What was found
571 HOURS FOLLOWING INSTALL OF NEW MAINLINE CARBON SEALS PER SB 731-72-3596, REV 5, ENGINE EXPERIENCED FLUCTUATING OIL PRESSURE. INSP OF ENG OIL FILTER SCREEN REVEALED A LARGE AMOUNT OF CARBON PARTICLES. ENG REMOVED FOR INSPECTION. CARBON AND METAL DEBRIS WAS FOUND IN HIGH PRESSURE (N2) COMPRESSOR IMPELLER AREA DURING BORESCOPE. INTERMITTENT BINDING OF N2 ROTATING GROUP FELT DURING ROTATION OF SPOOL AS ENG WAS BORESCOPED. ENG DISASSEMBLED, FOUND CARBON MATERIAL ORIGINATED FROM FAILED NR 5 CARBON SEAL. IN ADDITION, SEAL FAILURE CAUSED CERAMIC SEAL RUNNER TO FRACTURE. THE 'BINDING' OF THE N2 SPOOL WAS THE RESULT OF A SMALL PIECE OF SEAL TENSION SPRING WEDGED BETWEEN ONE VANE OF THE HP IMPELLER AND SHROUD.