What happened
On July 11, 2017, an Embraer EMB 202A, registration PT-AOM, was performing agricultural spraying operations near Barretos, São Paulo. The aircraft was engaged in applying herbicides over an orange plantation. During the flight, the pilot noticed vibrations during turns, which initially appeared manageable after performing magneto checks.
Approximately 45 minutes into the flight, the vibrations returned with greater intensity, followed by a sudden loss of engine power. Despite the pilot attempting to maintain a safe altitude, applying full available power, and activating the auxiliary fuel pump, the engine failed to respond. The pilot subsequently jettisoned the remaining chemical load and executed a forced landing in an orange grove. The aircraft sustained substantial damage, but the pilot escaped without injury.
The investigation
CENIPA investigators examined the engine, fuel, and operational procedures. While fuel samples from the wings were clean, traces of silica and aluminum silicate were found in the fuel filter and metering unit, though these were not determined to be the cause of the failure. Extensive bench tests on the engine, including inspections of the fuel injectors, spark plugs, and magneto synchronization, revealed no mechanical or electrical defects that could explain the power loss. The propeller governor also functioned normally.
Investigators also looked into operational practices. It was noted that the pilot did not have the auxiliary electric fuel pump running during the mission. Although technical instructions and manufacturer bulletins recommended keeping this pump active during all flight phases to ensure consistent fuel pressure, a local culture among agricultural pilots suggested only using it during takeoff and landing to prevent premature wear.
Findings
- Pilot judgment and decision-making processes contributed to the accident, as the pilot continued the mission after the first signs of vibration.
- The pilot's decision to continue the application rather than performing a precautionary landing at a nearby farm airstrip, located only 1.3 NM away, increased the risk.
- A lack of habitual use of checklists among the agricultural pilot group may have hindered the effective management of the emergency.
- The failure to keep the auxiliary electric fuel pump active during all phases of flight was identified as a critical operational factor.