The pilot of the motor-glider reported that, while enroute on a local flight he encountered an area of unexpected sink. Turning toward an area where lift was expected, additional sink was encountered. When the motor-glider was about 300 ft above the trees, the propeller was unfeathered and the engine was started. The motor-glider continued to descend due to downdraft and the pilot deployed the airframe parachute. The motor-glider continued to descend and impacted vegetation.The motor-glider sustained substantial damage to both wings and fuselage.

The pilot reported that there were no preaccident mechanical failures or malfunctions with the motor-glider that would have precluded normal operation.