As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS IN A 70 FOOT HOVER AND HAD JUST PLACED A SLING LOAD ON THE GROUND WHEN A LOUD BANG OCCURRED THE LOUD BANG WAS THE TURBINE EXPLODING. AT THIS TIME, THE PILOT LOWERED THE COLLECTIVE AND ENTERED AN AUTO ROTATION. AIRCRAFT TOUCHED DOWN IN A LEVEL ATTITUDE WITH MINOR DAMAGE TO AIRFRAME. SUBSEQUENT INSPECTION REVEALED THAT THE NR4 TURBINE WHEEL BURST. (K)