Narrative:

Flight to bwi approximately 180 mi northwest of psk VOR, we received a WX rerte. We were given vectors for in-trail spacing, told to reduce to slowest practical speed (220 KTS), and fly 190 degree heading. As we turned to the 190 degree heading, we noticed approximately 4 other aircraft 30 mi south, also at FL370 (our altitude FL370). Approximately 100 mi west of psk, we were given a 090 degree heading. As we rolled left through 130 degree heading, center turned us back right to 180 degrees and then 240 degree heading. I questioned the 240 degree heading as there was TCASII traffic in that area. The controller verified the turn to 240 degrees. As we were completing the turn to 240 degrees, the controller gave us a turn back left to 090 degrees and descent to FL330. The first officer was flying and started a left turn and descent at 1000 FPM. We received a TA (TCASII) as we descended through FL368. I noted the traffic was approximately 7 NM at our 2 O'clock position, converging. I told the first officer to increase descent rate and turn rate. I acquired the traffic visually and simultaneously disconnected the autoplt, lowered the nose (5000 FPM) and increased bank angle to 30 degrees. I noted the aircraft (another carrier) passed approximately 1 mi in front and 1300 ft above us. At this same time, the controller asked us to report out of FL330 and previous clearance was to descend and maintain FL330. I told the controller, 'you have company on a 090 degree heading and FL330. Where do you want us?' there was a pause by the controller, followed by a request to report out of FL350. We immediately reported we were out of FL350. The controller then assigned us 100 degree heading and FL330. As this controller handed us off, he replied, 'thanks for all your help back there.' contributing factors: WX, traffic congestion in sector, controller overload, confusing clrncs (multiple).

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Original NASA ASRS Text

Title: B737 WITH ZID AT FL370 EXPERIENCED TCASII TA WHILE BEING VECTORED FOR SPACING, CONFLICTING WITH ANOTHER SAME ALT ACR AND ANOTHER AT FL350.

Narrative: FLT TO BWI APPROX 180 MI NW OF PSK VOR, WE RECEIVED A WX RERTE. WE WERE GIVEN VECTORS FOR IN-TRAIL SPACING, TOLD TO REDUCE TO SLOWEST PRACTICAL SPD (220 KTS), AND FLY 190 DEG HDG. AS WE TURNED TO THE 190 DEG HDG, WE NOTICED APPROX 4 OTHER ACFT 30 MI S, ALSO AT FL370 (OUR ALT FL370). APPROX 100 MI W OF PSK, WE WERE GIVEN A 090 DEG HDG. AS WE ROLLED L THROUGH 130 DEG HDG, CTR TURNED US BACK R TO 180 DEGS AND THEN 240 DEG HDG. I QUESTIONED THE 240 DEG HDG AS THERE WAS TCASII TFC IN THAT AREA. THE CTLR VERIFIED THE TURN TO 240 DEGS. AS WE WERE COMPLETING THE TURN TO 240 DEGS, THE CTLR GAVE US A TURN BACK L TO 090 DEGS AND DSCNT TO FL330. THE FO WAS FLYING AND STARTED A L TURN AND DSCNT AT 1000 FPM. WE RECEIVED A TA (TCASII) AS WE DSNDED THROUGH FL368. I NOTED THE TFC WAS APPROX 7 NM AT OUR 2 O'CLOCK POS, CONVERGING. I TOLD THE FO TO INCREASE DSCNT RATE AND TURN RATE. I ACQUIRED THE TFC VISUALLY AND SIMULTANEOUSLY DISCONNECTED THE AUTOPLT, LOWERED THE NOSE (5000 FPM) AND INCREASED BANK ANGLE TO 30 DEGS. I NOTED THE ACFT (ANOTHER CARRIER) PASSED APPROX 1 MI IN FRONT AND 1300 FT ABOVE US. AT THIS SAME TIME, THE CTLR ASKED US TO RPT OUT OF FL330 AND PREVIOUS CLRNC WAS TO DSND AND MAINTAIN FL330. I TOLD THE CTLR, 'YOU HAVE COMPANY ON A 090 DEG HDG AND FL330. WHERE DO YOU WANT US?' THERE WAS A PAUSE BY THE CTLR, FOLLOWED BY A REQUEST TO RPT OUT OF FL350. WE IMMEDIATELY RPTED WE WERE OUT OF FL350. THE CTLR THEN ASSIGNED US 100 DEG HDG AND FL330. AS THIS CTLR HANDED US OFF, HE REPLIED, 'THANKS FOR ALL YOUR HELP BACK THERE.' CONTRIBUTING FACTORS: WX, TFC CONGESTION IN SECTOR, CTLR OVERLOAD, CONFUSING CLRNCS (MULTIPLE).

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.