What was found
(CAN) AT ARRIVAL, UPON SHUTTING DOWN ENG NR 2, THE GROUND CREW SAW FIRE AT ENGINE 2 AND REPORTED TO THE PILOT. THE PILOT SAW ALSO NACELLE OVERHEAT ALERT, FOLLOWED BY ENG NR 2 FIRE WARNING. SUBSEQUENTLY PILOT DISCHARGED FIRE BOTTLE NR 1 FOLLOWED 30 SECONDS LATER BY BOTTLE NR 2 AND THE FIRE EXTINGUISHED WITH NO INJURIES TO PASSENGERS. PASSENGERS DISEMBARKED NORMALLY. TROUBLESHOOTING REVEALED A LOOSE FUEL NOZZLE LINE B-NUT AT THE NOZZLE, NR 14. THE FUEL NOZZLES WERE REPORTEDLY REPLACED JUNE 13, 2012 AND SB 21803, REMOVAL OF BACK-UP O-RING WAS EMBODIED AT THAT TIME. OPERATOR IS INVESTIGATING REASON FOR LOOSE B-NUT AT THE NOZZLE NR 14.