What was found
NR 2 ENGINE FIRE LIGHT CAME ON DURING FLIGHT, THEN WENT OUT. NO OTHER INDICATIONS WHERE NOTICED, RETURNED TO BASE. REMOVED AFT OTBD FIRE DETECTOR AND INSPECTED FOUND CARBON AND DIRT ON PLUG TIPS. CLEANED CONNECTOR AND FEMALE END OF FIRE DETECTOR, RECLOCKED FIRE DETECTOR TO PUT A LOAD ON CONNECTOR WHEN INSTALLED FOR SECURITY. REF S92, AMM 26-11-01, OPS CHECK OK. NO DEFECTS NOTED AT THIS TIME.