What happened
The pilot in command (PIC) was engaged in an agricultural spraying operation over a corn field. During the course of the mission, the PIC executed approximately five or six passes across the field to ensure adequate coverage. The flight path for these operations followed a west-to-east direction, consistent with the established swath runs.
During one specific pass, the aircraft collided with a power line that traversed diagonally across the field. The pilot reported that he did not observe this particular strand of the power line during any of the previous passes. It was noted that the power lines generally bordered the field on the western side and the southwest corner, but the diagonal nature of the specific strand struck made it difficult to anticipate its presence within the spray area.
The investigation
The investigation focused on the circumstances surrounding the collision with the utility infrastructure. Examination of the flight path revealed that the power lines were situated along the perimeter of the field, specifically bordering the west and southwest boundaries. The operational pattern involved running parallel strips from west to east.
Despite the pilot's assertion that the line was not visible during earlier passes, the investigation confirmed the physical presence of the diagonal power line across the spray area. The discrepancy between visibility on previous passes and the collision suggests that the line may have been obscured by terrain, vegetation, or lighting conditions during the initial approaches, only becoming a hazard when intersected directly.
Findings
Several factors contributed to the incident. The primary issue was the failure of the pilot to identify a power line running diagonally across the field during the approach phase. Although the power lines bordering the field on the west and southwest were known hazards, the diagonal strand presented a unique obstacle that was not accounted for in the pre-flight or in-flight planning.
The operational pattern of west-to-east swath runs placed the aircraft directly into the path of the diagonal line. The pilot's statement indicates that this specific strand was not observed during the preceding five or six passes, highlighting a potential gap in situational awareness regarding overhead obstacles that do not align with the primary border lines of the field.