The Age article on old AU sighting

It is probably the closest Australia has come to scrambling fighter jets to intercept a UFO. Documents that have just become available under the 30-year rule at the National Archives of Australia reveal how two RAAF Mirage jets were placed on the second highest level of alert to determine the cause of unidentified radar contacts seen on screens at Mascot. The ''X Files'' viewed in Canberra also give details of other unexplained sightings, some of which are supported by witness statements to police.