Narrative:

I had been flying my glider for about 2 hours and been working both south and north of my home field. The total distance between the furthest points covered was about 20 miles. I had been north as far as I could get with the available thermals and then worked my way west looking for more lift. Finding no lift I turned back south to follow the valley back to the gliderport. I was in straight cruise at about 26-2700 ft. When a power plane suddenly appeared right above me at what I estimate to be 50-100 ft. He was almost on the same heading as me and was descending. My glider is equipped with powerflarm which will give an alert when it detects an active transponder signal. I had been getting alerts during the entire flight; but did not get an alert from this plane even when it was right above me. I was also monitoring tower radio traffic from a nearby airport and did not hear anything about a plane approaching from the north. However; there was a lot of radio traffic on both my primary and secondary frequencies and I could not keep up with it all. After the plane passed me; I heard someone notify the nearby airport tower of a close call with a glider that they estimated to be 50 ft below them. Because it was a few minutes after my encounter I thought they were talking about someone else. In hindsight; given the low number of gliders in the air at the time; I think it was probably a report of my encounter.I don't know what more I could have done to avoid this conflict. If I had gotten an alert on my powerflarm I most likely would have banked my glider to make it more visible to an approaching plane. I do not know if the other plane had an operational transponder; but if it had I should have had warning of its approach. I will recheck my powerflarm to make sure the antenna connections are secure.

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Original NASA ASRS Text

Title: Schleicher glider pilot reported an NMAC with a light single and did not get an alert from his PowerFlarm unit.

Narrative: I had been flying my glider for about 2 hours and been working both south and north of my home field. The total distance between the furthest points covered was about 20 miles. I had been north as far as I could get with the available thermals and then worked my way west looking for more lift. Finding no lift I turned back south to follow the valley back to the gliderport. I was in straight cruise at about 26-2700 ft. when a power plane suddenly appeared right above me at what I estimate to be 50-100 ft. He was almost on the same heading as me and was descending. My glider is equipped with PowerFlarm which will give an alert when it detects an active transponder signal. I had been getting alerts during the entire flight; but did not get an alert from this plane even when it was right above me. I was also monitoring Tower radio traffic from a nearby airport and did not hear anything about a plane approaching from the north. However; there was a lot of radio traffic on both my primary and secondary frequencies and I could not keep up with it all. After the plane passed me; I heard someone notify the nearby airport Tower of a close call with a glider that they estimated to be 50 ft below them. Because it was a few minutes after my encounter I thought they were talking about someone else. In hindsight; given the low number of gliders in the air at the time; I think it was probably a report of my encounter.I don't know what more I could have done to avoid this conflict. If I had gotten an alert on my PowerFlarm I most likely would have banked my glider to make it more visible to an approaching plane. I do not know if the other plane had an operational transponder; but if it had I should have had warning of its approach. I will recheck my PowerFlarm to make sure the antenna connections are secure.

Data retrieved from NASA's ASRS site 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.