What was found
AFTER TAKEOFF, ATTEMPTED TO ENGAGE B AUTOPILOT AT 1000' AND HEARD A/P DISENGAGE WARNING PLUS A/P DISCONNECT LIGHT THEN AUTOPILOT RE-ENGAGED AND WORKED UNTIL APPROACH AT 2000' AUTOPILOT B DISENGAGED BY ITSELF. BOTH F/D SWITCHES WENT TO "MA", RT WING FELT HEAVY ALL THE WAY LANDING. ACFT GROUNDED. REPLACED B FCC A/P COMPUTER, OPS CKS GOOD REF 22-11-33 AND 22-11-00 AND 34-36-00 IAW LWMP CK LIST LAND VERIFY AND INTERFACE TESTS GOOD. HGS SENSOR TEST GOOD. STATUS SCREW MOVED TO CAT 3.