What was found
DURING CRUISE FLIGHT, THE NR 1 ENGINE FIRE DETECTION LIGHT FALSE ACTIVATED. SYSTEM INSPECTED. NO FAULTS FOUND. CHANGED THE SYSTEM AMPLIFIER FOR TROUBLESHOOTING. ACFT RETURNED TO SERVICE. FAULTY PORTION OF THE NR 1 FIRE DETECTION SYSTEM WAS REPLACED FOR MULTIPLE NICKS IN THE WIRE SHIELDING AND SUSPECTED FAULTY SPLICES. NO FURTHER REOCCURRENCES HAVE BEEN REPORTED. SUPPLEMENTAL INFORMATION; THE DETECTORS IN THIS A/C HAVE BEEN REPLACED WITH P/N 477223 FLAME DETECTORS IAW COLUMBIA HELICOPTERS, INC. SERVICE BULLETIN NUMBER 107-26-S0004. DETAILS ARE ON FILE WITH OPERATOR CHIA823C.