What happened
On September 19, 1994, an EMB-711C aircraft, registration PT-NEN, was conducting a flight from Campo Grande, MS, to Fazenda Ilha Camargo, MT. During the flight, the pilot performed an unplanned technical landing at Fazenda Santana to seek navigational information regarding the destination.
After landing, the pilot left the engine running while leaving the aircraft to consult with a farm employee, leaving a passenger on board. Following a period of idling in high ambient temperatures (approximately 30°C), the pilot attempted a takeoff. Shortly after departing the ground, the aircraft entered a left-hand descent, striking trees before impacting the ground. The crash resulted in two fatalities and the total destruction of the aircraft.
The investigation
CENIPA investigators examined the wreckage and the propulsion group. Technical analysis by the CTA (Centro Tecnológico Aeroespacial) found no permanent mechanical abnormalities in the engine or propeller. However, the investigation highlighted several critical operational irregularities.
Investigators explored three primary hypotheses for the loss of power: an incorrect fuel selector position, a failure of the magnetos, or the formation of vapor lock. The investigation noted that the fuel selector was found in the open position and the electric pump was active. The high ambient temperature and the prolonged period of engine idling without the use of the electric fuel pump suggested that vapor lock—caused by the vaporization of light components in the Avgas—could have occurred in the fuel lines, leading to the power loss.
Findings
- Deficient Planning: The pilot's lack of adequate preparation for the takeoff from the farm contributed to procedural errors and a failure to prepare for potential emergencies.
- Improper Engine Shutdown: The pilot failed to shut down the engine after the technical landing, leaving the aircraft idling in high temperatures, which likely contributed to the fuel system issues.
- Procedural Errors: The rushed nature of the takeoff led to a potential breakdown in checklist discipline, including the possibility of incorrect fuel selector or magneto settings.
- Environmental Factors: High ambient temperatures (30°C) may have facilitated the formation of fuel vapor in the lines.