What happened
The pilot reported crossing the runway threshold at 90 knots, noting a soft touchdown on the main landing gear in the center of the runway. While the engines were at idle power, the pilot applied light toe brake pressure to slow the aircraft. During this braking application, a snap was felt followed by the collapse of the nose gear, which caused the aircraft to swerve to the left of the centerline.
The investigation
An on-scene examination of the engine mount revealed that the right attachment foot of the new one-piece design had separated. Specifically, the upper aft part of the right nose gear actuator attachment foot fractured away from the remainder of the engine mount.
Further inspection of the nose landing gear tire and rim showed no evidence of under-inflation or anomalies prior to the impact. The examination of the fracture at the forward edge of the right foot revealed relatively smooth features on flat planes, along with curved crack arrest markings. These markings were consistent with fatigue cracking originating from multiple points. This fatigue cracking spanned an arc of approximately 90 degrees, and at its deepest point, the crack had progressed through roughly 90 percent of the estimated 0.07-inch wall thickness of the foot.