On August 13, 1983, a Piper PA-25-260 (registration N8559L) was involved in an aviation accident near Whittemore, IA. Investigators recorded the probable cause as: The pilot's failure to maintain clearance from an unexpected wire while maneuvering to avoid it, which resulted in a collision with trees. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot trimming vegetation in a low area encountered an unexpected wire and collided with nearby trees while attempting to avoid it, resulting in a crash landing.
What happened
The pilot was conducting agricultural operations, specifically making a trim swath through a low-lying area. While operating near rising terrain, the aircraft approached an unexpected high-line wire that was positioned diagonally across the field. In an effort to avoid striking the wire, the pilot attempted to maneuver around it but was unable to clear nearby trees. The aircraft collided with the trees and remained airborne for approximately 380 feet before finally impacting the ground.
Findings
The primary factors contributing to this accident were the collision with the unexpected power line and the subsequent impact with trees while attempting to avoid it. The pilot's inability to clear the obstacles in time led to the loss of controlled flight and the eventual crash.
Safety message
Pilots conducting low-level agricultural operations should remain vigilant for unmarked or unexpected obstructions such as power lines, especially in areas with varying terrain. Thorough pre-flight reconnaissance and awareness of changing conditions are critical to avoiding collisions with fixed objects.
Probable cause
The pilot's failure to maintain clearance from an unexpected wire while maneuvering to avoid it, which resulted in a collision with trees.