Accident Details
The pilot was conducting practice maneuvers with a 100-foot long line attached, in preparation for a check ride scheduled for the following day. During the exercise, the helicopter was in a hover with the hook at the end of the line just touching the ground. The pilot then increased altitude, raising the hook off the ground by about 10 feet. At that moment, the engine suddenly decreased power to idle. The pilot immediately initiated an autorotation toward an open field.
During the autorotative landing, the helicopter touched down tail low. Subsequently, the main rotor blades contacted and severed the tailboom.
Post-Accident Inspection
A post-accident inspection of the engine revealed that the fuel nozzle screen had collapsed, with traces of contaminant present in the screen. Water and bacterial contaminants were found in the airframe filter bowl and the fuel pump filter bowl. It was also noted that Kerosene (K-1), which is not approved for the engine, had been used instead of Jet A fuel.
The engine was later test run in a test cell. Although the engine was found to run below normal rated shaft horsepower, no evidence of a mechanical failure or malfunction was identified.