Accident Overview
During an aerial application flight, the aircraft experienced an in-flight separation of a main rotor blade. This event led to the aircraft colliding with the ground. The accident occurred while the aircraft was engaged in its intended agricultural operations.
Findings
Inspection of the fracture surface on the failed main rotor blade revealed characteristics consistent with high stress, low cycle fatigue. This type of fatigue typically results from repeated loading cycles at elevated stress levels, which can initiate and propagate cracks over time.
Further Investigation
Laboratory findings from the fracture analysis will be compared with similar failures that have occurred subsequent to the issuance of Airworthiness Directive AI 80-14-12. This directive requires special inspection of the same failure area to detect potential fatigue damage. The comparison aims to identify commonalities and inform future safety actions.