What happened
The pilot, who was engaged in aerial application operations, conducted a survey pass around the field to locate a power line. During this initial pass, the pilot noted the position of the power line relative to the airfield.
On the fourth run, the biplane struck the bottom wire of the power line with its upper wing. The pilot later stated that he had underflown the lines on an earlier run. However, during the accident pass, he mistook the second line for the bottom wire until it was too close to correct his flight path.
The investigation
The investigation focused on the sequence of events leading to the collision with the power line. The pilot's statement indicated that the error occurred due to a misidentification of the wires during the approach.
Findings
The primary factor contributing to the accident was the pilot's failure to correctly identify the bottom wire of the power line during the fourth pass, resulting in a collision with the upper wing of the biplane.