As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NUMBER 2 FIRE DETECTION FAULT LIGHT CAME ON IN FLIGHT BLEED VALVE WENT TO CLOSE POSITION AND A AND B INDICATORS SHOW 8.5 AND 7. TEMP WAS NORMAL ON ALL ENGINE PARAMETERS. SUSPECT A BLEED AIR LEAK AROUND B-LOOP. FOUND AIR LEAK AT FIRE LOOP 6 O'CLOCK POSITION AND TWO MISSING INSULATORS ON CLAMPS RESECURED CLAMP AND INSTALLED INSULATORS, NO LEAKS NOTED IAW B747 MM CHAPTER 26-00-00.