Accident Overview
On August 16, 2008, at 1000 central daylight time, an Air Tractor AT-400A, registration N7307W, operated by Wilbur-Ellis Air LLC, collided with a tree during an off-airport forced landing in Luverne, Minnesota. The commercial pilot was not injured. The airplane sustained substantial damage to the left wing. The flight was conducted as an aerial application operation under Title 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed, and no flight plan was filed.
Engine Failure Sequence
The local flight had originated from the Luverne Municipal Airport (LYV) at 0950. After spraying approximately 40 acres, the pilot reported that the engine began making a "popping" sound accompanied by a higher-pitched whistle. In response, she pulled back on the elevator control to gain as much altitude as possible and began searching for a suitable landing area. While looking out the right side of the airplane, she noticed flames emanating from the right-side exhaust stack.
Forced Landing and Impact
Determining that landing on a nearby country road was not feasible, the pilot decided to attempt flying between a couple of trees to reach an open field beyond. The airplane touched down before reaching the trees and subsequently spun to the right, impacting one of the trees with its left wing. Post-accident inspection of the engine revealed that all compressor turbine blades were damaged, with most having broken off. Damage was also present on the outlet side of the compressor turbine guide vanes.