What was found
ON TAKEOFF ROLL, LARGE VIBRATION/NOISE FELT THROUGHOUT AIRCRAFT FELT ON RUDDER PEDALS AND THRUST LEVERS. FOUND DAMAGE TO LEFT ENGINE NR 8 & 9 FAN BLADES. REMOVED AND REPLACED NR 8, 9, 22 & 23 LEFT ENGINE FAN BLADES WITH SERVICEABLE UNITS. PERFORMED RUN CHECKS. OPS CHECKS GOOD. NO VIBRATION NOTED. BLADE NR 8 P/N ON 6018T30P06, S/N OFF KGAJ0009. BLADE NR 9 P/N ON 6018T30P06, S/N OFF KGAR9905. BLADE NR 22 P/N ON 6018T3P06, S/N OFF KGAJ0051. BLADE NR 23 P/N ON 6018T3P06, S/N OFF KGAJ0384.