Sorry gentlemen if I created a tangent there with my remark about 'engine autofeather' which should of course be propeller autofeather.
From the pictures the prop is certainly not feathered, but the conditions for an autofeather would surely have been present - throttles above 13,000 RPM, HP cock in Fuel On or Lock Out, torque below 40 PSI and decreasing. An autofeather will take about 2 or 3 seconds to complete, and that failure would have been instantaneous, but since the conditions for an autofeather existed the engine should have shut itself down via the autofeather feature.
I don't think "total loss of the front half of the engine" is covered by the checklist.
Well said, that was my take on it also.