What happened
On January 15, 2020, an Air Tractor AT-402B, registration PR-KPC, was performing an agricultural spraying operation in a rural area near Cruz Alta, Rio Grande do Sul. The aircraft, operated by Avante Aviação Agrícola Ltda., departed from the Tiago Terraboa landing strip to apply fungicide to a soybean crop.
During the final passes of the application, the pilot observed electrical power lines illuminated by sunlight. Believing the visible wires represented the lower level of the power grid, the pilot attempted to fly underneath them. However, the aircraft struck a different set of cables positioned lower than the ones initially perceived. Following the impact, the pilot successfully controlled the aircraft and returned to the origin landing strip to land.
The investigation
The CENIPA investigation confirmed that the pilot was fully qualified, holding valid medical and agricultural pilot certifications, and possessed significant flight experience. The aircraft was also in a valid state of airworthiness, with all maintenance logs up to date and the aircraft within weight and balance limits. Weather conditions were favorable for visual flight.
The investigation focused on the discrepancy between the pilot's intent and the actual wire positions. While the pilot and the company's Safety Manager were aware of the power lines in the area, the investigation found that no formal Operational Safety Risk Management (GRSO) had been documented for that specific application area. Although an informal company consensus existed to fly over the wires, the pilot's decision to fly under them was based on a visual misperception caused by sunlight reflection.
Findings
- Misperception of obstacle height: The pilot incorrectly identified the visible cables as the lower tier of the power lines.
- Inadequate risk management: There were no formal records of safety risk assessments for the specific application area.
- Flawed flight planning: Pre-flight preparations did not fully implement the company's established safety procedures.
- Organizational oversight: A lack of adequate supervision regarding the planning and execution of operational activities contributed to the error.
- Substantial aircraft damage: The impact caused significant damage to the vertical and horizontal stabilizers, rudder, elevator, and propeller.