N223GEdward B Resnick AR-1 · 2017

Shortly after departure, the commercial pilot undergoing instruction leveled the helicopter for cruise at an altitude of 300 feet above ground level, in compliance with the flight school's departure procedures. He reached down to the instrument panel pedestal with the intention of pulling the cyclic right trim knob; however, the flight instructor observed him instead reach for the adjacent engine fuel mixture control. The instructor yelled for him to stop, and attempted to swat his hand clear, however, the pilot then pulled the control and the engine lost all power. The flight instructor initiated an autorotation while simultaneously pushing the mixture control back down. The engine did not restart, and the helicopter landed hard, with the main rotor blades severing the tailboom. The high density altitude conditions, along with the helicopter's altitude and airspeed at the time of power loss, meant that it was operating on the edge of the "Avoid Operation" area of the height-velocity performance envelope. The pilot reported no mechanical malfunctions or failures with the helicopter that would have precluded normal operation.

During a descent for an off airport pinnacle landing, the helicopter encountered a downdraft about 75 to 100 feet above ground level (agl), and the pilot receiving instruction, increased collective. The flight instructor instructed the pilot receiving instruction to be less aggressive using the collective as the flight continued the descent to the landing area. As the helicopter descended through about 10 to 25 feet agl, it encountered a second downdraft and the pilot receiving instruction increased collective followed by a decrease in rotor RPM. Subsequently, the flight instructor took control of the helicopter as it contacted the ground and then became airborne again. The helicopter yawned to the right, and landed upright on sloping terrain. Post flight examination of the helicopter revealed that the tailboom was structurally damaged just aft of the fuselage attach point. The pilots reported no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operation.