Narrative:

Atl to day flight, working cvg approach control while transiting and descending into day area. Cleared to 10000 ft and asked by cvg to expedite through 11000 ft due to sbound company traffic at 11000 ft. We acknowledged and increased rate of descent. Passing 12000 ft, we heard TCASII TA and 'monitor rate of descent.' we eased our rate and both looked at TCASII and out the window to see if the previously called traffic was responsible for this alert. Almost immediately, the TCASII issued an RA command to climb, and we saw the target on the TCASII display at 1-2 O'clock crossing right to left 200-300 ft below. First officer started climb as I looked for traffic outside and notified cvg that we were climbing on a TCASII RA. His reply was 'negative, negative, I already told you about that traffic, continue descent.' I was stunned and angry at the same time. I told first officer to continue climb and repeated my initial transmission to cvg. At this time we visually picked up a cessna 172, just crossing beneath our nose, 300-500 ft. He was at about 11500 ft, wbound. Cvg approach control said he painted no such traffic and continued to sound perturbed that we had spoiled his traffic plan. He issued a vector and sent us to the next frequency. On the ground in day, I phoned cvg approach and the supervisor was just as upset as I was. The controller obviously made an erroneous assumption that our TCASII alert was caused by the traffic he was already working. But even if that had been a correct assumption, it would be a very dangerous precedent for him to presume to countermand a TCASII RA.

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Original NASA ASRS Text

Title: ACR X TCASII TA RA HAD NMAC WITH VFR SMA. SEE AND AVOID CONCEPT EVASIVE ACTION TAKEN.

Narrative: ATL TO DAY FLT, WORKING CVG APCH CTL WHILE TRANSITING AND DSNDING INTO DAY AREA. CLRED TO 10000 FT AND ASKED BY CVG TO EXPEDITE THROUGH 11000 FT DUE TO SBOUND COMPANY TFC AT 11000 FT. WE ACKNOWLEDGED AND INCREASED RATE OF DSCNT. PASSING 12000 FT, WE HEARD TCASII TA AND 'MONITOR RATE OF DSCNT.' WE EASED OUR RATE AND BOTH LOOKED AT TCASII AND OUT THE WINDOW TO SEE IF THE PREVIOUSLY CALLED TFC WAS RESPONSIBLE FOR THIS ALERT. ALMOST IMMEDIATELY, THE TCASII ISSUED AN RA COMMAND TO CLB, AND WE SAW THE TARGET ON THE TCASII DISPLAY AT 1-2 O'CLOCK XING R TO L 200-300 FT BELOW. FO STARTED CLB AS I LOOKED FOR TFC OUTSIDE AND NOTIFIED CVG THAT WE WERE CLBING ON A TCASII RA. HIS REPLY WAS 'NEGATIVE, NEGATIVE, I ALREADY TOLD YOU ABOUT THAT TFC, CONTINUE DSCNT.' I WAS STUNNED AND ANGRY AT THE SAME TIME. I TOLD FO TO CONTINUE CLB AND REPEATED MY INITIAL XMISSION TO CVG. AT THIS TIME WE VISUALLY PICKED UP A CESSNA 172, JUST XING BENEATH OUR NOSE, 300-500 FT. HE WAS AT ABOUT 11500 FT, WBOUND. CVG APCH CTL SAID HE PAINTED NO SUCH TFC AND CONTINUED TO SOUND PERTURBED THAT WE HAD SPOILED HIS TFC PLAN. HE ISSUED A VECTOR AND SENT US TO THE NEXT FREQ. ON THE GND IN DAY, I PHONED CVG APCH AND THE SUPVR WAS JUST AS UPSET AS I WAS. THE CTLR OBVIOUSLY MADE AN ERRONEOUS ASSUMPTION THAT OUR TCASII ALERT WAS CAUSED BY THE TFC HE WAS ALREADY WORKING. BUT EVEN IF THAT HAD BEEN A CORRECT ASSUMPTION, IT WOULD BE A VERY DANGEROUS PRECEDENT FOR HIM TO PRESUME TO COUNTERMAND A TCASII RA.

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.