Primary finding
Probable cause
The pilot's failure to stow the speed brake prior to attempting takeoff.
Investigator assessment
Analysis narrative
The pilot reported that following a landing and back-taxi in a motor glider, he failed to stow the speed brake prior to attempting a subsequent takeoff. During the takeoff attempt, the glider would not climb out of ground effect. The motor glider departed the end of the runway and impacted terrain which resulted in substantial damage to the fuselage.