A B767-200 FLC IN CRUISE AT FL370 EXPERIENCES LATERAL CTL PROBS WITH THE AILERONS. THIS WAS INDICATED BY HALTING AUTOPLT LATERAL CTL DISPLACEMENTS; AN AUTOPLT WARNING LIGHT AND ASSOCIATED EICAS CAUTION MESSAGES 50 NE OF LAS; NV.

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SCHEDULED ACR; DEPARTED SFO. LIGHT TO MODERATE RAIN PRIOR TO DEP WITH LIGHT RAIN AT DEP TIME. I HAND FLEW PLANE TO APPROX FL310; THEN ENGAGED CENTER AUTOPLT. AFTER CRUISE AT FL370 FOR A WHILE; AUTOPLT LIGHT; EICAS MESSAGE; AND CAUTION WARNING WERE ANNUNCIATED. ACFT WAS IN LNAV AND VNAV MODES WITH CENTER AUTOPLT COMMAND. SAT-60 DEGREES CELSIUS; APPROX 50 NM NE LAS VOR. ACFT FLEW SLIGHTLY PAST TURN POINT; THEN AUTOPLT MADE AGGRRESSIVE TURN TO COURSE. I DISCONNECTED AUTOPLT AND HAND FLEW ACFT TO COURSE ( WITH ALT; DEVIATIONS <200 FT; COURSE DEV'S <1 MI). THE FLT CTLS APPEARED TO BE JAMMED OR AUTOPLT DID NOT SEEM TO BE DISCONNECTED. THEN I USED SEC METHOD OF DISCONNECTING AUTOPLT WITH NO CHANGE IN FEEL OF FLT CTLS. I HAD TO USE APPROX 50-75 LBS OF FORCE TO TURN ACFT. ELEVATOR CTL NORMAL. CAPT THEN TOOK OVER CTL AND WAS ABLE TO BREAK FREE CTLS. AFTER COMPLETING IRREGULAR PROC IN FLT. MANUAL AND CONFERRING WITH MNTNC CTL CENTER; WE BELIEVED PROB TO BE FROZEN WATER ACCUMULATION. WE CONTINUED FLT TO JFK EXERCISING FLT CTLS EVERY 15 MINS OR SO. NO FURTHER PROB WERE ENCOUNTERED. I BELIEVE WHAT HAPPENED WAS DURING RAINS AT SFO; WATER POOLED IN AN AREA UNDER WING NEAR WHERE THE AILERON CABLES AND CENTERING MECHANISM ARE LOCATED. AT CRUISE; THE WATER FROZE AND THE CABLES WERE EITHER COVERED WITH ICE OR IMBEDED IN THE ICE. AFTER CONSIDERING FORCE; THE CTLS BROKE FREE. I THINK THIS FORCE BROKE THE ICE; BECAUSE THERE WERE NO FURTHER PROBS. THE NEXT DAY WE LEARNED THE WEEP HOLES UNDER THE WING HAD BEEN PLUGGED AND THERE WAS CONSIDERABLE STANDING WATER POOLED. I THINK BOEING NEEDS TO ADDRESS THIS PROB OF DRAINAGE BEFORE ANYTHING WORSE HAPPENS. THE CLR COM BTWN THE CREW AND GND MNTNC WAS EXCELLENT AND HELPED TO QUICKLY RECTIFY THE SIT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE CAPT HELD A PHONE CONFERENCE WITH AIRLINE MNTNC PERSONNEL; OPS AND UNION SAFETY AFTER THE FLT. AS A RESULT; THE ACFT MANUFACTURER SENT OUT A FIX TO THE WEEP HOLE PROB; INDICATING THAT THERE WAS DRAINAGE PROB THAT CAUSED ICING OF THE AILERON CTL CABLES IN FLT. RPTR WAS NOT SURE AS TO WHAT THE RECOMMENDATION WAS BUT SAID THAT THERE WAS NO A/D PUBLISHED BY THE FAA. THIS WAS THE SEC EVENT OF THIS NATURE EXPERIENCED BY THIS SAME ACFT. HES IS NOT CERTAIN OR AWARE IF THE NTSB HAS BEEN INVOLVED IN THIS ISSUE.