As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE 2 FIRE LEVEL THREE ALERT AOM CHECKLIST ACCOMPLISHED. ALERT REMAINED DISPLAYED. AIR TURN BACK. EMERGENCY DECLARED. TROUBLESHOT IAW FIM 26-11-00-1, FIG 103. FOUND PYLON "A" LOOP DETECTOR HAS OPEN CIRCUIT. LEADS TO NR 2 ENG PYLON "A" LOOP DETECTOR DISCONNECTED AT LEADS IAW AMM 26-11-03-4. R & R LOOP IAW 26-11-03-4.