Narrative:

On the seavu 1 arrival to lax approaching cataw; we were advised of traffic at our 1 - 2 O'clock position. We reported the aircraft in sight. We were told to maintain visual contact with that aircraft as he would be crossing our path to land on the south complex on runway 25L. He was told to maintain visual separation with us. As we made the turn at cataw and continued our descent on the profile we saw that he was merging with us rather than passing clear of us. Before we could call ATC (the controller was talking); we got a TCAS climb RA. We followed the RA and advised ATC. At the same time; we saw the target begin a descending right turn away from us. ATC acknowledged our climb and when the RA was over we re-intercepted the descent path and landed without further incident. Possible contributing factors: when we were pointed out to the target; we were on roughly parallel courses. He may not have realized that we were about to make a turn toward him; and may not have realized that we were on a descent profile. The lax arrs have multiple crossing restrs requiring close attention to the lateral and vertical paths. It was not a good idea to also have aircraft crossing in close proximity to each other during a high workload phase. Lax approach frequently changes your arrival or runway close in. This is not simply a matter of re-entering a new arrival. You also need to check the multiple fixes and crossing restrs. We had expected runway 25L which we normally get. We had just finished being switched to the north complex. The target was coming from the north and was switched to the south complex; so he was likely scrambling to change the arrival and runway as we had just done. If all he had to do was maneuver visually; it would be no problem. But if he had to do that while changing and checking a new arrival and tuning a new ILS; it is a recipe for distraction.

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Original NASA ASRS Text

Title: AN ACR FLT CREW INBOUND TO LAX GOT A TCAS CLIMB RA WHEN A CONFLICT DEVELOPED WITH ANOTHER ACR.

Narrative: ON THE SEAVU 1 ARR TO LAX APCHING CATAW; WE WERE ADVISED OF TFC AT OUR 1 - 2 O'CLOCK POS. WE RPTED THE ACFT IN SIGHT. WE WERE TOLD TO MAINTAIN VISUAL CONTACT WITH THAT ACFT AS HE WOULD BE XING OUR PATH TO LAND ON THE S COMPLEX ON RWY 25L. HE WAS TOLD TO MAINTAIN VISUAL SEPARATION WITH US. AS WE MADE THE TURN AT CATAW AND CONTINUED OUR DSCNT ON THE PROFILE WE SAW THAT HE WAS MERGING WITH US RATHER THAN PASSING CLR OF US. BEFORE WE COULD CALL ATC (THE CTLR WAS TALKING); WE GOT A TCAS CLB RA. WE FOLLOWED THE RA AND ADVISED ATC. AT THE SAME TIME; WE SAW THE TARGET BEGIN A DSNDING R TURN AWAY FROM US. ATC ACKNOWLEDGED OUR CLB AND WHEN THE RA WAS OVER WE RE-INTERCEPTED THE DSCNT PATH AND LANDED WITHOUT FURTHER INCIDENT. POSSIBLE CONTRIBUTING FACTORS: WHEN WE WERE POINTED OUT TO THE TARGET; WE WERE ON ROUGHLY PARALLEL COURSES. HE MAY NOT HAVE REALIZED THAT WE WERE ABOUT TO MAKE A TURN TOWARD HIM; AND MAY NOT HAVE REALIZED THAT WE WERE ON A DSCNT PROFILE. THE LAX ARRS HAVE MULTIPLE XING RESTRS REQUIRING CLOSE ATTN TO THE LATERAL AND VERT PATHS. IT WAS NOT A GOOD IDEA TO ALSO HAVE ACFT XING IN CLOSE PROX TO EACH OTHER DURING A HIGH WORKLOAD PHASE. LAX APCH FREQUENTLY CHANGES YOUR ARR OR RWY CLOSE IN. THIS IS NOT SIMPLY A MATTER OF RE-ENTERING A NEW ARR. YOU ALSO NEED TO CHK THE MULTIPLE FIXES AND XING RESTRS. WE HAD EXPECTED RWY 25L WHICH WE NORMALLY GET. WE HAD JUST FINISHED BEING SWITCHED TO THE N COMPLEX. THE TARGET WAS COMING FROM THE N AND WAS SWITCHED TO THE S COMPLEX; SO HE WAS LIKELY SCRAMBLING TO CHANGE THE ARR AND RWY AS WE HAD JUST DONE. IF ALL HE HAD TO DO WAS MANEUVER VISUALLY; IT WOULD BE NO PROB. BUT IF HE HAD TO DO THAT WHILE CHANGING AND CHKING A NEW ARR AND TUNING A NEW ILS; IT IS A RECIPE FOR DISTR.

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.