What happened
On February 6, 2014, a Neiva EMB-201A, registration PT-GTB, was performing agricultural spraying operations over a rice field at Fazenda do Tigre, located in Alegrete, Rio Grande do Sul. The aircraft, operated by Cristal Aviação Agrícola Ltda, had taken off from a temporary landing strip on the farm to apply fungicide.
Approximately eight minutes into the flight, the aircraft experienced an in-flight engine failure. In response to the emergency, the pilot jettisoned the chemical load and performed a forced landing within the crop field. While the pilot escaped the incident uninjured, the aircraft sustained substantial damage.
The investigation
CENIPA investigators examined the engine components, which were sent to the Institute of Aeronautics and Space (IAE) for detailed analysis. The investigation focused on a rupture identified in the upper front-left section of the engine block.
Technical analysis of the engine components revealed that the failure was likely caused by significant wear on the camshaft lobes. Specifically, one of the lobes showed a 30% reduction in thickness compared to the others. This wear reduced the valve opening amplitude, which restricted the volume of fuel entering the cylinder and hindered the exhaust of the burned mixture.
Investigators noted that the aircraft's maintenance records were up to date, and all periodic inspections had been performed. Because camshafts are typically replaced only during major engine overhauls, the dimensional wear was not detectable during standard, more frequent inspections.