Narrative:

I was just turning to base leg for runway 21 when I realized that the tower was trying to contact me. I misinterped where the other aircraft was. I was looking ahead of me because I thought I was supposed to be looking for traffic in the right traffic pattern. The traffic was actually to the right of me. I flew in front of the other aircraft, forcing it to go around and miss its final approach.

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Original NASA ASRS Text

Title: A STUDENT PLT IN A C172 TURNS BASE LEG WITHOUT TWR'S PERMISSION AND EXPERIENCES AN NMAC WITH AN ACFT Y ON FINAL AT FSD, SD.

Narrative: I WAS JUST TURNING TO BASE LEG FOR RWY 21 WHEN I REALIZED THAT THE TWR WAS TRYING TO CONTACT ME. I MISINTERPED WHERE THE OTHER ACFT WAS. I WAS LOOKING AHEAD OF ME BECAUSE I THOUGHT I WAS SUPPOSED TO BE LOOKING FOR TFC IN THE R TFC PATTERN. THE TFC WAS ACTUALLY TO THE R OF ME. I FLEW IN FRONT OF THE OTHER ACFT, FORCING IT TO GO AROUND AND MISS ITS FINAL APCH.

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.