What was found
THE MAINTENANCE TEAM DISCOVERED DURING POSTFLIGHT CHECKS THE LEFT INBOARD FLAP OUTBOARD ACTUATOR WAS MAKING A GRINDING NOISE WHEN THE FLAPS WERE OPERATED. AFTER EXTENSIVE TROUBLESHOOTING IT WAS DETERMINED THAT THE INBOARD FLAP ACTUATOR WAS FOUND TO BE DEFECTIVE. THE DEFECTIVE ACTUATOR WAS REMOVED AND A NEW ACTUATOR WAS INSTALLED. RIGGING AND OPERATIONAL CHECKS WERE SATISFACTORY AND THE AIRCRAFT WAS RETURNED TO SERVICE. A TEARDOWN REPORT WAS REQUESTED.