What happened
On April 22, 2014, an AT-502B agricultural aircraft, registration PR-VAJ, was performing pesticide application over a cotton plantation at Fazenda Santa Rita in São Desidério, Bahia. After completing its second application pass, the pilot initiated a right-hand reversal turn to position the aircraft for a third pass. During this maneuver, the aircraft experienced a vibration characteristic of an aerodynamic stall, leading to a rapid loss of airspeed and altitude. The aircraft struck the ground with the right main landing gear while banked to the right, sliding approximately 150 meters through the crop before coming to a halt. Immediately following the impact, a fire broke out, fueled by leaking fuel from the ruptured right wing tank, and completely destroyed the aircraft. The pilot was able to abandon the aircraft and escaped without injury.
The investigation
CENIPA's investigation focused on the aerodynamic factors and operational decision-making during the reversal turn. Investigators analyzed the relationship between bank angle, load factor, and stall speed, noting that increased bank angles significantly raise the required load factor and the stall speed. The investigation established that the pilot utilized a bank angle greater than his usual practice. Furthermore, a gust of wind during the maneuver likely increased the bank angle further, pushing the aircraft into a stall. The investigation also examined the aircraft's maintenance history, finding the AT-502B was within its weight and balance limits and had recently undergone a 50-hour inspection. The analysis highlighted that the flight planning did not sufficiently account for how environmental variables, such as wind and temperature, would affect the aircraft's performance during high-load maneuvers.