The ATSB said a fatigued right wing which broke off in flight caused the fatal air crash in Mount Isa last month.
A Cessna 210 VH-SUX crashed near Mount Isa on May 26 killing two men aboard.
The ATSB said evidence at the accident site indicated that the aircraft's right wing had separated while in flight, resulting in a rapid loss of control and subsequent collision with terrain.
Subsequent technical examination confirmed the aircraft's wing spar had fractured due to fatigue cracking, which reduced the spar's structural integrity to the point where operational loads produced an overstress fracture.
"The ATSB has notified the Civil Aviation Safety Authority, the US National Transportation Safety Board, the aircraft manufacturer and operator of the initial finding of fatigue cracking with the wing spar carry-through structure," ATSB Executive Director Nat Nagy said.
"The ATSB is working closely with those parties to ensure the continued safe operation of the the aircraft type."
The Cessna 210, which had been manufactured in 1976 and had accumulated over 12,000 flight hours, had been conducting a geological survey flight while flying at about 200 feet above ground level at the time of the accident.
The ATSB is working closely with those parties to ensure the continued safe operation of the the aircraft type.
The aircraft had been modified for geological survey work and had also been fitted with approved integral wing tip fuel tank and non-standard engine and propeller modifications.
"The ATSB notes that there is no evidence to indicate a connection between this accident and other recent investigations it has conducted involving this aircraft type," Mr Nagy said.
The Cessna 210 registered to Thomson Aviation, crashed around 26 kilometres north-east of Mount Isa airport killing a Sunshine Coast man, aged 36 and a Sydney man, named Geoffery Manche aged 26.
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