What happened
On March 24, 2020, at approximately 20:30 UTC, a Neiva EMB-202 aircraft, registration PT-UJH, was performing agricultural spraying operations over a soybean plantation at Fazenda Pequena Holanda in Alto Parnaíba, Maranhão. The aircraft was conducting a local flight for pesticide application when, approximately 15 minutes into the flight, the engine experienced a loss of power during a repositioning maneuver. The pilot managed to jettison the chemical load and executed an emergency landing in the plantation. The aircraft sustained substantial damage, while the pilot sustained minor injuries.
The investigation
CENIPA investigators faced significant challenges due to the aircraft being dismantled by the owner and maintenance personnel before the investigation team arrived, as the aircraft was being prepared for transport to Imperatriz. This unauthorized intervention compromised the collection of on-site evidence.
During the examination of the engine and its components, investigators found that the cylinder head temperature sensor for cylinder number 4 was missing, despite maintenance records from a previous 100-hour inspection claiming it had been verified. Additionally, investigators identified a non-aviation grade fuel system hose installed in the aircraft. While the pilot reported engine leaks and excessive oil consumption, no such leaks were found during the technical analysis.
Tests conducted on the Lycoming IO-540-K1J5D engine and its components—including the fuel pump, injectors, and magnetos—showed no evidence of mechanical failure. Although the fuel selector was found in the right tank position and that tank was empty, the presence of ethanol inside the fuel pump and injector contradicted the hypothesis of a fuel exhaustion event.
Findings
- The aircraft's maintenance logs for the cell, engine, and propeller were not up to date.
- A non-aeronautical component (a KORAX brand hose) was installed in the fuel system.
- The engine was missing a required cylinder head temperature sensor.
- The exact cause of the engine power loss remains undetermined due to the lack of mechanical evidence and the fact that the aircraft was dismantled prior to the investigation.