Accident
A helicopter was damaged during a forced landing after the engine lost power. According to the operator, the pilot was positioning the helicopter following maintenance. While in cruise flight, the engine lost power, and the pilot executed an autorotation. The helicopter landed hard, and the tailboom separated from the airframe.
Examination
Examination of the helicopter revealed that the engine compartment and engine were not damaged. The particle separator was undamaged and showed no signs of blockage. The fuel control and power turbine governor rigging were intact and appeared normal. The bleed valve was found in the open position; when manually closed, it freely returned to the open position. All pneumatic tubing was intact, and all B-nuts were at least finger tight. The N2 compressor rotated freely and smoothly with no unusual noises, and continuity to the main transmission was confirmed.
Findings
Fuel was present in the fuel supply line from the fire shield to the fuel nozzle in a normal amount. However, contamination was found in both the airframe and engine fuel filters. Disassembly and inspection of the fuel nozzle revealed contamination in the filter screen, which had collapsed. The contamination had the appearance of "DIEGME" (also known as Apple Jelly). No determination of engine power loss cause was provided in the source.