As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE DESCENDING THROUGH APPROXIMATELY 18,000 FEET, THE #9 UPPER CARGO SMOKE DETECTOR BLINKED FOR APPROXIMATELY 3 MINUTES. CREW COMPLETED EMERGENCY CHECKLIST. LIGHT WENT OUT AND STAYED OUT. NO SMOKE OBSERVED. REPLACED THE #9 UPPER SMOKE DETECTOR UNIT. OPS CHECKED GOOD IAW DC-9 MM.