What happened
On February 25, 2023, at approximately 15:30 UTC, a Cessna T-188C, registration PR-ACM, was performing a local agricultural spraying flight at Fazenda Santiago do Tinguara in Naviraí, Mato Grosso do Sul. The aircraft, operated by KNA Aviação Agrícola Ltda, had recently landed at the grass airstrip to refuel with ethanol and reload 600 kg of agricultural chemicals.
While taxiing toward the runway centerline to begin its takeoff roll, the left main landing gear leg fractured into two pieces. The aircraft came to a stop at the site of the failure, sustaining substantial damage. The pilot was able to exit the aircraft without injury.
The investigation
CENIPA investigators examined the fractured component and the aircraft's maintenance history. The investigation found that while the aircraft was within its maximum takeoff weight of 1,995 kg, the center of gravity (CG) was positioned at 80.60 cm from the mean aerodynamic chord, which was forward of the manufacturer's 90 cm limit.
Metallurgical analysis of the left landing gear leg revealed three distinct regions of surface wear. Investigators identified that debris, likely soil and particles common in agricultural operations, had accumulated between the gear leg and the clamps used to secure the brake line tubing. This accumulation, potentially exacerbated by moisture or liquid pesticides, caused abrasive wear. The analysis confirmed that this wear acted as a stress concentrator, initiating a fatigue crack that eventually led to the structural failure of the component.
Furthermore, the investigation reviewed maintenance records from a recent return-to-service overhaul. While inspections for corrosion and fittings were documented, the investigation could not rule out inadequacies in maintenance oversight or the failure to properly implement the manufacturer's Corrosion Prevention and Control Program (CPCP).