Background
A survey aircraft, conducting a mission on behalf of the Bureau of Mineral Resources (BMR), failed to arrive at its destination. After the search and rescue time expired, a search was initiated. The wreckage was later located on the eastern slope of Mt Barren Jack, northwest of the mouth of Carrolls Creek, along the planned survey track.
Accident Sequence
Observers at Burrinjuck reservoir near the mouth of Carrolls Creek reported that at the time of the accident, black clouds were spilling over and obscuring the mountain tops. The aircraft collided with trees on the mountainside while in a steep right bank and a tail-low attitude. During the impact sequence, the pilot was thrown from the aircraft. Medical opinion found no evidence of body trauma consistent with the seat belt being fastened at the time of impact. Both occupants were killed.
Investigation Findings
The investigation revealed that both engines were operating at high power at impact. No malfunction or defect was found that could have contributed to the accident. Due to destruction of the aircraft by fire, the status of the seat belt assemblies could not be determined.
The survey task required the pilot to adhere strictly to a particular track, with a target height of 500 feet above ground level while maintaining visual contact with the ground at all times. The pilot was suitably qualified to act as pilot in command of survey operations down to 200 feet above ground level.
The investigation concluded that the aircraft was being operated at a height substantially lower than 500 feet above ground level prior to the accident. Impact marks, wreckage, and mechanical evidence suggested that the aircraft impacted terrain while the pilot was attempting to carry out an evasive manoeuvre to remain clear of terrain. The reason why the aircraft was operated at such a height and why the pilot delayed turning away from the steeply rising terrain could not be determined.
Reported Factors
The following factors were reported: the pilot continued the flight into adverse weather conditions, and the pilot flew the aircraft towards steeply rising terrain at a height substantially lower than 500 feet above ground level.