What happened
During the landing phase of flight, a Cessna (type not specified) veered off the left side of the runway. After exiting the runway, the aircraft crossed a parallel taxiway and proceeded down an embankment. The pilot reported that upon applying the brakes during the landing roll, the left brake appeared to grab, causing a sudden jerk to the left. In an attempt to correct the directional control while still on the runway, the pilot applied power and right rudder; however, the aircraft quickly moved onto the grass.
The aircraft sustained damage as a result of the excursion.
The investigation
Investigators examined the nose landing gear fork, which was found to be fractured in two places near its attachment to the strut portion of the landing gear. The National Transportation Safety Board's Materials Laboratory analyzed the fork and determined that the deformation was consistent with excessive lateral loading. Examination of the fracture surfaces revealed signatures consistent with overstress. No evidence of fatigue or preexisting damage was identified, and no other anomalies were found in the aircraft or its systems that existed prior to the impact.