Narrative:

On this flight we were delayed at the departure station due to an FAA cabin and walkaround inspection that uncovered a discrepancy with the R1 door evacuate/evacuation slide. Air carrier maintenance was called and concluded a slide change was required. The new slide took about 35 mins to arrive from stores. This situation put us off the gate 46 mins late. Our schedule was to turn in san with a planned 48 min ground time. As the captain, it was my leg and I was going to try and make up as much time as possible to save the connections on the return flight to dfw. During descent into san on the baret 4 arrival, our clearance was to cross pillo intersection at 10000 ft. In the interest of saving time I was descending at 330 KIAS and flying gfms VNAV descent rate to make the crossing restr. First officer brought a TCASII target (open white diamond) to my attention at about 12000 ft MSL which indicated 1500 ft below us and about 5 mi at 12 O'clock position. I altered the descent rate from about 1600 FPM to about 1100 FPM. When we realized that this traffic was most likely VFR at 10500 ft, first officer asked ZLA about the traffic conflict. The controller gave us an immediate turn to a 270 degree heading, which was 20 degrees to the right of our heading for pillo. I got a visual on the traffic and we passed probably a little more than 500 ft to the north of a high performance light single engine airplane. We got a TCASII RA (climb) after we were slightly ahead and about the same altitude as the target. The TCASII aural warnings were so late that had we not turned to a heading of 270 degrees we would have hit him in all likelihood. I am not sure why center did not see this traffic on radar. I do not know if the target was on a VFR flight plan or whether flight following was involved.

Related reports:

Google
 

Original NASA ASRS Text

Title: AN MD80 FLT CREW HAS AN NMAC WITH A TCASII RA WHILE DSNDING INTO LAX.

Narrative: ON THIS FLT WE WERE DELAYED AT THE DEP STATION DUE TO AN FAA CABIN AND WALKAROUND INSPECTION THAT UNCOVERED A DISCREPANCY WITH THE R1 DOOR EVAC SLIDE. ACR MAINT WAS CALLED AND CONCLUDED A SLIDE CHANGE WAS REQUIRED. THE NEW SLIDE TOOK ABOUT 35 MINS TO ARRIVE FROM STORES. THIS SIT PUT US OFF THE GATE 46 MINS LATE. OUR SCHEDULE WAS TO TURN IN SAN WITH A PLANNED 48 MIN GND TIME. AS THE CAPT, IT WAS MY LEG AND I WAS GOING TO TRY AND MAKE UP AS MUCH TIME AS POSSIBLE TO SAVE THE CONNECTIONS ON THE RETURN FLT TO DFW. DURING DSCNT INTO SAN ON THE BARET 4 ARR, OUR CLRNC WAS TO CROSS PILLO INTXN AT 10000 FT. IN THE INTEREST OF SAVING TIME I WAS DSNDING AT 330 KIAS AND FLYING GFMS VNAV DSCNT RATE TO MAKE THE XING RESTR. FO BROUGHT A TCASII TARGET (OPEN WHITE DIAMOND) TO MY ATTN AT ABOUT 12000 FT MSL WHICH INDICATED 1500 FT BELOW US AND ABOUT 5 MI AT 12 O'CLOCK POS. I ALTERED THE DSCNT RATE FROM ABOUT 1600 FPM TO ABOUT 1100 FPM. WHEN WE REALIZED THAT THIS TFC WAS MOST LIKELY VFR AT 10500 FT, FO ASKED ZLA ABOUT THE TFC CONFLICT. THE CTLR GAVE US AN IMMEDIATE TURN TO A 270 DEG HDG, WHICH WAS 20 DEGS TO THE R OF OUR HDG FOR PILLO. I GOT A VISUAL ON THE TFC AND WE PASSED PROBABLY A LITTLE MORE THAN 500 FT TO THE N OF A HIGH PERFORMANCE LIGHT SINGLE ENG AIRPLANE. WE GOT A TCASII RA (CLB) AFTER WE WERE SLIGHTLY AHEAD AND ABOUT THE SAME ALT AS THE TARGET. THE TCASII AURAL WARNINGS WERE SO LATE THAT HAD WE NOT TURNED TO A HDG OF 270 DEGS WE WOULD HAVE HIT HIM IN ALL LIKELIHOOD. I AM NOT SURE WHY CTR DID NOT SEE THIS TFC ON RADAR. I DO NOT KNOW IF THE TARGET WAS ON A VFR FLT PLAN OR WHETHER FLT FOLLOWING WAS INVOLVED.

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.