What happened
On October 10, 2017, an Embraer 201 Neiva, registration PT-GOC, departed from the Sol e Lua Aviação Agrícola airfield in Lucas do Rio Verde, Mato Grosso, for a ferry flight to Sorriso. Shortly after takeoff, while in the climb phase, the aircraft entered a left turn and began losing altitude. The aircraft subsequently struck the terrain, resulting in substantial damage to the airframe. The pilot sustained minor injuries, and no other occupants were on board.
The investigation
CENIPA investigators examined the aircraft's engine, which had been converted to operate on hydrated ethyl alcohol (ethanol) in accordance with Brazilian regulatory guidelines (IS 137-201-001B). The investigation focused on the engine's performance and the maintenance history of the fuel system. While the pilot was fully qualified and the aircraft was within weight and balance limits, investigators found that the engine had recently undergone an overhaul and had flown only 8.5 hours since its installation.
Analysis of the fuel system revealed that the fuel injector for cylinder number two was obstructed. Investigators also noted that the aircraft had been inactive for several months prior to the accident. Furthermore, the investigation scrutinized the regulatory framework allowing for engine conversions to ethanol, noting that the use of certain materials, such as a steel fuel tank and a diesel-compatible fuel filter, may have been susceptible to corrosion.
Findings
- The engine power loss was caused by the obstruction of the cylinder number two fuel injector, likely due to oxidation within the system.
- The aircraft had undergone a period of inactivity prior to the flight, and there was no evidence that the manufacturer's recommended engine preservation procedures were followed.
- The use of ethanol, a hygroscopic substance, combined with inadequate maintenance/preservation during inactivity, likely contributed to the buildup of deposits and corrosion.
- The exact cause of the loss of control—whether due to improper control inputs or an aerodynamic stall during an attempt to return to the runway—could not be definitively determined due to the pilot's inability to recall flight details following the impact.