ACR X TCASII TA RA WITH ACR Y CLB THROUGH OCCUPIED ALT HAD LTSS FROM Y. EVASIVE ACTION TAKEN. SYS ERROR.

Narrative

ACR X INBOUND TO LAX ON SADDE 5 ARR. JUST PRIOR TO BAYST INTXN WE WERE GIVEN DIRECT TO SMO. WE WERE LEVEL AT 10000 FT; 250 KTS. APPROX 5 MI NW OF SMT; 2 TARGETS APPEARED ON TCASII AS TA'S AT 1-2 O'CLOCK POS; 5-10 MI AT 9300 FT. TARGETS THEN BECAME 1 TA AND WERE CLBING. TCASII RA WAS ISSUED TO DSND JUST AS WE STARTED TO INQUIRE ABOUT TFC. (ATC NEVER ISSUED A TA.) BEGAN IMMEDIATE DSCNT PER RA AND ADVISED ATC WE WERE DSNDING. HE SAID TO CLB. FO REITERATED THAT WE WERE DSNDING PER THE RA. ATC RESPONDED ADAMANTLY AND FRANTICALLY TO CLB. WE HAD DSNDED APPROX 500 FT AND WERE IMC. WE THEN FOLLOWED ATC'S COMMAND TO CLB. TCASII ADVISED CLR OF CONFLICT SHORTLY THEREAFTER. AN FAA OBSERVER WAS IN THE JUMPSEAT AND STATED HE SAW A 'CONTRAIL' PASS BY THE R SIDE WINDOW. TALKED TO SOCAL SUPVR. HE STATED THE ACFT IN CONFLICT WAS ACR Y ON A VTU 2 DEP AND WAS CLRED TO CLB TO 13000 FT. (HE STATED THE ACFT SHOULD HAVE BEEN ON THE GORMAN DEP.) THE CTLR TURNED THE ACFT TO A 310 DEG HDG; CLRNC TO 13000 FT. USUALLY; ACFT ON THE GORMAN DEP ARE STOPPED AT 9000 FT BECAUSE ARR TFC CROSSES AT 10000 FT. ATC WAS UNAWARE OF CONFLICT UNTIL EVASIVE ACTION WAS TAKEN. SUPVR STATED THAT CONFLICTING ACFT DID NOT 'BUST' AN ALT (SINCE HE WAS CLRED TO 13000 FT). HE TOLD ME ACR Y WAS RESPONDING TO A CLB RA AND HAD REACHED 10500 FT. ATC (ON ANOTHER FREQ FROM OURS) ISSUED COMMANDS FOR THEM TO DSND. SINCE WE WERE IMC; I DON'T KNOW AT THIS POINT HOW CLOSE WE CAME. ATC WAS DEFINITELY NOT IN THE LOOP UNTIL AFTER THE CONFLICT OCCURRED. THIS OCCURRENCE APPEARS TO BE A RESULT OF ATC CONFUSION OVER THE DEP/ALT ASSIGNED TO THE OTHER ACFT; AND A LACK OF CTLR AWARENESS. AN INTERESTING SIT. BOTH ACFT WERE RESPONDING APPROPRIATELY TO TCASII RA'S. BOTH LATER WERE GIVEN OPPOSITE COMMANDS BY ATC ON 2 SEPARATE FREQS; IMC. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR SAID THE 2 TARGETS WERE ABOUT AN INCH APART ON THE TCASII DISPLAY AND MERGED TOGETHER AT 9800 FT. RPTR STATED SHE WAS FOLLOWING THE RA AND DSNDING WHEN THE CTLR STARTED SCREAMING TO DISREGARD THE RA AND CLB; CLB NOW. RPTR FELT BTWN A ROCK AND A HARD PLACE WITH 2 CONFLICTING COMMANDS -- TCASII ORDERING DSND AND CTLR SCREAMING CLB. RPTR SAID DURING FLC ATC REVIEW SHE WAS INFORMED IT WAS ACR Y AND THE MISS DISTANCE WAS 1.44 MI AND 200 FT.