***This report was modified on November 15, 2012. Please see the docket for this accident to view the original report with revisions shown.*** The pilots’ failure to avoid and recover from the prohibited maneuver of aerodynamic spin during a training flight, for undetermined reasons. Contributing to the severity of the accident was the failure of the ballistic parachute rocket as a result of the manufacturer’s use of an inadequate thread sealant glue on the end caps of the rocket. Contributing to the severity of the occupants’ injuries was the separation of their shoulder belt attachment brackets at impact.