The instrument training flight was conducted in instrument meteorological conditions. The private pilot receiving instruction said that he initiated a “slight turn to the left which spatially disoriented me. We ended up in a spiral, and then my instructor took over and recovered [the airplane].” The flight instructor gave a similar account and stated that he “allowed the situation to deteriorate too far before taking control.” After landing, a visual inspection of the airplane revealed substantial damage in the form of “plastic deformation” to both wings consistent with overstress. The flight instructor reported that prior to the accident the airplane required a “1-3 degree” input in the roll axis to maintain the desired heading. When the flight instructor was asked if he felt the discrepancy was significant enough to declare an emergency, abort the mission, or perform a precautionary landing, and he replied, “No. We noticed it and briefed it, but no. It was noticed, but not a grounding condition.”