What was found
WHILE DESCENDING THROUGH 5,000FT INTO KDCA THE CREW REPORTED AN AILERON MIS TRIM MESSAGE ON EICAS. THE AUTO PILOT WAS THEN TURNED OFF AND REPORTED THAT THE AILERONS WERE LOCKED. THE CREW WAS ABLE TO FREE THE AILERONS BY FORCING THE AILERONS TO MOVE. THE AIRCRAFT THEN LANDED WITHOUT INCIDENT. MAINTENANCE PULLED THE COCKPIT FLOORBOARDS AND PERFORMED A DETAILED VISUAL INSPECTION ON THE CONTROL COLUMNS AND CABLES WITH NO DEFECTS NOTED. IT WAS THEN FOUND THAT THE AILERONS OPERATED NORMALLY WITHOUT THE AUTO PILOT SYSTEM ENGAGED. THE AUTO PILOT SYSTEM WAS THEN DEFERRED AND THE AIRCRAFT RELEASED FOR SERVICE. THE MEL WAS CLEARED IN KSDF LATER THAT NIGHT WHEN THE IC-600 NR 1 WAS REPLACED WHILE TROUBLESHOOTING ANOTHER OCCURRENCE OF THE AILERONS LOCKING.