ACR X TCASII RA WITH PROBABLE VFR ACFT EVASIVE ACTION TAKEN. POSSIBLE TCASII INDUCED LTSS WITH ANOTHER ACFT.

Narrative

ACR X SLC-SNA; FO FLYING. INBOUND SNA E SIDE 1 FMS ARR APPROX POS FO29L. SOCAL APCH ISSUED A L TURN TO 270 DEG AND DSCNT TO 3000 FT PASSING THROUGH APPROX 4000 FT APCH ISSUED R TURN (TO 330 DEG) FOR TFC AVOIDANCE. A MATTER OF SECONDS LATER A TCASII RA OCCURRED; DIRECTING A 'CLB MANEUVER OF 2000-2500 FPM. SOCAL APCH WAS IMMEDIATELY ADVISED OF OUR RESPONSE TO THE RA (BY ME) AS THE FO DISCONNECTED THE AUTOPLT AND INITIATED THE MANEUVER. AS THE MANEUVER WAS INITIATED THE CONFLICTING TFC WAS OBSERVED ON TCASII AT APPROX 10 O'CLOCK; RAPIDLY CLBING FROM WHITE TO YELLOW TO THE RED RA. WHEN 'CLR OF CONFLICT' MESSAGE WAS RECEIVED AND RECOVERY COMPLETED OUR ACFT WAS AT 6000 FT.SOCAL APCH VECTORED US TO INTERCEPT ILS RWY 19R AT SNA AND A NORMAL APCH AND LNDG WAS ACCOMPLISHED. AFTER DEPLANING I RESPONDED TO A REQUEST FROM SOCAL APCH TO CONTACT THEM. I SPOKE WITH A SUPVR. WE DISCUSSED THE ALT AT WHICH THE RA OCCURRED; JOINT CONCERNS REF THE NEAR MISS; AND HE INDICATED THAT SOCAL APCH QUALITY ASSURANCE WOULD INVESTIGATE THE INCIDENT. TCASII WORKS!! - IN THIS CASE; IN ALL LIKELIHOOD; IT SAVED A COUPLE OF HUNDRED LIVES AS WELL AS 2 ACFT. WE NEVER SAW THE RA TFC VISUALLY; SO; WITHOUT TCASII THE BEST WE COULD HAVE HOPED FOR WAS A NEAR MISS.