What was found
(CAN) AUTO PILOT SYS WOULD NOT STAY ENGAGED, FLIGHT CREW MANUALLY FLEW ACFT AND REPORTED STIFF AILERON CONTROL RESPONSE. SUBSEQUENT INVESTIGATION FOUND SOME SEIZED PULLEYS MS20220-3 IN AILERON CONTROL SYS. THESE PULLEYS WERE FOUND TO COATED WITH WHAT APPEARS TO BE LPS 3 THAT HAS CAKED ON AND HAS PREVENTED ANY FURTHER LUBRICATION TO ENTER THE BEARINGS. ONCE THE BEARINGS WERE CLEANED AND RE-LUBRICATED WITH LPS2 THEY TURNED FREELY. MFG RECOMENDS LPS3 AS THE LUBRICANT FOR THESE PULLEYS.