What was found
ON APPROACH, RECEIVED AUTOPILOT FAIL, SWPS FAIL, YD FAIL, AND VENTRAL RUDDER FAIL SIMULTANEOUSLY. ALSO YELLOW IAS FLAG DISPLAYED ON PFD 1 & 2. PFD 2 IAS CONSISTENTLY 10-15 KNOTS BELOW PFD 1 AND STANDBY UNTIL LANDING. FOR MAINTENANCE CONVIVENCE REMOVED GIA 1 AND INSTALLED SEVISABLE UNIT FROM GIA 2 POSITION. REMOVED GIA 2 AND INSTALLED SERVICEABLE UNIT FROM GIA 1 POSITION. COMPLETED GIA 1 AND GIA 2 RECONFIG AND OPERATIONAL CHECKS. OPS CHECKS GOOD. WORK PERFORMED IN REF TO AMM 31-41-05.