There are fears of an aviation catastrophe over Sydney after it was revealed an average of 10 near misses occur between aircraft using NSW airspace every year.
Increasingly crowded skies and a possible second international airport for Sydney have added to concerns of major airlines, safety groups and campaigners, who say significant extra investment is needed to manage air traffic safely.
Since January 2007, there have been 32 near misses between civil aircraft over Sydney, the worst of which involved a twin-engined Saab passenger plane coming close to hitting a helicopter over the city.
On occasions a Boeing 737 came close to hitting an Airbus and another Saab came close to hitting a Boeing 767.
The latter two incidents involved air traffic controllers becoming distracted or making mistakes, Australian Transport Safety Bureau reports said.
Since 2004 there have been 22 near misses involving military aircraft using NSW airspace, three of which came in areas used by civilian aircraft, figures obtained by AAP from the Australian Transport Safety Bureau and Defence Department show.
The increasing number of flights to and from Sydney Airport is one reason why some experts believe a major crash could occur.
Virgin Blue said recently in its submission to the federal government's forthcoming White Paper review of the aviation industry that it has underlying concerns about airspace management across Australia.
The review, due to be published later this year, is expected to outline detailed plans, including potential locations for a second major international airport near the city to relieve pressure on Sydney Airport.
The number of aircraft movements at the airport has increased by 10 per cent since 1999 and airport chief executive Russell Balding has said it is expected to continue rising, from just under 300,000 in 2009 to more than 425,000 in 2029.
"There is a continuing fear that sooner or later we will have a major air crash in Sydney," Allan Rees, president of the No Aircraft Noise lobby group, told AAP.
"Flight paths are increasingly complicated and the expansion of a nearby second airport increases that risk."
The Civil Aviation Safety Authority (CASA) has also recognised the increasing number of near misses and collisions between aircraft at smaller general aviation airports in NSW.
A report commissioned by CASA and published in July highlighted the need for immediate action to improve airspace management at smaller airports.
In the 35 years to 2003, there was an average of one mid-air collision at such airports a year but since December 2007 there have been seven, killing nine people.
Of the 32 near misses between civil aircraft in NSW since 2007, the Australian Transport Safety Bureau investigated only the three it considered most serious.
A Defence Department spokeswoman said military pilots were bound by strict rules to report incidents when they had flown close to other aircraft.
She said many of the incidents involving military aircraft occurred out at sea during manoeuvre exercises.
