Narrative:

We were inbound to atl on the ERLIN2 arrival; expecting runway 8L. We had to comply with a TCAS RA that we believe truly saved our lives. We were approximately 8-9 mi nne of atl being vectored by atl approach. We were heading south; level at 6000 ft. Approach gave us a normal vector to turn right to heading of 210 degrees and descend and maintain 5000 ft. We began the turn and descent simultaneously. I mentioned to the first officer; who was flying; that there seemed to be an aircraft in our 10 O'clock position moving right to left on TCAS (their heading approximately 280 degrees). This aircraft was approximately 2.5 - 3 mi away at the time; closing somewhat rapidly; and seemed to be at 5000 ft and on a collision course with us; but showed a down arrow indicating they were descending at at least 500 FPM. Our descent was rather slow; but we did notice that our altitude and the TCAS indicated altitude for the other aircraft did show that we were coming together. I thought this was strange; as they should have been descending at the same rate we were; since they never lost the downward arrow indicating at least 500 FPM. I mentioned immediately to the first officer again that something with this other aircraft was not right; and that we may have to very shortly avoid this aircraft. As I mentioned this; the aircraft was approximately 1.5 - 2 mi and on a collision course with us from right to left only 500 ft below us. We were approximately 300 ft from leveling off and we received an RA which we immediately complied with. I immediately took the controls as briefed with the first officer and initiated a level off. The TCAS RA was indicating on the vsi for us to maintain between level to -200 FPM descent at most. At that very moment; the first officer and I noticed that the other aircraft's position on the TCAS smallest 2.5 mi ring was exactly on the crosshairs of our aircraft; and was a red box displaying '00.' I immediately initiated a climb to avoid this aircraft. Keep in mind that we were IMC and could see absolutely nothing. As this was happening; ATC was notified and they said 'ok; comply with RA; and you can level off at 6000 ft.' we did so and began to see our altitude separate from this aircraft as we climbed and watched this aircraft continue on same path. ATC then vectored us further in both direction and altitude for the approach. We were then xferred to tower on 119.1 for final control to an uneventful landing. Once at the gate; I called and began to query supervisor of what had just happened. He first stated that they had already begun to pull the tapes and that they would be looking into what had happened. He then asked me how close I felt the aircraft had come. I explained that we were IMC the whole time; but that I thought for a brief moment we were at the same altitude and would have hit if we hadn't initiated a climb; and that we were within 100 ft or so from the other aircraft. Cannot remember exact words; but we were finally calm and in a state that we felt we could call. The supervisor confirmed that we were on a heading of 210 degrees descending from 6000 ft to 5000 ft; and that the controller working the flight possibly gave the other aircraft a l-hand turn vector earlier to heading 160 degrees that they did not comply with. And that if the other aircraft had turned as previously instructed earlier; they would not have been on a collision course with us. I explained that this controller did not seem frazzled or alarmed by our RA; and then paused for a little bit. Then after a moment; thanked us each time he made communication with us for a new vector/instruction. We believe that the other aircraft was an MD88 and that ATC had once before and once after the event tried to contact this aircraft without hearing a readback. None of the attempts to contact this aircraft that we heard; did we hear a readback; no was there any reference to us on their heading; etc. It was as if ATC was oblivious to the whole thing. Only after we said we were complying with an RA; and approximately 20-25 seconds had lapsed; do we believe anything had sunk in with ATC. We say this because at that time the controller started thanking us.

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Original NASA ASRS Text

Title: CARJ FLT CREW; WITH A80; EXPERIENCED NMAC BTWN 5000 FT AND 6000 FT WHILE DSNDING INTO ATL.

Narrative: WE WERE INBOUND TO ATL ON THE ERLIN2 ARR; EXPECTING RWY 8L. WE HAD TO COMPLY WITH A TCAS RA THAT WE BELIEVE TRULY SAVED OUR LIVES. WE WERE APPROX 8-9 MI NNE OF ATL BEING VECTORED BY ATL APCH. WE WERE HEADING S; LEVEL AT 6000 FT. APCH GAVE US A NORMAL VECTOR TO TURN R TO HDG OF 210 DEGS AND DSND AND MAINTAIN 5000 FT. WE BEGAN THE TURN AND DSCNT SIMULTANEOUSLY. I MENTIONED TO THE FO; WHO WAS FLYING; THAT THERE SEEMED TO BE AN ACFT IN OUR 10 O'CLOCK POS MOVING R TO L ON TCAS (THEIR HDG APPROX 280 DEGS). THIS ACFT WAS APPROX 2.5 - 3 MI AWAY AT THE TIME; CLOSING SOMEWHAT RAPIDLY; AND SEEMED TO BE AT 5000 FT AND ON A COLLISION COURSE WITH US; BUT SHOWED A DOWN ARROW INDICATING THEY WERE DSNDING AT AT LEAST 500 FPM. OUR DSCNT WAS RATHER SLOW; BUT WE DID NOTICE THAT OUR ALT AND THE TCAS INDICATED ALT FOR THE OTHER ACFT DID SHOW THAT WE WERE COMING TOGETHER. I THOUGHT THIS WAS STRANGE; AS THEY SHOULD HAVE BEEN DSNDING AT THE SAME RATE WE WERE; SINCE THEY NEVER LOST THE DOWNWARD ARROW INDICATING AT LEAST 500 FPM. I MENTIONED IMMEDIATELY TO THE FO AGAIN THAT SOMETHING WITH THIS OTHER ACFT WAS NOT RIGHT; AND THAT WE MAY HAVE TO VERY SHORTLY AVOID THIS ACFT. AS I MENTIONED THIS; THE ACFT WAS APPROX 1.5 - 2 MI AND ON A COLLISION COURSE WITH US FROM R TO L ONLY 500 FT BELOW US. WE WERE APPROX 300 FT FROM LEVELING OFF AND WE RECEIVED AN RA WHICH WE IMMEDIATELY COMPLIED WITH. I IMMEDIATELY TOOK THE CTLS AS BRIEFED WITH THE FO AND INITIATED A LEVEL OFF. THE TCAS RA WAS INDICATING ON THE VSI FOR US TO MAINTAIN BTWN LEVEL TO -200 FPM DSCNT AT MOST. AT THAT VERY MOMENT; THE FO AND I NOTICED THAT THE OTHER ACFT'S POS ON THE TCAS SMALLEST 2.5 MI RING WAS EXACTLY ON THE CROSSHAIRS OF OUR ACFT; AND WAS A RED BOX DISPLAYING '00.' I IMMEDIATELY INITIATED A CLB TO AVOID THIS ACFT. KEEP IN MIND THAT WE WERE IMC AND COULD SEE ABSOLUTELY NOTHING. AS THIS WAS HAPPENING; ATC WAS NOTIFIED AND THEY SAID 'OK; COMPLY WITH RA; AND YOU CAN LEVEL OFF AT 6000 FT.' WE DID SO AND BEGAN TO SEE OUR ALT SEPARATE FROM THIS ACFT AS WE CLBED AND WATCHED THIS ACFT CONTINUE ON SAME PATH. ATC THEN VECTORED US FURTHER IN BOTH DIRECTION AND ALT FOR THE APCH. WE WERE THEN XFERRED TO TWR ON 119.1 FOR FINAL CTL TO AN UNEVENTFUL LNDG. ONCE AT THE GATE; I CALLED AND BEGAN TO QUERY SUPVR OF WHAT HAD JUST HAPPENED. HE FIRST STATED THAT THEY HAD ALREADY BEGUN TO PULL THE TAPES AND THAT THEY WOULD BE LOOKING INTO WHAT HAD HAPPENED. HE THEN ASKED ME HOW CLOSE I FELT THE ACFT HAD COME. I EXPLAINED THAT WE WERE IMC THE WHOLE TIME; BUT THAT I THOUGHT FOR A BRIEF MOMENT WE WERE AT THE SAME ALT AND WOULD HAVE HIT IF WE HADN'T INITIATED A CLB; AND THAT WE WERE WITHIN 100 FT OR SO FROM THE OTHER ACFT. CANNOT REMEMBER EXACT WORDS; BUT WE WERE FINALLY CALM AND IN A STATE THAT WE FELT WE COULD CALL. THE SUPVR CONFIRMED THAT WE WERE ON A HDG OF 210 DEGS DSNDING FROM 6000 FT TO 5000 FT; AND THAT THE CTLR WORKING THE FLT POSSIBLY GAVE THE OTHER ACFT A L-HAND TURN VECTOR EARLIER TO HDG 160 DEGS THAT THEY DID NOT COMPLY WITH. AND THAT IF THE OTHER ACFT HAD TURNED AS PREVIOUSLY INSTRUCTED EARLIER; THEY WOULD NOT HAVE BEEN ON A COLLISION COURSE WITH US. I EXPLAINED THAT THIS CTLR DID NOT SEEM FRAZZLED OR ALARMED BY OUR RA; AND THEN PAUSED FOR A LITTLE BIT. THEN AFTER A MOMENT; THANKED US EACH TIME HE MADE COM WITH US FOR A NEW VECTOR/INSTRUCTION. WE BELIEVE THAT THE OTHER ACFT WAS AN MD88 AND THAT ATC HAD ONCE BEFORE AND ONCE AFTER THE EVENT TRIED TO CONTACT THIS ACFT WITHOUT HEARING A READBACK. NONE OF THE ATTEMPTS TO CONTACT THIS ACFT THAT WE HEARD; DID WE HEAR A READBACK; NO WAS THERE ANY REF TO US ON THEIR HDG; ETC. IT WAS AS IF ATC WAS OBLIVIOUS TO THE WHOLE THING. ONLY AFTER WE SAID WE WERE COMPLYING WITH AN RA; AND APPROX 20-25 SECONDS HAD LAPSED; DO WE BELIEVE ANYTHING HAD SUNK IN WITH ATC. WE SAY THIS BECAUSE AT THAT TIME THE CTLR STARTED THANKING US.

Data retrieved from NASA's ASRS site as of January 2009 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.