What was found
1ST STAGE PLANETARY PINION GEAR, PN 6435-20411-102, SN 1524, UNKNOWN TT, FAILED IN MAIN GEARBOX, PN 6435-20500-049, SN A6-165, LEAVING LARGE FRAGMENT OF FERROUS METAL IN SUMP, SUMP SCREEN. TEARDOWN INSP REVEALED ENTIRE TOOTH FRACTURED AT JUNCTION OF CASE TO CORE. SECONDARY DAMAGE FOUND ON 3 EACH 2ND STAGE PLANETARY PINION GEARS, PN 6435-20057-012, RING GEAR, PN 6435-20165-012, AND 1ST STAGE SUN GEAR, PN 6435-20412-102, ALL OF WHICH WERE BLENDED, RETURNED TO SERVICE. DURING OPERATION, CREW HEARD A LOUD NOISE AND EXPERIENCED A VIBRATION PRIOR TO REGISTERING A CHIP LIGHT. A PREVIOUS MDR WAS SUBMITTED 4-20-00, SAME PN GEAR FRACTURED A GEAR TOOTH AT 697.0 HRS ON DIFFERENT GEARBOX. (X)