What happened
On January 4, 2016, a Cessna 210L, registration PT-KJI, was performing a private flight from Cachoeira do Arari to Belém, Brazil. During the landing phase on runway 34 at Brigadeiro Protásio de Oliveira Airport (SBJC), the aircraft experienced a sudden right yaw. The pilot attempted to correct the directional control, but the aircraft veered off the right side of the runway. During the excursion, the aircraft passed through a flooded area and the nose gear collapsed. The aircraft sustained substantial damage, but the pilot and three passengers were unharmed.
The investigation
The investigation focused on the landing gear mechanism following the discovery that the right main landing gear remained in the retracted position during the landing. Technical inspections in a maintenance hangar revealed mirroring on the right main gear up-lock assembly (PN 1241078-6 RH), caused by friction from the locking pin.
Investigators found that the up-lock mechanism was intermittently preventing the gear from extending due to an incorrect clearance between the lock and the pin, which should have been 0.15 inches. Furthermore, the investigation established that the cockpit's landing gear indicator lights provided false information; the green light (indicating the gear was down and locked) illuminated even while the right main gear remained in the up position.
Findings
- The right main landing gear failed to unlock from the up position during the landing sequence.
- The cockpit instrumentation provided a false indication that the landing gear was down and locked.
- An improper adjustment between the up-lock and the landing gear pin prevented the gear from extending.
- The aircraft's maintenance history showed the last inspection occurred approximately 187 flight hours prior to the accident, and the specific cause of the mechanical failure or the failure to detect it during the previous inspection remains undetermined.