N28MR

Probable cause: The pilot s loss of control of the airplane during low-airspeed airwork and his failure to promptly recover the airplane from the aerodynamic stall, which resulted in a spin. Contributing to the accident were the pilot and certified flight instructor s intentional operation of the airplane for the purpose of performing instructional airwork with only a throw-over control yoke installed and the pilot s lack of recent flight experience in the airplane make and model. Contributing to the lack of accurate performance data (including the air minimum control airspeed) for the modified airplane was the lack of guidance by the Federal Aviation Administration for an installer of a supplemental…