What happened
The accident occurred while the aircraft was engaged in aero-logging operations. The pilot was in the process of lifting a load consisting of approximately 5,000 pounds of logs from a designated drop area. During this phase of flight, the helicopter experienced a sudden and severe mechanical malfunction involving the free-wheeling sprag clutch assembly.
This failure resulted in a torsional separation of the engine drive adapter, effectively disconnecting critical power transmission components. Despite the pilot's immediate efforts to execute an emergency descent toward a nearby clearing situated on a downward slope, the aircraft was unable to maintain controlled flight. The helicopter subsequently impacted a line of trees before dropping onto the terrain below.
The investigation
Examination of the wreckage and mechanical components revealed that the free-wheeling sprag clutch assembly had malfunctioned. This failure caused a torsional separation within the engine drive adapter, which was identified as the primary mechanical event leading to the loss of control.