What was found
DURING CRUISE, IN SMOOTH AIR AT FL 340. THE "CMD A" AUTOPILOT DISENGAGED. IT WAS IMMEDIATELY RE-ENGAGED AND WORKED NORMALLY UNTIL IT DISENGAGED AGAIN DESCENDING THROUGH FL 300 AT 280 KTS. IT WAS RE-ENGAGED NORMALLY. WE FLEW THE REMAINDER OF THE FLIGHT ON THE "CMD B" AUTOPILOT WHICH OPERATED NORMALLY. ACFT GROUNDED. FLIGHT FAULT REVIEW OF LEG 02 SHOWED VNAV PATH & LNAV ENG MCP DATA INVALID. CURRENT STATUS: NO FAULTS. PERFORMED MCP BITE TEST GROUP 32, NO DEFECTS NOTED. PERFORMED LAND VERIFY BITE TEST GROUP 49 IAW AMM 22-00-01-730-801. NO DEFECTS NOTED.