What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(.4) While practicing autorotations, the pilot, who was a commercial pilot in single and multiengine aircraft but a student pilot in helicopters, experienced a loss of engine power for unknown reasons. During the full autorotation, which was necessitated by the power loss, the landing was hard and resulted in main rotor flex, which cut off the tail boom. Density altitude at the time was 9,000 feet. (-23) student pilot practicing autorotation. He rolled off throttle to disengage main rotor. Engine quit. Autorotation completed. Main rotor blade contacted top and aft section of tail boom. After landing the engine was run on the ground by student and instructor. There were no engine abnormalities in engine run.
As the FAA filed it
(.4) WHILE PRACTICING AUTOROTATIONS, THE PILOT, WHO WAS A COMMERCIAL PILOT IN SINGLE AND MULTIENGINE AIRCRAFT BUT A STUDENT PILOT IN HELICOPTERS, EXPERIENCED A LOSS OF ENGINE POWER FOR UNKNOWN REASONS. DURING THE FULL AUTOROTATION, WHICH WAS NECESSITATED BY THE POWER LOSS, THE LANDING WAS HARD AND RESULTED IN MAIN ROTOR FLEX, WHICH CUT OFF THE TAIL BOOM. DENSITY ALTITUDE AT THE TIME WAS 9,000 FEET. (-23) STUDENT PILOT PRACTICING AUTOROTATION. HE ROLLED OFF THROTTLE TO DISENGAGE MAIN ROTOR. ENGINE QUIT. AUTOROTATION COMPLETED. MAIN ROTOR BLADE CONTACTED TOP AND AFT SECTION OF TAIL BOOM. AFTER LANDING THE ENGINE WAS RUN ON THE GROUND BY STUDENT AND INSTRUCTOR. THERE WERE NO ENGINE ABNORMALITIES IN ENGINE RUN.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.