During short final to landing at a heliport, as the helicopter approached a hover at about 6 ft AGL, the engine spooled down to idle RPM. The pilot continued with the landing and landed the helicopter without further incident. Following the landing the engine remained at idle RPM and did not respond to pilot inputs.
Investigation revealed internal damage to the engine compressor section. This damage was identified to be caused by the breaking off and subsequent ingestion of a compressor third stage stator vane blade. An analysis of the vane blade root indicated a pre-existing fatigue crack at the forward edge of the blade. The most recent inspection of the compressor had occurred 218.9 hours prior to the occurrence. The compressor case had accumulated 513.7 hours since overhaul. Erosion of the blade vane was not a factor. The investigation was unable to determine the origin of the fatigue crack.