LOSS OF SEPARATION WHEN AN ACR A320 OVERSHOT TURN TO LOC AND CONFLICTED WITH AN ACR B727. CTLR HAD ISSUED THE APCH CLRNC USING A HDG OF 300 DEGS FOR THE RWY 25L LOC INTERCEPT.

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VISTA 1 ARR TO LAX. INSTRUCTED TO DEPART SLI VOR HDG 310 DEGS; MAINTAIN 4000 FT. UPDATED HDG 300 DEGS TO INTERCEPT LAX RWY 25L ILS AND CLRED FOR THE APCH. LOC CAPTURE MODE ARMED (A320 AIRBUS) ON COMMAND FROM CAPT. 180 KTS AIRSPD ASSIGNED. LOC CAME ALIVE AND CAPT SAID 'IT'S NOT GOING TO CAPTURE IT' AND DISCONNECTED AUTOPLT TO INCREASE TURN ANGLE OF BANK TO AVOID OVERSHOOT. LAX APCH CTL GAVE A 280 DEG HDG. TCASII 'TFC; TFC' AUDIO ALERT AND YELLOW VISUAL SYMBOL ON NAV DISPLAY. I TOLD CAPT 'WE ARE TOO FAR TO THE N SIDE.' HE SAID; 'I KNOW; I'M TRYING TO COME BACK -- THE AUTOPLT COULD NOT HANDLE THAT BIG OF AN INTERCEPT.' TCASII RA AND 'MONITOR VERT SPD' AUDIO. I SAW A BLUE PAINT SCHEME B727 APPROX 500 FT BELOW AT 2 O'CLOCK AND 3000-4500 FT DISTANT. WE HELD ALT AT 4000 FT AND CONTINUED L TURN. APCH CTL GAVE 'COME L 220 DEGS IMMEDIATELY; TFC R; 2 O'CLOCK LESS THAN 1 MI.' I TOLD THEM WE HAD A VISUAL AND WERE COMING L TO INTERCEPT. THE TCASII RA CLRED AND AN AUDIO 'CLR OF CONFLICT' SOUNDED. WE LANDED AND CALLED THE APCH CTL SUPVR FROM THE JETWAY. HE SPOKE WITH THE CAPT AND SAID THERE WOULD BE NO NEED TO FOLLOW UP. I FEEL WE WERE GIVEN TOO GREAT AN INTERCEPT ANGLE FOR THE LOC (GREATER THAN 50 DEGS) AND WHEN THE AUTOPLT FAILED TO MAKE THE TURN THE CAPT MANUALLY ATTEMPTED TO AVOID AN OVERSHOOT BUT AT THAT SLOW AN AIRSPD (180 KTS ASSIGNED) COULD NOT USE TOO MUCH ANGLE OF BANK EITHER WITHOUT RUNNING THE RISK OF STALLING THE ACFT. THE TCASII SYS WORKED PERFECTLY AND ALLOWED ME TO HAVE A VISUAL ON THE B727 WELL PRIOR TO ANY RISK OF CONFLICT. IT WAS A BUSY DAY AT LAX WITH SOME HOLDING AND WE WERE ROUTED TO THE VISTA 1 ARR FROM THE JULIAN 4 ARR (COMING FROM MEXICO CITY) TO FACILITATE THE ARR FLOW. I THINK WE WERE GIVEN A HARD BASE TO FINAL TO 'SQUEEZE US IN' AND THERE WAS NOT MUCH WE COULD DO ONCE WE SAW THE LOC COME ALIVE. SUPPLEMENTAL INFO FROM ACN 398663: ON APCH TO RWY 24R AT LAX; IN WX; ON GS. AT ABOUT 6000 FT; RECEIVED A TCASII ALERT SHOWING AN ACFT 1000 FT DIRECTLY ABOVE US. TCASII SHOWED THAT ACFT ABOVE WAS DSNDING AT RATE DOWN TOWARDS US. AT ABOUT 600 FT WE RECEIVED A TCASII WARNING TO INCREASE RATE OF DSCNT. ONCE CLR OF CLOUDS; SAW A B767 OFF L SIDE ON RWY 25L APCH. APCH CTL MADE NO CALL UNTIL ABOUT TIME WE INITIATED INCREASE IN VERT SPD AT TCASII WARNING.