Narrative:

Bna approach gave air carrier X a heading and a descent to an altitude we understood to be 5000 ft MSL. Approach control advised an air carrier Y of our position and assigned altitude, which the controller said was 8000 ft MSL. We heard this on the radio and broke into say 'negative, we're cleared to 5000 ft MSL.' there was no conflict and approach control did not alter our course and altitude into bna. (When the approach controller told the commuter we were assigned 8000 ft MSL. We were approximately 6000 ft MSL descending to 5000 ft MSL.) supplemental information from acn 299434: pilot asked approach what altitude the X jet (I assumed to be us) was descending to. Approach said 8000 ft to which I immediately responded we were cleared to 5000 ft, the altitude in our reminder window. Approach asked the pilot if he could maintain visual separation on us and he said yes. At this time I noticed that one of the several targets on our TCASII screen was 2-3 mi behind and 200 ft above us. I assume this was the flight at 6000 ft and that we must have descended through his altitude in front of him. We never got any TCASII advisories nor received any heading or altitude changes from approach during this time and both aircraft continued to bna and landed. After arrival I called approach on the phone and explained that to the best of our knowledge we believed our clearance was to 5000 ft not 8000 ft. I was told 'there's not going to be a problem as long as you don't change your story' which I didn't understand.

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Original NASA ASRS Text

Title: ALT DEV ACR X DSCNT TO WRONG ALT THROUGH OCCUPIED ALT OF ACR Y.

Narrative: BNA APCH GAVE ACR X A HDG AND A DSCNT TO AN ALT WE UNDERSTOOD TO BE 5000 FT MSL. APCH CTL ADVISED AN ACR Y OF OUR POS AND ASSIGNED ALT, WHICH THE CTLR SAID WAS 8000 FT MSL. WE HEARD THIS ON THE RADIO AND BROKE INTO SAY 'NEGATIVE, WE'RE CLRED TO 5000 FT MSL.' THERE WAS NO CONFLICT AND APCH CTL DID NOT ALTER OUR COURSE AND ALT INTO BNA. (WHEN THE APCH CTLR TOLD THE COMMUTER WE WERE ASSIGNED 8000 FT MSL. WE WERE APPROX 6000 FT MSL DSNDING TO 5000 FT MSL.) SUPPLEMENTAL INFO FROM ACN 299434: PLT ASKED APCH WHAT ALT THE X JET (I ASSUMED TO BE US) WAS DSNDING TO. APCH SAID 8000 FT TO WHICH I IMMEDIATELY RESPONDED WE WERE CLRED TO 5000 FT, THE ALT IN OUR REMINDER WINDOW. APCH ASKED THE PLT IF HE COULD MAINTAIN VISUAL SEPARATION ON US AND HE SAID YES. AT THIS TIME I NOTICED THAT ONE OF THE SEVERAL TARGETS ON OUR TCASII SCREEN WAS 2-3 MI BEHIND AND 200 FT ABOVE US. I ASSUME THIS WAS THE FLT AT 6000 FT AND THAT WE MUST HAVE DSNDED THROUGH HIS ALT IN FRONT OF HIM. WE NEVER GOT ANY TCASII ADVISORIES NOR RECEIVED ANY HDG OR ALT CHANGES FROM APCH DURING THIS TIME AND BOTH ACFT CONTINUED TO BNA AND LANDED. AFTER ARR I CALLED APCH ON THE PHONE AND EXPLAINED THAT TO THE BEST OF OUR KNOWLEDGE WE BELIEVED OUR CLRNC WAS TO 5000 FT NOT 8000 FT. I WAS TOLD 'THERE'S NOT GOING TO BE A PROB AS LONG AS YOU DON'T CHANGE YOUR STORY' WHICH I DIDN'T UNDERSTAND.

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.