Narrative:

As we were turned onto final we had a target on the TCASII very close (on TCASII) at 10 O'clock position with 500 ft below us. Expecting a RA we reduced our descent (we did not have visual) we maintained about 400 ft separation 'til we had the aircraft (a 727 to runway 24L) in sight. By then we had crossed over final (to runway 24R) and were about 1/2 way between the runways. We then corrected back to runway 24R. Cause: the TCASII diverted our attention to traffic we were not advised of by ATC. Ready to do a RA deviation, our attention was on TCASII and not turning final. We did not know the traffic we were avoiding was on final to runway 24L. Visibility was poor at dusk with haze.

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Original NASA ASRS Text

Title: HDG TRACK DEV PLACES OTHER ACR IN CLOSER PROX TO RPTR'S THAN PLANNED.

Narrative: AS WE WERE TURNED ONTO FINAL WE HAD A TARGET ON THE TCASII VERY CLOSE (ON TCASII) AT 10 O'CLOCK POS WITH 500 FT BELOW US. EXPECTING A RA WE REDUCED OUR DSCNT (WE DID NOT HAVE VISUAL) WE MAINTAINED ABOUT 400 FT SEPARATION 'TIL WE HAD THE ACFT (A 727 TO RWY 24L) IN SIGHT. BY THEN WE HAD CROSSED OVER FINAL (TO RWY 24R) AND WERE ABOUT 1/2 WAY BTWN THE RWYS. WE THEN CORRECTED BACK TO RWY 24R. CAUSE: THE TCASII DIVERTED OUR ATTN TO TFC WE WERE NOT ADVISED OF BY ATC. READY TO DO A RA DEV, OUR ATTN WAS ON TCASII AND NOT TURNING FINAL. WE DID NOT KNOW THE TFC WE WERE AVOIDING WAS ON FINAL TO RWY 24L. VISIBILITY WAS POOR AT DUSK WITH HAZE.

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.