As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) SHORTLY AFTER TAKEOFF CREW OBSERVED A FIRE INDICATION ON NR1 ENGINE EXECUTED FIRE DRILL AND AN EMERGENCY LANDING. NO EVIDENCE OF FIRE FOUND. HEAT SOURCE WAS A 3/4 INCH CRACK AT THE THRUST REVERSER LINE ATTACH FITTING ON THE DUCT ASSEMBLY. THE HIGH TEMPERATURE AIR LEAK MELTED THE PROTECTIVE COVERING ON THE FIRE DETECTION WIRING ALLOWING CONTACT OF THE BARE WIRES. REPAIRED.