What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23)The pilot in command (flight instructor) stated that when he attempted to land the helicopter from a hover, the helicopter encountered what he identified as ground resonance. The pilot stated that he rolled the throttle off immediately. This improper action caused the ground resonance to intensify resulting in substantial damage to the airframe, tailboom skid landing gear, main and tail rotor blades and sudden stoppage to the engine, transmission and drive train. The occupants egressed through the right cabin entrance door. A small fire broke out as a result of engine oil on the hot exhaust. One occupant received minor cuts to the right arm and hand requiring stitches.
As the FAA filed it
(-23)THE PILOT IN COMMAND (FLIGHT INSTRUCTOR) STATED THAT WHEN HE ATTEMPTED TO LAND THE HELICOPTER FROM A HOVER, THE HELICOPTER ENCOUNTERED WHAT HE IDENTIFIED AS GROUND RESONANCE. THE PILOT STATED THAT HE ROLLED THE THROTTLE OFF IMMEDIATELY. THIS IMPROPER ACTION CAUSED THE GROUND RESONANCE TO INTENSIFY RESULTING IN SUBSTANTIAL DAMAGE TO THE AIRFRAME, TAILBOOM SKID LANDING GEAR, MAIN AND TAIL ROTOR BLADES AND SUDDEN STOPPAGE TO THE ENGINE, TRANSMISSION AND DRIVE TRAIN. THE OCCUPANTS EGRESSED THROUGH THE RIGHT CABIN ENTRANCE DOOR. A SMALL FIRE BROKE OUT AS A RESULT OF ENGINE OIL ON THE HOT EXHAUST. ONE OCCUPANT RECEIVED MINOR CUTS TO THE RIGHT ARM AND HAND REQUIRING STITCHES.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.