On September 5, 1995, at 1645 central daylight time, a Let L-23 Super Blanik, N99970, operated by the Redwing Soaring Association, sustained substantial damage when it impacted power lines during final approach in White Bear Lake, Minnesota. The private pilot reported no injuries. The local, personal flight was conducted under 14 CFR Part 91 in visual meteorological conditions. No flight plan was filed. The pilot reported that he was on final approach and extended the spoilers to reduce his altitude. He thought he retracted the spoilers. He experienced "quick" and "unexpected" altitude loss. The landing gear impacted a power line. The wire broke but the glider descended onto a road. He wrote "I question whether I actually retracted the spoilers. This may account for the excess loss of altitude." According to a Federal Aviation Administration (FAA) inspector, who examined the wreckage, no evidence of preimpact malfunction was discovered.