As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, RECEIVED A FIRE WARNING FROM THE NR 3 DETECTOR IN THE MAIN DECK CARGO COMPARTMENT. WARNING QUIT AFTER 40 MINUTES AND AIRCRAFT CONTINUED TO DESTINATION AND LANDED WITHOUT INCIDENT. REPLACED THE A-SMOKE DETECTOR IN THE NR 3 POSITION. OPERATIONAL CHECK GOOD.