What was found
DISCREPANCY: THE CREW REPORTED ON DEPARTURE, CLIMBING THROUGH 8,000 FEET THE ENGINE #2 FIRE WARNING WENT OFF. THE CREW LEVELED THE AIRPLANE AT 9,000 FEET TO RUN THE RED BOARDER CHECKLIST PROCEDURE. DURING STEP 1 OF THE CHECKLIST PROCEDURE (THRUST LEVER-VERIFY IDLE) THE ENGINE FIRE LIGHT WENT OUT. FLIGHT WAS CONTINUED WITH #2 ENGINE AT IDLE. ATC PROVIDED PRIORITY HANDLING INTO KDAL AIRPORT AT THE CREW’S REQUEST FOR THE LONG RUNWAY AND EMERGENCY SERVICES. AIRCRAFT LANDED SAFELY. CORRECTIVE ACTION: USA JET MAINTENANCE IN KDAL INSPECTED THE #2 ENGINE AND FOUND LARGE SECTION OF SEAL BLOWN OFF ON FUEL HEATER DUCT CAUSING FIRE WARNING. MAINTENANCE REMOVED AND REPLACED SEAL IAW DA20 AMM 73-10-0, PERFORMED LEAK CHECK AT IDLE AND T/O POWER WITH CREW IAW DA20 AMM 71-00-0. NO LEAKS NOTED. USA JET MAINTENANCE ALSO PERFORMED #2 ENGINE FIRE TEST IAW DA20 AMM 26-10-0, OPERATIONAL CHECK GOOD.