Narrative:

We were cleared by approach to fly the VOR DME 2 runway 12 approach and since the approach was line selectable; we briefed and flew it as an approach navigation approach. We had been left high by approach and had to deviation around WX joining the final; so the last couple of minutes were rushed joining the approach and engaging the approach mode; however; the autoplt captured the glideslope correctly from the intercept altitude. Prior to beginning the approach; we had intercepted the cun 302 radial inbound (the final approach course) in navigation. I had raw data displayed with the radial hard tuned. In navigation; the aircraft overshot the radial to the right and stayed there from about 17 miles out where we intercepted in navigation all the way until I disconnected the autoplt to line up for landing (about a 2 mile final). The raw data consistently displayed the aircraft right of track up to a full DOT toward the end of the approach. We could see the runway from about 8 miles out so I let the autoplt continue to fly the airplane to see if it would correct. It never did. Again; the glideslope track was nearly right on the PAPI; but the lateral track left us far enough to the right of the radial that I believe this would be an issue if the approach had to be flown for real down to the MDA of 401 ft AGL. I don't think this approach would have left the aircraft in a position to complete a normal transition to visual and land. The aircraft does not have GPS updating but the DME/DME updating was working and we had the required rnp throughout the approach.callback conversation with reporter revealed the following information: the captain states that he has not had this problem occur previously in 1200 hours of flying the A320. He also states he used approach navigation on arrival back in the us and it functioned normally.

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Original NASA ASRS Text

Title: AN A320 CREW RPTS THE ACFT FLYING THE VOR DME2 RWY 12 AT CUN APCH NAV WITH A SIGNIFICANT OFFSET TO THE R.

Narrative: WE WERE CLRED BY APCH TO FLY THE VOR DME 2 RWY 12 APCH AND SINCE THE APCH WAS LINE SELECTABLE; WE BRIEFED AND FLEW IT AS AN APCH NAV APCH. WE HAD BEEN LEFT HIGH BY APCH AND HAD TO DEV AROUND WX JOINING THE FINAL; SO THE LAST COUPLE OF MINUTES WERE RUSHED JOINING THE APCH AND ENGAGING THE APCH MODE; HOWEVER; THE AUTOPLT CAPTURED THE GLIDESLOPE CORRECTLY FROM THE INTERCEPT ALT. PRIOR TO BEGINNING THE APCH; WE HAD INTERCEPTED THE CUN 302 RADIAL INBOUND (THE FINAL APCH COURSE) IN NAV. I HAD RAW DATA DISPLAYED WITH THE RADIAL HARD TUNED. IN NAV; THE ACFT OVERSHOT THE RADIAL TO THE R AND STAYED THERE FROM ABOUT 17 MILES OUT WHERE WE INTERCEPTED IN NAV ALL THE WAY UNTIL I DISCONNECTED THE AUTOPLT TO LINE UP FOR LNDG (ABOUT A 2 MILE FINAL). THE RAW DATA CONSISTENTLY DISPLAYED THE ACFT R OF TRACK UP TO A FULL DOT TOWARD THE END OF THE APCH. WE COULD SEE THE RWY FROM ABOUT 8 MILES OUT SO I LET THE AUTOPLT CONTINUE TO FLY THE AIRPLANE TO SEE IF IT WOULD CORRECT. IT NEVER DID. AGAIN; THE GLIDESLOPE TRACK WAS NEARLY RIGHT ON THE PAPI; BUT THE LATERAL TRACK LEFT US FAR ENOUGH TO THE R OF THE RADIAL THAT I BELIEVE THIS WOULD BE AN ISSUE IF THE APCH HAD TO BE FLOWN FOR REAL DOWN TO THE MDA OF 401 FT AGL. I DON'T THINK THIS APCH WOULD HAVE LEFT THE ACFT IN A POSITION TO COMPLETE A NORMAL TRANSITION TO VISUAL AND LAND. THE ACFT DOES NOT HAVE GPS UPDATING BUT THE DME/DME UPDATING WAS WORKING AND WE HAD THE REQUIRED RNP THROUGHOUT THE APCH.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE CAPT STATES THAT HE HAS NOT HAD THIS PROB OCCUR PREVIOUSLY IN 1200 HOURS OF FLYING THE A320. HE ALSO STATES HE USED APCH NAV ON ARR BACK IN THE US AND IT FUNCTIONED NORMALLY.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.