Narrative:

I was the captain and PF on a flight from ZZZ to bos. After being vectored and cleared for a visual approach to runway 33L; we were told there was another aircraft on approach to runway 32 to our left. While on approach at 2400 ft MSL; with the autoplt engaged and the localizer and GS captured we received a traffic alert followed by an RA to climb. We executed a missed approach; informed the tower and were vectored for an uneventful approach to runway 33L. Boston tower seemed surprised that we were going around; stating that the other aircraft had (us) in sight. Obviously the runway ctrlines of runways 33L and 32 converge somewhere over hingham bay. Aircraft being vectored to the 2 runways too far out run the risk of coming closer than the TCAS system allows. It appears that the other aircraft; whether or not they had us in sight; flew too close to us and caused the conflict. It's somewhat disconcerting that boston tower would vector aircraft to the 2 runways and then fail to monitor closely enough to recognize and warn them of the conflict; and would; moreover; be surprised that the proximity caused an RA.

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Original NASA ASRS Text

Title: B757-200 ON APCH TO BOS RWY33L EXPERIENCES TCAS RA WITH ACFT ON FINAL FOR RWY 32.

Narrative: I WAS THE CAPT AND PF ON A FLT FROM ZZZ TO BOS. AFTER BEING VECTORED AND CLRED FOR A VISUAL APCH TO RWY 33L; WE WERE TOLD THERE WAS ANOTHER ACFT ON APCH TO RWY 32 TO OUR L. WHILE ON APCH AT 2400 FT MSL; WITH THE AUTOPLT ENGAGED AND THE LOC AND GS CAPTURED WE RECEIVED A TFC ALERT FOLLOWED BY AN RA TO CLB. WE EXECUTED A MISSED APCH; INFORMED THE TWR AND WERE VECTORED FOR AN UNEVENTFUL APCH TO RWY 33L. BOSTON TWR SEEMED SURPRISED THAT WE WERE GOING AROUND; STATING THAT THE OTHER ACFT HAD (US) IN SIGHT. OBVIOUSLY THE RWY CTRLINES OF RWYS 33L AND 32 CONVERGE SOMEWHERE OVER HINGHAM BAY. ACFT BEING VECTORED TO THE 2 RWYS TOO FAR OUT RUN THE RISK OF COMING CLOSER THAN THE TCAS SYS ALLOWS. IT APPEARS THAT THE OTHER ACFT; WHETHER OR NOT THEY HAD US IN SIGHT; FLEW TOO CLOSE TO US AND CAUSED THE CONFLICT. IT'S SOMEWHAT DISCONCERTING THAT BOSTON TWR WOULD VECTOR ACFT TO THE 2 RWYS AND THEN FAIL TO MONITOR CLOSELY ENOUGH TO RECOGNIZE AND WARN THEM OF THE CONFLICT; AND WOULD; MOREOVER; BE SURPRISED THAT THE PROX CAUSED AN RA.

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.