Narrative:

We were asked if we had dbq in sight while at 4000 MSL and 240 KTS and 18 miles from the airport. We called dbq in sight. ZAU center cleared us the visual to runway 18 and handed us off to tower. We checked in with dbq at 4000 MSL heading 300 at 240 KIAS and slowing to 200 KIAS. To the best of my recollection; dbq tower controller responded with 'roger you're cleared the visual to runway 18' and gave us a traffic sequence. Our altimeter was set to 30.00'. The copilot was flying closer to the airport on a 300 heading to facilitate a downwind for runway 18. I observed on our TCAS a myriad of aircraft targets (6 aircraft plus) within a 6 mile range. Our TCAS was configured at 6 mile range with a below search priority in order to facilitate a proper target sort. While on a 300 heading toward the airport I broke out on TCAS a single target bearing 360 range 4 miles and -05 (3500MSL) below our current position. I pointed out to the first officer and started a heavy raster scan search with no visual pick up. The target resolved to a TA showing climb -04 hi aspect 180 out. Still no tally. The TA resolved to an RA with a climb command. I instructed the copilot to disengage the autopilot and climb; follow the TCAS vsi command. He complied with all TCAS commands. Simultaneously while the copilot was deviating from altitude of 4000 MSL to 4500 MSL I informed tower of the conflict; and informed him of what we were doing in detail. The tower controller appeared not to have any situational awareness on that particular target. Then we heard on the radio the aircraft identification himself and said it was him climbing underneath us at 3700 ft MSL. The closest the target came to us according to our TCAS was -03 with a climb indication. We never gained visual on the target. Once the target passed our 3/9 line we requested our decent back to 4000. Dbq tower asked us what we wanted to do. We requested a right teardrop entry back to runway 18 and landed uneventfully. There was VFR traffic saturation in the class D airspace and just outside the airspace which caused the dbq tower controller to have low situational awareness. The fact that the tower controller has no real time updated radar intel does not help his situational awareness. Provide the tower with better equipment and training in order to provide proper traffic separation. It also does not help when the tower still gives you ATC instructions while you're on a visual approach clearance. Based on this situation it appeared that he still wanted to maintain direct control over us rather than let us fly the visual to 18 and provide our own separation of aircraft with our on board systems (TCAS) plus visual lookout. Our equipment appears to provide us with better information rather than his.

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Original NASA ASRS Text

Title: Air carrier issued a visual approach to Runway 18 at DBQ experienced a TCAS RA with unreported traffic; reporter indicating aircraft equipment may provide better traffic information than the tower radar equipment.

Narrative: We were asked if we had DBQ in sight while at 4000 MSL and 240 KTS and 18 miles from the airport. We called DBQ in sight. ZAU Center cleared us the visual to Runway 18 and handed us off to Tower. We checked in with DBQ at 4000 MSL heading 300 at 240 KIAS and slowing to 200 KIAS. To the best of my recollection; DBQ Tower Controller responded with 'Roger you're cleared the visual to Runway 18' and gave us a traffic sequence. Our altimeter was set to 30.00'. The Copilot was flying closer to the airport on a 300 heading to facilitate a downwind for Runway 18. I observed on our TCAS a myriad of aircraft targets (6 aircraft plus) within a 6 mile range. Our TCAS was configured at 6 mile range with a below search priority in order to facilitate a proper target sort. While on a 300 heading toward the airport I broke out on TCAS a single target bearing 360 range 4 miles and -05 (3500MSL) below our current position. I pointed out to the First Officer and started a heavy raster scan search with no visual pick up. The target resolved to a TA showing climb -04 hi aspect 180 out. Still no tally. The TA resolved to an RA with a climb command. I instructed the copilot to disengage the autopilot and climb; follow the TCAS VSI command. He complied with all TCAS commands. Simultaneously while the Copilot was deviating from altitude of 4000 MSL to 4500 MSL I informed tower of the conflict; and informed him of what we were doing in detail. The Tower Controller appeared not to have any situational awareness on that particular target. Then we heard on the radio the aircraft ID himself and said it was him climbing underneath us at 3700 FT MSL. The closest the target came to us according to our TCAS was -03 with a climb indication. We never gained visual on the target. Once the target passed our 3/9 line we requested our decent back to 4000. DBQ Tower asked us what we wanted to do. We requested a right teardrop entry back to Runway 18 and landed uneventfully. There was VFR traffic saturation in the CLASS D AIRSPACE and just outside the airspace which caused the DBQ Tower Controller to have low situational awareness. The fact that the Tower Controller has no real time updated radar intel does not help his situational awareness. Provide the Tower with better equipment and training in order to provide proper traffic separation. It also does not help when the Tower still gives you ATC instructions while you're on a visual approach clearance. Based on this situation it appeared that he still wanted to maintain direct control over us rather than let us fly the visual to 18 and provide our own separation of aircraft with our on board systems (TCAS) plus visual lookout. Our equipment appears to provide us with better information rather than his.

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.