As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ACFT WAS PERFORMING A TRAINING MISSION WHEN THE MID SPAR MAIN ROTOR BLADE WEIGHT CAME LOOSE. THE ACFT PRECAUTIONARY LANDED WITH NO INJURIES. THE MID SPAR BLADE BLEW OUT THE MAIN ROTOR END CAP. THE END CAP DID NOT COME COMPLETELY OFF BUT WAS TORN LOSE AT THE AFT ATTACHMENT POINT.