What happened
During a training flight, a student pilot was performing a practice power-off autorotation. While executing a go-around from a simulated landing flare, the student applied excessive aft cyclic input. Simultaneously, the instructor pilot applied a small amount of up collective to arrest a slight sink rate but failed to take sufficient remedial action to prevent the student's excessive cyclic movement.
This sequence of inputs caused the tail rotor to impact the ground, which immediately led to a loss of tail rotor effectiveness. The helicopter began to spin as a result of the strike. The instructor pilot then assumed total control of the aircraft and performed an emergency landing.
The investigation
Following the engine shutdown after the emergency landing, an inspection of the aircraft revealed damage to both the tail boom and the tail rotor.