What happened
On April 1, 2008, at approximately 07:45 UTC, a Neiva EMB-201 aircraft, registration PT-GIO, was performing agricultural spraying operations over a cotton plantation at Fazenda Santa Clara, near Primavera do Leste, Mato Grosso. The aircraft took off from a local airstrip for a local flight.
During the takeoff roll, the pilot reported smelling burnt fuel. Shortly after beginning the application process, the pilot deactivated the electric fuel pump. This action led to a gradual reduction in fuel flow and a subsequent loss of engine power. Although the pilot managed to temporarily restore power by reactivating the electric fuel pump, the engine failed completely during a return turn, forcing the pilot to perform an emergency landing in the cotton field.
The investigation
CENIPA investigators examined the wreckage and the engine components to determine the cause of the power loss. The investigation confirmed that the pilot was properly rated and experienced for the operation, and the aircraft was airworthy with up-to-date maintenance records. Meteorological conditions were favorable for flight.
Upon inspection of the engine, investigators discovered that a protrusion on the tachometer pin (P/N 78368) had broken off. A fragment of this broken protrusion became lodged between gear P/N LW-10290 and the crankcase, causing the gear to shift out of alignment. This displacement caused the mechanical fuel pump to cease functioning, which was initially compensated for by the auxiliary electric pump. However, the misalignment also prevented gear P/N LW-10290 from driving gear P/N LW-13642, which subsequently caused the magnetos to stop operating. The resulting loss of spark led to the engine failure.
Findings
- The engine failed due to a loss of spark from the magnetos.
- The failure was triggered by a broken tachometer pin protrusion that displaced the fuel pump gear.
- The displacement of the gear also interrupted the drive to the magneto components.
- The aircraft sustained substantial damage to the airframe, including a broken hopper and damaged landing gear, due to a high sink rate during impact.
- The pilot remained uninjured.