What was found
DURING CRUISE FLIGHT AT FL 350, NR 4 ENGINE FLAMED OUT. SEVERAL ATTEMPTS TO RESTART, THE LAST AT FL 250 AT 300 KIAS WERE UNSUCCESSFUL. REMOVED AND REPLACED NR 4 ENGINE FUEL FILTER DUE TO CONTAMINATION IAW DC-8 M/M 73-11-10. PERFORMED VISUAL INSPECTION OF BOOST PUMP AREA, NO DEBRIS. OPS AND LEAK CHECKED OK. ENGINE RUN PERFORMED IAW JRH.