Narrative:

There were approximately 2 aircraft in the pattern at det when we were cleared into the air traffic area for a visual to runway 15. When the tower was contacted we were informed that we were currently #2 for landing as we entered downwind. We were cleared to land as I set up a base leg. I turned final approximately 2 1/2- 3 mi off the approach end of the runway. The approach was proceeding normally under visual conditions when suddenly an small aircraft entered final approach path in front of and below my aircraft. He cut in front of us on final from the west. It was apparent that due to the disparity in approach speed differences a collision was imminent. I initiated evasive action and turned my aircraft off of final and climbed. Simultaneous to our actions the local controller became aware of the situation and gave immediate instructions for the small aircraft to break off his approach and turn west. As I climbed east and reentered downwind for runway 15, the local controller issued us a landing clearance, and apologies for the incident. Subsequent discussions with the local controller confirmed what has been perceived as a problem at det for sometime. It is an unsafe practice that almost ended with tragic consequences....it is the practice of having the local controller also assume the role of ground control. It was division of attention on the part of the local controller being distracted by a ground control situation in which her attention to the local traffic pattern was momentarily disrupted by the ground control problem. Had she been able to maintain her duties of local controller instead do trying to accomplish both jobs simultaneously.

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Original NASA ASRS Text

Title: SMT AND SMA HAVE NMAC ON FINAL APCH AT DET.

Narrative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

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.