Just to add to the N1/N2/Ng confusion, Allison 250 has N1 as gas generator spool, N2 for free turbine...RR Tay uses N1 for (LP) fan, N2 for HP...RR Gem has Nh for high press spool, Nl for LP spool & Nf for free turbine...GE CT58 Ng for gas generator, Nf for power turbine...etc, etc...bottom line is - don't get tangled in an argument about what N1 stands for (even on a CAA oral) 'cos different manufacturers/different engines use the same thing for different things (if you see what I mean)
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Ground tested, no fault found