COMMUTER HAS CLOSE PROX WITH MLG DURING VECTORS FOR APCH. TCASII TA.

Narrative

DURING APCH TO LAX ARPT; WE WERE ON RADAR VECTOR TO FINAL; DSNDING TO 2000 FT ON A HDG OF 340 DEGS. WE RECEIVED A SERIES OF INSTRUCTIONS AS FOLLOWED: ATC ASKED US IF WE COULD ACCEPT A L TURN TO 240 DEGS; KEEPING IN MIND THERE IS SOME WX; CALLS TO THE L WHICH IS SHOWING ON HIS RADAR TO THE L OF US. MY WX; RADAR WAS NOT SHOWING ANY CELLS AT ALL; SO I RESPONDED BY ROGER THEN RIGHT AWAY ATC ISSUED A L TURN 240 DEGS. THEN SHORTLY AFTER ANOTHER L TURN TO 220 DEGS FOLLOWED BY STOP YOUR DSCNT 'ABOUT' 2500 FT FOLLOWED BY CLB TO 3000 FT AND ANOTHER L TO 190. THEN HE CAME BACK SAYING EXPEDITE YOUR TURN TO 190 DEGS; CLB TO 3000 FT. WE WERE IN LIGHT TO MODERATE TURB ABOUT 230 KTS OF GND SPD AND DURING THESE INSTRUCTIONS MY TCASII GAVE US A TA ALERT AT 12 O'CLOCK. WHILE WE WERE TURNING TO THE L; I LOOKED UP AND I SAW AN ACR JET IN A L TURN TOWARD THE ARPT. I BELIEVE I DID POINT THIS OUT TO MY FO WHO WAS FLYING AND TO ANOTHER PLT WHO WAS OCCUPYING THE JUMP SEAT. FOR SOMEONE WHO'S BEEN FLYING IN AND OUT OF LAX ARPT; I CONSIDERED THAT WAS A ROUTINE FLT WITH A ROUTINE APCH TILL ABOUT XX40 LCL TIME WHEN I RECEIVED A TELEPHONE CALL FROM LAX APCH SUPVR ASKING ME 'WHY WE WERE NOT TURNING.' AFTER 5-8 CONVERSATIONS; HE TOLD ME ATC HAD FAILED TO PROVIDE THE MIN SEPARATION REQUIREMENT AND THAT THE ACR CREW WERE VERY UNHAPPY. DURING THE ENTIRE APCH ATC FAILED AT ALL TIMES TO ASK OR REQUEST US TO EXPEDITE OUR TURN TILL THE VERY LAST INSTRUCTION WHICH BY THEN WE WERE ABOUT 2800 FT CLBING AND ON 200 HDG. HE ALSO FAILED TO RECOGNIZE THAT WE WERE TURNING INTO THE WIND.