What happened
On November 20, 2018, an EMB-202 aircraft, registration PT-UII, crashed while performing agricultural spraying operations in Pelotas, Rio Grande do Sul. The aircraft had departed from the Contagem landing strip to apply urea to a rice crop. Approximately five minutes after takeoff, the aircraft experienced a sudden loss of control and struck the ground, resulting in the destruction of the aircraft and the fatal injury of the pilot.
At the time of the accident, meteorological conditions were favorable for visual flight, with high visibility and no significant cloud cover in the area.
The investigation
CENIPA investigators examined the wreckage and found that the aircraft impacted the ground with high energy. The distribution of debris indicated that the aircraft was in a descending attitude with a left wing bank at the moment of impact. While the engine and propeller showed no signs of mechanical failure and were functioning at power during the impact, the left wing was found separated from the fuselage.
Laboratory analysis of the left wing spar revealed that the lower flange had suffered from fatigue across nearly its entire surface. Investigators also identified evidence of improper maintenance involving the inadequate threading of 3/16-inch diameter pins. This improper procedure created stress concentrators that likely facilitated the initiation of the fatigue process. Although the aircraft had undergone several scheduled inspections, including 100-hour and annual inspections, these procedures failed to detect the progressive fatigue cracking in the spar.