Narrative:

We were talking with final approach control in bna. We were on about an 8 mi final when approach pointed out traffic at 11 O'clock that had shot through the localizer (we were on simultaneous approachs). We told them we were IMC. We were captured on localizer and nearing capturing the GS at 3000 ft. Meanwhile, there was a single engine airplane on an approach that had gone through the localizer. Whether this traffic was on the same runway or the parallel runway was unclr. This single engine traffic was unresponsive to the controller making us very uneasy. We noted on the TCASII, traffic at 9 O'clock less than 1/2 mi 200 ft below us. Seeing that we were about to intercept the GS, we were concerned of descending on either the traffic which shot through the localizer, or the unresponsive single engine aircraft (whichever was at 9 O'clock). About this time, we received an RA from our TCASII to 'climb, climb.' we followed the RA and went missed approach. When talking to the controllers (who were upset), they stated that while doing simultaneous approachs we may receive RA's. The problem is: is the TCASII set up to react correctly on simultaneous approachs or do we ignore the RA's? From my experience, I have never received an RA while IMC shooting simultaneous approachs. It seems something was wrong and unusual with this situation. Callback conversation with reporter revealed the following information: the reporter believes that the targets were both real, but she's not positive. TRACON asked the captain to call when on the ground and TRACON proceeded to give the captain a hard time for going around and messing up their traffic situation. Both light transport pilots were very uncomfortable not knowing where the small aircraft was going. The reporter's air carrier suggests to its pilots that they may turn the TCASII to TA only when in the traffic pattern, a very good temporary solution.

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Original NASA ASRS Text

Title: AN ACR LTT RESPONDED TO A TCASII COMMAND BY MAKING A MISSED APCH.

Narrative: WE WERE TALKING WITH FINAL APCH CTL IN BNA. WE WERE ON ABOUT AN 8 MI FINAL WHEN APCH POINTED OUT TFC AT 11 O'CLOCK THAT HAD SHOT THROUGH THE LOC (WE WERE ON SIMULTANEOUS APCHS). WE TOLD THEM WE WERE IMC. WE WERE CAPTURED ON LOC AND NEARING CAPTURING THE GS AT 3000 FT. MEANWHILE, THERE WAS A SINGLE ENG AIRPLANE ON AN APCH THAT HAD GONE THROUGH THE LOC. WHETHER THIS TFC WAS ON THE SAME RWY OR THE PARALLEL RWY WAS UNCLR. THIS SINGLE ENG TFC WAS UNRESPONSIVE TO THE CTLR MAKING US VERY UNEASY. WE NOTED ON THE TCASII, TFC AT 9 O'CLOCK LESS THAN 1/2 MI 200 FT BELOW US. SEEING THAT WE WERE ABOUT TO INTERCEPT THE GS, WE WERE CONCERNED OF DSNDING ON EITHER THE TFC WHICH SHOT THROUGH THE LOC, OR THE UNRESPONSIVE SINGLE ENG ACFT (WHICHEVER WAS AT 9 O'CLOCK). ABOUT THIS TIME, WE RECEIVED AN RA FROM OUR TCASII TO 'CLB, CLB.' WE FOLLOWED THE RA AND WENT MISSED APCH. WHEN TALKING TO THE CTLRS (WHO WERE UPSET), THEY STATED THAT WHILE DOING SIMULTANEOUS APCHS WE MAY RECEIVE RA'S. THE PROB IS: IS THE TCASII SET UP TO REACT CORRECTLY ON SIMULTANEOUS APCHS OR DO WE IGNORE THE RA'S? FROM MY EXPERIENCE, I HAVE NEVER RECEIVED AN RA WHILE IMC SHOOTING SIMULTANEOUS APCHS. IT SEEMS SOMETHING WAS WRONG AND UNUSUAL WITH THIS SIT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR BELIEVES THAT THE TARGETS WERE BOTH REAL, BUT SHE'S NOT POSITIVE. TRACON ASKED THE CAPT TO CALL WHEN ON THE GND AND TRACON PROCEEDED TO GIVE THE CAPT A HARD TIME FOR GOING AROUND AND MESSING UP THEIR TFC SIT. BOTH LTT PLTS WERE VERY UNCOMFORTABLE NOT KNOWING WHERE THE SMA WAS GOING. THE RPTR'S ACR SUGGESTS TO ITS PLTS THAT THEY MAY TURN THE TCASII TO TA ONLY WHEN IN THE TFC PATTERN, A VERY GOOD TEMPORARY SOLUTION.

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.