As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EXESSIVE VIBRATION IN LT ENGINE DURING CLIMB OUT. ( 1.8 ) AT CLIMB POWER . VIBRATION COULD BE FELT IN COCKPIT (ACFT RETURNED TO DEPARTURE AFTER T/O -- EMERGENCY DECLARED) REMOVED AND REINSTALLED NR 1 ENG. FAN BLADES IAW AMM 72-21-02. LUBED FAN BLADES IAW ESM 72-00-21. OPS CHECK AND ENGINE VIBRATION CHECK IAW MM ENGINE RUN, OPS CHECK GOOD.