An ATSB report into the fatal crash of an Ayres Thrush in April 2012 has failed to establish why the pilot of the aircraft lost control.
The aircraft was being ferried between St George, QLD, and Moree, NSW, when it crashed into a wheat field 36 km north-west of Moree.
According to the report, the ATSB found that "the aircraft departed controlled flight and the pilot was unable to recover before impact with the ground. On the basis of the evidence available to the ATSB, it was not possible to determine with any certainty the reasons for the loss of control."
Witnesses to the crash stated that they saw the Thrush in a steep, clockwise spiral descent prior to impact.
Possible causes investigated included structural failure, pilot incapacitation, wire or bird strike, engine problems or handling issues.
The ATSB estimated that the Thrush was 242 kg above it's maximum take-off weight at the time, but this is not considered a factor in causing the loss of control.
The full report is available on the ATSB website.