What was found
PILOT FELT THE AIRCRAFT VIBRATION DURING CLIMB UP TO AROUND 30,000 FEET. FOUND HIGH VIBRATION ON THE NR 1 ENGINE, CAUSED AIR RETURN AT TPE ON 3-11-99. MAINTENANCE PERFORMED CONDITION CHECK OF ONE ENGINE FAN INLET. EXHAUST OUTLET AND MCD, BSI FOR HPC. HPT AND LPT AS REQUIRED. RESULTS OF INSPECTION ARE NORMAL. (X)