What happened
On May 9, 2017, a Cessna A1sd88B agricultural aircraft, registration PR-AAM, was performing local crop dusting operations near the Paranavaí Aerodrome (SSPI) in Paraná, Brazil. The aircraft had completed several flight segments over sugarcane fields, taking off and landing at a nearby farm.
During the final approach to runway 13, the pilot executed a "flare landing" (pouso de pista) under visual meteorological conditions and calm winds. After touchdown, the aircraft traveled 187 meters along the runway before veering to the right. The aircraft exited the paved surface and rotated 120 degrees onto the grass, where it came to a stop. The impact with vegetation caused the left landing gear leg to break, resulting in substantial damage to the aircraft. The pilot was uninjured.
The investigation
CENIPA investigators examined the runway surface and the aircraft's braking system to determine the cause of the excursion. Although the pilot stated that no brakes were applied during the landing roll, investigators identified braking marks on the runway from both wheels. Specifically, the marks from the right wheel indicated intermittent locking.
Technical inspections of the PR-AAM braking system, including hydrostatic pressure tests on the hydraulic lines and visual inspections of the brake pads and hoses, revealed no mechanical discrepancies, leaks, or malfunctions. The investigation also considered the inherent aerodynamic characteristics of the aircraft, noting that the conventional landing gear configuration and the high center of gravity typical of agricultural aircraft make them susceptible to directional instability during landing.
Findings
- The pilot was properly rated and experienced for the operation.
- The aircraft was airworthy and within weight and balance limits.
- The landing was performed using a flare technique, which increases the risk of runway excursions in conventional gear aircraft.
- Improper application of flight controls during the landing roll contributed to the loss of directional control.