You seem to keep referring to the IP main shaft, but is there any mention of a pertinent shaft defect in this accident report?....
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No, but I am not sure of the direction you want to go. The Shaft did not fail, at least not prior to disintegration. If you look at the section through this space, you see that the Turbine Plane is foreward of the aft bearing (shaft). The attach to the shaft is aft of the bearing plane. So the wheel is connected via a bearing that is remote from its geometrical plane involving a 180 degree return to the Drive Arm. I assume the circumferential fracture is located at the seam between wheel and ARM. The bore of the Wheel at that point is the same diameter as the ARM, does the Wheel slip over the ARM, as it moves "AFT"? Nice trick! Or does it slam into the Stator platform (LPT) which provides some false bearing support? OR, is the circumferential fracture at the aft terminus of the ARM, where it flats to enter the three way join? If the true bearing architecture gives way to a new and "false" support, where is it located? On the Stator? This surface is of course irregular, ad hoc, and incapable of maintaining tolerance that prevent the Wheel from going wildly eccentric, here's why: The bore of the IPT is much larger than the diameter of the IShaft, of course. Unlike a standard slip fit or "Press Join" to an axle (with a keyway, or splines) and without restraint, the wheel cannot maintain any local integrity....
I have searched for the proper schematic, and the usual places are not available, so I do hope I am not remembering the T5, or 7.... So my words are memory based. Bottom line? Can you help me with a better description of this "false bearing". Also, how do the blades remain attached , my opinion is they exited forward as they were pushed out the pine trees by the stator?
Last edited by Lyman; 9th May 2012 at 19:39.