Narrative:

On downwind, we were advised of short turn on for visual to 17L. Base turn was made about 1 mi outside marker. On base, our runway was changed to 18R. Captain retuned ILS and FMS set up. I set aircraft up to turn 'on top' marker for runway. Captain said turn inside marker ok. If I wanted to. Heading select used to turn inside marker referring to HSI display. During turn, while checking inside, aircraft apparently turned farther than expected and when I looked out, I 'locked in' on 17R. Tower called to confirm our line up for 18R, then cleared a visual to 18L, if possible. At same time, we realized our line up error. Captain misunderstood tower to say 17L approach ok. Tower said negative. 18L visual ok. By then, it was too late (500' AGL) to change runways and go around was executed. The missed line up was caused by inattention to backup instruments and aircraft turning farther than expected, while my head was in cockpit. Also, constant runway changes at dfw are common and confusing, i.e., 17L, 17R, 18L, 18R, etc. Atlanta runs a much better set of 4 parallels. I see no need for dfw's erratic runway changes.

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Original NASA ASRS Text

Title: ACR LGT WRONG RWY APCH GO AROUND.

Narrative: ON DOWNWIND, WE WERE ADVISED OF SHORT TURN ON FOR VISUAL TO 17L. BASE TURN WAS MADE ABOUT 1 MI OUTSIDE MARKER. ON BASE, OUR RWY WAS CHANGED TO 18R. CAPT RETUNED ILS AND FMS SET UP. I SET ACFT UP TO TURN 'ON TOP' MARKER FOR RWY. CAPT SAID TURN INSIDE MARKER OK. IF I WANTED TO. HDG SELECT USED TO TURN INSIDE MARKER REFERRING TO HSI DISPLAY. DURING TURN, WHILE CHKING INSIDE, ACFT APPARENTLY TURNED FARTHER THAN EXPECTED AND WHEN I LOOKED OUT, I 'LOCKED IN' ON 17R. TWR CALLED TO CONFIRM OUR LINE UP FOR 18R, THEN CLRED A VISUAL TO 18L, IF POSSIBLE. AT SAME TIME, WE REALIZED OUR LINE UP ERROR. CAPT MISUNDERSTOOD TWR TO SAY 17L APCH OK. TWR SAID NEGATIVE. 18L VISUAL OK. BY THEN, IT WAS TOO LATE (500' AGL) TO CHANGE RWYS AND GO AROUND WAS EXECUTED. THE MISSED LINE UP WAS CAUSED BY INATTENTION TO BACKUP INSTRUMENTS AND ACFT TURNING FARTHER THAN EXPECTED, WHILE MY HEAD WAS IN COCKPIT. ALSO, CONSTANT RWY CHANGES AT DFW ARE COMMON AND CONFUSING, I.E., 17L, 17R, 18L, 18R, ETC. ATLANTA RUNS A MUCH BETTER SET OF 4 PARALLELS. I SEE NO NEED FOR DFW'S ERRATIC RWY CHANGES.

Data retrieved from NASA's ASRS site as of August 2007 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.