Air Tractor AT-802A N9078G accident near Turton, South Dakota

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.

NTSB analysis

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.

Text from the NTSB. Open the NTSB docket for CHI08CA246 for the full record.