What happened
On February 3, 2022, a Cessna A188B agricultural aircraft, registered as PR-THT, was performing a takeoff from an unpaved landing strip at Fazenda Rabelo in São Simão, Goiás. The aircraft was engaged in an agricultural application flight operated by Textor Aviação Agrícola Ltda. Shortly after leaving the ground, the aircraft lost lift and collided with a nearby plantation. The single occupant of the aircraft escaped the crash without injury, though the aircraft sustained substantial damage.
The investigation
CENIPA investigators examined the aircraft's engine, the pilot's credentials, and the environmental conditions at the time of the accident. The pilot was found to be fully qualified, holding valid commercial licenses and a current medical certificate, with approximately 1,470 flight hours. Meteorological data indicated favorable flying conditions, with temperatures near 27°C and calm winds. The takeoff strip, measuring approximately 940 meters, was determined to be sufficient for the required takeoff distance under the prevailing conditions.
Technical inspections focused on the Continental IO-520-D engine. While the fuel system and ignition components appeared functional, bench tests revealed an ignition delay during the verification of magneto advance, which caused delayed combustion and reduced engine efficiency. Furthermore, upon removing the cylinders, investigators discovered carbon buildup on the valve seats, particularly the exhaust valves. This carbonization prevented the valves from seating perfectly, leading to a loss of compression.
Findings
- The engine was delivering less power than required for takeoff due to ignition delay and loss of compression.
- Carbon accumulation on the exhaust valve seats caused a loss of cylinder compression.
- The pilot was properly qualified and experienced for the operation.
- The aircraft was within weight and balance limits and had valid airworthiness documentation.
- The takeoff strip length was adequate for the aircraft's performance requirements.