Narrative:

We were taxiing for departure on 12L at stl. A company aircraft was instructed to s-turn to make room for departing traffic on 12L. An medium large transport was cleared for takeoff and we were told to position and hold and be ready. We acknowledged and complied. Soon after getting into position the tower said that this 'wasn't going to work' and to clear 12L to the left side. We complied and asked for, and received, permission to turn around on the parallel runway 13. We thought the medium large transport was landing on 12L as was implied by stl tower. I look out for the traffic and he is not on final for 12L. I look further to the right rear of the aircraft and see he is lined up and apparently landing on runway 13. I tell the captain this and we become very concerned because the hold short line for 12L on the left side puts part of our aircraft on runway 13. The next thing I hear is the medium large transport declaring a go around. We questioned the tower and were told the medium large transport had gone around. Further investigation revealed that medium large transport aircraft are not allowed to use runway 13 at all due to the wing span. I feel that there was some confusion between stl tower and the medium large transport crew and the tower was trying to push out too many departures. I believe, in my opinion that the medium large transport lined up on the wrong runway and realized the mistake at the last moment averting a potential accident.

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Original NASA ASRS Text

Title: COMMUTER CLRING RWY AT TKOF END. MLG ON FINAL WENT AROUND FROM LOW ALT.

Narrative: WE WERE TAXIING FOR DEP ON 12L AT STL. A COMPANY ACFT WAS INSTRUCTED TO S-TURN TO MAKE ROOM FOR DEPARTING TFC ON 12L. AN MLG WAS CLRED FOR TKOF AND WE WERE TOLD TO POS AND HOLD AND BE READY. WE ACKNOWLEDGED AND COMPLIED. SOON AFTER GETTING INTO POS THE TWR SAID THAT THIS 'WASN'T GOING TO WORK' AND TO CLR 12L TO THE L SIDE. WE COMPLIED AND ASKED FOR, AND RECEIVED, PERMISSION TO TURN AROUND ON THE PARALLEL RWY 13. WE THOUGHT THE MLG WAS LNDG ON 12L AS WAS IMPLIED BY STL TWR. I LOOK OUT FOR THE TFC AND HE IS NOT ON FINAL FOR 12L. I LOOK FURTHER TO THE R REAR OF THE ACFT AND SEE HE IS LINED UP AND APPARENTLY LNDG ON RWY 13. I TELL THE CAPT THIS AND WE BECOME VERY CONCERNED BECAUSE THE HOLD SHORT LINE FOR 12L ON THE L SIDE PUTS PART OF OUR ACFT ON RWY 13. THE NEXT THING I HEAR IS THE MLG DECLARING A GAR. WE QUESTIONED THE TWR AND WERE TOLD THE MLG HAD GONE AROUND. FURTHER INVESTIGATION REVEALED THAT MLG ACFT ARE NOT ALLOWED TO USE RWY 13 AT ALL DUE TO THE WING SPAN. I FEEL THAT THERE WAS SOME CONFUSION BTWN STL TWR AND THE MLG CREW AND THE TWR WAS TRYING TO PUSH OUT TOO MANY DEPS. I BELIEVE, IN MY OPINION THAT THE MLG LINED UP ON THE WRONG RWY AND REALIZED THE MISTAKE AT THE LAST MOMENT AVERTING A POTENTIAL ACCIDENT.

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.