Corrosion-induced rudder failure leads to agricultural aircraft crash in Brazil

Casualties unknown • SÃO BORJA, RS, BR

An EMBRAER EMB-2020 aircraft experienced a loss of rudder control due to severe component corrosion, resulting in a forced landing and substantial damage in São Borja.

What happened

On December 19, 2021, an EMBRAER EMB-202 aircraft, registration PT-VZS, was performing agricultural spraying operations over a soybean field in the Capeati landing area, near São Borja, Rio Grande do Sul. The aircraft was operated by Estiva Aviação Agrícola Ltda. during a local flight for pesticide application.

During a maneuvering turn to reposition the aircraft over the crop, the pilot experienced a sudden loss of rudder control when the right pedal became stuck in the full-down position. The aircraft began to bank heavily to the left. The pilot attempted to level the wings and execute a forced landing within the field. However, during the deceleration phase prior to touchdown, the aircraft entered a left turn again, causing it to strike the ground and capsize. The aircraft sustained substantial damage, while the pilot sustained minor injuries.

The investigation

CENIPA investigators examined the rudder control system and discovered that the rudder cable had disconnected because the rudder pulley pin had fractured. Metallographic and stereoscopic examinations revealed that the fracture was caused by intense exfoliation corrosion at the cable attachment point. This corrosion had severely degraded the component, reducing its thickness from approximately 5.0 mm to just 0.5 mm.

While the aircraft had undergone a 100-hour inspection in October 2021, the investigation found that the maintenance and preservation procedures were ineffective. The investigation also noted that the pilot was operating with an expired medical certificate and expired agricultural and single-engine ratings, although the pilot possessed significant experience in the aircraft type.

Findings

  • The rudder pulley pin failed due to advanced exfoliation corrosion.
  • Maintenance and preservation procedures by the operator were insufficient to detect the advanced stage of corrosion.
  • The pilot was flying with an expired medical certificate and expired aircraft ratings (MNTE and PAGA).
  • The aircraft was within weight and balance limits and had a valid airworthiness certificate.
  • Meteorological conditions were favorable for the flight.

Probable cause

The accident was caused by the failure of the rudder control pulley pin due to severe exfoliation corrosion, which led to a loss of directional control. Contributing factors included inadequate aircraft maintenance/preservation oversight and management supervision.

Frequently asked questions

What happened in the 2021-12-19 aircraft accident near SÃO BORJA, RS, BR?

An EMBRAER EMB-2020 aircraft experienced a loss of rudder control due to severe component corrosion, resulting in a forced landing and substantial damage in São Borja.

What aircraft was involved and where did it happen?

The accident on 2021-12-19 involved a aircraft, registration PTVZS, at SÃO BORJA, RS, BR.

What was the probable cause of the accident?

The accident was caused by the failure of the rudder control pulley pin due to severe exfoliation corrosion, which led to a loss of directional control. Contributing factors included inadequate aircraft maintenance/preservation oversight and management supervision.

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