ACFT EQUIP PROB. ENG FIRE WARNING. ENG SHUTDOWN AND ACFT RETURNED FOR LNDG.

Narrative

UPON TAXIING OUT AT DTW A R ENG FIRE DETECTION 1 LOOP FAULT ILLUMINATED. COCKPIT OPS MANUAL PROCS DID NOT RESOLVE THE PROB. I CONTACTED DISPATCH; MAINT AND IT WAS MEL'D TO PROCEED TO PHX. CLBING THROUGH 8000-9000 FT; THE R ENG FIRE LOOP LIGHT ILLUMINATED WITH A CONTINUOUS REPETITIVE CHIME; INDICATING AN ENG FIRE. THE R THROTTLE WAS RETARDED AND THE CONTINUOUS REPETITIVE CHIME INDICATIONS STOPPED. I INSTRUCTED THE FO TO COMMUNICATE THE PROB; PLUS WOULD FLY AND HANDLE THE COMS WITH ATC AND THE PAX. I REQUESTED A VECTOR BACK TO DTW AND WAS ON THE WAY BACK IN SHORT ORDER. I DIDN'T DECLARE AN EMER; BECAUSE IN MY JUDGEMENT IT WAS AN INDICATION PROB AND NOT A TRUE FIRE. LNDG UNEVENTFUL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: AFTER THE R ENG DETECTION 'A' LOOP FAULT ILLUMINATED ON TAXI OUT; RPTR CAPT CONTACTED HIS COMPANY MAINT WHO WALKED HIM THROUGH THE PROC TO CORRECT THE PROB. RESETTING CIRCUIT BREAKERS WAS PART OF THE PROC. THE PROB APPEARED TO BE CORRECTED; THEIR COMPANY DISPATCH SENT A RELEASE AND THEY DEPARTED. SHORTLY AFTER TKOF THE CONTINUOUS REPETITIVE CHIME SOUNDED ACCOMPANIED BY THE ENG FIRE LOOP LIGHT. THE THROTTLE WAS REDUCED TO IDLE AND WARNINGS WENT OUT; BUT ADVANCING THE THROTTLES BROUGHT THEM BACK ON; SO RPTR CAPT HAD THE FO SHUT DOWN THE ENG WITH THE APPROPRIATE CHKLIST. RPTR HAD NO DIFFICULTY WITH FLYING THE ACFT WITH THE ENG SHUT DOWN; COORDINATED WITH APCH CTL AND TWR TO AN UNEVENTFUL LNDG. THOUGH RPTR HAD NOT DECLARED AN EMER; THE GND EMER CREW AND EQUIP WERE STANDING BY; PRESUMABLY HAVING BEEN NOTIFIED BY THE TWR. POST FLT INSPECTION OF THE ENG REVEALED A GNDED LOOP CIRCUITRY SO THE WARNING WAS NOT AN ACTUAL FIRE; BUT FAULTY CIRCUIT.