As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING VIBRATION SURVEY, TEST 7 IAW AMM 71-00-00, PB501. AFTER T/C 78482002 WAS ACCOMPLISHED, VIBRATION LEVELS FOUND TO BE BEYOND BALANCING CAPABILITIES ON THE NR 1 ENGINE INITIATED MIG 2C 40-0013418. ACFT GROUNDED. REMOVED AND REPLACED ALL THE NR 1 ENGINE FAN BLADES IAW AMM 72-21-02-000-801. ACCOMPLISHED A VIBRATION SURVEY ACCOMPLISHED ON T/C 78472002. VIBRATION LEVELS WELL WITHIN LIMITS.