Flight Details
A flight instructor was building hours in a powered glider in preparation for his glider instructor rating examination. He departed from the airport with power and climbed westward in search of thermals. Upon reaching 4,000 feet above ground level (agl), he shut down the engine, leaving the battery power on. He continued to climb to 4,500 ft.
Engine Restart Attempts
After approximately 30 minutes of non-powered flight, the instructor attempted to restart the engine. The starter cranked only briefly, and the propeller traveled one full revolution before stopping. A second attempt also proved unsuccessful.
Forced Landing
Realizing he was too far from the airport to glide back, the instructor located a field for a forced landing. During the landing roll, the main landing gear wheels dug into the soft terrain, causing the glider to nose over and come to rest inverted.
Post-Accident Examination
An examination after the accident revealed that the single battery had been depleted while powering the avionics during the non-powered flight. The depleted level was insufficient to power the starter during the engine restart sequence.
Damage
The powered glider sustained substantial damage to the engine mount truss.
Pilot Report
The pilot reported no preimpact malfunctions or failures of the airframe or engine that would have precluded normal operation.