Narrative:

I was captain on flight scheduled arriving bwi at XA53 jul/xa/05. We were flying the OTT6 arrival in cloudy/layered skies with cumulo nimbus around. Potomac approach control gave us a descent clearance to cross deale intersection at 6000 ft. The STAR continues after deale intersection to ravnn intersection then a left turn to ripkn intersection after which; expect radar vectors. After we were in the left turn to ripkn intersection; the controller; I believe; asked our heading; and we replied we were turning towards ripkn intersection. He said 'turn right to 090 degrees and descend to 4000 ft.' then almost immediately he said 'turn left to 320 degrees.' almost simultaneously; we got a TCASII 'traffic' and an RA to descend. We saw B737 traffic at approximately 2 O'clock position; level; about 1 mi. We continued left to 320 degrees and descended to 4000 ft MSL. The rest of the radar vectoring went fine; and the controller mentioned he 'thought' he had given us a 090 degree heading after deale intersection; which neither myself nor first officer heard. As we switched controllers; the one during this time apologized and said it had been a long day. I asked if we needed to do paperwork; and he said no; but I thought I would submit this just in case.

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Original NASA ASRS Text

Title: B757 FLT CREW INBOUND TO BWI AT 6000 FT EXPERIENCED CONFLICT WITH SAME ALT TFC AS CTLR ISSUED TURN AND TCASII ACTIVATE SIMULTANEOUSLY.

Narrative: I WAS CAPT ON FLT SCHEDULED ARRIVING BWI AT XA53 JUL/XA/05. WE WERE FLYING THE OTT6 ARR IN CLOUDY/LAYERED SKIES WITH CUMULO NIMBUS AROUND. POTOMAC APCH CTL GAVE US A DSCNT CLRNC TO CROSS DEALE INTXN AT 6000 FT. THE STAR CONTINUES AFTER DEALE INTXN TO RAVNN INTXN THEN A L TURN TO RIPKN INTXN AFTER WHICH; EXPECT RADAR VECTORS. AFTER WE WERE IN THE L TURN TO RIPKN INTXN; THE CTLR; I BELIEVE; ASKED OUR HDG; AND WE REPLIED WE WERE TURNING TOWARDS RIPKN INTXN. HE SAID 'TURN R TO 090 DEGS AND DSND TO 4000 FT.' THEN ALMOST IMMEDIATELY HE SAID 'TURN L TO 320 DEGS.' ALMOST SIMULTANEOUSLY; WE GOT A TCASII 'TFC' AND AN RA TO DSND. WE SAW B737 TFC AT APPROX 2 O'CLOCK POS; LEVEL; ABOUT 1 MI. WE CONTINUED L TO 320 DEGS AND DSNDED TO 4000 FT MSL. THE REST OF THE RADAR VECTORING WENT FINE; AND THE CTLR MENTIONED HE 'THOUGHT' HE HAD GIVEN US A 090 DEG HDG AFTER DEALE INTXN; WHICH NEITHER MYSELF NOR FO HEARD. AS WE SWITCHED CTLRS; THE ONE DURING THIS TIME APOLOGIZED AND SAID IT HAD BEEN A LONG DAY. I ASKED IF WE NEEDED TO DO PAPERWORK; AND HE SAID NO; BUT I THOUGHT I WOULD SUBMIT THIS JUST IN CASE.

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.