What was found
WHILE ON APPROACH, THE NR 2 ENGINE FIRE WARNING ANNUNCIATED. DECLARED AN EMERGENCY, BUT TOOK NO FURTHER ACTIONS UNTIL LANDING. THE AIRCRAFT LADED WITHOUT INCIDENT. AFTER LANDING, THE FIRE WARNING EXTINGUISHED. AS A PRECAUTION, THE CREW RAN THE QRH ON GROUND ENGINE FIRE CHECKLIST AND SHUT THE AIRCRAFT DOWN ON THE RUNWAY. THE NR 2 ENGINE WAS INSPECTED WITH NO EVIDENCE OF FIRE. THE AIRCRAFT WAS TAXIED TO THE GATE VIA THE NR 1 ENGINE. THE FIRE LOOP WAS REPLACED, THE SUBSEQUENT OPERATIONAL CHECK WAS GOOD, AND THE AIRCRAFT WAS RETURNED TO SERVICE.