What happened
Shortly after taking off from runway 26, the pilot of a Blanik L-13 reported that the control stick became difficult to move. The pilot chose to proceed with the air tow, intending to release at 200 feet above ground level (AGL).
Following the release, the pilot attempted to turn the glider to return to the runway for landing. During this maneuver, the pilot continued to experience control difficulties and suspected that the passenger in the front seat might have been holding the forward control stick. Although the pilot instructed the passenger to release the stick, control was only momentarily regained before being lost again. The pilot was unable to maintain control of the Blanik L-13, resulting in a collision with runway 08. There were no fatalities reported.
The investigation
An examination of the wreckage showed no mechanical problems with the glider's control mechanisms. However, an inspection of a different Blanik L-13 demonstrated that applying very little force to the forward control stick is sufficient to render the rear stick ineffective.