As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER TAKEOFF OUT, NR 2 ENGINE FIRE WARNING CAME ON. THE THROTTLES WERE RETARDED AND THE WARNING EXTINGUISHED. THE AC RETURNED TO AIRPORT. AFTER INVESTIGATION, MAINTENANCE FOUND THE DUCT FOR THE FUEL HEAT VALVE HAD COME OUT OF ITS SLEEVE CAUSING A DUCT LEAK. THE DUCT WAS REPAIRED AND LEAK CHECKED SERVICEABLE. (TC NR 20080328011)