Tristan Swanwick, 31st December 2007,23739,22992322-952,00.html

AIRCRAFT carrying thousands of people are flying over populated areas without ground-based supervision as air traffic controllers struggle to keep up with the workload in the skies.

And the controllers say Australia's proud record of airline safety is in jeopardy because the body overseeing the nation's airways is not training enough controllers.

The Courier-Mail has obtained a scathing letter from the national union of air traffic controllers to Airservices Australia complaining of a "critical threat" to continued flight safety.

Civil Air Australia president Michael Haines told Airservices Australia that airspace was being left uncontrolled "on an almost daily basis due to the lack of adequate staffing".

"At the same time, I fear that Airservices is concealing from regulatory and safety organisations the fact that airspace is closing due to low staff levels," he wrote.

Airspace over Townsville, Cairns, Mackay, Coolangatta south to Coffs Harbour, central Australia, western NSW and Launceston has been uncontrolled at times during the past month.

Airlines are told when airspace is not controlled and they must decide whether to continue flying through the area.

A pilot claimed that services normally provided by Melbourne tower were unavailable due to staff shortages at least once last month.

When airspace is uncontrolled, pilots must regularly broadcast their identification, route, position and altitude. Most large planes also carry computerised collision avoidance systems as a "last resort".

A Qantas pilot, who declined to be named, compared the air traffic control situation in Australia to Africa.

"The fact that nothing has happened is down to the pilots and the air traffic controllers doing the best they can with what they've got," he said.

Airservices Australia is a government-owned corporation which employs 90 per cent of Australia's air traffic controllers.

Spokesman Terry O'Connor admitted there was a shortage of trained controllers but he rejected claims of mismanagement and said safety was not at risk.

"We're aware of the issues they have raised – it's something that's been a potential concern for us for some months," he said. "We wrote to our airline customers about these shortages a couple of months ago and CASA (Civil Aviation Safety Authority) is aware of it as well."

But CASA spokesman Peter Gibson said he was not aware of a shortage of trained staff.

"Shortages is the job of Airservices Australia to manage," Mr Gibson said.

Mr Haines used his letter to Airservices CEO Greg Russell to accuse the corporation of pursuing a "profit over safety trajectory". He said senior Airservices management had recently instructed some controllers to withhold from authorities incident reports about airspace closing due to understaffing.

"This suggestion that we're somehow trying to hide the situation is simply not true," Mr O'Connor said.