Annex14
Look at the disc fracture face photo, in the upper left of the disc, just below the dovetail serrations you will note a dark area which is the forward face of the disc. It is this that I wonder about compared to the lighter metallic surface of the rear surface of the disc that is more clearly evident. Is it dark because of the effect of fire/temperature? Or is it dark because of the lighting shadow?
Sometimes these surfaces can tell you somethings relative to conditions that were happening at the time.