What was found
PILOTS REPORT: "ON APPROACH, CAPTAIN FLYING, TOUCHED AILERON TRIM TO TRIM RT. TRIM PRESSED FOR LESS THAN 1 SECOND, TRIM CONTINUED TO TRIM TO THE RT AND ACFT ROLLED AND CONTINUED TO ROLL RIGHT. CAPTAIN FORCEFULLY MAINTAINED LEVEL FLIGHT WHILE THE F/O TRIMMED THE AILERON CONTINUOUSLY TO THE LT UNTIL ADVISED TO STOP WHEN PRESSURE FELT NORMAL. ACFT LANDED NORMALLY AND THEN GROUNDED." MX REPORT: "AILERON TRIM SWITCH STICKING WHEN ACTIVATED, KEEPS TRIMMING WHEN NOT DEPRESSED. NEW AILERON TRIM SWITCH FITTED AND CHECKED SATIS IAW MM 27-13-00".