NTSB Factual Report

The pilot stated that he was conducting a full down practice autorotation which involved landing the helicopter as the final step.  During the landing, the helicopter bounced, which resulted in the main rotor striking the tail boom, severing the tail rotor drive shaft. The pilot stated that the accident could have been prevented if he had applied more forward cyclic after the helicopter had contacted the ground. The pilot reported no preimpact mechanical malfunctions or failures that would have precluded normal operation. 

NTSB Probable Cause

The pilot's incorrect application of the cyclic control during the landing.