deposits on IPT fragment
Since we look at the rear side of that IPT disk fragment the question came in my mind what kind of deposit is visible on the picture, Fig. 14, ATSB report. Starting with a shiny polished piece of craftmenship somewhere this dark greyish layer must come from.
Is it the normal agglomeration of exhaustgas that leaked into that space between the rear surface of the disk and the structure connected to or held by that demolished stator ring ?
Or, is it kind of oil cooking coming from an insidious leak somewhere at the rear end of the IPT shaft ?
Another question, how come that the supporting ring underneath the fir tree groves doesn´t show any sighn of wear when it travelled backward towards the nr. 1 nozzle guide vanes ring of the LPT ?? Or did it not at all hit that ring shifting backward, but instead desintegrated before it even got so far ??? How comes that still a ring of that demolished part is hanging inside the wrecked engine??
Is this all possible ??