Originally Posted by AeroTech
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Barit1, may be no indication of N2 & oil pressure ?
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Nope - the other way around. We had N2 INDICATION(!) & OP (gearbox driven by starter), we could initiate FF, but no lightoff (no airflow - the core wasn't turning - duh!) The starter would spin up to cutout speed since it had minimal load, then everything coasted to a stop.
When we finally realized there was no turbomachinery rotation (despite the positive N2 indication), the first thing we checked was the tower shaft.
I had expected a brittle fracture in the shear section - but instead it was a very smooth plastic failure. The surfaces looked like they were machined & polished.
