Turbine D
Thanks for your considered and very rational views over the past few pages. I think your processes are valid but am curious why the IPT blades were not "cookie cutted" away unpowering the IPT when the IPT migrated rearwards.
For your info, the two bangs were separated by about 1/2 second, so the two bangs were from very different processes. I like your thoughts of an HPC stall (boom) followed by the disc burst (boom). A time plot P30 would be of great help.