Narrative:

We were being vectored for a visual approach to sna on a 20 degree heading, level at 5000'. Controller issued a traffic alert to us at 12 O'clock and either 5 or 8 miles climbing out of 4200'. We began looking for traffic but could not see it. A couple of minutes passed and approach issued a followup alert - traffic at 12 O'clock and 3 miles climbing out of 4600'. Controller issued us a 20 degree turn to the right for vectors 'behind' traffic. He again issued an alert to us with traffic at 12 O'clock and less than a mile. Traffic was not in sight at this point. The captain and I were both looking for traffic at 12 O'clock when the captain spotted aircraft at approximately 1-2 O'clock. I leaned aa forward at the same time the spoat thed traffic and caught a glimpse of a light twin (small transport Y) with a 'T' tail. He was in a wings level climb at approximately 4800' one O'clock and 1 to 2000' horizontally from us. The captain called for a climb - I was already adding power and pulled our aircraft into a climbing left turn. As I did this the other aircraft also began a left bank and passed under us by about 200'. We reached an altitude of 5500' before returning to our assigned altitude of 5000'. In order to make all of the la basin safe all aircraft must have altitude encoding x-ponders (it saved our lives, this time). I also believe that politics should be removed from the safety issue and the TCA expanded to include lgb, bur, ont and sna airports.

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Original NASA ASRS Text

Title: MLG ON VECTOR FOR VISUAL APCH GIVEN SEVERAL TRAFFIC CALLS ON SMT AND STILL HAD NMAC WITH SMT.

Narrative: WE WERE BEING VECTORED FOR A VISUAL APCH TO SNA ON A 20 DEG HEADING, LEVEL AT 5000'. CTLR ISSUED A TFC ALERT TO US AT 12 O'CLOCK AND EITHER 5 OR 8 MILES CLIMBING OUT OF 4200'. WE BEGAN LOOKING FOR TFC BUT COULD NOT SEE IT. A COUPLE OF MINUTES PASSED AND APCH ISSUED A FOLLOWUP ALERT - TFC AT 12 O'CLOCK AND 3 MILES CLIMBING OUT OF 4600'. CTLR ISSUED US A 20 DEG TURN TO THE RIGHT FOR VECTORS 'BEHIND' TFC. HE AGAIN ISSUED AN ALERT TO US WITH TFC AT 12 O'CLOCK AND LESS THAN A MILE. TFC WAS NOT IN SIGHT AT THIS POINT. THE CAPT AND I WERE BOTH LOOKING FOR TFC AT 12 O'CLOCK WHEN THE CAPT SPOTTED ACFT AT APPROX 1-2 O'CLOCK. I LEANED AA FORWARD AT THE SAME TIME THE SPOAT THED TFC AND CAUGHT A GLIMPSE OF A LIGHT TWIN (SMT Y) WITH A 'T' TAIL. HE WAS IN A WINGS LEVEL CLIMB AT APPROX 4800' ONE O'CLOCK AND 1 TO 2000' HORIZONTALLY FROM US. THE CAPT CALLED FOR A CLIMB - I WAS ALREADY ADDING POWER AND PULLED OUR ACFT INTO A CLIMBING LEFT TURN. AS I DID THIS THE OTHER ACFT ALSO BEGAN A LEFT BANK AND PASSED UNDER US BY ABOUT 200'. WE REACHED AN ALT OF 5500' BEFORE RETURNING TO OUR ASSIGNED ALT OF 5000'. IN ORDER TO MAKE ALL OF THE LA BASIN SAFE ALL ACFT MUST HAVE ALT ENCODING X-PONDERS (IT SAVED OUR LIVES, THIS TIME). I ALSO BELIEVE THAT POLITICS SHOULD BE REMOVED FROM THE SAFETY ISSUE AND THE TCA EXPANDED TO INCLUDE LGB, BUR, ONT AND SNA ARPTS.

Data retrieved from NASA's ASRS site as of August 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.