What was found
(CAN) ON DESCENT, THE ACFT FELT AS THOUGH IT WERE SLIDING SIDEWAYS. CREW CONFIRMED NO RUDDER TRIM. MANUAL TRIM WAS USED. ACFT LANDED AT DESTINATION AIRPORT UNEVENTFULLY. MX INVESTIGATION DETERMINED THE RUDDER TRIM SWITCH WAS JAMMED IN THE FULL LT POSITION. THE RUDDER/AILERON TRIM CONTROL PANEL ASSEMBLY WAS REMOVED AND REPLACED WITH A SERVICEABLE PANEL ASSY AND GROUND TESTED SERVICEABLE. ACFT RETURNED TO SERVICE.