Narrative:

We were being vectored for a visual approach by approach control to runway 19R, sna. We were given a descent clearance from 5000 ft MSL to 3000 ft and a right turn directly at the lemon OM (to intercept the localizer from lemon would be a right 135 degree turn). I was hand flying the airplane through 3500 ft MSL and descending when we got a TCASII warning on an aircraft within 1 mi at our 11 O'clock position and 3000 ft. At the same time approach control told us about the traffic. I immediately began a climbing right turn, leveling off at 3800 ft MSL, heading just inside lemon OM, which satisfied the TCASII action requirements. The captain obtained visual contact with a single engine aircraft as it passed under us, left to right. The aircraft never changed altitude or direction, and he continued sebound, crossing the runway 19R localizer path approximately 3 mi from the end of the runway at 3000 ft MSL. When we were well clear of the conflict we turned toward the runway and resumed our descent (after being cleared for the visual approach, which we were not cleared for prior to the conflict). It was a saturday afternoon and approach control was very busy. However, his traffic warning to us was very late. The aircraft was at a hard altitude (3000 ft) VFR, not talking to approach control or the sna tower. He was also inside the air traffic area. I would also assume he was not visually looking for traffic, since we must have 'filled' the front windscreen as we tried to avoid him, and he never altered his path or altitude. He did have an encoding transponder. Sna needs more airspace protection.

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Original NASA ASRS Text

Title: LGT HAS A CONFLICT WITH AN SMA IN THE SNA ARSA.

Narrative: WE WERE BEING VECTORED FOR A VISUAL APCH BY APCH CTL TO RWY 19R, SNA. WE WERE GIVEN A DSCNT CLRNC FROM 5000 FT MSL TO 3000 FT AND A R TURN DIRECTLY AT THE LEMON OM (TO INTERCEPT THE LOC FROM LEMON WOULD BE A R 135 DEG TURN). I WAS HAND FLYING THE AIRPLANE THROUGH 3500 FT MSL AND DSNDING WHEN WE GOT A TCASII WARNING ON AN ACFT WITHIN 1 MI AT OUR 11 O'CLOCK POS AND 3000 FT. AT THE SAME TIME APCH CTL TOLD US ABOUT THE TFC. I IMMEDIATELY BEGAN A CLBING R TURN, LEVELING OFF AT 3800 FT MSL, HDG JUST INSIDE LEMON OM, WHICH SATISFIED THE TCASII ACTION REQUIREMENTS. THE CAPT OBTAINED VISUAL CONTACT WITH A SINGLE ENG ACFT AS IT PASSED UNDER US, L TO R. THE ACFT NEVER CHANGED ALT OR DIRECTION, AND HE CONTINUED SEBOUND, XING THE RWY 19R LOC PATH APPROX 3 MI FROM THE END OF THE RWY AT 3000 FT MSL. WHEN WE WERE WELL CLR OF THE CONFLICT WE TURNED TOWARD THE RWY AND RESUMED OUR DSCNT (AFTER BEING CLRED FOR THE VISUAL APCH, WHICH WE WERE NOT CLRED FOR PRIOR TO THE CONFLICT). IT WAS A SATURDAY AFTERNOON AND APCH CTL WAS VERY BUSY. HOWEVER, HIS TFC WARNING TO US WAS VERY LATE. THE ACFT WAS AT A HARD ALT (3000 FT) VFR, NOT TALKING TO APCH CTL OR THE SNA TWR. HE WAS ALSO INSIDE THE ATA. I WOULD ALSO ASSUME HE WAS NOT VISUALLY LOOKING FOR TFC, SINCE WE MUST HAVE 'FILLED' THE FRONT WINDSCREEN AS WE TRIED TO AVOID HIM, AND HE NEVER ALTERED HIS PATH OR ALT. HE DID HAVE AN ENCODING XPONDER. SNA NEEDS MORE AIRSPACE PROTECTION.

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