What happened
During a flight intended to provide required recurrent flight checks under 14 CFR Part 135, a flight instructor and a student pilot were performing a practice autorotation. The aircraft entered a landing pattern parallel to runway 22R. At 500 feet above ground level and 80 knots indicated airspeed, the instructor initiated an engine failure simulation.
The pilot responded by entering an autorotation at 60 knots indicated airspeed and 398 rpm rotor speed. As the aircraft reached 60 feet above ground level, the pilot performed a flare that was more aggressive than necessary for the existing conditions. Following instructions from the flight instructor, the pilot lowered the nose.
At 30 feet above ground level, the pilot began increasing the collective, causing the rotor speed to drop to 380 rpm. During this phase, the flight instructor took control of the aircraft. The instructor leveled the helicopter and reduced the collective. At approximately 5 feet above ground level, the instructor applied the final collective input.
As the rotor speed decreased, the tail rotor lost effectiveness, causing the aircraft to yaw to the left even with full right anti-torque pedal applied. The helicopter touched down with the nose approximately 15 degrees to the left of the direction of travel. The right skid made contact first, and the aircraft drifted to the right. Despite corrective inputs from the instructor, the helicopter rolled to the right. The front portion of the right skid dug into the soft turf, pivoting the aircraft forward until the main rotor blades contacted the ground. There were no injuries reported.
The investigation
The investigation found no mechanical malfunctions with the aircraft.