What happened
The aircraft executed a landing on runway 28R under crosswind conditions. Wind data indicated a velocity from 200 degrees at 10 to 14 knots during the final approach segment, dropping to 12 knots as the pilot crossed the threshold. The Cessna 185 touched down initially on the left wheel, resulting in a minor bounce. Upon the second touchdown on the left gear, the pilot raised the tail of the aircraft. The right main landing gear contacted the runway while the tail remained elevated.
At approximately 40 mph, the pilot lowered the tail and the aircraft began to turn to the left. To correct this deviation, the pilot applied full rudder input and utilized right-side braking. Subsequently, the pilot noticed a sinking sensation on the right side of the airframe, followed by the collapse of the right strut. After deplaning, the pilot confirmed that the entire right main landing gear assembly had separated from the aircraft.
The investigation
Metallurgical testing was conducted on the right wheel spindle attaching nuts and bolts to determine the cause of the structural failure. The analysis demonstrated that the rear bolts failed at the interface between the spindle and the strut. The failure mode was identified as tensile overload, indicating that the components were subjected to forces exceeding their design limits during the landing sequence.
Findings
The maximum demonstrated crosswind velocity for this specific aircraft model is 15 knots. The operational conditions during the incident involved a crosswind component approaching this limit. The combination of the crosswind, the bounce, and the corrective braking inputs likely contributed to the excessive stress placed on the right main landing gear assembly, leading to the bolt failure.