Narrative:

Another feather in TCASII's hat, and with it, a feather in the hat of the new TCASII RA procedures. It saved our necks! On GHM4 arrival into bna, inbound on the 066 degree radial from bna. Approach control cleared us to descend from 11000 ft MSL (after ghm) to 3000 ft MSL. The first officer flying, I acknowledged the descent clearance to 3000 ft. The observer on the jump seat (first officer name) was on headset and confirmed our clearance to descend to 3000 ft. Passing approximately 5500 ft, the first officer and I both heard bad english voice trying to check-in on frequency as he was departing bna. Approach control did not acknowledge his call and simultaneously, we both observed a target on our TCASII ascending from approximately 1500 ft below us and directly at us. As we discussed the need to query approach control about the target, and as we were descending through 4800 ft, another carrier asked about traffic descending in front of them (they were inquiring about us). Immediately, 3 things happened: 1) we got a 'descend' TCASII RA, 2) ATC calls us to climb immediately to 6000 ft and turn to a heading of 030 degrees, and 3) the other carrier transmits they are turning left to avoid us. Immediately, myself, the first officer and observer obtain visual contact with the other carrier in a turn. The first officer turns to 030 degree heading and initially levels, then continues to descend to comply with the RA. I direct a descent while telling approach control that we will not be climbing but descending to comply with the RA. Immediately, next, the RA clears, a new controller is heard and we tell him we are continuing our clearance to descend to 3000 ft. Approach control asks us if we had previously been cleared to 3000 ft and we affirm it. He then confirms our descent clearance to 3000 ft and continues to control us to an uneventful landing. The other carrier is heard to say that they will be filing an incident report. Upon discussion with approach control, supervisor (name) after landing, he confirmed that after listening to the tapes, we were indeed cleared to 3000 ft and apologized for this controller. The first officer, observer and I all agreed that the controller's preoccupation with a small VFR aircraft trying to check-in, preempted his attention to 1) the other carrier who tried to check-in twice before the incident, and 2) us, which he had given a non-standard clearance to. (I was told subsequent to the incident that the initial standard descent clearance issued by approach control upon check-in on arrival is to 6000 ft to avoid the standard departure clearance of 5000 ft.) I believe we as a crew could really have done nothing more than we did and we appreciate the new TCASII RA procedures for making our decision not to comply with ATC a 'no brainer.' kudos to the first officer and observer! My only recommendation here would be that since the standard departure clearance is 5000 ft, then it would be prudent to put an 'at or above 6000 ft' restr on all the arrs until 10 DME. This would ensure the compliance by all aircraft inbound to deconflict with departures and puts an extra requirement to cancel the altitude restr to approach control if the traffic is light. This will insure that if approach is busy or there is a radio problem, there still will be deconfliction. Supplemental information from acn 627524: after receiving radio and radar contact I descended the B737 from 11000 ft to, what I thought I said, 6000 ft. After talking to other aircraft, and while the B747 was trying to check in after a few attempts, the departure radar east controller had observed the B737 descending through 5900 ft and asked me if he had (B737) broken his altitude. I observed the 2 aircraft in proximity and issued a traffic alert and instructed the B737 to climb immediately to 6000 ft and called traffic. The B737 crew advised that they were responding to an RA and would descend. After the aircraft diverged I asked the B737 crew if I had assigned 3000 ft instead of 6000 ft. He replied to the affirmative. After reviewing the recordings it was determined that I did in fact assign 3000 ft.

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Original NASA ASRS Text

Title: A B737 FLT CREW IS GIVEN THE WRONG ALT BY BNA TRACON WHICH RESULTS IN A TCASII RA.

Narrative: ANOTHER FEATHER IN TCASII'S HAT, AND WITH IT, A FEATHER IN THE HAT OF THE NEW TCASII RA PROCS. IT SAVED OUR NECKS! ON GHM4 ARR INTO BNA, INBOUND ON THE 066 DEG RADIAL FROM BNA. APCH CTL CLRED US TO DSND FROM 11000 FT MSL (AFTER GHM) TO 3000 FT MSL. THE FO FLYING, I ACKNOWLEDGED THE DSCNT CLRNC TO 3000 FT. THE OBSERVER ON THE JUMP SEAT (FO NAME) WAS ON HEADSET AND CONFIRMED OUR CLRNC TO DSND TO 3000 FT. PASSING APPROX 5500 FT, THE FO AND I BOTH HEARD BAD ENGLISH VOICE TRYING TO CHK-IN ON FREQ AS HE WAS DEPARTING BNA. APCH CTL DID NOT ACKNOWLEDGE HIS CALL AND SIMULTANEOUSLY, WE BOTH OBSERVED A TARGET ON OUR TCASII ASCENDING FROM APPROX 1500 FT BELOW US AND DIRECTLY AT US. AS WE DISCUSSED THE NEED TO QUERY APCH CTL ABOUT THE TARGET, AND AS WE WERE DSNDING THROUGH 4800 FT, ANOTHER CARRIER ASKED ABOUT TFC DSNDING IN FRONT OF THEM (THEY WERE INQUIRING ABOUT US). IMMEDIATELY, 3 THINGS HAPPENED: 1) WE GOT A 'DSND' TCASII RA, 2) ATC CALLS US TO CLB IMMEDIATELY TO 6000 FT AND TURN TO A HDG OF 030 DEGS, AND 3) THE OTHER CARRIER XMITS THEY ARE TURNING L TO AVOID US. IMMEDIATELY, MYSELF, THE FO AND OBSERVER OBTAIN VISUAL CONTACT WITH THE OTHER CARRIER IN A TURN. THE FO TURNS TO 030 DEG HDG AND INITIALLY LEVELS, THEN CONTINUES TO DSND TO COMPLY WITH THE RA. I DIRECT A DSCNT WHILE TELLING APCH CTL THAT WE WILL NOT BE CLBING BUT DSNDING TO COMPLY WITH THE RA. IMMEDIATELY, NEXT, THE RA CLRS, A NEW CTLR IS HEARD AND WE TELL HIM WE ARE CONTINUING OUR CLRNC TO DSND TO 3000 FT. APCH CTL ASKS US IF WE HAD PREVIOUSLY BEEN CLRED TO 3000 FT AND WE AFFIRM IT. HE THEN CONFIRMS OUR DSCNT CLRNC TO 3000 FT AND CONTINUES TO CTL US TO AN UNEVENTFUL LNDG. THE OTHER CARRIER IS HEARD TO SAY THAT THEY WILL BE FILING AN INCIDENT RPT. UPON DISCUSSION WITH APCH CTL, SUPVR (NAME) AFTER LNDG, HE CONFIRMED THAT AFTER LISTENING TO THE TAPES, WE WERE INDEED CLRED TO 3000 FT AND APOLOGIZED FOR THIS CTLR. THE FO, OBSERVER AND I ALL AGREED THAT THE CTLR'S PREOCCUPATION WITH A SMALL VFR ACFT TRYING TO CHK-IN, PREEMPTED HIS ATTN TO 1) THE OTHER CARRIER WHO TRIED TO CHK-IN TWICE BEFORE THE INCIDENT, AND 2) US, WHICH HE HAD GIVEN A NON-STANDARD CLRNC TO. (I WAS TOLD SUBSEQUENT TO THE INCIDENT THAT THE INITIAL STANDARD DSCNT CLRNC ISSUED BY APCH CTL UPON CHK-IN ON ARR IS TO 6000 FT TO AVOID THE STANDARD DEP CLRNC OF 5000 FT.) I BELIEVE WE AS A CREW COULD REALLY HAVE DONE NOTHING MORE THAN WE DID AND WE APPRECIATE THE NEW TCASII RA PROCS FOR MAKING OUR DECISION NOT TO COMPLY WITH ATC A 'NO BRAINER.' KUDOS TO THE FO AND OBSERVER! MY ONLY RECOMMENDATION HERE WOULD BE THAT SINCE THE STANDARD DEP CLRNC IS 5000 FT, THEN IT WOULD BE PRUDENT TO PUT AN 'AT OR ABOVE 6000 FT' RESTR ON ALL THE ARRS UNTIL 10 DME. THIS WOULD ENSURE THE COMPLIANCE BY ALL ACFT INBOUND TO DECONFLICT WITH DEPS AND PUTS AN EXTRA REQUIREMENT TO CANCEL THE ALT RESTR TO APCH CTL IF THE TFC IS LIGHT. THIS WILL INSURE THAT IF APCH IS BUSY OR THERE IS A RADIO PROB, THERE STILL WILL BE DECONFLICTION. SUPPLEMENTAL INFO FROM ACN 627524: AFTER RECEIVING RADIO AND RADAR CONTACT I DSNDED THE B737 FROM 11000 FT TO, WHAT I THOUGHT I SAID, 6000 FT. AFTER TALKING TO OTHER ACFT, AND WHILE THE B747 WAS TRYING TO CHK IN AFTER A FEW ATTEMPTS, THE DEP RADAR E CTLR HAD OBSERVED THE B737 DSNDING THROUGH 5900 FT AND ASKED ME IF HE HAD (B737) BROKEN HIS ALT. I OBSERVED THE 2 ACFT IN PROX AND ISSUED A TFC ALERT AND INSTRUCTED THE B737 TO CLB IMMEDIATELY TO 6000 FT AND CALLED TFC. THE B737 CREW ADVISED THAT THEY WERE RESPONDING TO AN RA AND WOULD DSND. AFTER THE ACFT DIVERGED I ASKED THE B737 CREW IF I HAD ASSIGNED 3000 FT INSTEAD OF 6000 FT. HE REPLIED TO THE AFFIRMATIVE. AFTER REVIEWING THE RECORDINGS IT WAS DETERMINED THAT I DID IN FACT ASSIGN 3000 FT.

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.