Turbine D
A quick read of the Patent referenced by Diversification explains that the scavenge pipes penetrate from the bearing collection area through the Gas Path, and even if cracked, or broken, there is a positive pressure (!) that prevents oil spill into the combusted gases. This may not have worked in this case? The scavenge pipes lead to an oil collection tray and thence to the Oil Tank., and a de-aerating chamber. I see the cross section of the delivery tube as approx. five eigths an inch, and at 70psi, that is a fair amount of oil.
What confuses. It is the Spline wear addressed by the AD that allows "aft migration" of the IP Disc, and I cannot visualize splines at the roller bearing case. The Drive Arm seems a solid "Coupling" without allowance for movement, so other than a plasticized wheel, what would allow the drift back into the Stator? I had thought it was a compromised ball bearing at #2 that let slip the wheel.
For the record, and to address a poster's PM:
I consider the RB 211 a work of art, no less, and if anyone thinks differently, you are not reading my posts. My disagreement is with the Stewards of this engine, who allow a reputation to suffer because of bumbling greed, and Pride.
bearfoil