What was found
ENGINE NR 3 FIRE WARNING LIGHT ON CLIMBOUT 100 AGL. FOLLOWED RED TAB PROCEDURES. WARNING LIGHT WENT OUT WHEN THRUST LEVER RETARDED. FIRE WARNING SYSTEM CHECKED OK. RETURNED TO STL. *S/D* REMOVED TUBE PART NUMBER 777790, DUCT PART NUMBER 1211318-002, FLANGE PART NUMBER 259-1068-501. INSTALLED TUBE, DUCT, AND DUCT FLANGE. LEAK CHECKS GOOD. DUE TO DUCT BREAK NR 3 UPPER COWL DAMAGED. REMOVED AND REPLACED SAME.