What happened
A flight instructor was performing an autorotation demonstration for a student when the accident occurred. The instructor initiated a straight-in autorative approach to runway 30 from 600 feet above ground level (agl). While the descent rate remained stable until reaching 200 feet agl, the pilot experienced a sudden increase in the rate of descent.
The pilot began the flare at 50 feet agl; however, the vertical speed did not decrease at the expected rate, resulting in a hard landing. During the impact, the tail boom struck the ground first during a right yawing moment. This caused the helicopter to roll to the right, which crushed the right skid and severed the tail boom. The movement subsequently allowed the rotor blades to contact the ground.
At the time of the flight, the pilot observed winds from the northwest at 8 knots, with gusts up to 12 knots and light turbulence. The pilot suggested that wind shear may have been a contributing factor to the increased descent rate.