TCASII COMPUTER GAVE INTRUDER WARNING AND RA TO CLB; FLT CLBED; MADE A GAR.

Narrative

WE WERE TURNING L BASE ON A VISUAL APCH TO RWY 25L AT MCCARRAN ARPT; LAX. OUR POS WAS ABOUT 6 DME E OF LAS VOR AND 2-3 S OF THE 25L LOC. WE WERE CLRED FOR A VISUAL APCH TO 25L REF TFC AT OUR 1 O'CLOCK WHO WAS ON A VISUAL TO 25R FROM THE ESE OF THE ARPT. WE WOULD BE TURNING INSIDE OF HIM ON OUR BASE TO FINAL; AS HE WAS AT OUR 1 O'CLOCK 1-2 MI DURING OUR L BASE TURN. OUR ALT WAS 6500 MSL; LNDG GEAR DOWN; FLAP POS 15 AND SPD 150 KIAS. AS WE PASSED THROUGH HDG ABOUT 010 DEG INSIDE OUR TFC WHO WAS NOW APPROX 1 MI OR LESS AS WE CONTINUED OUR BASE TO FINAL TURN. WE THEN GOT A 'MONITOR VERT SPD' FROM TCASII. WE SLOWED OUR DSCNT AND TRIED TO VISUALLY FIGURE OUR EXACT POS FROM OUR TFC AS WE CONTINUED OUR FINAL TURN AT ABOUT 15 DEG BANK. TCASII THEN COMMANDED A 'CLB; CLB; CLB' AND SHOWED A 1500 FPM CLB TO KEEP UP CLR OF TFC. AS WE STARTED A CLB; TCASII GAVE US ANOTHER 'CLB; CLB; CLB' STILL SHOWING A 1500 FPM CLB TO AVOID TFC. WE THEN INITIATED A MISSED APCH AND CLBED TO ABOVE 7000 MSL WHEN TCASII DISCONTINUED THE CLB COMMAND. I CALLED TWR AND TOLD THEM WE HAD A TCASII COMMANDED CLB; AND WE WERE NOT TOO HIGH TO CONTINUE OUR APCH. WE WERE INSTRUCTED TO GO BACK TO APCH CTL AND WERE VECTORED FOR AN UNEVENTFUL APCH AND LNDG. I MADE THE PULL UP BASED ON TCASII INFO BECAUSE IN OUR BASE TURN WE WERE BELLY UP TO OUR TFC WHICH MADE IT VERY HARD VISUALLY TO CONFIRM THAT OUR COURSES WOULD NOT CONVERGE TOO CLOSELY. ALSO; I WASN'T TOTALLY CERTAIN TCASII HADN'T PICKED UP ANOTHER TARGET WE HADN'T SEEN. THIRDLY; I DIDN'T THINK THERE WAS TIME TO CALL TWR TO HAVE THEM CONFIRM OUR POS FROM TFC. ALSO; THE VOLUME OF THE TCASII COMMANDS IS SO LOUD THAT IT GREATLY DETRACTS FROM CREW COORD DURING CRITICAL PHASES OF FLT. ALSO; I DON'T BELIEVE THE TCASII COMPUTER CAN KEEP UP WITH OUR PROJECTED FLT PATH WHEN THE ACFT TURN RATE IS HIGH. ALSO; THERE WAS NO TFC ABOVE US AS WE INITIATED THE MISSED APCH.