As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CLIMB, CREW NOTED CHIP DETECTOR LIGHT ILLUMINATED. CREW RETURNED TO DEPARTURE AIRPORT. MAINTENANCE FOUND ENGINE MAKING A GRINDING NOISE AND FELT SOME DISTRESS IN THE POWER SECTION WHEN ROTATED. ENGINE WAS REMOVED FOR INVESTIGATION. DURING TEARDOWN, THE 1ST STAGE PLANETARY GEAR WAS FOUND MISSING ONE TOOTH. FURTHER SPALLING WAS FOUND ON THE SUN GEAR. THE DAMAGED COMPONENTS ARE BEING REPLACED. ENGINE WAS 4222.0 HRS/5454 CYCLES TSO.