What happened
On December 31, 2012, an EMB-201A Ipanema, registration PT-GSB, was performing agricultural spraying operations over a rice plantation at Fazenda São Pedro, near Sonora, Mato Grosso. During the recovery phase following the final application of pesticides, the aircraft was executing a reversal turn when the right wing detached from the airframe. This structural failure led to an immediate loss of control, causing the aircraft to impact the ground. The impact destroyed the aircraft and resulted in one fatality for the pilot.
The investigation
CENIPA investigators examined the wreckage and recovered components of the right wing, spars, and fasteners for laboratory analysis at the Department of Aerospace Science and Technology (DCTA) and Embraer's competence center. The investigation focused on the fracture surfaces of the wing spars. Investigators also analyzed flight data from the aircraft's DGPS unit, which provided altitude, heading, and speed logs.
Technical analysis revealed that the fracture in the right wing spar occurred due to a fatigue process on the lower flange. Furthermore, investigators found evidence of improper maintenance; specifically, cracks were discovered with paint residue inside them, suggesting that certain inspections had failed to identify or properly address structural issues. The presence of non-standard pins in the wing spar holes also indicated that previous maintenance work had been performed in disagreement with official service manuals.
Findings
- The primary cause of the structural failure was a fatigue process on the lower flange of the right wing spar, which led to a failure of the spar flange and subsequent overload of the remaining section.
- The pilot's tendency to perform aggressive maneuvers near the aircraft's operational limits likely contributed to the fatigue process and the eventual wing separation.
- Maintenance deficiencies were identified, including improper repairs and inadequate inspection of the wing spars.
- Organizational factors, such as the manager's accumulation of roles, may have hindered effective oversight of maintenance activities.
- A lack of organizational criteria to limit high-load maneuvers contributed to the disregard for operational limits.