Narrative:

While approaching uncontrolled paso robles airport I set up for a 45 degree entry to what I thought was a left downwind for runway 19. Runway 19 was active per prior traffic on unicom, although at the time of my approach there was no other radio traffic on the unicom channel. Visibility was broadcast on tweb as 10 mi but there was considerable haze as descent was made to pattern altitude, thus making the runways hard to see. I had apparently misread my directional gyro and was instead actually entering left downwind for runway 1 and not runway 19 as intended. On turning base my aircraft came within 500' vertical and 1000' horizontal of a small biplane, small aircraft Y, which crossed from left to right above our flight path. Neither I nor the pilot of the biplane took evasive action. No radio calls were heard from the biplane. At that point I discovered my error and aborted my intended landing by turning left downwind to runway 19 and climbing out of the pattern. This occurrence could have been avoided by improved preflight or in-flight planning, reviewing airport maps in an airport guide and reviewing pertinent landmarks for approach planning, prior to approaching any airport, familiar or unfamiliar. It could also have been prevented by overflying the intended airport at a safe altitude above the air traffic area to review airport layout.

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Original NASA ASRS Text

Title: INEXPERIENCED SMA PLT ATTEMPTS NON STANDARD VFR APCH TO PRB, GETS CONFUSED AND FLIES THE RECIPROCAL OF HIS INTENDED HEADING, HAS CLOSE ENCOUNTER WITH A BIPLANE.

Narrative: WHILE APCHING UNCONTROLLED PASO ROBLES ARPT I SET UP FOR A 45 DEG ENTRY TO WHAT I THOUGHT WAS A LEFT DOWNWIND FOR RWY 19. RWY 19 WAS ACTIVE PER PRIOR TFC ON UNICOM, ALTHOUGH AT THE TIME OF MY APCH THERE WAS NO OTHER RADIO TFC ON THE UNICOM CHANNEL. VISIBILITY WAS BROADCAST ON TWEB AS 10 MI BUT THERE WAS CONSIDERABLE HAZE AS DSCNT WAS MADE TO PATTERN ALT, THUS MAKING THE RWYS HARD TO SEE. I HAD APPARENTLY MISREAD MY DIRECTIONAL GYRO AND WAS INSTEAD ACTUALLY ENTERING LEFT DOWNWIND FOR RWY 1 AND NOT RWY 19 AS INTENDED. ON TURNING BASE MY ACFT CAME WITHIN 500' VERTICAL AND 1000' HORIZONTAL OF A SMALL BIPLANE, SMA Y, WHICH CROSSED FROM LEFT TO RIGHT ABOVE OUR FLT PATH. NEITHER I NOR THE PLT OF THE BIPLANE TOOK EVASIVE ACTION. NO RADIO CALLS WERE HEARD FROM THE BIPLANE. AT THAT POINT I DISCOVERED MY ERROR AND ABORTED MY INTENDED LNDG BY TURNING LEFT DOWNWIND TO RWY 19 AND CLIMBING OUT OF THE PATTERN. THIS OCCURRENCE COULD HAVE BEEN AVOIDED BY IMPROVED PREFLT OR INFLT PLANNING, REVIEWING ARPT MAPS IN AN ARPT GUIDE AND REVIEWING PERTINENT LANDMARKS FOR APCH PLANNING, PRIOR TO APCHING ANY ARPT, FAMILIAR OR UNFAMILIAR. IT COULD ALSO HAVE BEEN PREVENTED BY OVERFLYING THE INTENDED ARPT AT A SAFE ALT ABOVE THE ATA TO REVIEW ARPT LAYOUT.

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.