What was found
AFTER SITTING IN RAIN, ON DEPARTURE, AIRCRAFT CLIMBED TO 38,000 FT. AFTER APPROX 10 MIN THE AUTO PILOT KICKED OUT. PILOT REPORTED CONTROLS FELT STUCK. PILOT APPLIED PRESSURE TO CONTROLS AND THEY BECAME UNSTUCK AND OPERATED OK. LANDED OK. MAINTENANCE REMOVED AC PANEL AND HAD ABOUT GAL OF WATER DRAIN OUT. THE RIB AT APPROX STA 449.00 DOES NOT HAVE DRAIN HOLE AT BOTTOM TO ALLOW WATER TO FLOW FWD TO FUSELAGE DRAIN PORTS. CONTROL CABLE PULLEYS WERE SETTING IN WATER. BELIEVE WATER FROZE CAUSED CONTROL PROBLEM. ORDER WAS ISSUED TO DRILL HOLE IN RIB SO ANY WATER IN AREA WOULD DRAIN FORWARD TO FUSELAGE DRAIN PORTS.