Narrative:

Our aircraft was on the RMG2 arrival into atl, proceeding direct to atl at the time. Traffic congestion was extremely heavy, with numerous proximate targets shown on the TCASII display. We had been given a descent and had leveled off at 11000 ft in preparation for further descent/approach to atl runway 26R. Communications chatter was heavy. We heard the approach controller call us once, but was unable to have him hear our reply transmission (presumably because of being stepped on by other aircraft). Our TCASII system activated with the 'traffic,' callout. We were searching for the target aircraft. When we finally established communications with the controller, he indicated that this was his third attempt to contact us. We were given a vector to fly, and complied with the instruction. At about that time, TCASII announced 'monitor vertical speed' and indicated for us to maintain our altitude and not to descend. We noted an MD80 passing well off our left wing and TCASII indicated the aircraft was 600 ft below us. Almost immediately after that, TCASII announced 'clear of conflict.' there was no evasive action taken by either aircraft, and it appeared that both aircraft complied with the controller's instructions. I believe that many contributing factors could be found including typical atl airport congestion, rapid controller instructions, poor communications discipline by pilots (stepping on each other), atl approach/departure plans (the opposing aircraft should not be given an instruction to climb to 14000 ft until the arrival aircraft is altitude restr or separated horizontally -- not merely 'expected to be' in this operating environment).

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Original NASA ASRS Text

Title: A DC10 FLT CREW RECEIVE A TCASII ALERT WHILE APCHING ATL. FLT CREW CONCERNED WITH APCH TFC VOLUME AND CONGESTION.

Narrative: OUR ACFT WAS ON THE RMG2 ARR INTO ATL, PROCEEDING DIRECT TO ATL AT THE TIME. TFC CONGESTION WAS EXTREMELY HVY, WITH NUMEROUS PROXIMATE TARGETS SHOWN ON THE TCASII DISPLAY. WE HAD BEEN GIVEN A DSCNT AND HAD LEVELED OFF AT 11000 FT IN PREPARATION FOR FURTHER DSCNT/APCH TO ATL RWY 26R. COMS CHATTER WAS HVY. WE HEARD THE APCH CTLR CALL US ONCE, BUT WAS UNABLE TO HAVE HIM HEAR OUR REPLY XMISSION (PRESUMABLY BECAUSE OF BEING STEPPED ON BY OTHER ACFT). OUR TCASII SYS ACTIVATED WITH THE 'TFC,' CALLOUT. WE WERE SEARCHING FOR THE TARGET ACFT. WHEN WE FINALLY ESTABLISHED COMS WITH THE CTLR, HE INDICATED THAT THIS WAS HIS THIRD ATTEMPT TO CONTACT US. WE WERE GIVEN A VECTOR TO FLY, AND COMPLIED WITH THE INSTRUCTION. AT ABOUT THAT TIME, TCASII ANNOUNCED 'MONITOR VERT SPD' AND INDICATED FOR US TO MAINTAIN OUR ALT AND NOT TO DSND. WE NOTED AN MD80 PASSING WELL OFF OUR L WING AND TCASII INDICATED THE ACFT WAS 600 FT BELOW US. ALMOST IMMEDIATELY AFTER THAT, TCASII ANNOUNCED 'CLR OF CONFLICT.' THERE WAS NO EVASIVE ACTION TAKEN BY EITHER ACFT, AND IT APPEARED THAT BOTH ACFT COMPLIED WITH THE CTLR'S INSTRUCTIONS. I BELIEVE THAT MANY CONTRIBUTING FACTORS COULD BE FOUND INCLUDING TYPICAL ATL ARPT CONGESTION, RAPID CTLR INSTRUCTIONS, POOR COMS DISCIPLINE BY PLTS (STEPPING ON EACH OTHER), ATL APCH/DEP PLANS (THE OPPOSING ACFT SHOULD NOT BE GIVEN AN INSTRUCTION TO CLB TO 14000 FT UNTIL THE ARR ACFT IS ALT RESTR OR SEPARATED HORIZLY -- NOT MERELY 'EXPECTED TO BE' IN THIS OPERATING ENVIRONMENT).

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.