What happened
Upon touchdown, the Cessna 172 experienced a violent jerk to the left. The aircraft continued off the left side of the runway into the grass, resulting in a nose-over. A single black skid mark was noted on the runway surface.
The investigation
Mechanical examination focused on the left main wheel, which could not be turned manually. Investigators found that the piston for the left brake assembly was partially extended and stuck in place. The exposed circumference of the piston showed signs of wear, with a shiny area at the bottom and rust-colored oxidation at the top. Additionally, the upper portion of the left brake assembly and the top of the piston face were covered in rust and dark brown debris. Maintenance records indicated that the aircraft had flown less than 20 hours over the previous three years.
Findings
Investigators concluded that the primary factor in the excursion was a seized left brake assembly caused by corrosion and lack of use.