Narrative:

I was the PNF on a lear 45. We were flying the irons 4 arrival into dca. ZDC was controling. We were being stepped down for the arrival. We (the PF and myself) believed we were cleared to descend to FL240. Center then called traffic off to our right side (about 2 O'clock position). We believed center called his altitude to be FL250. Traffic was sighted visually by both of us. We also saw the target on the TCASII. Distance was estimated at 7 mi. As we were leaving FL250, I noticed the TCASII said the traffic was 1000 ft below our altitude -- meaning traffic's altitude was FL240. Traffic's path was slowly converging with ours. I informed the pilot that there must be a mistake on someone's part and advised he stop the descent. We leveled at FL247. We began to climb to FL250 when ZDC called us and said to climb to FL250. We were already beginning to level off when he finished his transmission. The controller never had to issue a turn to us or to the other aircraft. TCASII never gave us a TA or an RA. The traffic passed 1000 ft below us a few mins later, without further incident. Several mins later, the controller called back and said we were involved in an altitude deviation. We did not respond to the statement. We felt that descending into washington dc's airspace was not the proper time or place for an argument. The flight proceeded to dca without further incident.

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Original NASA ASRS Text

Title: CLRNC CONFUSION AND POSSIBLE ALTDEV ON THE IRONS 4 ARR TO DCA, VA.

Narrative: I WAS THE PNF ON A LEAR 45. WE WERE FLYING THE IRONS 4 ARR INTO DCA. ZDC WAS CTLING. WE WERE BEING STEPPED DOWN FOR THE ARR. WE (THE PF AND MYSELF) BELIEVED WE WERE CLRED TO DSND TO FL240. CTR THEN CALLED TFC OFF TO OUR R SIDE (ABOUT 2 O'CLOCK POS). WE BELIEVED CTR CALLED HIS ALT TO BE FL250. TFC WAS SIGHTED VISUALLY BY BOTH OF US. WE ALSO SAW THE TARGET ON THE TCASII. DISTANCE WAS ESTIMATED AT 7 MI. AS WE WERE LEAVING FL250, I NOTICED THE TCASII SAID THE TFC WAS 1000 FT BELOW OUR ALT -- MEANING TFC'S ALT WAS FL240. TFC'S PATH WAS SLOWLY CONVERGING WITH OURS. I INFORMED THE PLT THAT THERE MUST BE A MISTAKE ON SOMEONE'S PART AND ADVISED HE STOP THE DSCNT. WE LEVELED AT FL247. WE BEGAN TO CLB TO FL250 WHEN ZDC CALLED US AND SAID TO CLB TO FL250. WE WERE ALREADY BEGINNING TO LEVEL OFF WHEN HE FINISHED HIS XMISSION. THE CTLR NEVER HAD TO ISSUE A TURN TO US OR TO THE OTHER ACFT. TCASII NEVER GAVE US A TA OR AN RA. THE TFC PASSED 1000 FT BELOW US A FEW MINS LATER, WITHOUT FURTHER INCIDENT. SEVERAL MINS LATER, THE CTLR CALLED BACK AND SAID WE WERE INVOLVED IN AN ALTDEV. WE DID NOT RESPOND TO THE STATEMENT. WE FELT THAT DSNDING INTO WASHINGTON DC'S AIRSPACE WAS NOT THE PROPER TIME OR PLACE FOR AN ARGUMENT. THE FLT PROCEEDED TO DCA WITHOUT FURTHER INCIDENT.

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.