Primary finding
Probable cause
An inadvertent encounter with a wind gust while maneuvering.
Investigator assessment
Analysis narrative
Both pilots were alternating flying duties in a Burkhart Grob G 103 Twin II glider. They had been soaring along a ridge for approximately 1 hour in non-turbulent wind. The rear seat pilot was flying on the upwind side of the ridge, about 500 feet above the summit, when a gust of wind suddenly forced the glider to the downwind side of the ridge, about 25 feet below the summit. The glider then impacted trees, sustained substantial damage, and both pilots were seriously injured. The reported wind at an airport about 25 miles northeast of the accident site, about the time of the accident, was 270 degrees at 6 knots. Examination of the glider did not reveal any preimpact mechanical malfunctions, nor did the pilots report any.
Source record
Factual narrative
Both pilots were alternating flying duties in a Burkhart Grob G 103 Twin II glider. They had been soaring along a ridge for approximately 1 hour in non-turbulent wind. The rear seat pilot was flying on the upwind side of the ridge, about 500 feet above the summit, when a gust of wind suddenly forced the glider to the downwind side of the ridge, about 25 feet below the summit. The glider then impacted trees, sustained substantial damage, and both pilots were seriously injured. The reported wind at an airport about 25 miles northeast of the accident site, about the time of the accident, was 270 degrees at 6 knots. Examination of the glider by a Federal Aviation Administration inspector did not reveal any preimpact mechanical malfunctions, nor did the pilots report any.