What was found
DURING CLIMB, FELT AN ABNORMAL VIBRATION. WHILE RUNNING ENGINE ABNORMAL VIBRATION CHECKLIST, THE VIBRATION INCREASED AND GEN 2 OFF BUS MESSAGE DISPLAYED, AND GEN 2 VOLTAGE DROPPED RAPIDLY. RAN GEN 2 OFF BUS CHECKLIST, WHICH DIRECTED ENGINE SHUTDOWN. VIBRATION CONTINUED TO INCREASE IN AMPLITUDE DURING SHUTDOWN. AFTER SHUT DOWN VIBRATION MOSTLY WENT AWAY OCCASIONALLY FELT A FLUTTER. POST-FLIGHT INSPECTION REVEALED HEAVY SOOT ON BOTTOM OF THE NR 2 NACELLE. ENGINE WAS WINDMILLED FOR 20 MINUTES. REPLACED THE NR 2 ENGINE STARTER GENERATOR