As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) ENGINE TO MAIN TRANSMISSION DRIVESHAFT AFT OUTER COUPLING TO FREEWHEEL ASSEMBLY FLANGE INCORRECTLY ASSEMBLED. TWO WASHERS WERE INSTALLED UNDER EACH OF THE FOUR ATTACHMENT BOLT HEADS. WASHERS SHOULD ONLY BE INSTALLED UNDER EACH NUT. THE BOLTS WERE NOT FULLY SEATED AGAINST THE COUPLING AND INADEQUATELY TORQUED.