TAXIWAY EXCURSION.

Narrative

LIGHT RAIN FALLING IN LULL BTWN TSTMS. LANDED RWY 13R AND RPTED BRAKING ACTION FAIR TO TWR. ATIS RPTED WATER STANDING ON ARPT. ROLLED TO END OF RWY WITH R TURNOFF WITH 180 DEG TURN BACK TO TAXIWAY TO TERMINAL. I SWUNG AS WIDE AS POSSIBLE IN TURN; STEERING THE NOSE GEAR AS NEAR AS POSSIBLE TO THE FAR SIDE OF TAXIWAY TO KEEP THE MAIN GEAR TRACKING THE CTR OF THE TAXIWAY. BECAUSE OF THE WET SURFACE; THE VISUAL CONTACT WITH THE SURFACE WAS POOR; BUT THE ACFT ROLLED OUT TRACKING THE CTRLINE CORRECTLY AS THE NOSE GEAR SWING ON AROUND TO LINE UP AT COMPLETION OF TURN. EVERYTHING APPEARED NORMAL. NOTHING LOOKED OR FELT UNUSUAL BUT WE COMMENTED WHILE TAXIING IN THAT THE TAXIWAY SEEMED EXTREMELY NARROW FOR A WDB. THE NEXT AFTERNOON WE PICKED UP THE SAME ACFT AT DFW TO GO TO LGA AND FOUND IN THE LOG THAT THE AUSTIN MAIN HAD RPTED MUD ON #4 AND #8 TIRES; HAD PERFORMED AN INSPECTION; AND FOUND NO ACFT DISCREPANCIES. CLEANED MUD FROM TIRES AND APPROVED FOR SVC. NO ONE IN THE COCKPIT NOTICED ANYTHING UNUSUAL; AND WE WOULD NOT HAVE KNOWN HAD WE NOT SEEN THE LOGBOOK THE NEXT DAY. I AM NOT SURE JUST WHERE THE TIRE CONTACTED THE MUD. THE TURNOFF RUNUP PAD WAS POORLY LIGHTED AND WE WONDER IF MUD MIGHT HAVE WASHED ONTO THE TAXIWAY BY THE HVY RAIN PRIOR TO OUR LNDG. I DO NOT BELIEVE WE LEFT THE PAVED SURFACE. THE ASPHALT IN THAT AREA MAY HAVE BEEN TOO SOFT TO SUPPORT US. AT ANY RATE; THE TAXIWAYS AT AUS ARE ALL TOO NARROW FOR OP OF A WDB.