What was found
JFK/BRU AIR TURNBACK DUE TO ENGINE VIBRATION HIGH ALERT ON NR 2 ENGINE AT 700 FT ON TAKEOFF NR 2 ENGINE COMPRESSOR READS 5.8 VIBRATION AND SOUND PRESENT. WHEN THROTTLE RETARDED VIBRATION CEASED. DUMPED FUEL AND RETURNED BACK FOR LANDING AT JFK. NR 2 ENGINE BOROSCOPED AT AP-2 & AP-3, NO DAMAGE OBSERVED. ALL FAN BLADES REPLACED DUE TO 17 BLADES DAMAGED. ENGINE VIBRATION SURVEY ACCOMPLISHED PER MD-11 MM 71-02-08.