Narrative:

We were at approximately 2000 ft on a visual approach to runway 25L at lax, monitoring the ILS, on course and on GS. I manually was hand flying the approach. I received a TCASII RA command to climb. I initiated a climb and told the first officer to tell the tower that we were climbing in response to a TCASII command. He so informed the tower and they replied that our traffic was on a visual approach to runway 24. I stopped the climb momentarily thinking they must have the traffic in sight. At that time, my first officer said 'I have him and he's overshooting badly and heading for us.' I acquired the aircraft visually and initiated a climb and banked away from him. He slid underneath us with 0 horizontal clearance and approximately 300 ft of vertical clearance. The first officer informed the tower of his position and the tower responded that they were not in radio contact with the aircraft. He reappeared to our right and below us as he turned back towards runway 24. I realigned my aircraft with the runway and made a normal landing. The TCASII probably saved our lives. The danger in this situation though was the tower telling us that the aircraft the TCASII had ordered us to climb was on approach to 24. That made me think that the TCASII had made a mistake and the tower knew the position of the other aircraft. It caused me to slow or stop my climb greatly reduced our vertical clearance when the other aircraft continued to intercept our approach path.

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Original NASA ASRS Text

Title: CAPT OF MLG ACFT TOOK EVASIVE ACTION ON A FINAL VISUAL APCH WHEN ANOTHER ACFT OVERSHOT THE TURN FROM BASE LEG TO FINAL ON A PARALLEL (ALMOST) RWY INTERSECTING FLT PATHS.

Narrative: WE WERE AT APPROX 2000 FT ON A VISUAL APCH TO RWY 25L AT LAX, MONITORING THE ILS, ON COURSE AND ON GS. I MANUALLY WAS HAND FLYING THE APCH. I RECEIVED A TCASII RA COMMAND TO CLB. I INITIATED A CLB AND TOLD THE FO TO TELL THE TWR THAT WE WERE CLBING IN RESPONSE TO A TCASII COMMAND. HE SO INFORMED THE TWR AND THEY REPLIED THAT OUR TFC WAS ON A VISUAL APCH TO RWY 24. I STOPPED THE CLB MOMENTARILY THINKING THEY MUST HAVE THE TFC IN SIGHT. AT THAT TIME, MY FO SAID 'I HAVE HIM AND HE'S OVERSHOOTING BADLY AND HDG FOR US.' I ACQUIRED THE ACFT VISUALLY AND INITIATED A CLB AND BANKED AWAY FROM HIM. HE SLID UNDERNEATH US WITH 0 HORIZ CLRNC AND APPROX 300 FT OF VERT CLRNC. THE FO INFORMED THE TWR OF HIS POS AND THE TWR RESPONDED THAT THEY WERE NOT IN RADIO CONTACT WITH THE ACFT. HE REAPPEARED TO OUR R AND BELOW US AS HE TURNED BACK TOWARDS RWY 24. I REALIGNED MY ACFT WITH THE RWY AND MADE A NORMAL LNDG. THE TCASII PROBABLY SAVED OUR LIVES. THE DANGER IN THIS SITUATION THOUGH WAS THE TWR TELLING US THAT THE ACFT THE TCASII HAD ORDERED US TO CLB WAS ON APCH TO 24. THAT MADE ME THINK THAT THE TCASII HAD MADE A MISTAKE AND THE TWR KNEW THE POS OF THE OTHER ACFT. IT CAUSED ME TO SLOW OR STOP MY CLB GREATLY REDUCED OUR VERT CLRNC WHEN THE OTHER ACFT CONTINUED TO INTERCEPT OUR APCH PATH.

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.