What was found
ON DOWNWIND INTO KDEN GOT NR 3 TRITONE FIRE BELL, LIGHTS IN FUEL AND FIRE HANDLE FOR 5 SECONDS, SHUT ENGINE DOWN PER QRH. DISCHARGED 1 AGENT TO NR 3 ENGINE, FIRE INDICATION WENT AWAY AFTER RETARDING NR 3 THROTTLE TO IDLE. REMOVED AND REPLACED NR 3 ENG RT UPPER TURBINE A AND B FIRE DETECTOR AND RAIL ASSY MFG P/N 224-0153-5039 (S/N UR-024) IAW AMM 26-11-03-4-1. ALL CHECKS NORMAL CONDUCTED ENGINE RUN IAW JRH AND PERFORMED CFDS FDCU RETURN TO SERVICE ALL PASSED.