Incident Overview
A pilot reported that during landing, the aircraft crossed the runway threshold at 90 knots and touched down softly on the main landing gear in the center of the runway. After touchdown, the pilot applied light toe brake pressure to slow the aircraft. Upon application, the crew felt a snap, followed by collapse of the nose landing gear, which caused the aircraft to swerve to the left of the centerline. At the time, the power setting was at idle.
Examination Findings
An on-scene examination revealed that a "new" one-piece foot design right attachment foot on the engine mount had separated. The nose landing gear tire and rim showed no pre-impact anomalies or under-inflation. A detailed examination of the engine mount showed that the upper aft part of the right nose gear actuator attachment foot had fractured away from the rest of the engine mount. The fracture at the forward edge of the right foot exhibited relatively smooth features on flat planes, with curved crack arrest markings consistent with fatigue cracking from multiple origins. The fatigue cracking was evident over an arc of approximately 90 degrees, and at its deepest penetration, the fatigue crack had propagated through approximately 90 percent of the estimated 0.07-inch wall thickness of the foot.
Conclusions
The investigation determined that the nose gear collapse was a result of the fatigue crack in the engine mount attachment foot, which ultimately led to the structural failure of the component during normal landing braking.