As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(AUS) RT ENGINE HAD TWO UNAPPROVED CYLINDERS FITTED. PN 653452 CYLINDERS ARE NOT APPROVED FOR THE GTSIO520-H MODEL CYLINDERS UNLESS MODIFIED. THE TWO CYLINDERS FITTED WERE NOT MODIFIED IAW APPROVED SCHEME. THE REMAINING PN 653453A4 CYLINDERS FITTED ARE APPROVED FOR THIS MODEL ENGINE. PERSONNEL/MAINTENANCE ERROR. UNAPPROVED PART.