What was found
(CAN) WHILE EN-ROUTE AT 29,000 FT, THE FLIGHT CREW EXPERIENCED AILERON CONTROL LOCKUP. A/P TRIM CAUTION MSG. AIRCRAFT DESCENDED TO 15,000 FT FOR 5 MIN. CONTROL RETURNED. AIRCRAFT CONTINUED TO DESTINATION WITHOUT INCIDENT. AIRCRAFT TOOK OFF IN HEAVY RAIN AND STANDING WATER ON THE RUNWAY. MORE INFO TO FOLLOW WHEN AVAILABLE.AILERON CONTROL SYSTEM WAS INSPECTED. FOUND THAT THE LT AND RT AILERON MIXER ASSY. HAD A SMALL AMOUNT OF ROTATIONAL RESISTANCE . BOTH LT AND RT AILERON MIXER ASSY WERE REPLACED. AIRCRAFT RETURNED TO SERVICE.