As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) NOTED A KNOCKING NOISE NEAR TAIL ROTOR GEARBOX AFTER AIRCRAFT LANDED FOR MAINTENANCE. FOUND EXCESSIVE PLAY BETWEEN AFT TAIL ROTOR DRIVESHAFT SEGMENT AND HANGER BEARING. DISASSEMBLED AFT SEGMENT AND FOUND WEAR ON BEARING MATING SURFACE OF THE SHAFT, AS IF IT HAD SPUN INSIDE THE HANGER BEARING. NOTHING ON BEARING INDICATED ANY DAMAGE OR THAT IT HAD SEIZED. SHAFT SEGMENT AND BEARING REPLACED. (TC NR 20180117008).