As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ENGINE DISASSEMBLY, DISCOVERED ONE TANG OF RING, RETAINING HAD SEPARATED FROM RING. SEPARATED PIECE WAS FOUND LODGED IN THE FAN GEARBOX ELEMENT OF OIL PUMP. RING RETAINING P/N 3073754-1 WAS INSTALLED 2,639.7 HOURS PREVIOUSLY DURING INCORPORATION OF SB 72-3498. FRACTURE OCCURRRED IN FILLET RADIUS. SUBMITTER STATED CAUSE IS UNKNOWN. THIS REPAIR STATION HAS IMPLEMENTED FLUORESCENT PENETRANT INSPECTION (PFI) OF THE PART ANY TIME ACCESS IS GAINED TO THIS AREA.