What happened
On August 9, 2011, at approximately 14:00 UTC, a Neiva EMB-202, registration PT-UOD, was performing agricultural spraying operations over an orange grove near Fazenda Santa Maria, in São Carlos, São Paulo. The aircraft had departed from Fazenda Palmeiras in Analândia earlier that afternoon.
During the mission, the pilot performed a spraying pass at an altitude of 20 meters. While executing a reversal maneuver—a technique known in agricultural aviation as a "balão" to realign the aircraft for a pass in the opposite direction—the pilot encountered a sudden lateral wind gust. This gust, described by the pilot as a "wind shear" effect, caused the aircraft to enter a stall, resulting in a loss of control and a subsequent impact with the ground at the edge of a sugarcane field. The aircraft sustained substantial damage, but the pilot escaped the crash uninjured.
The investigation
CENIPA's investigation focused on the aerodynamic conditions during the maneuver and the aircraft's configuration. The pilot was fully qualified with valid commercial and agricultural licenses. The aircraft was within weight and balance limits, and its maintenance records were up to date, with the last 100-hour inspection completed approximately 270 flight hours prior.
Investigators analyzed the impact of the aircraft's winglets on maneuverability. The pilot reported reduced aileron effectiveness, though the manufacturer's manual did not indicate different stall or speed limitations for winglet-equipped models. The investigation also considered the aerodynamic demands of the "balão" maneuver, which requires high bank angles at low speeds and low altitudes. Calculations showed that at a weight of 1,550kg, the stall speed would be approximately 86 mph, which is higher than the ideal climb and go-around speed of 80 mph.
Findings
- The loss of control occurred during a high-bank reversal maneuver at low altitude.
- A sudden change in wind direction or localized turbulence, potentially exacerbated by high ambient temperatures, may have disrupted the aircraft's roll or yaw stability.
- The pilot's execution of the maneuver may have involved an inadequate assessment of wind conditions, temperature, and bank angle, leading to a reduction in airspeed and a subsequent stall.
- The investigation could not definitively determine the exact cause, as the contributing factors remained indeterminate.