incident occurred when the Airlink plane, carrying up to 19 passengers, took off but then slowed down by 40 knots as it rose to 5000 feet in heavy turbulence.
The pilot did not inform the controller that he had slowed down and was momentarily unaware that the SAAB 340, carrying up to 34 passengers, was closing in from behind at a rate of about one nautical mile a minute.
"It just ate the other plane up," said one controller who witnessed the incident.
The controller on duty instructed the Airlink plane to turn left to avoid a possible collision.
Another controller who witnessed the incident and its aftermath told The Australian that the two controllers involved immediately reported the so-called "breakdown of separation" between the aircraft.
On such occasions, controllers say the accepted practice is for those controllers involved to be stood down so they can calm their nerves and for the incident to be investigated.
"In normal circumstances, the system says you stand the controllers down because safety is paramount," said the controller.
"But the line manager asked them to continue apparently because they were already one man short on that shift and they would have lost another two, which would mean severe restrictions on air traffic out of Sydney.
"The feeling in the (terminal control tower) was that it was inappropriate.
"Your mind is not on the job if something like that has just happened -- you can't give the attention to the job that you need (to)."
Airservices denied it had acted unsafely, saying that it was appropriate for the controllers to continue on duty because they were not at fault in the incident.
Peter McGuane, executive secretary of Civil Air, last night said it was not normal procedure for controllers to keep working after a safety incident.
The incident is one of several to have occurred while there is a national shortage of air-traffic controllers. That shortage has left large areas of sky uncontrolled for hours at a time, forcing pilots to fend for themselves to avoid collisions.