What was found
FLT 6216 - LOS-JNB - DURING FLIGHT ALL FOUR ENGINE ICING LIGHTS ILLUMINATED AND WOULD NOT EXTINGUISH WITH FUEL HEAT ON. CONTINUED FLIGHT TO JNB AND LANDED WITHOUT INCIDENTS. INITIAL INSPECTION OF ENGINE FUEL FILTERS SHOW EVIDENCE OF RUST COLORED DEPOSITS. DRAINED AND SUMPED FUEL FROM ALL TANKS, ENTERED TANKS AND CHECKED FOR COMTAMINATION, NONE FOUND. REPLACED FINE AND COARSE FILTERS AT ALL FCU'S MAIN FUEL FILTERS, APU FUEL FILTER, PERFORMED ENGINE RUN ALL ENGINES PERFORMED SATISFACTORY. AIRCRAFT RETURNED TO SERVICE. (M)