On May 7, 1997, an Air Tractor AT-301 (registration N23640) was involved in an aviation accident near Huron, SD. Investigators recorded the probable cause as: The pilot's failure to maintain clearance from power transmission cables during the downwind entry over trees. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An aircraft struck power transmission cables while entering a downwind approach over trees during an agricultural spraying operation, resulting in a ground impact and wreckage examination revealing the line wrapped around the propeller.
What happened
The pilot reported completing a turn to enter the specific field designated for spraying operations. Upon initiating the entry, the aircraft flew downwind over the surrounding tree line before crossing into the target area. During this phase of the approach, the airplane collided with overhead power transmission cables. The impact caused the aircraft to lose control and strike the ground, where it eventually came to rest in a wheat field.
The investigation
A physical examination of the wreckage was conducted to determine the nature of the collision. Inspectors found that a section of the transmission line had become wrapped around the propeller assembly, confirming the point of contact between the aircraft and the utility infrastructure.
Probable cause
The pilot's failure to maintain clearance from power transmission cables during the downwind entry over trees.