As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
98-307 - MAIN CARGO SMOKE DET POS NR 4 CAME ON IN FLT. REMOVED AND REPLACED DET PRECAUTIONARY FOR RETURN BK DUE TO NR 4 SMOKE DET LIGHT ON DURING CLIMB-OUT. RAMP INSP ALL CARGO FOR EVIDENCE OF SMOKE, NONE FOUND. CARGO SMOKE DETECTION SYS TEST NORM ON GRND. ALL WORK DONE IAW MM CHAPTER 26-16-1,PG 401