Sail Plane
Flight Crew Flight Instructor; Flight Crew Commercial
Flight Crew Last 90 Days 20; Flight Crew Total 1000; Flight Crew Type 500
Communication Breakdown; Situational Awareness
Conflict NMAC
General None Reported / Taken
Airspace Structure; Human Factors
Glider departed X52 grass runway 18 and was under tow during glider training flight to a release altitude of about 1;000 feet AGL. Transition pilot was in front seat handling tow under supervision of CFI-G. After departure tow plane continued climb while turning to north heading. Not more than one statue mile east of X52 and about one statute mile west of VRB Class D boundary; a single engine low-wing powered plane with tri-gear passed directly overhead of our glider; coming over us from our right side; from about 2 o'clock. For the very brief observation period it showed no sign of evasive maneuver or recognition of our glider. My estimate was 100 feet vertical separation; directly overhead. Because of the momentary view and poor angle; I was unable to read N-number but the plane was mostly white with a narrow trim stripe on the side. Immediately after it passed over I glanced at the altimeter and noted slightly above 800 feet AGL. I asked the [pilot] in front seat to note the time. The tow pilot was unaware of incident based on our radio exchange. We assumed no airplane had departed VRB. No response from the airplane after my radio call (122.900) asking if pilot had seen us at any time. Glider tow and flight continued uneventfully.VRB is about 7 miles west of X52 and less than 5 miles from ocean waters. The glider [pilots] advise VRB Tower by land line or Tower frequency the start-stop plan for X52 glider ops each day; and Tower includes this advisory on ATIS. Nonetheless it is almost a daily routine to see 1-2 aircraft pass directly over X52 between an estimated 1;000 - 2;000 feet AGL; usually on east or west headings. At least one training school provides student pilots with training aids identifying a 'marshalling' point landmark shopping center less than ½ mile east of X52; despite informal requests from [glider pilots] to move such point to 2 miles north of south of X52. There is essentially no communication heard on X52 CTAF 122.900 even when such airplanes are passing overhead below 2;000 feet AGL. There is also belief that many student power pilots are uncomfortable with their English language skills.
Glider pilot reported an NMAC with a small powered aircraft while performing training exercises.