As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AN INSPECTION REQUIRED BY CSB99-6 ON GTSIO-520-M ENGINES WAS PERFORMED AND THIS INSPECTION REVEALED A STRESS RISER CONDITION CAUSED BY A DISCREPANCY IN THE COUNTERWEIGHT BUSHING INSTALLATION PROCESS. THE ENGINE WAS REMOVED FOR FURTHER INSPECTION AND REPAIR. REVISION TO AD 99-09-17 WILL BE MADE TO INCORPORATE THE ADDITIONAL MODEL TYPE GTSIO-520-M ENG.