What happened
During a landing approach to the runway, the pilot was at the controls while receiving instruction. As the helicopter neared the runway, the pilot flared and leveled the aircraft approximately 3 feet above the ground with no forward airspeed.
At this point, the Certified Flight Instructor (CFI) observed that the engine and rotor RPM began to decrease, causing the helicopter to turn to the left. The CFI took control of the aircraft in an attempt to correct the situation; however, the helicopter underwent a 360-degree rotation. During this maneuver, the left landing skid struck the ground, causing the helicopter to roll onto its left side before coming to rest. There were no injuries reported.
The investigation
An examination of the helicopter and its powerplant revealed no failures occurring prior to the impact. Investigators noted that the right landing skid had separated from the struts and its fasteners had been sheared. Additionally, dirt was found packed into the heel of the skid. The middle and aft skid shoes showed deformation and a clockwise twist on the skid. The observed damage was consistent with the skid making contact with the ground while moving in a right lateral direction under significant impact force.