VFR CPR SMT DESCENDED THROUGH ALT OF ACR LGT RESULTING IN NEAR MID AIR COLLISION.

Narrative

LGT X RECEIVED STANDARD DEP CLRNC FROM LAX TO MSP VIA A LOOP 5 DEP; DAGGETT TRANSITION AS FILED TO MAINTAIN 2000'. AFTER TAKING OFF ON 24L AND XING THE SHORELINE ON A 250 DEG HDG; WE WERE CLRED TO CLB TO AND MAINTAIN 13000'. APPROX 5 DME W OF LAX VOR; WE WERE CLRED TO TURN LEFT DIRECT LAX VOR; CROSS THE VOR AT OR ABOVE 10000' TO MAINTAIN 13000'. AFTER XING THE LAX VOR ABOVE 10000' AND ESTABLISHED OUTBND ON THE LAX 041 DEG RADIAL; WE WERE SWITCHED FROM DEP CTL TO LOS ANGELES CENTER. CENTER SAID; 'MAINTAIN 13000'. YOU HAVE TFC AT 1 O'CLOCK; NBND; SMT Y; DSNDING TO 14000'. HE HAS YOU IN SIGHT.' WE LOOKED FOR THE TFC; BUT NONE OF US COULD SEE THE OTHER ACFT. WE WERE APCHING A LINE OF TOWERING CUMULUS OVER THE SAN GABRIEL MOUNTAINS; AND OUR ATTN WAS DIRECTED AT THE RADAR SCOPE AND THE WX. WE WERE TRYING TO PICK A ROUTE THROUGH THE CUMULUS AND FORMULATE A REQUEST FOR DEVIATION TO THE CENTER. INFLT VIS WAS QUITE GOOD; ESPECIALLY FOR THE LAX AREA; APPROX 8-10 MI. AT 12700'; I BEGAN TO EASE THE NOSE OVER TO LEVEL AT 13000'. FOR SOME REASON; I GLANCED OUT OF THE F/O'S #2 WINDOW AND SAW THAT IT WAS ALMOST ENTIRELY FILLED WITH THE BOTTOM OF A TWIN ENGINED; PROP DRIVEN; WHITE ACFT IN A HARD RIGHT TURN. HIS ALT WAS APPROX 13000'; AND OUR LAT SEP WAS APPROX 200'. I CONTINUED APPLYING FORWARD PRESSURE ON THE YOKE; ENOUGH SO THAT I WAS SURE WE WOULD NOT COLLIDE AND NOT SO MUCH AS TO PUT ANY PAX INTO THE OVERHEAD BINS. WE DSNDED TO 12400'. AT THIS POINT; ALL DANGER OF A COLLISION HAD PASSED; AND I RESUMED THE CLB TO 13000' AND LEVELED OFF. WE RPTED THE NEAR MISS TO LOS ANGELES CENTER. THE CENTER REPLIED; 'HE SAID HE HAD YOU IN SIGHT.' NOT WANTING TO TIE UP A BUSY FREQ WITH A SITUATION THAT WAS ALREADY OVER; WE REQUESTED A DEVIATION FOR WX AND WERE TRANSFERRED TO ANOTHER FREQ. IN DISCUSSING THE EVENT LATER IN THE FLT; THE S/O SAID THAT HE THOUGHT CENTER HAD SAID THE TFC WAS DSNDING THROUGH 14000' NOT TO 14000' THAT THE F/O AND I THOUGHT WE HEARD. IN ANY CASE; WE WERE ON AN IFR FLT PLAN; ON THE APPROPRIATE RADIAL FOR THE ASSIGNED DEP TRANSITION; CLBING TO OUR ASSIGNED ALT. IN SHORT; WE WERE WHERE WE WERE SUPPOSED TO BE; DOING WHAT WE WERE SUPPOSED TO BE DOING. THE PLT OF THE OTHER ACFT WAS EITHER DSNDING TO 14000' AND WENT THROUGH HIS ALT; OR WAS DSNDING VISUALLY THROUGH 14000' WITH CENTER ADVISORIES; HAD US IN SIGHT AND LOST US ONLY TO RECOVER VISUAL CONTACT AT THE LAST MINUTE; OR HE NEVER HAD US IN SIGHT UNTIL THE LAST MINUTE AND TOLD CENTER THAT HE DID. REGARDLESS; WE BOTH HAD TO TAKE EVASIVE ACTION TO AVOID A COLLISION. IT IS TRUE THAT THE FREQ WAS BUSIER THAN IT NORMALLY IS DUE TO WX CONDITIONS OVER THE MOUNTAINS. HOWEVER; WE SHOULD HAVE BEEN GIVEN MORE THAN 1 TFC ADVISORY BY CENTER. THE CENTER SHOULD NOT HAVE RELIED SOLELY ON THE OTHER PLT'S STATEMENT THAT HE HAD US IN SIGHT. WHILE WE DID TRY TO ACQUIRE THE OTHER ACFT VISUALLY; WE WERE TRYING TO SEE A SMALL; WHITE AIRPLANE AGAINST A BACKGROUND OF WHITE; TOWERING CUMULUS. HAPPILY FOR ALL CONCERNED; WE DID SEE EACH OTHER IN TIME. JUST. CALLBACK CONVERSATION WITH RPTR REVEALED FOLLOWING INFO. RPTR MADE NO FOLLOW-UP INQUIRY CONCERNING THIS NMAC. HE STILL DOES NOT KNOW IF THE CTLR SAID THE SMT WAS DSNDING THROUGH 14000' OR TO 14000'. IF THE SMT WAS DSNDING THROUGH 14000'; THE CTLR HAD THE RESPONSIBILITY FOR CONFLICT RESOLUTION. IF THE SMT WAS DSNDING TO 14000'; CONFLICT WAS RESOLVED. FROM THAT; WE CAN ASSUME THAT THE SMT WAS DSNDING THROUGH 14000'; AND THE CTLR WAS RESPONSIBLE TO ISSUE A TFC ALERT. THE REQUIREMENT FOR THE CTLR TO RESOLVE THE CONFLICT WAS REMOVED WHEN THE SMT PLT SAID HE HAD THE OTHER ACFT IN SIGHT. THE CTLR COULD RIGHTLY THINK THAT THE SMT WOULD NOT DSND INTO A NEAR MID AIR CONFLICT WITH THE LGT. NEVERTHELESS; HE DID AND THAT IS THE REASON FOR THE INCIDENT. ANALYST CALLED RPTR FOR 2 PRIMARY REASONS. FIRST; THE RPTR'S STATEMENT THAT THEY WERE ON THE PROPER ROUTE AT THE PROPER ALT AND DOING WHAT THEY WERE SUPPOSED TO DO BE DOING IMPLIED THAT HE HAD NO RESPONSIBILITY TO AVOID THE OTHER ACFT. ANALYST TRIED TO EXPLAIN THAT ALL THINGS BEING EQUAL; HE NEVER LOST HIS RESPONSIBILITY TO NOT HIT ANOTHER ACFT; REGARDLESS OF HOW RIGHT HE WAS OR WHETHER OR NOT HE WAS IFR IN THE RIGHT PLACE. SECONDLY; ANALYST WANTED TO EXPLAIN THE CTLR'S RESPONSIBILITY IN THIS INCIDENT AND WHY THE CTLR DID NOT DO MORE. MISSION WAS ACCOMPLISHED.