Narrative:

Aircraft X was instructed to taxi up to the hold line runway 30R and say direction of flight. Aircraft X fumbled his words and I was able to catch his direction of flight. Aircraft X was then observed in position with aircraft Y on short final. I sent aircraft Y around and departed aircraft X.I believed he understood the instructions and did not check on the words he fumbled. Listening to the tape it was clear he read back in position. Will work on listening closer to poor read backs.

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Original NASA ASRS Text

Title: A BJC Local Controller reports on asking an aircraft direction of flight. The pilot reports direction and also says something unintelligible to the Controller. Local observes aircraft in position with another aircraft on final. The Controller sends final traffic around and realizes he did not listen correctly to the read back or receive clarification.

Narrative: Aircraft X was instructed to taxi up to the hold line runway 30R and say direction of flight. Aircraft X fumbled his words and I was able to catch his direction of flight. Aircraft X was then observed in position with aircraft Y on short final. I sent aircraft Y around and departed aircraft X.I believed he understood the instructions and did not check on the words he fumbled. Listening to the tape it was clear he read back in position. Will work on listening closer to poor read backs.

Data retrieved from NASA's ASRS site 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.