Originally Posted by M Invernoz
So. I understand at a high N1 Percent??
The shafts are not all named the same on individual engines. Typically, the high pressure compressor shaft is the one the starter acts upon (if there is more than one shaft installed, of course). So the relevant number is usually N2, Nh (on the PW120 series) or whatever else the high pressure spool RPM figure may be called in the individual engine. There may be limitations involving other spools: for example on the RR Tay engine, N1 rotation must be indicated before the fuel levers may be opened.
Originally Posted by M Invernoz
Some kind of flameout? or a hot start, right?
When starting the engine, not only the compressors have to come up to speed, but also the normal gas flow pattern in the engine has to be established. A strong tailwind will increase the pressure the hot gas flow has to overcome when leaving the engine, and also (try to) spin the fan backwards, thereby applying some adverse/opposite torque to the respective turbine, resulting in more drag that also needs to be overpowered by the gas flow. Generally, higher drag and slower turbine speeds will lead to higher exhaust gas temperatures (nicely visible on a turboprop: an identical power setting will show higher EGTs with lower prop RPM and vv.). So the flameout is not really a problem, but a hot start definitely is.