The Australian Transport Safety Bureau (ATSB) is investigating  a separation error  between two Airbus A330s on March 30 in the far-northwest corner of the continent. While a spokesman for the AirServices Australia (the government-owned ATC service provider) said this represented the least severe type of separation error, an AIN source in the region said there’s more to the story. 

An AirAsia X A330 headed northwesterly at FL380 while a Garuda Airlines A330 flew southeasterly from Indonesia to Sydney at FL390. According to reports, the Garuda aircraft somehow fell through an ATC crack in the Brisbane Control Center area when airspace responsibility there changed hands for a few hours, something AirServices said is normal when the military operates the airspace. AIN's source claims the airspace was completely uncontrolled. 

When the airspace near Curtin returned to AirServices control, no one was talking to Garuda flight, because it had arrived in the area after the airspace changed hands. Controller attempts to contact the aircraft on a hunch and track its takeoff time from Indonesia were unsuccessful, so controllers assumed it was not in their airspace. About this same time, the AirAsia X Airbus was given an order to climb to FL400. The loss of separation assurance occurred at 18:41 UTC.

Only when the Garuda flight contacted the Melbourne Control Centre in an adjacent sector did anyone realize the Airbus had been flying completely uncontrolled in the area. No one knows how close the two aircraft actually came to each other, but as one Australian news source said, ”If this were a trivial matter, the ATSB wouldn’t even be investigating.”