As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON APPROACH INTO DAY, A MOMENTARY ACTIVATION OF MAIN CARGO FIRE SYSTEM, FOLLOWED IMMEDIATELY BY THE GREEN SYSTEM NORMAL LIGHT AND THEN YELLOW MAINTENANCE LIGHT. NO ACCOMPANING FIRE OR SMOKE NOTED. AIRCRAFT LANDED WITHOUT INCIDENT. REMOVED AND REPLACED SMOKE DETECTOR IN POSITION 12, LEFT UPPER CARGO DECK. (M)