What happened
During an approach for operations on runway 17R, the pilot was cleared for landing. While crossing the threshold at 40 knots and 40 feet above ground level, the pilot experienced a high rate of descent and felt the helicopter begin to sink. In an attempt to correct the situation, the pilot decreased the collective and pushed the cyclic forward. However, the aircraft continued to descend, impacting the runway with significant force. The impact caused the aircraft to slide approximately 6 feet along the runway surface.
Findings
The aircraft sustained substantial damage during the event. Calculations performed during the investigation determined the density altitude to be 8,622 feet. At this altitude, the out of ground effect hover ceiling was calculated at approximately 5,600 feet, while the in ground effect hover ceiling was estimated to be between 6,200 and 7,600 feet. The pilot suspected the aircraft entered a settling with power condition during the final stages of the approach.