Primary finding
Probable cause
The student pilot’s failure to maintain directional control during the takeoff roll.
Investigator assessment
Analysis narrative
During the takeoff roll, the airplane veered to the left of the runway centerline, and the solo student pilot was unable to maintain directional control. The airplane departed the left side of the runway and nosed over in a marshy area, which resulted in substantial damage to the rudder and right-wing lift strut. Postaccident examination did not reveal any anomaly with the airplane’s flight control systems or nosewheel steering. Tire abrasions noted on the runway were consistent with the left main landing gear tire and indicated a trajectory toward the left side of the runway. Although the left main landing gear wheel exhibited more resistance than the right wheel during hand rotation, and the left brake assembly anchor bolts showed corrosion and surface pitting, there was no evidence that the left brake had locked up. Further, the three evenly spaced linear tire impressions in the grass extending from the runway edge to the wreckage suggest that the wheels were rotating freely before the airplane nosed over. The student pilot’s loss of control, which could have resulted from an inadvertent application of the left brake during the takeoff roll, resulted in the runway excursion.
Source record
Factual narrative
On January 4, 2024, about 1246 central standard time, a Cessna 172N airplane, N3477E, was substantially damaged when it was involved in an accident at Middleton Municipal Airport-Morey Field (C29), Middleton, Wisconsin. The student pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The student pilot departed C29 on a solo flight and transitioned to Sauk / Prairie Airport (91C), Prairie Du Sac, Wisconsin, where he performed a series of uneventful takeoffs and landings before returning to C29. After landing, the student taxied back to runway 28 and configured the airplane for takeoff. During the takeoff roll, the airplane veered to the left of the runway centerline, and the student pilot was unable to maintain directional control. The airplane departed the left side of the runway and nosed over in marshy area adjacent to the runway. Postaccident examination of the airplane by an FAA inspector revealed the airplane’s rudder and right-wing lift strut were substantially damaged. During hand rotation of the main landing gear wheel assemblies, more resistance was noted to the left main landing gear wheel when compared to the right. Tire abrasions noted on the runway from the left main landing gear tire indicated a trajectory toward the left side of the runway. Additionally, three evenly spaced linear impressions were noted in the grass, extending from the runway edge to the wreckage. Further examination of the airplane’s hydraulic brake system revealed angular wear on the inboard brake pad of the left main landing gear brake assembly, while the outboard pad exhibited even wear. The left brake assembly anchor bolts showed signs of corrosion and surface pitting. The left brake disc displayed angular wear consistent with that of the inboard brake pad. No anomaly was noted with the nosewheel steering or flight control systems. Review of the airplane’s maintenance records revealed the last 100-hour inspection was completed on December 19, 2023, and the airplane had accrued a total of 17,459.5 hours of service. During the inspection, the left main landing gear tire and one left brake pad were replaced. The airplane accrued 14.4 hours of service since the last 100-hour inspection that was completed 16 days before the accident. According to the airplane’s maintenance publications, the brake assembly anchor bolts should be free of corrosion or damage to their surface area to prevent binding with the pressure plate or torque plate.