As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENGINE FIRE LOOP 1 STATUS MESSAGE INTERMITTENT IN FLIGHT. PERFORMED MEG CHECK BETWEEN PINS 18 AND 2 ON D2382 LOOP 1 AND PINS 18 AND 20 ON D2838 AT P54 PANEL BOTH WERE GOOD AT 110 MEG OHMS. REPLACED UPPER AFT ENGINE FIRE DETECTOR (T5681), IAW B767-300 AMM 26-11-02. OPERATIONS CHECK GOOD.