Primary finding
Probable cause
The failure of the starter generator which resulted in the subsequent loss of engine power. Contributing to the accident were the low altitude at which the airplane was operating, the tall grass, and the ditch.
Investigator assessment
Analysis narrative
The pilot reported that while in cruise flight at approximately 500 feet above ground level, the radios began "popping and breaking squelch." He stated that he realized the generator system failed and approximately 30 seconds later, the engine began to lose power. He advanced the throttle and turned back toward the departure airport. The pilot stated the engine then began to vibrate and rapidly lose power. The pilot dumped the chemical load and identified a road on which to land. During the landing, the left wing caught in the tall grass alongside the road, spinning the airplane around and into a ditch. Inspection revealed the starter generator failed which was followed shortly thereafter by the loss of engine power. The pilot reported the starter generator was on fire after the accident.
Source record
Factual narrative
On August 10, 2008, at 0635 central daylight time, an Air Tractor AT-802A, N9078G, collided with a ditch during an off airport forced landing in Turton, South Dakota. The pilot was not injured. The airplane received substantial damage. The aerial application flight was operated by Wilbur-Ellis Air LLC under Title 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed and no flight plan was filed. The flight originated from Huron, South Dakota, at 0615. The pilot reported that while in cruise flight at approximately 500 feet above ground level, the radios began "popping and breaking squelch." He stated he realized the generator system failed and approximately 30 seconds later, the engine began to lose power. He advanced the throttle and turned back toward the departure airport. The pilot stated the engine then began to vibrate and rapidly lose power. The pilot dumped the chemical load and identified a road on which to land. During the landing, the left wing caught in the tall grass alongside the road, spinning the airplane around and into a ditch. The pilot reported the starter generator failed which was followed shortly thereafter by the loss of engine power. He reported the starter generator was on fire after the accident.