As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER SHUTDOWN, DURING ROTOR BRAKE APPLICATION, CREW REPORTED GRINDING NOISE COMING FROM TRANSMISSION AREA, AND EXCESSIVE VIBRATIONS WERE FELT THROUGH THE AIRFRAME. ACFT WAS INSPECTED BY MAINTENANCE, THE ROTOR BRAKE FLANGE AND OUTPUT SPLINE WERE FOUND TO BE DAMAGED BEYOND LIMITS. THE MAIN GEAR BOX WAS REMOVED FROM THE ACFT AND ARE AWAITING MFG TO REMOVE THE OUTPUT SPLINE IN ORDER TO DETERMINE THE FAILURE OF THE SPLINE.