What was found
THE CREW REPORTED ENGINE NR 1 HP INDICATION IN YELLOW RANGE AFTER TAKEOFF, THE ACFT RETURNED TO DEPARTURE AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AND REPLACED THE NR 1 ENGINE. OPERATIONAL CHECKS WERE GOOD. SUPPLEMENT TO FOLLOW: CONDITION REPORT FROM MFG INDICATED HOT SECTION DETERIORATED. THE HIGH PRESSURE TURBINE MODULE EXHIBITED SULFIDATION AND EROSION OF AIRFOILS AS WELL AS A CRACKED COMBUSTION LINER. THE 1ST STAGE HPT VANES EXHIBITED COATING LOSS ON THE AIRFOILS AND EROSION/CRACKING ON THE AIRFOIL TRAILING EDGES. (BURN-THROUGH) (K)