Control Stick Pop Leads to Forced Landing and Upset

Incident Description

During cruise flight at approximately 700 feet above ground level, the pilot felt the control stick "pop" and the nose of the airplane pitch downward. The pilot pulled back the throttle and turned off the magnetos. The passenger adjusted the elevator trim, but the pitch attitude did not change. The pilot then entered a side slip, which brought the nose up to level. He straightened the nose of the airplane just prior to impact with terrain. The airplane subsequently flipped inverted, resulting in substantial damage to the wings and fuselage.

Examination Findings

A postaccident examination of the airplane revealed that the UP elevator turnbuckle had become detached at the elevator torque tube. The turnbuckle was not safety wired. The examination also noted that new cables were installed in the airplane in 2007.