Narrative:

On approach coming from las on ziggy STAR over the mountains we were given a late descent out of 10000 ft due to known VFR traffic at 9500 ft. We had the runway in sight and were given descent to 4000 ft and cleared for visual approach to runway 26R. I started to configure early since we were high and most of my attention was inside the cockpit flying the aircraft. Approach control called out unknown traffic (no transponder) and we looked but did not make contact. I called for gear and flaps and final descent checklist approximately 6000 ft MSL. After responding to the checklist and checking the items, I looked outside and saw the traffic at 12:30 O'clock, approximately same altitude and about 500 ft horizontally. I broke left and thought I saw him (it was some kind of high wing small aircraft, I think) also break left. It wasn't a violent action, and we landed without incident. When the controller initially called the traffic he said unknown altitude, 'probably low.' I think this gave us a false sense of security. Also, our attention was too much in the cockpit due to the unusually high profile, and the reading of the checklist. My recommendation is that all GA aircraft be equipped with mode C transponder, and given more education on high use airspace.

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Original NASA ASRS Text

Title: MLG HAS NMAC WITH SMA ON APCH TO ONT.

Narrative: ON APCH COMING FROM LAS ON ZIGGY STAR OVER THE MOUNTAINS WE WERE GIVEN A LATE DSCNT OUT OF 10000 FT DUE TO KNOWN VFR TFC AT 9500 FT. WE HAD THE RWY IN SIGHT AND WERE GIVEN DSCNT TO 4000 FT AND CLRED FOR VISUAL APCH TO RWY 26R. I STARTED TO CONFIGURE EARLY SINCE WE WERE HIGH AND MOST OF MY ATTN WAS INSIDE THE COCKPIT FLYING THE ACFT. APCH CTL CALLED OUT UNKNOWN TFC (NO XPONDER) AND WE LOOKED BUT DID NOT MAKE CONTACT. I CALLED FOR GEAR AND FLAPS AND FINAL DSCNT CHKLIST APPROX 6000 FT MSL. AFTER RESPONDING TO THE CHKLIST AND CHKING THE ITEMS, I LOOKED OUTSIDE AND SAW THE TFC AT 12:30 O'CLOCK, APPROX SAME ALT AND ABOUT 500 FT HORIZLY. I BROKE L AND THOUGHT I SAW HIM (IT WAS SOME KIND OF HIGH WING SMA, I THINK) ALSO BREAK L. IT WASN'T A VIOLENT ACTION, AND WE LANDED WITHOUT INCIDENT. WHEN THE CTLR INITIALLY CALLED THE TFC HE SAID UNKNOWN ALT, 'PROBABLY LOW.' I THINK THIS GAVE US A FALSE SENSE OF SECURITY. ALSO, OUR ATTN WAS TOO MUCH IN THE COCKPIT DUE TO THE UNUSUALLY HIGH PROFILE, AND THE READING OF THE CHKLIST. MY RECOMMENDATION IS THAT ALL GA ACFT BE EQUIPPED WITH MODE C XPONDER, AND GIVEN MORE EDUCATION ON HIGH USE AIRSPACE.

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.