The pilots of two aircraft involved in a near-miss had no idea they were taking off on intersecting runways, with the incident prompting changes to a regional airport's rules.
The Australian Transport Safety Bureau released its final report on Tuesday, almost 12 months after the planes almost collided at Mildura Airport.
A Piper PA-28 Cherokee was on a solo private flight to Broken Hill, while a QantasLink Dash 8, with three crew and 33 passengers, was departing on a scheduled service to Sydney on June 6, 2023.
Both aircraft made the required mandatory calls on the local common traffic advisory frequency (CTAF), used by pilots to coordinate and self-separate at non-controlled aerodromes, like Mildura.
ATSB Director of Transport Safety Stuart Godley said the pilot of the Cherokee had incorrectly identified the plane was on runway 35 instead of runway 36.
This mistake meant the Dash 8 pilots didn't believe the Cherokee was at Mildura, given that the nearby Wentworth Airport used the same CTAF.
When the Cherokee was ready for its take-off roll, its pilot believed the Dash 8 would be still backtracking on the other runway, as the Dash 8 did not give a rolling call - a notification the aircraft was beginning take-off - on the CTAF.
At the time, such calls were not mandatory.
"Subsequently, both aircraft began take-off rolls towards the intersection of their respective runways, and the Dash 8 passed about 600 metres in front of the Cherokee," Dr Godley said.
Terrain and buildings at Mildura Airport also blocked the ability for the pilots to see each other.
"With the inability to see another aircraft when each aircraft is at the threshold at Mildura Airport, the lack of a requirement for mandatory rolling calls increased the risk of aircraft not being aware of each other immediately prior to take-off," Dr Godley said.
Mildura Airport has since introduced a requirement for mandatory rolling calls immediately prior to take-off while QantasLink has made the calls part of the minimum requirements for operations at CTAF aerodromes.
