The Australian Transport Safety Bureau late last week published their investigation report in to the fatal crash of a U206G near Norseman, WA, in March 2022.
Investigators concluded the aircraft crashed after the pilot most likely lost control during a low-level turn whilst on survey operations. The report said the ATSB was not able to determine why the pilot lost control.
U206G VH-JVR was on a survey mission 67 nm west of Norseman when the crash happened. The pilot had completed 24 survey lines when the Cessna impacted the ground. Tracking data showed the crash site was underneath the path the aircraft would have taken during a procedure turn to line-up for another survey run.
Although the aircraft was being tracked at the company headquarters using a Spidertracks system, the alarm wasn't raised until 30 minutes after the Cessna was due back, an estimated three hours after the crash.
Rescuers found the wreckage 1.7 nm west of its last recorded position. The pilot had survived the initial impact and managed to get out of the aircraft, but later succumbed to the injuries suffered in the crash.
ATSB Chief Commissioner Angus Mitchell said that a stall during the turn was the most probably cause.
“While an aerodynamic stall situation is a plausible explanation for the loss of control, this could not be conclusively established due to a lack of available evidence, including no recorded data beyond the last known position of the aircraft, and no witness observations,” he said.
Mitchell said the investigation made several findings regarding risks to aviation safety relevant to air work operators.
“Air work such as mustering, spraying and geophysical survey are conducted at low levels out of operational necessity, which creates an inherently high‑risk operating environment,” he said.
“Operators are responsible for effectively managing this heightened risk with adequate and effective processes and controls.”
Investigators found that the operator’s pilots were trained to use 45-60° angle-of-bank turns at low altitude to position the aircraft onto survey lines, which increased the risk of an aerodynamic stall at low level.
However, procedures or limitations specific to procedure turns were not included in the company operations manual, which the ATSB believes increased the risk of inconsistencies and reduced safety margins.
The full report is on the ATSB website.