CEN18LA270

The pilot was conducting an aerial application flight; a witness saw the airplane maneuvering before entering a flat spin. Ground scars at accident site were consistent with a wings- and nose-level impact attitude. Examination of the engine and airframe revealed no evidence of mechanical malfunctions or anomalies. The airplane was not equipped with an elevator down-spring or rudder-aileron interconnect system. According to the manufacturer, these systems were required and improved the stability and handling characteristics of the airplane. Although the circumstances of the accident are consistent with a stall/spin and loss of control, the reason for the loss of control could not be determined based on the available information; and whether the lack of the elevator down-spring and rudder-aileron interconnect systems contributed to the loss of control was not determined.

On August 13, 2018, about 1815 central daylight time, an Air Tractor 602 airplane, N629LA, was substantially damaged when it was involved in an accident near Bismarck, Illinois. The commercial pilot sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight. A witness, who was an agricultural pilot, saw the airplane maneuvering at low altitude over a corn field when it appeared to enter a flat spin. The airplane impacted the ground, and the pilot was taken to the hospital by first responders. The wreckage was found upright in the field. Ground scars at accident site were consistent with a wings- and nose-level impact attitude. Figure 1 shows the airplane location (red) and ground scar location (green) overlaid on a satellite image of the field. The single red dot located to the northwest of the main wreckage denotes the location of the rudder, which was found about 50 feet from the fuselage. Figure 1. Wreckage and Ground Scars at Accident Location The fuselage sustained severe damage to all components forward of the cockpit area. The firewall, main landing gear attachments, and hopper were crushed and segmented by the impact forces. These components remained loosely attached to the fuselage. The aft fuselage showed evidence of crumpling of the structure between the cockpit and the vertical stabilizer. All flight control surfaces were located with the main wreckage and continuity was established from the cockpit area to the control surfaces. The flap actuator was extended about 1 inch, which corresponded to a 7° flap extension. The flap torque tube was continuous to the flap arms on both sides of the fuselage. The airplane was not equipped with an elevator down-spring or rudder-aileron interconnect system. According to the manufacturer, these systems were required and increased the airplane's stability and handling characteristics. The propeller remained attached to the engine and all five of the blades were found in the immediate vicinity of the engine. Two blades were fractured near the blade root and found buried in the soil. The visible blades exhibited chordwise scoring and abrasion of the leading edges, consistent with rotation at the time of impact.