Narrative:

Taxi instructions were issued by stl ground to taxi to runway 12L, hold short runway 12R at taxiway C. Subsequently issued instruction to taxi across runway 12R, hold short of runway 12L. We proceeded across runway 12R and misidented taxiway P for the hold pad of runway 12L. I (captain) made the turn on to taxiway P and held just short of runway 6/24 when I saw another aircraft on runway 6. I immediately stopped until instructed by ground to continue on taxiway C and hold short of runway 12L. Takeoff and remainder of flight to ord uneventful. First officer did his briefing which I don't think I listened to very well due to other tasks interrupting me. He was trying hard to keep up and in fact was following my taxi route and made a comment about where we were going. I should have recognized the task saturated state in the cockpit and resultant decrease in the level of safety, but was 'tunnel-vision' about getting the aircraft out and failed to stop the chain of errors. Had I taken a min and recognized our state of mind at that time and stopped the aircraft to give the first officer more time I feel he would have seen my error and prevented the event. Supplemental information from acn 557423: after crossing runway 12R at taxiway C for hold short of runway 12L, captain turned left onto runway 6/24. I asked if we were cleared onto runway and he said no. We determined that we were on an active runway by mistake.

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Original NASA ASRS Text

Title: AN A320 CREW, TAXIING FOR TKOF AT STL, MADE A WRONG TURN ONTO AN ACTIVE RWY WITHOUT A CLRNC.

Narrative: TAXI INSTRUCTIONS WERE ISSUED BY STL GND TO TAXI TO RWY 12L, HOLD SHORT RWY 12R AT TXWY C. SUBSEQUENTLY ISSUED INSTRUCTION TO TAXI ACROSS RWY 12R, HOLD SHORT OF RWY 12L. WE PROCEEDED ACROSS RWY 12R AND MISIDENTED TXWY P FOR THE HOLD PAD OF RWY 12L. I (CAPT) MADE THE TURN ON TO TXWY P AND HELD JUST SHORT OF RWY 6/24 WHEN I SAW ANOTHER ACFT ON RWY 6. I IMMEDIATELY STOPPED UNTIL INSTRUCTED BY GND TO CONTINUE ON TXWY C AND HOLD SHORT OF RWY 12L. TKOF AND REMAINDER OF FLT TO ORD UNEVENTFUL. FO DID HIS BRIEFING WHICH I DON'T THINK I LISTENED TO VERY WELL DUE TO OTHER TASKS INTERRUPTING ME. HE WAS TRYING HARD TO KEEP UP AND IN FACT WAS FOLLOWING MY TAXI RTE AND MADE A COMMENT ABOUT WHERE WE WERE GOING. I SHOULD HAVE RECOGNIZED THE TASK SATURATED STATE IN THE COCKPIT AND RESULTANT DECREASE IN THE LEVEL OF SAFETY, BUT WAS 'TUNNEL-VISION' ABOUT GETTING THE ACFT OUT AND FAILED TO STOP THE CHAIN OF ERRORS. HAD I TAKEN A MIN AND RECOGNIZED OUR STATE OF MIND AT THAT TIME AND STOPPED THE ACFT TO GIVE THE FO MORE TIME I FEEL HE WOULD HAVE SEEN MY ERROR AND PREVENTED THE EVENT. SUPPLEMENTAL INFO FROM ACN 557423: AFTER XING RWY 12R AT TXWY C FOR HOLD SHORT OF RWY 12L, CAPT TURNED L ONTO RWY 6/24. I ASKED IF WE WERE CLRED ONTO RWY AND HE SAID NO. WE DETERMINED THAT WE WERE ON AN ACTIVE RWY BY MISTAKE.

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.