BELLANCA 7GCBC crash near Midlothian, Texas, United States

The flight instructor's inability to move the control stick after takeoff for undetermined reasons, which resulted in an exceedance of the airplane's critical angle of attack and inadvertent aerodynamic stall. The reason for the inability to move the control stick could not be determined, because postaccident examination revealed no evidence of flight control malfunctions or anomalies that would have precluded normal operation.