As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT DEPARTED WITH NR 2 ENGINE "B" LOOP ON DEFERRAL. ENROUTE, NR 2 ENGINE "A" LOOP FIRE DETECTOR BECAME INOPERATIVE. SHUTDOWN NR 2 ENGINE AND RETURNED. DECLARED EMERGENCY AND FLT LANDED WITH OUT FURTHER INCIDENT. REPLACED MULTIPLE COMPONENTS IN NR 2 ENGINE FIRE DETECTION SYSTEM. ALL COMPONENTS OPS CHECKED GOOD