What happened
On December 26, 2013, a Neiva EMB-201, registration PT-GPJ, was performing agricultural spraying operations near Rosário do Sul, Rio Grande do Sul. The aircraft, operated by Aero Agricola Rosariense Ltda., had departed from the Rosário do Sul Aerodrome to apply chemical products to a crop.
Upon completing the second application pass and initiating a reversal turn, the aircraft experienced a sudden loss of engine power. The pilot was forced to perform an emergency landing in an open field nearby. The impact resulted in substantial damage to the engine, propeller, cowling, and landing gear, though the pilot escaped the incident uninjured.
The investigation
The investigation focused on the cause of the engine power loss. The pilot reported observing a drop in the engine fuel flow indicator at the moment the power loss occurred. Subsequent bench tests conducted on the carburetor, distributor valve, fuel injector, and electric fuel pump all showed normal functionality, ruling out mechanical component failure.
Investigators determined that the pilot was operating at a low altitude with the electric fuel pump turned off. This procedure contradicted both the aircraft's instrument panel instructions and the manufacturer's manual, which recommend keeping the electric pump active throughout all agricultural operations. Given the ambient temperature of 40°C, the investigators concluded that the lack of fuel pump operation allowed for the formation of vapor bubbles within the fuel system.
Findings
- The primary cause of the engine power loss was vapor lock within the fuel system.
- The formation of vapor bubbles was facilitated by high ambient temperatures (40°C) and the pilot's decision to fly with the electric fuel pump deactivated.
- The pilot's decision-making regarding the use of the fuel pump deviated from established manufacturer procedures and cockpit instructions.