What was found
DURING APPROACH, THE NUMBER FOUR ENGINE FIRE WARNING SOUNDED. THE CREW SECURED THE ENGINE, FIRE WARNING EXTINGUISHED. MAINTENANCE INSPECTED THE ENGINE, NO EVIDENCE OF A FIRE WAS NOTED. MAINTENANCE PERFORMED AN INTENSIFIED INSPECTION OF THE WARNING SYSTEM WIRING WITH DISCREPANCIES NOTED IN THE PYLON AREA. THE WIRING WAS REPLACED BETWEEN THE AMPLIFIER AND PYLON DISCONNECT. MAINTENANCE TESTED THE SYSTEM IN ACCORDANCE WITH THE DOUGLAS MAINTENANCE MANUAL WITH NORMAL OPERATION.