What was found
DURING CLIMB OF THE AIRCRAFT AS FLIGHT TP-831 FROM LIM TO CUZ, THE PILOT IN COMMAND REPORTED: "ENGINE NR 1 ABNORMAL VIBRATION 4.2 LP WITH SOUND DURING CLIMB", THEREFORE, THE AIRCRAFT WAS RETURNED TO LIM AIRPORT (ATB). ADDITIONAL THE PILOT REPORTED: "LANDING WEIGHT 39200 KGS AND VERTICAL SPEED 100 FT AT TOUCHDOWN. NO OVERWEIGHT LANDING". ONCE THE AIRCRAFT WAS POSITIONED AT THE MAINTENANCE RAMP, MAINTENANCE PERSONNEL PERFORMED A FAN TRIM BALANCE IN ACCORDANCE WITH AMM 72-21-00-750-801-A. PERFORMED ENGINE RUN UP AS PER EMM 72-00-00-700-805 TO VERIFY ENGINE VIBRATION PARAMETERS WITH A RESULT OF 1.7 VIBRATIONS UNITS FOR ENGINE NR 1. THE AIRCRAFT WAS RETURNED TO SERVICE.