Narrative:

Traffic observed on TCASII, no visual. We were notified by ATC about it. First officer (PNF) reported traffic in sight. However, it was not seen by captain (PF). At the same time, it turned towards us, and our TCASII issued an RA. Since I did not see the traffic, I initiated a climb as directed by TCASII. Once 'clear of conflict,' we returned to our assigned altitude.

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Original NASA ASRS Text

Title: CAPT CLBED IN RESPONSE TO TCASII RA EVEN THOUGH FO HAD THE TFC IN SIGHT.

Narrative: TFC OBSERVED ON TCASII, NO VISUAL. WE WERE NOTIFIED BY ATC ABOUT IT. FO (PNF) RPTED TFC IN SIGHT. HOWEVER, IT WAS NOT SEEN BY CAPT (PF). AT THE SAME TIME, IT TURNED TOWARDS US, AND OUR TCASII ISSUED AN RA. SINCE I DID NOT SEE THE TFC, I INITIATED A CLB AS DIRECTED BY TCASII. ONCE 'CLR OF CONFLICT,' WE RETURNED TO OUR ASSIGNED ALT.

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.