What happened
Following the replacement of a cylinder, a pilot was conducting a short test flight after completing the necessary brake-in process. While flying at 500 feet above the ground, the helicopter experienced a large yaw and a loss of engine power. During the subsequent autorotation, the pilot was forced to maneuver to clear ground obstacles, which resulted in a loss of main rotor RPM. The helicopter subsequently fell vertically from approximately 50 feet, resulting in a hard landing. There was no fire following the impact.
The investigation
The investigation examined the aircraft and found that all three main rotor blades were destroyed and the tail boom had separated from the airframe. Prior to recovery, ten gallons of aviation fuel were drained from the aircraft. Investigators found no discrepancies with the airframe or the engine that could have contributed to the reported loss of engine power. Weather conditions were determined not to be a factor in the accident.
Findings
- The pilot held a private pilot certificate with 1,200 total hours, including 80 hours in rotorcraft and 40 hours in this specific make and model.
- The loss of engine power could not be determined.