Narrative:

On climb out passing 11000 ft with clearance to FL230, we initially observed a hollow diamond target at our 10 O'clock position showing 1000 ft above us. As we continued our climb, the target rapidly became a red square and we received the reduce climb, verbal warning. The vsi display showed a red border for all climbs and a small green border for a slow descent. I reversed our climb and topped out at approximately 12000 ft. The TCASII showed us level with the target momentarily. I was able to spot the target visually at about the time we reversed our climb. It was a low wing single engine GA aircraft. The WX conditions were very hazy above a broken to overcast layer. My first officer notified ATC that we were complying with a TCASII directive and was told that there was no target, 'except a VFR target at 12500 ft.' the controller was moderately busy, but had made no attempt to notify us of the traffic or to modify our clearance. I would guess that our nearest approach to the other aircraft was approximately 1/2 mi at co-altitude. The hazard here is obvious, and I question the controller's judgement and procedural compliance in not calling the traffic to our attention or modifying our clearance.

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Original NASA ASRS Text

Title: MD88 CREW, IN RESPONSE TO A LOW WING GA ACFT, HAD A TCASII RA IN CVG CLASS E AIRSPACE.

Narrative: ON CLBOUT PASSING 11000 FT WITH CLRNC TO FL230, WE INITIALLY OBSERVED A HOLLOW DIAMOND TARGET AT OUR 10 O'CLOCK POS SHOWING 1000 FT ABOVE US. AS WE CONTINUED OUR CLB, THE TARGET RAPIDLY BECAME A RED SQUARE AND WE RECEIVED THE REDUCE CLB, VERBAL WARNING. THE VSI DISPLAY SHOWED A RED BORDER FOR ALL CLBS AND A SMALL GREEN BORDER FOR A SLOW DSCNT. I REVERSED OUR CLB AND TOPPED OUT AT APPROX 12000 FT. THE TCASII SHOWED US LEVEL WITH THE TARGET MOMENTARILY. I WAS ABLE TO SPOT THE TARGET VISUALLY AT ABOUT THE TIME WE REVERSED OUR CLB. IT WAS A LOW WING SINGLE ENG GA ACFT. THE WX CONDITIONS WERE VERY HAZY ABOVE A BROKEN TO OVCST LAYER. MY FO NOTIFIED ATC THAT WE WERE COMPLYING WITH A TCASII DIRECTIVE AND WAS TOLD THAT THERE WAS NO TARGET, 'EXCEPT A VFR TARGET AT 12500 FT.' THE CTLR WAS MODERATELY BUSY, BUT HAD MADE NO ATTEMPT TO NOTIFY US OF THE TFC OR TO MODIFY OUR CLRNC. I WOULD GUESS THAT OUR NEAREST APCH TO THE OTHER ACFT WAS APPROX 1/2 MI AT CO-ALT. THE HAZARD HERE IS OBVIOUS, AND I QUESTION THE CTLR'S JUDGEMENT AND PROCEDURAL COMPLIANCE IN NOT CALLING THE TFC TO OUR ATTN OR MODIFYING OUR CLRNC.

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.