Narrative:

Air carrier X was being handled by atl approach control and being flown by the first officer. Autoplt was engaged and we were on a downwind leg for runway 9R on a 280 degree heading. Initially, our assigned altitude was 7000 ft, but while descending out of about 8500 ft, the controller amended our altitude assignment to 8000 ft, which we complied with. This amendment caused us to be wary of conflicting traffic. Almost immediately, we received a TA on our TCASII, about our 10 O'clock position on a converging course and descending toward our altitude. About the time the captain spotted the traffic visually, we received a TCASII RA commanding a descent. I disconnected the autoplt and began a descent to comply with the RA. At virtually the same time I began the descent, the controller directed us to turn to a 300 degree heading and gave the converging air carrier Y a left turn to a 250 degree heading and told him to stop his descent. I immediately complied as did air carrier Y. The RA ceased and a 'clear of conflict' was heard. We had only descended about 200 ft. Upon landing the captain called approach control whereupon he learned that air carrier Y inbound from the southwest had been cleared to 5000 ft and that according to approach's radar we had come within 1.2 mi and 200 ft altitude separation of the other aircraft. Supplemental information from acn 250159: phone call to atl approach control supervisor. The supervisor informed me that he had 'pulled the tapes' and his initial observation of them confirmed my aircraft's actions as well as those of the conflicting traffic. However, he stated that he had not had time to thoroughly analyze the tapes. The supervisor then said that he would be filing an 'operational error report' due to the close proximity of aircraft involved. The supervisor informed me that the 'tapes showed the aircraft to be separated 1.2 mi horizontally and 200 ft vertically.' our courses were definitely converging and evasive action was required to avoid a 'near hit.' that widebody transport looked pretty impressive up until the time that our courses began to diverge.

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Original NASA ASRS Text

Title: ACR X TCASII RA SAME ALT ASSIGNED HAD LTSS FROM ACR Y. SYS ERROR.

Narrative: ACR X WAS BEING HANDLED BY ATL APCH CTL AND BEING FLOWN BY THE FO. AUTOPLT WAS ENGAGED AND WE WERE ON A DOWNWIND LEG FOR RWY 9R ON A 280 DEG HDG. INITIALLY, OUR ASSIGNED ALT WAS 7000 FT, BUT WHILE DSNDING OUT OF ABOUT 8500 FT, THE CTLR AMENDED OUR ALT ASSIGNMENT TO 8000 FT, WHICH WE COMPLIED WITH. THIS AMENDMENT CAUSED US TO BE WARY OF CONFLICTING TFC. ALMOST IMMEDIATELY, WE RECEIVED A TA ON OUR TCASII, ABOUT OUR 10 O'CLOCK POS ON A CONVERGING COURSE AND DSNDING TOWARD OUR ALT. ABOUT THE TIME THE CAPT SPOTTED THE TFC VISUALLY, WE RECEIVED A TCASII RA COMMANDING A DSCNT. I DISCONNECTED THE AUTOPLT AND BEGAN A DSCNT TO COMPLY WITH THE RA. AT VIRTUALLY THE SAME TIME I BEGAN THE DSCNT, THE CTLR DIRECTED US TO TURN TO A 300 DEG HDG AND GAVE THE CONVERGING ACR Y A L TURN TO A 250 DEG HDG AND TOLD HIM TO STOP HIS DSCNT. I IMMEDIATELY COMPLIED AS DID ACR Y. THE RA CEASED AND A 'CLR OF CONFLICT' WAS HEARD. WE HAD ONLY DSNDED ABOUT 200 FT. UPON LNDG THE CAPT CALLED APCH CTL WHEREUPON HE LEARNED THAT ACR Y INBOUND FROM THE SW HAD BEEN CLRED TO 5000 FT AND THAT ACCORDING TO APCH'S RADAR WE HAD COME WITHIN 1.2 MI AND 200 FT ALT SEPARATION OF THE OTHER ACFT. SUPPLEMENTAL INFO FROM ACN 250159: PHONE CALL TO ATL APCH CTL SUPVR. THE SUPVR INFORMED ME THAT HE HAD 'PULLED THE TAPES' AND HIS INITIAL OBSERVATION OF THEM CONFIRMED MY ACFT'S ACTIONS AS WELL AS THOSE OF THE CONFLICTING TFC. HOWEVER, HE STATED THAT HE HAD NOT HAD TIME TO THOROUGHLY ANALYZE THE TAPES. THE SUPVR THEN SAID THAT HE WOULD BE FILING AN 'OPERROR RPT' DUE TO THE CLOSE PROX OF ACFT INVOLVED. THE SUPVR INFORMED ME THAT THE 'TAPES SHOWED THE ACFT TO BE SEPARATED 1.2 MI HORIZLY AND 200 FT VERTICALLY.' OUR COURSES WERE DEFINITELY CONVERGING AND EVASIVE ACTION WAS REQUIRED TO AVOID A 'NEAR HIT.' THAT WDB LOOKED PRETTY IMPRESSIVE UP UNTIL THE TIME THAT OUR COURSES BEGAN TO DIVERGE.

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.