What happened
During a 25-minute flight, the aircraft experienced a partial loss of engine power while climbing between 400 and 500 feet above ground level. Following the power loss, the flight instructor reversed course to return to the airport; however, the aircraft lacked sufficient altitude to complete the return.
The instructor subsequently performed a forced landing on desert terrain. As the aircraft slowed to a speed between 20 and 30 miles per hour, it impacted the upslope side of a ditch and rolled into the ditch. At the start of the flight, there were 35 gallons of fuel in the tanks.
Findings
The investigation could not determine the specific reason for the partial engine power loss.