Narrative:

On descent into lax, we were cleared to 17000 ft. A few mins later, center pointed out an small transport aircraft at 16500 ft, 10 O'clock and ? Mi. We saw the traffic and acknowledged it. As we approached civit we were cleared for the profile descent to runway 25. Since we were well above the profile, I started to descend. This was just as we turned about 30 degrees right over civit. I looked to my left to check the traffic. He was right next to us. I immediately stopped the descent (we had gone down 200 ft) and went back to 17000 ft. The traffic passed directly beneath us. There is no doubt in my mind that we would have had a midair with the small transport aircraft. We lost sight of the small transport aircraft, so I asked center for an IFR descent with traffic separation. I made it clear, by tone of voice, that I was not happy with the situation. We were 'high and hot' the whole approach. I'm sure we missed some crossing altitudes on the profile, but I could care less. There is, absolutely, no excuse for any VFR or IFR crossing traffic to be in the descent corridor of the profile. I asked for and received a phone number for ZLA. I called them from my hotel and expressed my concerns. The fact that I acknowledge traffic en route does not relieve center of separation responsibility. Visual approachs are a different matter. A similar clearance will kill someone in the future. P.south. It was XA30 body time at the end of a 10.5 hour day and 7.5 flying time. No TCASII installed!

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Original NASA ASRS Text

Title: CAPT OF LGT ACR ACFT TOOK EVASIVE ACTION TO AVOID ANOTHER ACFT DURING A PROFILE DSCNT.

Narrative: ON DSCNT INTO LAX, WE WERE CLRED TO 17000 FT. A FEW MINS LATER, CTR POINTED OUT AN SMT ACFT AT 16500 FT, 10 O'CLOCK AND ? MI. WE SAW THE TFC AND ACKNOWLEDGED IT. AS WE APCHED CIVIT WE WERE CLRED FOR THE PROFILE DSCNT TO RWY 25. SINCE WE WERE WELL ABOVE THE PROFILE, I STARTED TO DSND. THIS WAS JUST AS WE TURNED ABOUT 30 DEGS R OVER CIVIT. I LOOKED TO MY L TO CHK THE TFC. HE WAS RIGHT NEXT TO US. I IMMEDIATELY STOPPED THE DSCNT (WE HAD GONE DOWN 200 FT) AND WENT BACK TO 17000 FT. THE TFC PASSED DIRECTLY BENEATH US. THERE IS NO DOUBT IN MY MIND THAT WE WOULD HAVE HAD A MIDAIR WITH THE SMT ACFT. WE LOST SIGHT OF THE SMT ACFT, SO I ASKED CTR FOR AN IFR DSCNT WITH TFC SEPARATION. I MADE IT CLR, BY TONE OF VOICE, THAT I WAS NOT HAPPY WITH THE SIT. WE WERE 'HIGH AND HOT' THE WHOLE APCH. I'M SURE WE MISSED SOME XING ALTS ON THE PROFILE, BUT I COULD CARE LESS. THERE IS, ABSOLUTELY, NO EXCUSE FOR ANY VFR OR IFR XING TFC TO BE IN THE DSCNT CORRIDOR OF THE PROFILE. I ASKED FOR AND RECEIVED A PHONE NUMBER FOR ZLA. I CALLED THEM FROM MY HOTEL AND EXPRESSED MY CONCERNS. THE FACT THAT I ACKNOWLEDGE TFC ENRTE DOES NOT RELIEVE CTR OF SEPARATION RESPONSIBILITY. VISUAL APCHS ARE A DIFFERENT MATTER. A SIMILAR CLRNC WILL KILL SOMEONE IN THE FUTURE. P.S. IT WAS XA30 BODY TIME AT THE END OF A 10.5 HR DAY AND 7.5 FLYING TIME. NO TCASII INSTALLED!

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.