What happened
The airplane was climbing normally after takeoff when it suddenly pitched upward to an extreme attitude between 70 and 80 degrees. The aircraft stalled, dropped its right wing, leveled out, and impacted the ground in a near-flat position. The weight and center of gravity were within allowable limits.
The investigation
Examination of the wreckage revealed no pre-impact mechanical issues that could cause an inadvertent pitch-up. The pilot reported only that he was unable to move the control column far enough forward to stop the climb. The pilot's seat was found in the full forward position. The right locking pin was engaged in its hole, but the left pin was positioned 1/4 inch forward of the front locking hole. Deep scratches were visible on the rail sides where the seat attachments slide. A fresh scratch was noted on the outboard side recessed surface near the aft end.
Findings
The pilot's inability to move the control column forward suggests the seat may not have been properly locked in place. The discrepancy in the left locking pin position and evidence of recent movement indicate the seat shifted during flight. This likely reduced the pilot's ability to apply sufficient forward pressure on the controls to prevent the stall.
Safety message
Pilots must ensure their seats are fully locked in both locking holes before flight to maintain proper control reach and leverage.