Dg Flugzeugbau Gmbh DG 800B N800YG accident near Clements, California

Probable cause

The motorglider pilot's decision to perform an in-flight engine start with insufficient altitude, which resulted in an off-airport landing and collision with trees after the engine did not start. Contributing to the accident was the pilot's distraction by the engine restart procedures during a critical portion of the landing approach.

NTSB analysis

After gliding for about 2 ½ hours cross-country, the motorglider began to encounter reduced lift conditions. The private pilot intended to start the engine so that he could return to the departure airport under powered flight but also identified a nearby field for landing in case the engine did not start. As the glider overflew the field, the pilot extended the propeller and attempted three times to start the engine; however, it did not start. With limited altitude, increased drag from the propeller and mast, and an unanticipated headwind, the glider was unable to reach the landing target and impacted trees, resulting in substantial damage.

Postaccident examination did not reveal any anomalies with the airframe or engine that would have precluded normal operation, and the engine started on the third attempt. The pilot stated that he had used a tow plane for departure on the accident flight and that the engine had not been operated for about 5 months leading up to the accident. He further stated that, in his experience, motorgliders could be prone to engine starting difficulties, especially after a period of nonuse.

The pilot attempted the engine start at an altitude below that recommended by the glider manufacturer, thereby reducing his margin for error when the engine did not start. He also reported that he spent too much time and attention on starting the engine and not enough on landing. Had the pilot initiated the engine start procedure at a higher altitude, he likely would have had sufficient time to complete the emergency starting and off-airport landing procedures, restow the propeller, and focus on the task of the off-airport landing.

Text from the NTSB. Open the NTSB docket for WPR16LA096 for the full record.