Narrative:

Descending on bucko arrival to dca with clearance to cross druzz at 15000'. We were 12-15 NM west of druzz at approximately 19000' descending. We received from ATC VFR traffic 12 O'clock, 16500'. We did not hear the distance. We had no visibility on the traffic, but a few seconds later we received a TCAS traffic advisory followed very shortly by an RA to 'reduce descent,' which we did. I notified center and he then issued a clearance to level at 17000', which we did. Seconds later TCAS reported 'clear traffic.' we were then cleared to 15000'.

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Original NASA ASRS Text

Title: ACR LGT FLT CREW RECEIVES TCAS RA WHILE IN DESCENT TO DCA.

Narrative: DSNDING ON BUCKO ARR TO DCA WITH CLRNC TO CROSS DRUZZ AT 15000'. WE WERE 12-15 NM W OF DRUZZ AT APPROX 19000' DSNDING. WE RECEIVED FROM ATC VFR TFC 12 O'CLOCK, 16500'. WE DID NOT HEAR THE DISTANCE. WE HAD NO VIS ON THE TFC, BUT A FEW SECS LATER WE RECEIVED A TCAS TFC ADVISORY FOLLOWED VERY SHORTLY BY AN RA TO 'REDUCE DSNT,' WHICH WE DID. I NOTIFIED CENTER AND HE THEN ISSUED A CLRNC TO LEVEL AT 17000', WHICH WE DID. SECS LATER TCAS RPTED 'CLR TFC.' WE WERE THEN CLRED TO 15000'.

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.