What happened
On October 15, 2022, at approximately 18:00 UTC, a Cessna A188B, registration PR-ATD, was performing aerial firefighting operations near Canápolis, Minas Gerais. The aircraft had departed from a landing strip at Fazenda Campo Limpo to combat a wildfire.
During the second pass over the fire line, while flying at an altitude of approximately 4 meters and a speed of 100 knots, the aircraft experienced a sudden loss of engine power. The pilot executed an emergency landing in a nearby area to avoid the flames. Although the landing maneuver was successful, the aircraft was subsequently overtaken by the advancing wildfire, which resulted in the total destruction of the airframe. The pilot survived the occurrence without injuries.
The investigation
CENIPA investigators examined the engine and propeller to determine the cause of the power loss. Analysis of the propeller blades showed bending patterns consistent with low engine RPM at the moment of impact, corroborating the pilot's report of power loss.
Technical inspections of the Continental IO-550-D engine revealed significant particulate matter in the fuel distributor filter, originating from corrosion on the internal piston. Additionally, severe oxidation and corrosion were found within the fuel pump. However, investigators noted that because the aircraft used ethanol—a fuel with high water content—and was exposed to intense heat during the post-crash fire, these corrosive conditions may have developed after the accident. Furthermore, the engine examination was delayed by 30 days, which could have also contributed to the observed oxidation.
Investigators also considered the possibility that flying through superheated air near the fire line altered the air-fuel mixture by reducing oxygen density, potentially causing a loss of combustion efficiency. However, this hypothesis could not be definitively proven.
Findings
- The pilot was fully qualified, with valid medical and aeronautical licenses.
- The aircraft was in compliance with all regulatory requirements, including valid airworthiness certificates and up-to-date maintenance logs.
- The aircraft was within weight and balance limits.
- Meteorological conditions were suitable for flight.
- The exact cause of the engine failure remains undetermined, as investigators could not definitively link the observed fuel system corrosion to the pre-accident flight or confirm the impact of superheated air on engine performance.