Narrative:

After landing from a CAT III approach (RVR 1000-1400') on runway 9R at phl, I requested to roll to the end of 9R to exit runway at taxiway charlie and then to the ramp. Since the north section of taxiway C was partially blocked, phl tower instructed us to use taxiway whiskey to taxiway romeo to the ramp. Runway 9L was closed. Seeing the taxiway west sign with an arrow to the right, I immediately turned right after clearing the runway. I had actually turned onto taxiway aa. Since the tower could not see us, they eventually inquired as to our position. Not knowing we were on aa, we replied we were on taxiway west. Not until we saw a sign for taxiway delta did we realize we were on the wrong taxiway. I then taxied down D to right to the ramp west/O incident. This type of incident could have resulted in an accident for someone had runway 9L been in use. I believe this couldn't been averted with better taxiway signs. Had there been a sign for taxiway aa on the right side of taxiway C, it would not get mistaken for taxiway whiskey. I also believe there should be taxiway signs along the taxiway--either painted on the surface or along the edge. Once you pass a sign, you can neither back the aircraft up nor see down to the next sign in reduced visibilities. Callback conversation with reporter revealed the following: reporter was specifically asked to describe the taxiway signs located at the intersection of txwys aa, C and west. He said that, between runway 9R and taxiway aa on the left side of taxiway C, there was a sign that simply said 'aa.' on the opp side of taxiway C, there was another sign that said 'C,' with an arrow pointing in the 12 O'clock direction, and it also said 'west,' with an arrow pointing in the 2 O'clock direction. He reiterated his statement that, after turning 90 degrees onto aa rather than 45 degrees onto west, there was nothing to give him a clue that he had erred until he arrived at the intersection of taxiway D.

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Original NASA ASRS Text

Title: AFTER CLEARING RWY 9R AT C, MLG TURNED ONTO TXWY AA INSTEAD OF W, AS CLEARED.

Narrative: AFTER LNDG FROM A CAT III APCH (RVR 1000-1400') ON RWY 9R AT PHL, I REQUESTED TO ROLL TO THE END OF 9R TO EXIT RWY AT TXWY CHARLIE AND THEN TO THE RAMP. SINCE THE N SECTION OF TXWY C WAS PARTIALLY BLOCKED, PHL TWR INSTRUCTED US TO USE TXWY WHISKEY TO TXWY ROMEO TO THE RAMP. RWY 9L WAS CLOSED. SEEING THE TXWY W SIGN WITH AN ARROW TO THE RIGHT, I IMMEDIATELY TURNED RIGHT AFTER CLRING THE RWY. I HAD ACTUALLY TURNED ONTO TXWY AA. SINCE THE TWR COULD NOT SEE US, THEY EVENTUALLY INQUIRED AS TO OUR POS. NOT KNOWING WE WERE ON AA, WE REPLIED WE WERE ON TXWY W. NOT UNTIL WE SAW A SIGN FOR TXWY DELTA DID WE REALIZE WE WERE ON THE WRONG TXWY. I THEN TAXIED DOWN D TO R TO THE RAMP W/O INCIDENT. THIS TYPE OF INCIDENT COULD HAVE RESULTED IN AN ACCIDENT FOR SOMEONE HAD RWY 9L BEEN IN USE. I BELIEVE THIS COULDN'T BEEN AVERTED WITH BETTER TXWY SIGNS. HAD THERE BEEN A SIGN FOR TXWY AA ON THE RIGHT SIDE OF TXWY C, IT WOULD NOT GET MISTAKEN FOR TXWY WHISKEY. I ALSO BELIEVE THERE SHOULD BE TXWY SIGNS ALONG THE TXWY--EITHER PAINTED ON THE SURFACE OR ALONG THE EDGE. ONCE YOU PASS A SIGN, YOU CAN NEITHER BACK THE ACFT UP NOR SEE DOWN TO THE NEXT SIGN IN REDUCED VISIBILITIES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR WAS SPECIFICALLY ASKED TO DESCRIBE THE TXWY SIGNS LOCATED AT THE INTXN OF TXWYS AA, C AND W. HE SAID THAT, BTWN RWY 9R AND TXWY AA ON THE LEFT SIDE OF TXWY C, THERE WAS A SIGN THAT SIMPLY SAID 'AA.' ON THE OPP SIDE OF TXWY C, THERE WAS ANOTHER SIGN THAT SAID 'C,' WITH AN ARROW POINTING IN THE 12 O'CLOCK DIRECTION, AND IT ALSO SAID 'W,' WITH AN ARROW POINTING IN THE 2 O'CLOCK DIRECTION. HE REITERATED HIS STATEMENT THAT, AFTER TURNING 90 DEGREES ONTO AA RATHER THAN 45 DEGREES ONTO W, THERE WAS NOTHING TO GIVE HIM A CLUE THAT HE HAD ERRED UNTIL HE ARRIVED AT THE INTXN OF TXWY D.

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.