Primary finding
Probable cause
The pilot’s improper flare, which resulted in a hard landing and the main rotor blades contacting the tail boom.
Investigator assessment
Analysis narrative
On the day of the accident, the pilot had been practicing autorotations. The first was a power-on autorotation to the ground, followed by two hovering autorotations, all of which were uneventful. The pilot then briefed and set up for a power off autorotation to the ground. The entry began at 600 ft above ground level (agl) and the glide was normal. He set up a 70-knot glide speed and added collective to keep the rotor at 480 rpm. The helicopter was heavy with fuel and the added pilot-rated passenger, so the decent was faster than anticipated. The pilot reported that at 40 ft agl, he accomplished an “auto-rotative flare attitude” and that the “flare was not aggressive enough for the weight,” and as a result, he held the flare longer than usual. The ground speed bled off, but the leveling of the helicopter was not accomplished in a timely manner. The tail skid contacted the ground hard and the main rotor blades flexed down resulting in contact with the tail boom and the fuselage behind the rotor head. The helicopter’s tailboom and main rotor blades were substantially damaged. The pilot reported that there were no pre-accident mechanic malfunctions or failures with the helicopter that would have precluded normal operation.