Narrative:

I had just descended from FL450 to an assigned altitude of I believe 9000 ft and was on a heading of 060 degrees approximately 7 mi east of brd. We advised that we had brd 'in sight' and queried ATC as to our heading and if they still wanted us on that heading as we were beginning to pass the airport heading northeast. The controller responded by asking us if we had the NOTAMS for brd. This caused a bit of consternation on my part as it is nonstandard to query about NOTAMS and I was concerned that ATC knew something that I didn't. We asked about runway closures or anything else that would be pertinent to the outcome of a safe approach and landing. This was a major distraction. ATC responded that they were unaware of any runway closures and queried an air carrier aircraft who had just taxied out as to runway status. The air carrier crew advised that they were unaware of any runway closures just some taxiway work. We were then cleared to 7000 ft; still on a heading of 060 degrees. We advised ATC once again that we had the airport in sight and I was becoming a little agitated due to being held high; on a heading; NOTAM distraction; too much discussion in the cockpit about the same; etc. We were advised that an air carrier had just departed the airport. No problem; we asked ATC what runway they had departed as were still concerned over the 'NOTAM issue;' and would consider using that runway. We were advised that the air carrier aircraft departed runway 34. There is no runway 34 depicted on our commercial airport chart. More confusion. At the same time all of this discussion was occurring we were cleared 'direct the airport.' this; at the same time; air carrier was departing on what we later determined was a right downwind from a runway that we didn't know was in use (not depicted on our chart). The confusion continued as we were high and close and I interpreted the 'cleared to the airport' as 'cleared for a visual approach' because I couldn't imagine that ATC would keep us this high; this close; and clear us direct to the airport with another aircraft potentially being in conflict with us. I began to descend and saw the air carrier both on the TCAS and visually and descended even further to approximately 6000 ft to avoid further closing with the aircraft. The air carrier aircraft responded to their RA and climbed out to avoid further closure. I was queried by ATC as to what altitude I was at and responded with 6000 ft climbing back to 7000 ft (by then we realized that I had erroneously descended to 6000 ft). ATC advised that we were cleared for a visual approach to brd and to call ZMP upon landing. I was advised that; while there was a TCAS 'incident;' no loss of separation had occurred.

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Original NASA ASRS Text

Title: A C525 PLT ON APCH TO BRD DSNDED BELOW HIS CLRED ALT AND RECEIVED A TCAS RA.

Narrative: I HAD JUST DSNDED FROM FL450 TO AN ASSIGNED ALT OF I BELIEVE 9000 FT AND WAS ON A HDG OF 060 DEGS APPROX 7 MI E OF BRD. WE ADVISED THAT WE HAD BRD 'IN SIGHT' AND QUERIED ATC AS TO OUR HDG AND IF THEY STILL WANTED US ON THAT HDG AS WE WERE BEGINNING TO PASS THE ARPT HDG NE. THE CTLR RESPONDED BY ASKING US IF WE HAD THE NOTAMS FOR BRD. THIS CAUSED A BIT OF CONSTERNATION ON MY PART AS IT IS NONSTANDARD TO QUERY ABOUT NOTAMS AND I WAS CONCERNED THAT ATC KNEW SOMETHING THAT I DIDN'T. WE ASKED ABOUT RWY CLOSURES OR ANYTHING ELSE THAT WOULD BE PERTINENT TO THE OUTCOME OF A SAFE APCH AND LNDG. THIS WAS A MAJOR DISTR. ATC RESPONDED THAT THEY WERE UNAWARE OF ANY RWY CLOSURES AND QUERIED AN ACR ACFT WHO HAD JUST TAXIED OUT AS TO RWY STATUS. THE ACR CREW ADVISED THAT THEY WERE UNAWARE OF ANY RWY CLOSURES JUST SOME TXWY WORK. WE WERE THEN CLRED TO 7000 FT; STILL ON A HDG OF 060 DEGS. WE ADVISED ATC ONCE AGAIN THAT WE HAD THE ARPT IN SIGHT AND I WAS BECOMING A LITTLE AGITATED DUE TO BEING HELD HIGH; ON A HDG; NOTAM DISTR; TOO MUCH DISCUSSION IN THE COCKPIT ABOUT THE SAME; ETC. WE WERE ADVISED THAT AN ACR HAD JUST DEPARTED THE ARPT. NO PROB; WE ASKED ATC WHAT RWY THEY HAD DEPARTED AS WERE STILL CONCERNED OVER THE 'NOTAM ISSUE;' AND WOULD CONSIDER USING THAT RWY. WE WERE ADVISED THAT THE ACR ACFT DEPARTED RWY 34. THERE IS NO RWY 34 DEPICTED ON OUR COMMERCIAL ARPT CHART. MORE CONFUSION. AT THE SAME TIME ALL OF THIS DISCUSSION WAS OCCURRING WE WERE CLRED 'DIRECT THE ARPT.' THIS; AT THE SAME TIME; ACR WAS DEPARTING ON WHAT WE LATER DETERMINED WAS A R DOWNWIND FROM A RWY THAT WE DIDN'T KNOW WAS IN USE (NOT DEPICTED ON OUR CHART). THE CONFUSION CONTINUED AS WE WERE HIGH AND CLOSE AND I INTERPED THE 'CLRED TO THE ARPT' AS 'CLRED FOR A VISUAL APCH' BECAUSE I COULDN'T IMAGINE THAT ATC WOULD KEEP US THIS HIGH; THIS CLOSE; AND CLR US DIRECT TO THE ARPT WITH ANOTHER ACFT POTENTIALLY BEING IN CONFLICT WITH US. I BEGAN TO DSND AND SAW THE ACR BOTH ON THE TCAS AND VISUALLY AND DSNDED EVEN FURTHER TO APPROX 6000 FT TO AVOID FURTHER CLOSING WITH THE ACFT. THE ACR ACFT RESPONDED TO THEIR RA AND CLBED OUT TO AVOID FURTHER CLOSURE. I WAS QUERIED BY ATC AS TO WHAT ALT I WAS AT AND RESPONDED WITH 6000 FT CLBING BACK TO 7000 FT (BY THEN WE REALIZED THAT I HAD ERRONEOUSLY DSNDED TO 6000 FT). ATC ADVISED THAT WE WERE CLRED FOR A VISUAL APCH TO BRD AND TO CALL ZMP UPON LNDG. I WAS ADVISED THAT; WHILE THERE WAS A TCAS 'INCIDENT;' NO LOSS OF SEPARATION HAD OCCURRED.

Data retrieved from NASA's ASRS site as of January 2009 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.