Turbine D
It is an assumption that there was Stretch due excess Heat. Would not the Disc fail instantly even at in limit RPM once the Drive Arm fractured? Also, Contact of any description IPT/NGV Platform would be exactly simultaneous with aft movement of Shaft??
Given the AD's, and their warning of Metal/Metal with aftward drift, isn't the better assumption that the Disc Fractured after contact with Stationery Parts, melted, Disintegrated, and caused burst?? I see no need to entertain Fire, or Blade shear to explain this Engine Explosion. The simpler explanation is generally assumed to be the more likely cause, No?
Applying Occam, then, we can simplify the assumed failure to include no fire, no overspeed (save after fracture), and no need to index the Failure with cockpit data (displayed), at least insofar as it is not immediate in nature, and relies on the EEC, which failed to control the engine in the first place? This demands on actual events in the IPT locale, and taken in sum, they argue against a failure due to Fire.
In this way: Any fire would need time to act on the IPT bore. The more logical assumption is that the bearings (balls) wore beyond their ability to prevent axial (aft) movement, and the Drive Arm was pushed into the Stator Ring. The ten Radial Struts here, were under suspicion via AD targeting their Bolts on the case. They were to be inspected during Strip or borescope. The Splines, oddly enough, at this point, though worn, may not have actually caused the failure. The Splines were subject to inspection, but were just canaries in the mine; What caused the Spline wear also caused the Bearing wear, also caused the Oil Problem, etc.
So we take serious note of the AD's in the Burst, or we rely on The Manufacturer's claim that the Burst was caused by Oil Fire. It is more or less that simple, IMO.