Turbine D
Hi. From the larger (135 degree) piece of Turbine Wheel recovered, I note the lack of flange, (bolt area). Instead, there is what EASA called a circumferential Fracture in Edelweiss, Miami. So I conclude the Drive Arm remained intact forward of the Wheel bore where it fastens to the L shaped Bearing sleeve. The Shaft flange makes up the aft portion of the bolted together assembly. It resembles a sandwich, in section.
We have made note of the molten metal "plated" to the flaring portion of the Wheel bore, so melted metal is known, and the folded over remnant of bore indicates your sub-ductile peening of this area. Also, there is Metal "Spatter" mentioned in the ATSB report, located on the aft face of the Turbine wheel. Your note of the lack of heat rub at the rim demonstrates the lack of effacement with the Stator Platform, as the Platform effaces the Blade roots, not the rim of the IPT. Here we are again at "Push and Shove" of the IPT Blades out in the forward direction from their fir tree roots, as the Wheel slips backwards into the Plane of the Stator Platform. If we find a Blade from the IP Wheel, I think the effacement Blade to Platform will show, and may even show molten metal.
I've yet to look at the Steps in the Wheel. Am I looking for "Spiral" or "Radial" stepping?? While we are at it, please look at #16. The segment of NGV Platform facing the aft Rim of IPT shows clearly the tracks of circumferential contact at the effacement IPT Wheel Rim/NGV Platform. It has characteristics of patent wear, not critical failure. The outer surface of the NGV Platform and the edge of the Platform itself show where chaotic contact Blade/Platform may have separated all the Blades. Note the missing metal where the Blade roots contacted the Platform??
This may sound farfetched, but so is IPT Burst. In looking at the fracture face of the recovered wheel piece, I note a layered area sub surface, with the surface seemingly uniform above it. This obviously degraded area looks like patent damage to me. To You??
The trajectory of the found piece was obviously eastward. I have a problem with the "drawing" of the location of the missing pieces in the core, then out the case and "up". The origin of the pieces are shown above or below the longitudinal axis of the engine. If the piece, for instance, shown above the L/A was a part of the Wheel, it would not have exited to starboard. At this point in the core, its rotation is clockwise, and therefore it would have exited to port. Now this may be picky, but it is misleading. Also, no one knows for how long the pieces remained inside their circular prison, (case). They could have rolled around its perimeter and exited anywhere.
Last edited by bearfoil; 29th January 2011 at 00:31.