As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
REAR V-BELT GROOVE CASTING MATERIAL THICKNESS OF APPROXIMATELY .024 INCH IS CONSIDERED INSUFFICIENT AND RESULTS IN THE REAR V-BELT GROOVE BEING HIGHLY PRONE TO BREAKAGE. THIS IS ONE OF THREE SEPARATE OCCURRENCES OF REAR V-BELT GROOVE BREAKAGE NOTED THAT SEEM ISOLATED TO PN LW-18506 STARTER RING GEAR SUPPORT ASSEMBLIES. ONE STARTER RING GEAR SUPPORT WAS FOUND BROKEN WHEN RECEIVED FROM THE MANUFACTURER.