What was found
FLAP FAIL CASS MESSAGE INDICATED WHEN FLAP DEPLOYED FROM FULL UP. UPON INVESTIGATION FOUND THE LT FLAP HAD A SLIGHT TWIST. THE OTBD ACTUATOR HAD NOT ENGAGED TO DRIVE THE FLAP AND THE INBD ACTUATOR DROVE THE INBOARD SIDE DOWN ABOUT 3 DEGREES BEFORE THE SYSTEM DETECTED AN ASYMMETRY AND STOPPED THE MOVEMENT. AFTER THE FLAP WAS UNLOADED/UNTWISTED DURING MX INVESTIGATION THE FLAP APPEARS TO HAVE A SLIGHT DOWN TURN ON THE INBD TRAILING EDGE. THE CURRENT SUSPECTED CAUSE IS THE FLEXIBLE DRIVE SHAFT BETWEEN THE ACTUATORS MIGRATED INBD AND BECAME DISENGAGED WITH THE OTBD ACTUATOR.