What was found
NR 4 ENG ROLLED BACK AT 0300Z; WINDMILL N2 = 12 PERCENT, N1 = 28 PERCENT, OIL PRESSURE = 3 PSI, OIL QTY = 16 QTS. FOUND RT CDP SENSOR CLOGGED. CLEARED BLOCKAGE, PERFORMED POWER RUN, OPS CHECKED SERVICEABLE. TROUBLESHOT NR 4 ENG, ENG LOSES POWER OR FLAMES OUT. PERFORMED INLET/EXHAUST VISUAL INSPECTION, CHECKED FLIGHT IDLE, CHECKED N1 ROTOR, SPECIFIC GRAVITY, CHIP DETECTORS, INSPECTED & REPLACED FUEL FILTER, & INSPECTED ENG FUEL PUMP IMPELLER ROTATION. NO DEFECTS. FUEL FILTER P/N: CH0697101552N00 REMOVED & REPLACED. LEAK CHECK REQUIRED FOR NR 4 ENG DUE TO FUEL FILTER REPLACED AND FUEL PUMP INSPECTION. GROUND RAN NR 4 ENG. FILTER AND FUEL PUMP LEAK CHECKED OK.