Narrative:

On arrival gfk; heavy rain and thunderstorms in vicinity and on top of gfk airport. After several attempts to get vectors for ILS runway 35L approach at gfk; without success due to WX; heard another aircraft tell gfk approach that he had broken out at 2800 ft and was proceeding VFR to the field (gfk). We requested descent to VMC conditions to facilitate a visual approach to gfk. Approach controller rogered our request; descended us to 2800 ft and told us to report the airport in sight for a left base. Passing through 3000 ft; immediately after being told to report the field in sight; I saw a runway oriented north/south and told my first officer to 'call the field in sight' and then began a descent to 1500 ft AGL (pattern altitude) while turning for a left downwind. Shortly thereafter; approach called with a low altitude alert. My so then noticed our error and stated that the field we were setting up to was grand forks AFB. Climbed back to 2800 ft and proceeded with vectors to ILS runway 35L final at gfk. Circumstances/timing of letdown (nearly on top of grand forks AFB -- with similarly aligned runway) confused the issue. This; coupled with task fixation to get on the ground due to WX and fuel; led to assumption that the airport in sight was the airport we were to enter a left base for (ie; gfk). Busy; confusing time during approach with many changes of plan and less than optimum communication to/from approach set up a potential landing at the wrong airport and corresponding descent leading to low altitude alert.

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Original NASA ASRS Text

Title: FLT CREW IS CLEARED TO DESCEND BELOW CEILING FOR A VISUAL APCH. FLT CREW ACQUIRED NEARBY ARPT AND WHILE MANEUVERING FOR AN APCH AT THE WRONG ARPT; SET OFF A LOW ALT ALERT. FLT CREW WAS SUBSEQUENTLY VECTORED FOR ILS AT INTENDED ARPT.

Narrative: ON ARR GFK; HVY RAIN AND TSTMS IN VICINITY AND ON TOP OF GFK ARPT. AFTER SEVERAL ATTEMPTS TO GET VECTORS FOR ILS RWY 35L APCH AT GFK; WITHOUT SUCCESS DUE TO WX; HEARD ANOTHER ACFT TELL GFK APCH THAT HE HAD BROKEN OUT AT 2800 FT AND WAS PROCEEDING VFR TO THE FIELD (GFK). WE REQUESTED DSCNT TO VMC CONDITIONS TO FACILITATE A VISUAL APCH TO GFK. APCH CTLR ROGERED OUR REQUEST; DSNDED US TO 2800 FT AND TOLD US TO RPT THE ARPT IN SIGHT FOR A L BASE. PASSING THROUGH 3000 FT; IMMEDIATELY AFTER BEING TOLD TO RPT THE FIELD IN SIGHT; I SAW A RWY ORIENTED N/S AND TOLD MY FO TO 'CALL THE FIELD IN SIGHT' AND THEN BEGAN A DSCNT TO 1500 FT AGL (PATTERN ALT) WHILE TURNING FOR A L DOWNWIND. SHORTLY THEREAFTER; APCH CALLED WITH A LOW ALT ALERT. MY SO THEN NOTICED OUR ERROR AND STATED THAT THE FIELD WE WERE SETTING UP TO WAS GRAND FORKS AFB. CLBED BACK TO 2800 FT AND PROCEEDED WITH VECTORS TO ILS RWY 35L FINAL AT GFK. CIRCUMSTANCES/TIMING OF LETDOWN (NEARLY ON TOP OF GRAND FORKS AFB -- WITH SIMILARLY ALIGNED RWY) CONFUSED THE ISSUE. THIS; COUPLED WITH TASK FIXATION TO GET ON THE GND DUE TO WX AND FUEL; LED TO ASSUMPTION THAT THE ARPT IN SIGHT WAS THE ARPT WE WERE TO ENTER A L BASE FOR (IE; GFK). BUSY; CONFUSING TIME DURING APCH WITH MANY CHANGES OF PLAN AND LESS THAN OPTIMUM COM TO/FROM APCH SET UP A POTENTIAL LNDG AT THE WRONG ARPT AND CORRESPONDING DSCNT LEADING TO LOW ALT ALERT.

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.