Narrative:

We were issued taxi out instructions from gate to taxi to the outer taxiway (en route to takeoff runway 3L), hold short of wolf. Coming out of the alley way between concourses the captain taxied straight ahead until we came to a taxi line. We followed the line until we had come to what we thought was the instructed place (outer short of wolf). I told ground east I was switching frequencys. Before I went over to new frequency he asked if I had seen an air carrier flight taxiing and I said 'no.' on check-in on ground west frequency, we were told to turn left on wolf, cross runway 27/9 transition to taxiway Y and call on taxiway Y. The captain followed the taxi line and I called crossing runway 27/9. We made a right turn on what we thought was a connecting taxiway from wolf to Y taxiway. Soon we discovered we were on a concrete apron with no taxiway. We informed ground we didn't know where we were at the same time the captain was making a 180 degree turn back eastbound. I told ground I could now see the taxiway fox sign. We were told to head back west and call on taxiway Y which we did. By this time, the captain and I figured out what we had done. Instead of crossing runway 27/9 on taxiway wolf, we were instead on fox. We had then turned right on taxiway U on the concrete apron north of the tower. At no time did the captain or I feel we were close to violating an active runway since we at all times had blue taxi lights in sight. That whole ramp area north of runway 27/9 is very poorly marked for aircraft taxiing out of where we came from.

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Original NASA ASRS Text

Title: AN ACR MLG FAILED TO TAXI WHERE IT WAS DIRECTED AT DTW IN THE FOG.

Narrative: WE WERE ISSUED TAXI OUT INSTRUCTIONS FROM GATE TO TAXI TO THE OUTER TXWY (ENRTE TO TKOF RWY 3L), HOLD SHORT OF WOLF. COMING OUT OF THE ALLEY WAY BTWN CONCOURSES THE CAPT TAXIED STRAIGHT AHEAD UNTIL WE CAME TO A TAXI LINE. WE FOLLOWED THE LINE UNTIL WE HAD COME TO WHAT WE THOUGHT WAS THE INSTRUCTED PLACE (OUTER SHORT OF WOLF). I TOLD GND EAST I WAS SWITCHING FREQS. BEFORE I WENT OVER TO NEW FREQ HE ASKED IF I HAD SEEN AN ACR FLT TAXIING AND I SAID 'NO.' ON CHK-IN ON GND WEST FREQ, WE WERE TOLD TO TURN L ON WOLF, CROSS RWY 27/9 TRANSITION TO TXWY Y AND CALL ON TXWY Y. THE CAPT FOLLOWED THE TAXI LINE AND I CALLED XING RWY 27/9. WE MADE A R TURN ON WHAT WE THOUGHT WAS A CONNECTING TXWY FROM WOLF TO Y TXWY. SOON WE DISCOVERED WE WERE ON A CONCRETE APRON WITH NO TXWY. WE INFORMED GND WE DIDN'T KNOW WHERE WE WERE AT THE SAME TIME THE CAPT WAS MAKING A 180 DEG TURN BACK EBOUND. I TOLD GND I COULD NOW SEE THE TXWY FOX SIGN. WE WERE TOLD TO HEAD BACK W AND CALL ON TXWY Y WHICH WE DID. BY THIS TIME, THE CAPT AND I FIGURED OUT WHAT WE HAD DONE. INSTEAD OF XING RWY 27/9 ON TXWY WOLF, WE WERE INSTEAD ON FOX. WE HAD THEN TURNED R ON TXWY U ON THE CONCRETE APRON N OF THE TWR. AT NO TIME DID THE CAPT OR I FEEL WE WERE CLOSE TO VIOLATING AN ACTIVE RWY SINCE WE AT ALL TIMES HAD BLUE TAXI LIGHTS IN SIGHT. THAT WHOLE RAMP AREA N OF RWY 27/9 IS VERY POORLY MARKED FOR ACFT TAXIING OUT OF WHERE WE CAME FROM.

Data retrieved from NASA's ASRS site as of July 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.