Narrative:

While descending into cvg we were cleared to 3;000 ft. Later our clearance was amended to 3;500 ft due to a VFR aircraft 'popping up'. Controller issued vectors to base which put us head on to VFR aircraft at 2;900 ft-3;000 ft crossing ILS 18L final approach path. We were IMC at 3;500 ft. Using TCAS both pilots observed the target at 500 below our altitude. TCAS changed to yellow as we approached target head on. TCAS showed VFR target climbing to -300 ft which changed target to red and caused RA climb status. I disconnected the autopilot and climbed to around 4;300 ft to miss the climbing target. At this point we were clear of the conflict and nearly on the localizer. Controller issued clearance to join localizer and descend to 3;000 ft again. Some where around 3;000 ft we descended through the ceiling and visually navigated to landing on 18L. The event occurred because of an aircraft operating below the class B airspace (2;900 ft) at the same position where IFR arrivals would normally be descending to a similar altitude while tracking the ILS and then they began climbing into us. The approach controller was pressing for us to accept a visual approach clearance due to a proceeding aircraft having the airport in sight above 3;000 ft to the west of cvg. The radar vectors were issued to keep us in close for a possible visual approach. Unfortunately we didn't break through the ceiling until below 3;000 ft. When a known target exists on the radar; which will cross the IFR approach course; please don't vector an aircraft head on to them at similar altitudes (3;500 ft IFR/3;000 ft VFR). I really wished that we would be given a longer downwind vector or a base vector that at least didn't cause us to converge on the same point in IMC conditions.

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Original NASA ASRS Text

Title: An air carrier Captain reported an NMAC with a small aircraft on approach to CVG; and was critical of ATC handling.

Narrative: While descending into CVG we were cleared to 3;000 FT. Later our clearance was amended to 3;500 FT due to a VFR aircraft 'popping up'. Controller issued vectors to base which put us head on to VFR aircraft at 2;900 FT-3;000 FT crossing ILS 18L final approach path. We were IMC at 3;500 FT. Using TCAS both pilots observed the target at 500 below our altitude. TCAS changed to yellow as we approached target head on. TCAS showed VFR target climbing to -300 FT which changed target to RED and caused RA CLIMB status. I disconnected the autopilot and climbed to around 4;300 FT to miss the climbing target. At this point we were clear of the conflict and nearly on the localizer. Controller issued clearance to join localizer and descend to 3;000 FT again. Some where around 3;000 FT we descended through the ceiling and visually navigated to landing on 18L. The event occurred because of an aircraft operating below the Class B airspace (2;900 FT) at the same position where IFR arrivals would normally be descending to a similar altitude while tracking the ILS and then they began climbing into us. The Approach Controller was pressing for us to accept a visual approach clearance due to a proceeding aircraft having the airport in sight above 3;000 FT to the west of CVG. The radar vectors were issued to keep us in close for a possible visual approach. Unfortunately we didn't break through the ceiling until below 3;000 FT. When a known target exists on the radar; which will cross the IFR approach course; please don't vector an aircraft head on to them at similar altitudes (3;500 FT IFR/3;000 FT VFR). I really wished that we would be given a longer downwind vector or a base vector that at least didn't cause us to converge on the same point in IMC conditions.

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.