Narrative:

First officer was flying, autoplt engaged. Descending to 14000 ft out of FL240 approaching bands intersection. ATC advised we had VFR traffic at 12 O'clock, opposite direction, 15 mi at 13500 ft unconfirmed. At a guess, we were at 17000 ft descending rapidly on the arrival (speed brakes extended). We were then handed off to socal approach. At about 15000 ft we got a TA and the traffic appeared on the TCASII inside the 6 mi range. Almost immediately we got an RA 'descend, descend, descend.' the TCASII gave us an accurate location of 12:30 - 1 O'clock position and less than 2 mi. The first officer had disconnected the autoplt and increased our descent rate to comply with the RA. Approaching 14000 ft the TCASII RA changed to 'climb, climb, climb.' I was visually scanning. The traffic (light/medium propeller twin) appeared at less than 1 mi. We banked slightly to the left and passed it. We passed with less than 500 ft horizontal separation and appeared to be level at 14000 ft. I never saw the traffic take any evasive action. We checked in with socal and advised him of the near miss. He had no comment at all. The WX in the los angeles basin was the usual dense smog, almost up to 14000 ft. Without the TCASII depiction it is unlikely we would have found the traffic at our closure rate. If we had had TCASII with range depiction on our ehsi we would have had considerably more time to look for the traffic and would likely have been able to avoid him with a larger margin of safety. A TCASII display of larger range on any TCASII instrument would have been more useful but the ehsi would have been the best. As we are all aware, ads-B would not have given us any warning unless the other aircraft had been equipped with ads-B.

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Original NASA ASRS Text

Title: ARTCC ADVISED B767 FREIGHTER OF VFR TFC. FREIGHTER FLC HAS NEAR MISS WITH LIGHT TWIN DURING DSCNT. IT WAS NOT VISIBLE IN HAZY CONDITIONS. FOLLOWING TCASII RA, RESULTED IN POSITIVE RESULT.

Narrative: FO WAS FLYING, AUTOPLT ENGAGED. DSNDING TO 14000 FT OUT OF FL240 APCHING BANDS INTXN. ATC ADVISED WE HAD VFR TFC AT 12 O'CLOCK, OPPOSITE DIRECTION, 15 MI AT 13500 FT UNCONFIRMED. AT A GUESS, WE WERE AT 17000 FT DSNDING RAPIDLY ON THE ARR (SPD BRAKES EXTENDED). WE WERE THEN HANDED OFF TO SOCAL APCH. AT ABOUT 15000 FT WE GOT A TA AND THE TFC APPEARED ON THE TCASII INSIDE THE 6 MI RANGE. ALMOST IMMEDIATELY WE GOT AN RA 'DSND, DSND, DSND.' THE TCASII GAVE US AN ACCURATE LOCATION OF 12:30 - 1 O'CLOCK POS AND LESS THAN 2 MI. THE FO HAD DISCONNECTED THE AUTOPLT AND INCREASED OUR DSCNT RATE TO COMPLY WITH THE RA. APCHING 14000 FT THE TCASII RA CHANGED TO 'CLB, CLB, CLB.' I WAS VISUALLY SCANNING. THE TFC (LIGHT/MEDIUM PROP TWIN) APPEARED AT LESS THAN 1 MI. WE BANKED SLIGHTLY TO THE L AND PASSED IT. WE PASSED WITH LESS THAN 500 FT HORIZ SEPARATION AND APPEARED TO BE LEVEL AT 14000 FT. I NEVER SAW THE TFC TAKE ANY EVASIVE ACTION. WE CHKED IN WITH SOCAL AND ADVISED HIM OF THE NEAR MISS. HE HAD NO COMMENT AT ALL. THE WX IN THE LOS ANGELES BASIN WAS THE USUAL DENSE SMOG, ALMOST UP TO 14000 FT. WITHOUT THE TCASII DEPICTION IT IS UNLIKELY WE WOULD HAVE FOUND THE TFC AT OUR CLOSURE RATE. IF WE HAD HAD TCASII WITH RANGE DEPICTION ON OUR EHSI WE WOULD HAVE HAD CONSIDERABLY MORE TIME TO LOOK FOR THE TFC AND WOULD LIKELY HAVE BEEN ABLE TO AVOID HIM WITH A LARGER MARGIN OF SAFETY. A TCASII DISPLAY OF LARGER RANGE ON ANY TCASII INST WOULD HAVE BEEN MORE USEFUL BUT THE EHSI WOULD HAVE BEEN THE BEST. AS WE ARE ALL AWARE, ADS-B WOULD NOT HAVE GIVEN US ANY WARNING UNLESS THE OTHER ACFT HAD BEEN EQUIPPED WITH ADS-B.

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.