As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WATER RUDDER (TAIL WHEEL) TORQUE TUBE FOUND TO HAVE A SPIRAL CRACK ENCIRCLING THE VERTICAL PORTION OF THE TUBE. EXTERNALLY THE TUBE ASSEMBLY SHOWED NO MAJOR DEFECTS. INTERNALLY THE TUBE WAS SEVERLY CORRODED AT THE INTERFACE OF THE TUBE JOINT AND THE WELDED SPLINE SHAFT. THE SUBMITTER SUGGESTS THAT A INTERNAL CORROSION PREVENTATIVE COMPOUND BE APPLIED BEFORE THE UNIT IS PUT INTO SERVICE.