An Australian Transport Safety Bureau (ATSB) investigation into the crash of a Cessna 210 near Albany in 2017 has attributed an in-flight break-up to abnormal operation.
VH-DBU was flying between Albany and Bunbury in WA on 24 October 2017 when it crashed in the Mount Lindesay National Park 30 nm north-west of Albany.
The investigation showed that the aircraft broke up in flight before impacting the ground. The pilot, who was the only person on board, was killed.
The pilot left Albany airport and did some local flying around Princess Royal Harbour before taking up a track for Bunbury. Around 1100 that morning the crash occurred.
"Witnesses recalled hearing a distinctive noise described as a sharp bang, crack of a whip, gunshot, or thunder and lightning," the ATSB has reported. "The aircraft was then seen in a steep descent until it disappeared out of sight, with smoke appearing shortly after indicating a post-impact fire.
"The investigation found, for reasons that could not be established, abnormal operation of the aircraft produced high levels of unusual aerodynamic loading that exceeded the strength of the right wing and initiated an in-flight break-up and impact with terrain.
"No pre-existing aircraft structural deficiency or damage, which could have contributed to the in-flight break-up, was found during the investigation. Local weather at the time was generally calm and clear."
The ATSB report also focuses on the fact that methamphetamines (ice) were found in the pilots' system with no natural explanation for them being there. Although the bureau was unable to determine what effects, if any, the drug had on the crash, they explored the impact of ice on a pilots ability to fly safely.
"The ATSB found that [methamphetiamines] increased the risk of operational misjudgements or mishandling due to impairment and involuntary action or inaction due to incapacitation, but this did not necessarily contribute to the accident," the report states.
"The ATSB’s safety message from this investigation is for operators and industry associations to consider how they can make information available to pilots and employees about support services for problematic substance use."
The full investigation report is on the ATSB website.