What was found
FLIGHT CREW HAD A ZONE 1 FIRE WARNING WITH NO OTHER INDICATIONS. ON INSPECTION ON THE ENGINE, NR 14 CYLINDER WAS FOUND TO HAVE A LOOSE EXHAUST VALVE GUIDE CAUSING THE COMBUSTION CHARGE ACCESS TO THE EXHAUST SYSTEM. THE EXHAUST PIPE ADAPTER FOR THIS CYLINDER WAS WORN AND IT IS SUSPECTED THAT FLAMES FROM THIS CYLINDER LEAKED ONTO THE FIRE WARNING SYSTEM. THE FIRE WARNING SYSTEM ALSO HAD A 3 OHMS RESISTANCE VS. 2 OHMS WHICH WOULD HAVE MADE THE SYSTEM MORE SENSITIVE. NO OTHER FAULTS FOUND.