As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON TAKING OFF THE ACFT EXPERIENCED AN UNCOMMANDED YAW. THE PILOT IMMEDIATELY LANDED & SHUTDOWN THE ACFT. UPON MX INSPECTION IT WAS FOUND THAT THE TAIL ROTOR SEGMENTED DRIVESHAFT LOCATED ABOVE THE HORIZONTAL STABILIZER ON THE TAIL BOOM HAD SHEARED CAUSING A LOSS OF POWER TO THE TAIL ROTOR & SUBSEQUENT UNCOMMANDED YAW OF THE ACFT.