Narrative:

While entering the nut tree airport area from napa and on skaggs radial from 040, other aircraft were landing on runway 2. At 3500' I flew past the airport and made started a 180 and descending planning to enter the left 45 for runway 2. Before I was able to start the 180 and descent, the unicom operator said winds had changed and soon as planes were out of pattern and off runway they would change to 20. At that time I turned a wide 180 to the left and back to a position to descend and enter a right 45 for runway 20. As I descended out of 3500 and entered the 5 mi radius, I announced my intentions. On reaching approximately 1500 MSL I announced entering the right 45. At approximately 1200 I was startled by the sighting of a plane climbing and coming from under my right wing very close. I pushed the yoke forward and to the left. The brief second I saw the other aircraft it had turned to its left also and up. I then returned to my 45 entry and descended to pattern altitude of 1,113, announcing downwind and right base. While making the right base turn I saw another aircraft at 11 O'clock and about 1/2 mi out also turning right base and several hundred feet higher. I heard no radio xmissions from either plane. As I started to turn final I had gone past the lining up with the runway and had to make a semi s-turn and at that time decided to go around. I announced that I was flying over the airport for a go around. The plane that was behind me was a twin and he made a touch and go and did not come back. I announced the crosswind. I turned at 800 MSL and downwind at 1,110 and base and landed. On pulling into the nut tree lot, I spoke with a gentleman there that was by the nut tree plane and he said that many do not announce their intentions while entering or departing that airport.

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Original NASA ASRS Text

Title: SMA HAS AN NMAC WHILE ENTERING THE TRAFFIC PATTERN.

Narrative: WHILE ENTERING THE NUT TREE ARPT AREA FROM NAPA AND ON SKAGGS RADIAL FROM 040, OTHER ACFT WERE LNDG ON RWY 2. AT 3500' I FLEW PAST THE ARPT AND MADE STARTED A 180 AND DESCENDING PLANNING TO ENTER THE LEFT 45 FOR RWY 2. BEFORE I WAS ABLE TO START THE 180 AND DSCNT, THE UNICOM OPERATOR SAID WINDS HAD CHANGED AND SOON AS PLANES WERE OUT OF PATTERN AND OFF RWY THEY WOULD CHANGE TO 20. AT THAT TIME I TURNED A WIDE 180 TO THE LEFT AND BACK TO A POSITION TO DSND AND ENTER A RIGHT 45 FOR RWY 20. AS I DESCENDED OUT OF 3500 AND ENTERED THE 5 MI RADIUS, I ANNOUNCED MY INTENTIONS. ON REACHING APPROX 1500 MSL I ANNOUNCED ENTERING THE RIGHT 45. AT APPROX 1200 I WAS STARTLED BY THE SIGHTING OF A PLANE CLIMBING AND COMING FROM UNDER MY RIGHT WING VERY CLOSE. I PUSHED THE YOKE FORWARD AND TO THE LEFT. THE BRIEF SECOND I SAW THE OTHER ACFT IT HAD TURNED TO ITS LEFT ALSO AND UP. I THEN RETURNED TO MY 45 ENTRY AND DESCENDED TO PATTERN ALT OF 1,113, ANNOUNCING DOWNWIND AND RIGHT BASE. WHILE MAKING THE RIGHT BASE TURN I SAW ANOTHER ACFT AT 11 O'CLOCK AND ABOUT 1/2 MI OUT ALSO TURNING RIGHT BASE AND SEVERAL HUNDRED FEET HIGHER. I HEARD NO RADIO XMISSIONS FROM EITHER PLANE. AS I STARTED TO TURN FINAL I HAD GONE PAST THE LINING UP WITH THE RWY AND HAD TO MAKE A SEMI S-TURN AND AT THAT TIME DECIDED TO GO AROUND. I ANNOUNCED THAT I WAS FLYING OVER THE ARPT FOR A GO AROUND. THE PLANE THAT WAS BEHIND ME WAS A TWIN AND HE MADE A TOUCH AND GO AND DID NOT COME BACK. I ANNOUNCED THE XWIND. I TURNED AT 800 MSL AND DOWNWIND AT 1,110 AND BASE AND LANDED. ON PULLING INTO THE NUT TREE LOT, I SPOKE WITH A GENTLEMAN THERE THAT WAS BY THE NUT TREE PLANE AND HE SAID THAT MANY DO NOT ANNOUNCE THEIR INTENTIONS WHILE ENTERING OR DEPARTING THAT ARPT.

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.