Air Tractor AT-400A N7307W accident near Luverne, Minnesota

Probable cause

The failure of the compressor turbine blades which resulted in the loss of power. Factors associated with the accident were the low altitude and the trees.

NTSB analysis

The accident occurred during an aerial application flight. The pilot reported she had sprayed approximately 40 acres when the engine began making a "popping" sound with a higher pitched whistle. She reported she pulled back on the elevator control to gain as much altitude as possible and began looking for a place to land. She stated that while looking out the right side of the airplane, she noticed flames coming from the right side exhaust stack. The pilot determined she was not able to land on the country road, so she decided to try and fly between a couple of trees to land in an open field. She stated the airplane touched down prior to the trees and it spun to the right, impacting one of the trees with the left wing. Inspection of the engine revealed that all of the compressor turbine blades were damaged with most of them having broken off. Damage was also present to the outlet side of the compressor turbine guide vanes.

Text from the NTSB. Open the NTSB docket for CHI08CA257 for the full record.