What was found
IAH TO HRL - ON APPROACH TO HRL, THE FLAPS FAILED AT 20 DEGREES WHEN SELECTED TO 30 DEGREES. THE QRH WAS FOLLOWED AND THE AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE WAS ABLE TO RESET THE FLAP SYSTEM AND OPERATE THE FLAPS IN ORDER TO FERRY THE AIRCRAFT TO SDF. SDF MAINTENANCE TROUBLESHOT THE FLAP SYSTEM AND PERFORMED A TORQUE CHECK ON THE FLAP SYSTEM AND FOUND THE NR 3 LT FLEX SHAFT FAILING THE TORQUE CHECK AND THE FLAP SYSTEM WAS OUT OF RIG. MAINTENANCE REPLACED THE FLEX SHAFT AND COMPLETELY RE-RIGGED THE FLAP SYSTEM. THE TEST FLIGHT THAT FOLLOWED WAS SUCCESSFUL AND NO FURTHER DEFECTS WERE NOTED.