A319 FLT CREW WHILE ON VISUAL APCH TO RWY 21 GEG; LINE UP ACFT WITH RWY 23 AT SKA.

Narrative

WHILE PROCEEDING DIRECT PHORT (ILS RWY 21 FAF) WE RPTED THE ARPT IN SIGHT; AND WERE SUBSEQUENTLY CLRED FOR A VISUAL APCH. DSNDING TO 3600 FT MSL WE ARMED THE APCH; INTERCEPTED GLIDE PATH; TURNED L TO ALIGN WITH THE RWY; AND BEGAN SLOWING/CONFIGURING. AS WE DSNDED FROM PHORT IT BECAME READILY APPARENT THAT WE HAD A RWY/APCH MISMATCH. I ADVISED THE PF THAT HIS APCH DID NOT LOOK RIGHT. JUST AS I BEGAN DIRECTING A CORRECTION; THE TWR ASKED IF WE WERE ALIGNING WITH THE WRONG RWY. WE THEN CORRECTED TO COURSE AND CONTINUED TO A NORMAL LNDG. BOTH PLTS WERE PREVIOUSLY AWARE OF THE PROX OF THE AFB TO OUR DEST. HOWEVER; AS THE TURN TO FINAL WAS INITIATED AT PHORT; THE AFB RWY CAME INTO ALIGNMENT; AND THE PF STOPPED HIS TURN. THIS SITUATION REINFORCES THE VALUE OF INSTALLING AVAILABLE APCH AIDS WHEN PLANNING FOR VISUAL APCHS. FATIGUE MAY HAVE BEEN CONTRIBUTED TO INITIAL RWY MISIDENTIFICATION; AS BOTH PLTS HAD FLOWN ABOUT 15 HRS IN THE PREVIOUS 36; AND WERE ENDING A 12 HR DUTY PERIOD. THERE WAS ALSO THE DISTR OF LOOKING FOR BALLOONS THAT TWR HAD RPTED IN THE AREA OF THE FINAL APCH.