As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK, NUMBER 1 ENGINE FIRE WARNING BELL AND LIGHT CAME ON IN FLIGHT. RETARDED NUMBER 1 THROTTLE AND LIGHT EXTINGUISHED. FOUND COUPLER BEFORE START VALVE LEAKING. REMOVED AND REPLACED COUPLER ASSEMBLY. PERFORMED IDLE LEAK CHECK WITH NO DISCREPANCIES.