What was found
PASSING 12,300', EXPERIENCED A LOUD BANG & SHUTTER FROM LT ENG. LT ENG VIB, AMBER CAS ILLUMINATED. POWER REDUCED TO IDLE, ENG VIB CAS EXTINGUISHED BUT SIGNIFICANT VIBRATION FELT IN CONTROLS. ELECTED TO DIVERT DUE TO WX & ACFT WEIGHT. POST FLIGHT INSPECTION N1 FAN DOES NOT TURN FREELY & REQUIRES SIGNIFICANT FORCE TO MOVE. ENG OIL VISUALLY INSPECTED & FOUND NORMAL. ACFT CURRENTLY IN MX FOR EVALUATION & REPAIR. INSTALLING RENTAL ENG, OWNED ENG OUT FOR FURTHER EVALUATION & REPAIR.