Narrative:

I entered left traffic runway 24 rialto -- announced on unicom -- downwind, base, and final. No other traffic made any calls on unicom. On final, an small aircraft a or small aircraft B turned from left base to final (unannounced) 75 in front of me at my altitude (approximately 200 AGL). I turned toward his tail, and descended below him on his left. Separation was 20 ft at closest point. Immediate action was required to avoid collision. Near midair collision was not filed.

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Original NASA ASRS Text

Title: PLT OF SMA PRIVATE ACFT HAD A NMAC WITH ANOTHER SMA ACFT DURING APCH AT A NON-CTLED ARPT.

Narrative: I ENTERED L TFC RWY 24 RIALTO -- ANNOUNCED ON UNICOM -- DOWNWIND, BASE, AND FINAL. NO OTHER TFC MADE ANY CALLS ON UNICOM. ON FINAL, AN SMA A OR SMA B TURNED FROM L BASE TO FINAL (UNANNOUNCED) 75 IN FRONT OF ME AT MY ALT (APPROX 200 AGL). I TURNED TOWARD HIS TAIL, AND DSNDED BELOW HIM ON HIS L. SEPARATION WAS 20 FT AT CLOSEST POINT. IMMEDIATE ACTION WAS REQUIRED TO AVOID COLLISION. NMAC WAS NOT FILED.

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.