Continued from previous thread here.
Turbine D
You propose a "false bearing" developing between IPT and LPT NR. You also suggest two possible causes for this contact. Fire is one, and Shaft failure another. I would offer that in the two previous failures, the disc was
retained because there was
not overspeed. In one case, (Miami) the Disc had separated from the Drive Arm in a "Circumferential Fracture". The second is still under investigation. For the reputed cause of QF32 uncontained failure, RR has offered "Oil Fire". Oil Fire in the Roller Bearing case was due to uncontrolled combustion specifically (Your tenet). There is not evidence of oil fire showing on the LPT module, and the gases involved would have to have overcome the Pressure in the IP/LP cavity, no mean feat. So what is left is heat acting on the Drive Arm from the front face, having escaped two sets of seals, and blowing past Roller bearings that presumably were still serviceable. Sounds unlikely, and that leaves Shaft Failure as the cause of disintegration of the IPT. The Shaft failure that comes to mind is the one predicted as a result of Spline wear/failure by the AD's.
Do you have an opinion on the generation and advance of the "Oil Fire"? How do you read the AD's prior to November 4? Do you consider the Splines as exonerated?