AN AIRBUS 319 CREW RPTED PRIMARY FLT DISPLAY MISALIGNMENT WHILE ON APCH TO MSP.

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WE WERE CLRED DIRECTLY TO WASHY INTXN TO INTERCEPT THE LOC TO RWY 12L AND DSND TO 3000 FT. I ENTERED DIRECT WASHY INTXN INTO MCDU AND WE WERE PROCEEDING DIRECT. ALL INDICATIONS ON CAPT'S PRIMARY FLT DISPLAY WERE NORMAL AND WE DSNDED TO 3000 FT. APCH QUESTIONED WHETHER WE COULD MAKE THE APCH FROM OUR POS. WE SAID 'YES.' THEN; CTLR STATED THAT IT LOOKED AS IF WE WERE HDG DIRECTLY TO MSP VOR; INSTEAD OF WASHY INTXN. THE PFD MAP THEN STARTED TO DRIFT ON CAPT'S PRIMARY FLT DISPLAY. MY PRIMARY FLT DISPLAY WAS FURTHER MISALIGNED. NO 'ACCURACY DOWNGRADE' WAS DISPLAYED AND ACCURACY LEVEL WAS 'HIGH.' WE WERE L OF COURSE AND ATTEMPTING TO CORRECT TO THE R. BY THEN; WE WERE TOO CLOSE AND TOO HIGH TO ATTEMPT THE APCH. WE WERE GIVEN A TURN TO PARALLEL RWY HDG AND THEN WE WERE TURNED OUT FOR ANOTHER APCH. MAYBE A TURN TO FINAL FURTHER OUT WOULD HAVE BEEN PRUDENT CONSIDERING WX. SUPPLEMENTAL INFO FROM ACN 481043: PERHAPS; IN IFR CONDITIONS; THE CTLRS SHOULD CLR AN ACFT TO A POS FURTHER OUT ON AN APCH IN THE EVENT THE INERTIAL REF SYS DRIFT; MORE TIME AND SPACE WOULD BE AVAILABLE TO CORRECT THE SIT.