What was found
5206/22MAR CLT-LFT TAIL 536 ENGINE VIBE WARNING, FOLLOWED QRH, UNABLE TO CLIMB FURTHER. RETURNING TO CLT. EMERGENCY DECLARED 0235Z ENGINE VIBE WENT UP TO 2.0 LANDED OVERWEIGHT, BUT WITHOUT FURTHER/OTHER ISSUE 70.4 - 70 LANDING WEIGHT. L ENGINE VIB WENT TO 2.0 ON CLIMB / REMOVED FAN BLADES , SPINNER AND BLADEPORT PLUG TO FOM. CLEANED AND LUBED FAN BLADES IAW CRJ 700 AMM 72-21-02-640-801. REPLACED FAN RETAINING PINS IAW CRJ 700 AMM 72-21-02-400-801-A01-PSA. PERFORMED LH ENG BLADE SHAKER LIMIT AND BLADE RETAINING RING TORQUE CHECK AND REPLACED BUMPERS AS NEEDED IAW CRJ700 AMM 72-21-02-400-801-A01-PSA. VIBRATION CHECK GOOD. PERFORMED LH ENGINE VIBE CHECK IAW CRJ900 AMM 71ˆ’00ˆ’00ˆ’720ˆ’806 . VIBE CHECK GOOD"