What was found
(CAN) DURING ENGINE START, THE PILOT IN COMMAND WAS UNABLE TO MOVE THE CYCLIC FORWARD. AFTER A VISUAL INSPECTION BY THE MAINTENANCE PERSONNEL, ICE BUILDUP WAS FOUND UNDER THE SERVO VALVE PROTECTION COVER. PRIOR TO THAT DAY, HEAVY RAIN WENT THROUGH THE AREA FOLLOWED BY A DROP IN TEMPERATURE. TROUBLESHOOTING THIS PROBLEM IS THAT WATER INFILTRATION DURING HEAVY RAIN AND DROP OF TEMPERATURE BELOW FREEZING LEVEL WILL CAUSE THE FORE AND AFT SERVO TO FREEZE UP.