What was found
AIRCRAFT WENT TO CWS PITCH AND ROLL UNCOMMANDED ON B AUTO PILOT CAPABILITY AND WERE UNABLE TO RE-ENGAGE L NAV. THIS WAS (STILL ON ARRIVAL, NO VECTOR LEG). PER CREW, AT 10,000 FEET WITH COMMAND B ENGAGED, ACFT INTO CWS PITCH AND ROLL AND ROLLED THE AIRCRAFT LEFT. THE FO THEN RECEIVED A MAP DISSAGREE, FOLLOWED BY THE NAV DISPLAYED BLANKING OUT FOR APROXIMATLY 60 SECONDS. THEY ALSO LOST L NAV REPLACED MODE CONTROL PANEL IAW AMM 22-11-34-400-801, OPERATIONAL TEST PASSED IAW AMM MODE CONTROL PANEL TEST IAW AMM22-11-34-740. LAND 3 TEST PASSED IAW 22-97-00-710. PERFORMED LAND VERIFY TEST SUCCESSFULLY. AIRCRAFT IS BEING PLACED BACK IN SERVICE.