Narrative:

On jul/xx/94 during descent into cmh we received an RA on the TCASII. The type of aircraft I was flying was a bae 800. The chain of events are as follows. We arrived into cmh approach control airspace from over bremn intersection at 10000 ft. Upon contacting approach we were cleared direct to sumie locator (cm NDB) and to descend to 6000 ft. During this descent we were instructed to contact approach on 118.2. After coming up on 118.2 the controller was very busy with other aircraft, 2 of which seemed to be having a separation conflict. My first officer attempted to contact the controller at least 2 times but was unsuccessful. As we were approaching our assigned altitude of 6000 ft we noticed rapidly converging traffic at our altitude on the TCASII. At this point we were still unable to talk to the approach controller due to frequency congestion. A TA was given from the TCASII. Shortly following the TA we were able to pick the aircraft up visually. A few seconds after we saw the traffic the TCASII gave us an RA. Due to the close proximity of the other aircraft the RA had to be followed. I initiated a climb and received a clear of conflict message at approximately 6800 ft. Contact with the controller was finally made and he cleared us back to 6000 ft on a 270 degree heading. We were then vectored for the approach. The other aircraft turned out to be a DC9. He received an RA as well and initiated a descent. After a phone conversation with the TRACON supervisor it was determined that the situation developed due to controller planning. The TRACON supervisor did mention that the 2 aircraft ahead of us did in fact have a separation conflict and that they both had to abort their approach. It was this situation that diverted the controller's attention from realizing that the DC9 and my aircraft were on a collision course at the same altitude. The TCASII performed exactly as advertised and prevented a midair collision.

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Original NASA ASRS Text

Title: FLC OF A CPR ATX JET STOPPED DSCNT AND CLBED IF RESPONSE TO A TCASII RA.

Narrative: ON JUL/XX/94 DURING DSCNT INTO CMH WE RECEIVED AN RA ON THE TCASII. THE TYPE OF ACFT I WAS FLYING WAS A BAE 800. THE CHAIN OF EVENTS ARE AS FOLLOWS. WE ARRIVED INTO CMH APCH CTL AIRSPACE FROM OVER BREMN INTXN AT 10000 FT. UPON CONTACTING APCH WE WERE CLRED DIRECT TO SUMIE LOCATOR (CM NDB) AND TO DSND TO 6000 FT. DURING THIS DSCNT WE WERE INSTRUCTED TO CONTACT APCH ON 118.2. AFTER COMING UP ON 118.2 THE CTLR WAS VERY BUSY WITH OTHER ACFT, 2 OF WHICH SEEMED TO BE HAVING A SEPARATION CONFLICT. MY FO ATTEMPTED TO CONTACT THE CTLR AT LEAST 2 TIMES BUT WAS UNSUCCESSFUL. AS WE WERE APCHING OUR ASSIGNED ALT OF 6000 FT WE NOTICED RAPIDLY CONVERGING TFC AT OUR ALT ON THE TCASII. AT THIS POINT WE WERE STILL UNABLE TO TALK TO THE APCH CTLR DUE TO FREQ CONGESTION. A TA WAS GIVEN FROM THE TCASII. SHORTLY FOLLOWING THE TA WE WERE ABLE TO PICK THE ACFT UP VISUALLY. A FEW SECONDS AFTER WE SAW THE TFC THE TCASII GAVE US AN RA. DUE TO THE CLOSE PROX OF THE OTHER ACFT THE RA HAD TO BE FOLLOWED. I INITIATED A CLB AND RECEIVED A CLR OF CONFLICT MESSAGE AT APPROX 6800 FT. CONTACT WITH THE CTLR WAS FINALLY MADE AND HE CLRED US BACK TO 6000 FT ON A 270 DEG HDG. WE WERE THEN VECTORED FOR THE APCH. THE OTHER ACFT TURNED OUT TO BE A DC9. HE RECEIVED AN RA AS WELL AND INITIATED A DSCNT. AFTER A PHONE CONVERSATION WITH THE TRACON SUPVR IT WAS DETERMINED THAT THE SIT DEVELOPED DUE TO CTLR PLANNING. THE TRACON SUPVR DID MENTION THAT THE 2 ACFT AHEAD OF US DID IN FACT HAVE A SEPARATION CONFLICT AND THAT THEY BOTH HAD TO ABORT THEIR APCH. IT WAS THIS SIT THAT DIVERTED THE CTLR'S ATTN FROM REALIZING THAT THE DC9 AND MY ACFT WERE ON A COLLISION COURSE AT THE SAME ALT. THE TCASII PERFORMED EXACTLY AS ADVERTISED AND PREVENTED A MIDAIR COLLISION.

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.