What was found
DECENDING THROUGH FL 320, FELT A SHUTTER ICAS HAD A CYAN ENG SHUTDOWN LT DISPLAYED FOR A FEW SECONDS ACOMPANIED BY A DECREASING LT ITT. LT ENG THEN RETURNED ITSELF TO NORMAL OPS. PRESSED EVENT MARKER AT TIME OF INCIDENT. IT APPEARS THAT 60 TO 80 PERCENT OF THE 3RD STAGE HIGH-PRESSURE COMPRESSOR ABRAIDABLE MATERIAL IS MISSING. BORESCOPED 1ST, 3RD AND 4TH STAGE COMPRESSORS. NOTED SIGNIFICANT EROSION OF ABRADABLE LINER IN 3RD STAGE COMPRESSOR SMATT AND AE JD MMG-DS ENGINE REPLACEMENT. REMOVED & INSTALLED ENGINE. OPS CHECKED AND LEAK CHECKED GOOD. WORK PERFORMED IAW MM CH 71-00-30.