What was found
AT CRUISE THRUST, NR 3 ENGINE STARTED COMPRESSOR STALLING FL 310. ALL PARAMETERS SHOWING MAJOR FLUCUATIONS, ALONG WITH AIRCRAFT YAW. NR 3 THROTTLE PULLED TO IDLE AND ALL INDICATIONS STABILIZED. AFTER A FEW MINUTES N1 STARTED FLUCUATIONS OF 10-12 PERCENT AND EGT 60 DEG CELSIUS. ENGINE SHUTDOWN AND DIVERTED TO MEM. THERE IS TIP CLANG ON SEVERAL STAGES OF THE HIGH PRESSURE COMPRESSOR. REMOVED AND REPLACED NR 3 ENGINE AS PER FED EX WORK CARDS 71T0701-3, LEAK AND OPS CHECK GOOD. A/C RETURNED TO SERVICE.