Primary finding
Probable cause
The inflight disconnection of the right aileron 'otellier coupler fitting due to lubricants on the coupler slide lock plate, and the failure of the glider manufacturer to include appropriate precautionary information in the maintenance and/or flight manual. Factors in the accident were: the failure of the glider and fitting manufacturers to mandate fail/safe devices for the coupler fitting, and the design of the glider regarding the facilitation of the coupler connections during the glider assembly process.