On May 22, 1999, at 1225 hours Pacific daylight time, an I.C.A. Brasov IS-29D2, N8217A, sustained substantial damage when it made an off-field landing in an open field 5 miles southeast of the Mountain Valley Airport, Tehachapi, California. The glider, operated by Skylark North under 14 CFR Part 91, was rented by the pilot. The commercial glider pilot, the sole occupant, was not injured. The flight originated from the Mountain Valley Airport, at 1200 the day of the accident for a local area personal flight. Visual meteorological conditions were observed and no flight plan was filed. In a telephone interview with the Safety Board, the pilot said that he spoke with other pilots before the flight to determine the soaring conditions. The pilots he spoke with reported that the lift conditions were not great but were generally satisfactory. A glider instructor pilot told him that there were areas of lift and areas of sink out there, but that there shouldn't be a problem making the airport from where he was let go from the tow plane. The pilot stated that after release from the tow plane he experienced "a little bit of lift and then a huge sink rate and couldn't make it over the ridge" that separated him from the airport. He realized that he would not make it back to the airport and attempted to make a forced landing southeast of the airport and collided with ground obstructions during the landing roll.