Narrative:

Approaching sanderson field I monitored 122.8 and heard 2 aircraft in right hand pattern so I entered a 45 degree to right downwind and reported. I also called on a 2 mi final to runway 23. About 3/4 mi out a helicopter seen entering short final from a right base (difficult to see because of the low sun). I assumed he would go someplace other than the runway and would not be a conflict, but he got to the end of the runway and stopped. I don't know if he landed or was hovering low. My closure rate was surprising and I reacted late. I added full power pulled up and banked right. I don't know how close I came, but much too close for comfort. We communicated as helicopter and cardinal and he asked if I would be landing and I said yes thinking we could talk about it. When I landed and turned off the runway he was nowhere to be found. Approaching the airport on 122.8 I heard 2 aircraft in right traffic, turns out they were both helicopters. The pattern should be left. I relied on what I heard. I guess helicopters use right traffic there I don't know. I shouldn't have assumed the helicopter entering final in front of me would land somewhere else on the field. I was the one in a final position to prevent an accident and I shouldn't have delayed.

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Original NASA ASRS Text

Title: NMAC. UNCTLED ARPT, 2 OTHER ACFT RPTED IN R TFC PATTERN, RPTR ENTERED PATTERN AND SAW HELI, THOUGHT HELI WOULD LAND SOMEWHERE OTHER THAN RWY, HAD TO LAST MIN GAR TO EVADE THE HELI.

Narrative: APCHING SANDERSON FIELD I MONITORED 122.8 AND HEARD 2 ACFT IN R HAND PATTERN SO I ENTERED A 45 DEG TO R DOWNWIND AND RPTED. I ALSO CALLED ON A 2 MI FINAL TO RWY 23. ABOUT 3/4 MI OUT A HELI SEEN ENTERING SHORT FINAL FROM A R BASE (DIFFICULT TO SEE BECAUSE OF THE LOW SUN). I ASSUMED HE WOULD GO SOMEPLACE OTHER THAN THE RWY AND WOULD NOT BE A CONFLICT, BUT HE GOT TO THE END OF THE RWY AND STOPPED. I DON'T KNOW IF HE LANDED OR WAS HOVERING LOW. MY CLOSURE RATE WAS SURPRISING AND I REACTED LATE. I ADDED FULL PWR PULLED UP AND BANKED R. I DON'T KNOW HOW CLOSE I CAME, BUT MUCH TOO CLOSE FOR COMFORT. WE COMMUNICATED AS HELI AND CARDINAL AND HE ASKED IF I WOULD BE LNDG AND I SAID YES THINKING WE COULD TALK ABOUT IT. WHEN I LANDED AND TURNED OFF THE RWY HE WAS NOWHERE TO BE FOUND. APCHING THE ARPT ON 122.8 I HEARD 2 ACFT IN R TFC, TURNS OUT THEY WERE BOTH HELIS. THE PATTERN SHOULD BE L. I RELIED ON WHAT I HEARD. I GUESS HELIS USE R TFC THERE I DON'T KNOW. I SHOULDN'T HAVE ASSUMED THE HELI ENTERING FINAL IN FRONT OF ME WOULD LAND SOMEWHERE ELSE ON THE FIELD. I WAS THE ONE IN A FINAL POS TO PREVENT AN ACCIDENT AND I SHOULDN'T HAVE DELAYED.

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.