What was found
AIR TURNBACK DUE TO NR 3 ENGINE FIRE WARNING. NOTICED EGT AT 850 DEGREES, ON TAKEOFF AT 100 DEGREE HIGHER THAN NR 2 AND NR 4 ENGINES. REMOVED AND REPLACED T/R DRIVE DUCT ASSEMBLY IAW MM, PERFORMED PNEUMATIC LEAK TEST IAW MM, NO LEAKS FOUND. DISCOVERED TURBINE CASE COOLING EXHAUST DUCT MISALIGNED, CORRECTED INSTALLATION IAW MM AND SECURED DUCT. ACCOMPLISHED ENGINE RUN UP IAW MM; ENGINE RUN UP CHECKS GOOD. NO FUEL DUMPED.