ACR X TCASII RA FROM VFR ACFT HAD LTSS FROM MTR. PLTDEV. TCASII INDUCED LTSS.

Narrative

I RECEIVED A RADAR HDOF FROM ZLA ON ACR X DSNDING TO 14000 FT. I WAS PROVIDING ATC SVCS TO MTR EBOUND AT 10000 FT. THE MTR WAS ASSIGNED A VECTOR OF 100 DEGS AND WAS LEVEL AT 10000 FT. ACR X CHKED ONTO THE FREQ AND WAS ISSUED A DSCNT TO CROSS THE PMD VORTAC AT OR BELOW 13000 FT MAINTAIN 11000 FT. I OBSERVED A VFR TARGET APPROX 4-5 MI S OF THE PMD VORTAC AT 11500 FT UNVERIFIED. ACR X WAS ON CONVERGING COURSES WITH THE TARGET AT 11500 FT. I ELECTED TO HAVE ACR X EXPEDITE DSCNT TO AND MAINTAIN 11000 FT FOR VFR TFC 12 O'CLOCK; 10 MI. ACR X REACHED THE ASSIGNED ALT APPROX 6-8 MI FROM THE VFR TARGET. THE MTR WAS STILL ON AN ASSIGNED HDG OF 100 DEGS AND WAS RAPIDLY CLOSING ON ACR X ON CONVERGING COURSES. BY THIS TIME; APPROPRIATE IFR/VFR SEPARATION DID EXIST BTWN THE 3 AFFECTED ACFT. NEITHER OF THE AFFECTED ACFT WERE NEARER THAN 5 MI FROM ONE ANOTHER. INITIALLY; ACR X HAD RESPONDED TO A TCASII RA FROM THE VFR TARGET. ACR X HAD INITIALLY DEVIATED FROM THE ASSIGNED ALT BUT SEPARATION WAS NOT LOST AS ACR X OPTED TO ARREST THE DSCNT AND RETURN TO THE ASSIGNED ALT. AT THIS POINT IN TIME; ACR X WAS APPROX 10 MI; AT ITS CLOSEST POINT; TO THE MTR. I CONCLUDED FROM PAST PRACTICE THAT THIS SCENARIO HAD POTENTIAL TO BE A TCASII NIGHTMARE AND IMMEDIATELY COMMENCED ISSUING ACR X AS TFC TO THE MTR. THE MTR WAS UNABLE TO VISUALLY MAKE CONTACT WITH ACR X. I THEN COMMENCED TO INFORM ACR X OF THE MTR TFC; 1 O'CLOCK; 10 MI; EBOUND; IFR; 10000 FT. ACR X ACKNOWLEDGED THE TFC BUT DID NOT RPT IT AS BEING IN SIGHT. AT APPROX 2 MI FROM THE VFR TARGET AND APPROX 1 MI FROM MTR ACR X ADVISED THEY WERE RESPONDING TO A TCASII RA AND WERE DSNDING AND TURNING. I IMMEDIATELY ADVISED MTR OF ACR X INTENTIONS OF RESPONDING TO THE TCASII RA; AND ISSUED AN IMMEDIATE TURN TO THE L HDG 070. MTR ADVISED THAT HE HAD VISUAL CONTACT ON ACR X AND I ADVISED MTR TO MAINTAIN VISUAL SEPARATION FROM ACR X AS HE WAS RESPONDING TO A TCASII RA. ACR X ADVISED HE HAD OBTAINED VISUAL CONTACT WITH THE MTR AS IT PASSED BELOW. ACR X ADVISED THAT NO VISUAL CONTACT HAD BEEN MADE ON THE VFR TARGET.