NTSB Factual Report

The pilot receiving instruction was practicing an autorotation when the main rotor rpm decayed. The flight instructor took control of the helicopter and attempted to correct the low main rotor rpm. However, the helicopter landed hard in a nose high attitude, which resulted in structural damage to the tailboom. The pilot reported no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operation.

NTSB Probable Cause

The pilot’s failure to maintain adequate main rotor rpm during a practice autorotation and the flight instructor's delayed action, which resulted in a hard landing.