As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) MAIN ROTOR TRANSMISSION EPICYCLIC RING GEAR GASKET FAULTY. GASKET WAS EXTRUDING FROM BETWEEN THE UPPER AND LOWER CASES AND BREAKING INTO PIECES AND CAUSING AN OIL LEAK WHICH WAS PROGRESSIVELY WORSENING. ON DISASSEMBLY THE MATING CASE FLANGES SHOWEDSIGNS OF FRETTING.