Narrative:

We were flying to apa. Den approach cleared us for a visual approach to 17L via the north shore of the reservoir located to the north of the airport. We were handed off to apa tower just prior to reaching the north shore. We called three to four times without response from the tower; finally getting clearance to land on 17L when we were on a 3 mile straight in final. We became aware of a TCAS contact within a mile or so of our position on our right while we were around 500 ft AGL and made visual contact with the light airplane shortly after. It quickly became apparent that the airplane was supposed to be on a right base to 17R; but was overshooting the center line. We observed the airplane increasing its bank to what we guessed was around 45 degrees. Our last observation of this airplane was its underside with a large bank angle. It had been heading straight at us at the same altitude. We knew its pilot couldn't see us any longer due to its bank angle. We went around at about 200 ft. We conservatively estimated the distance between our airplanes to have been a maximum of 200 ft. On the go-around; the tower asked us to expedite a turn downwind if possible. We complied because we knew that an experimental airplane had taken off from 17L shortly before our planned landing and was directly in front of us. However; we weren't aware of another light airplane on the downwind. It was directly in our path. As we were turning downwind; that airplane was observed on TCAS to be at our altitude and its 'dot' on the TCAS screen was touching the center point of our TCAS screen with a '00' difference in altitude. Our TCAS was set to the 6 mile range. We were in a turn to downwind at the time and never saw that airplane so I don't know how close we got. After landing; I contacted the tower supervisor; who reviewed the tapes. He admitted that the controller 'could have done better.' however; he stated that they use different frequencies for 17L and 17R; which explains somewhat why we weren't aware of the traffic on final to 17R. But; we should have been warned of the conflict. He stated that the controller asked for the early downwind turn due to very slow traffic (the experimental) ahead of us. He didn't comment on our conflict downwind. He also stated that they have hundreds of light airplanes based on the field and many are on training flights and that the speed of jet airplanes and their local traffic are not compatible. I should add that when we went missed; our TCAS screen (on the 6 mile range) was swamped with contacts; all within a mile or two. It was difficult to pick out the threats. Also; we never had a TCAS alert other than the targets turning yellow on either incident. I'm surmising that; because of the bank angles and number of contacts involved; the TCAS was unable to provide us with the avoidance commands we would normally expect. The real estate between 17L and 17R is minimal and having two tower frequencies for airplanes that close exacerbates the problem. We never heard the airplanes on 17R and we weren't warned of the conflict. Neither were we warned of the traffic on the downwind during the missed approach. The fact that there was no clear airspace either ahead of us or downwind for a safe missed approach is a huge problem. Any airplane making an approach should be able to make a safe go-around regardless of differences in airspeed.

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Original NASA ASRS Text

Title: Cessna Citation inbound to APA and cleared for a Visual Approach to Runway 17L experienced a conflict with traffic turning final for Runway 17R. The reporter questions the lack of traffic information and general ATC services.

Narrative: We were flying to APA. DEN Approach cleared us for a Visual Approach to 17L via the north shore of the reservoir located to the north of the airport. We were handed off to APA Tower just prior to reaching the north shore. We called three to four times without response from the Tower; finally getting clearance to land on 17L when we were on a 3 mile straight in final. We became aware of a TCAS contact within a mile or so of our position on our right while we were around 500 FT AGL and made visual contact with the light airplane shortly after. It quickly became apparent that the airplane was supposed to be on a right base to 17R; but was overshooting the center line. We observed the airplane increasing its bank to what we guessed was around 45 degrees. Our last observation of this airplane was its underside with a large bank angle. It had been heading straight at us at the same altitude. We knew its pilot couldn't see us any longer due to its bank angle. We went around at about 200 FT. We conservatively estimated the distance between our airplanes to have been a maximum of 200 FT. On the go-around; the Tower asked us to expedite a turn downwind if possible. We complied because we knew that an experimental airplane had taken off from 17L shortly before our planned landing and was directly in front of us. However; we weren't aware of another light airplane on the downwind. It was directly in our path. As we were turning downwind; that airplane was observed on TCAS to be at our altitude and its 'dot' on the TCAS screen was touching the center point of our TCAS screen with a '00' difference in altitude. Our TCAS was set to the 6 mile range. We were in a turn to downwind at the time and never saw that airplane so I don't know how close we got. After landing; I contacted the Tower Supervisor; who reviewed the tapes. He admitted that the Controller 'could have done better.' However; he stated that they use different frequencies for 17L and 17R; which explains somewhat why we weren't aware of the traffic on final to 17R. But; we should have been warned of the conflict. He stated that the Controller asked for the early downwind turn due to very slow traffic (the experimental) ahead of us. He didn't comment on our conflict downwind. He also stated that they have hundreds of light airplanes based on the field and many are on training flights and that the speed of jet airplanes and their local traffic are not compatible. I should add that when we went missed; our TCAS screen (on the 6 mile range) was swamped with contacts; all within a mile or two. It was difficult to pick out the threats. Also; we never had a TCAS alert other than the targets turning yellow on either incident. I'm surmising that; because of the bank angles and number of contacts involved; the TCAS was unable to provide us with the avoidance commands we would normally expect. The real estate between 17L and 17R is minimal and having two Tower frequencies for airplanes that close exacerbates the problem. We never heard the airplanes on 17R and we weren't warned of the conflict. Neither were we warned of the traffic on the downwind during the missed approach. The fact that there was no clear airspace either ahead of us or downwind for a safe missed approach is a huge problem. Any airplane making an approach should be able to make a safe go-around regardless of differences in airspeed.

Data retrieved from NASA's ASRS site as of April 2012 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.