What happened
On October 21, 1998, at approximately 17:00 local time, an Aero Commander S-2R, registration PT-KLK, was performing agricultural spraying operations over a rice plantation in Nhu-Porã, São Borja, RS. The aircraft had departed from the Aeroclube de São Borja to treat a farm in the area.
During its fourth pass over the field, while aligning for a westward trajectory, the aircraft's left wingtip collided with a ground marker (known locally as a "bandeirinha"). The ground worker, who was tasked with signaling the aircraft's path, was struck by the wing. Following the impact, the pilot, believing the collision might have been with a bird, performed a precautionary landing. The aircraft sustained minor damage to the leading edge of the left wing. Tragically, the ground worker passed away five days after the incident.
The investigation
CENIPA's investigation examined the operational procedures, the training of ground personnel, and environmental factors. The investigation established that the pilot was fully qualified, with a valid commercial license and up-to-date medical certification. The aircraft's maintenance records, including engine and propeller logs, were current and adequate.
Investigators focused on the selection and training of the ground markers, who were chosen randomly from among the farm workers. The study also analyzed the impact of lighting conditions, noting that the sun was positioned directly in the pilot's line of sight during the maneuver, which likely hindered the visibility of the ground personnel.