What happened
On September 30, 2010, at approximately 1700 Alaska daylight time, a Cessna 150F, registration N3569L, was performing a solo visual flight rules instructional flight from Bradley Sky Ranch Airport in North Pole, Alaska, destined for Fairbanks. During the takeoff roll, when the aircraft reached a speed of approximately 50 mph, it swerved to the left. The student pilot reported that rudder inputs and corrective actions failed to stop the leftward veer. As the aircraft swerved, the nose wheel dug into the dirt runway, causing the airplane to nose over. The student pilot was not injured.
The investigation
An inspection conducted by an FAA inspector revealed that the left nose wheel steering linkage rod end had fractured. Subsequent examination of the fracture surfaces and the surrounding area by a metallurgist showed deformation patterns and fracture features consistent with a bending overstress separation. The investigation found no evidence of preexisting fatigue or corrosion cracking.