What happened
On May 4, 2017, a Cessna A1-88B, registration PR-ERL, departed from São Marco farm in Itaberá, São Paulo, to conduct a test flight. The purpose of the flight was to evaluate the performance of the engine and propeller group following a conversion from AvGas to ethanol fuel. Approximately 30 minutes into the flight, the engine lost power and subsequently shut down. The pilot managed to perform a successful emergency landing in a nearby plantation, resulting in light damage to the aircraft. The pilot remained uninjured.
The investigation
CENIPA investigators examined the aircraft's documentation and physical components following the engine failure. While the aircraft's airworthiness certificate was valid, investigators found that the requirements declared to ANAC via form F-400-04—which mandated specific cockpit markings and placards regarding ethanol use—were not actually implemented in the cockpit. Additionally, the aircraft's logbooks were found to be outdated.
A critical finding during the physical inspection was the discovery of a non-aviation component within the fuel system. The engine was equipped with a VOX brand fuel filter, which was identified as an automotive part designed for diesel trucks rather than an approved aeronautical component.
Findings
- The engine failure was linked to the use of an unapproved automotive fuel filter designed for diesel engines.
- The use of a non-aeronautical filter may fail to provide the necessary fuel flow conditions and may have insufficient filtration efficiency, allowing impurities to compromise engine operation.
- Required cockpit placards and instructional markings for ethanol operation were missing from the aircraft.
- Aircraft maintenance records and logbooks were not up to date.