What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS CENTER AUTOPILOT KICKED OFF 2 HOURS AT CRUISE. RESET 50 MINUTES LATER AND CLEARED NO LAND 3 ANNUNCIATOR. CENTER AUTOPILOT RESET OK. IN DESCENT CENTER AUTOPILOT UNCOMMANDED TURN TO RIGHT AND DISENGAGED. NO LAND 3 ILLUMINATED. USED LEFT AUTPILOT NO PROBLEM. MAINTENANCE ACCOMPLISHED FIM 22-02-00-810-801. CTR FCC FAILED. REMOVED & REPLACED CTR FCC IAW AMM 22-11-01. PERFORMED GROUND TEST LAND 40 IAW AMM 22-00-02. ALL OPS CHECK OK.