What was found
PASSING FLIGHT LEVEL 230, ON CLIMB-OUT RECEIVED ENGINE FIRE WARNING ON NR 3 ENGINE, ENGINE SHUT DOWN, NO OTHER FIRE INDICATION FIRE WARNING LIGHT STAYED ON FOR 20 MINUTES. FOUND FDCU3 FAULTING BOTH A AND B LOOP DETERMINED THE R4 RESPONDER B LOOP DEFECT REMOVED AND REPLACED SAME P/N ON 7101-13 S/N ON 40784 UNABLE TO DETERMINE S/N OFF. B LOOP RTS CONNECTOR D5018J TO BE THE CLOSE PINS 1-2. CLEANED SAME AND RECONNECTED PRECAUTIONARY REPLACED NR 3 FDCU P/N ON 8038-03-03, S/N ON 920, P/N OFF 8038-02-03, S/N OFF 541. FDCU3 RTS CHECK ACCOMPLISHED WITH NO DEFECTS NOTED. COWLS CLOSED AND SECURED NR 3 ENGINE RUN ACCOMPLISHED ALL INDICATIONS NIL. NO ALERTS. (M)