Narrative:

Proceeding north 1 mi off coastline, 1000 ft MSL. Saw underside of cessna taking a climbing left turn to avoid a collision. No time for me to react. Could clearly see undercarriage. Cessna appeared to be roughly perpendicular to my flight path. I was surprised to have any traffic coming from that direction, since it is open ocean and I was not near an airport traffic pattern. I was scanning heavily to the front, expecting other traffic to be also paralleling the coast. Also scanning from the coast, expecting other traffic from the mainland to turn and parallel the coast. Perhaps the cessna was further offshore than I was and this was part of returning onshore. In the future, I will definitely be more careful about including even 'unlikely' segments of the sky in my scan. Positive factors: I have wingtip strobes, which were probably highly visible to the other pilot. Also, my plane though small is almost all polish aluminum which might have caught a sun 'glint' and been visible to the other pilot.

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Original NASA ASRS Text

Title: EXPERIMENTAL RV6 PLT AND A CESSNA HAD AN AIRBORNE CONFLICT IN CLASS G AIRSPACE OVER WATER NEAR SHORE.

Narrative: PROCEEDING N 1 MI OFF COASTLINE, 1000 FT MSL. SAW UNDERSIDE OF CESSNA TAKING A CLBING L TURN TO AVOID A COLLISION. NO TIME FOR ME TO REACT. COULD CLRLY SEE UNDERCARRIAGE. CESSNA APPEARED TO BE ROUGHLY PERPENDICULAR TO MY FLT PATH. I WAS SURPRISED TO HAVE ANY TFC COMING FROM THAT DIRECTION, SINCE IT IS OPEN OCEAN AND I WAS NOT NEAR AN ARPT TFC PATTERN. I WAS SCANNING HEAVILY TO THE FRONT, EXPECTING OTHER TFC TO BE ALSO PARALLELING THE COAST. ALSO SCANNING FROM THE COAST, EXPECTING OTHER TFC FROM THE MAINLAND TO TURN AND PARALLEL THE COAST. PERHAPS THE CESSNA WAS FURTHER OFFSHORE THAN I WAS AND THIS WAS PART OF RETURNING ONSHORE. IN THE FUTURE, I WILL DEFINITELY BE MORE CAREFUL ABOUT INCLUDING EVEN 'UNLIKELY' SEGMENTS OF THE SKY IN MY SCAN. POSITIVE FACTORS: I HAVE WINGTIP STROBES, WHICH WERE PROBABLY HIGHLY VISIBLE TO THE OTHER PLT. ALSO, MY PLANE THOUGH SMALL IS ALMOST ALL POLISH ALUMINUM WHICH MIGHT HAVE CAUGHT A SUN 'GLINT' AND BEEN VISIBLE TO THE OTHER PLT.

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.