Thanks for the feedback everyone. The engine response times are custom-coded based on videos taken in the real RJ. It would be expected for the spool times to be much quicker than higher-bypass engines that you would find on an A320 or 737 as there's a lot less rotating mass in the LF507s by comparison. I will bring this up with our development team though just to double-check everything.
With regards to some systems (like the TRP and YD) not being functional following a change of aircraft state on the EFB, this possibly could be misunderstood for the FGC test. If the aircraft's power supply is changed when switching states (such as Cold and Dark > Turnaround) an FGC Test will be triggered once the power is restored. Off the top of my head, the FGC Test takes 45 seconds to complete after power has been applied to the aircraft and during that time, a few systems such as the TRP and YD will not be functional. Once the FGC Test is complete, an FGC PASS message will appear at the top right corner of the PFD.
I suspect it may be possible to confuse the FGC Test logic if a change of aircraft state is made before an FGC test is completed (I.e. if the aircraft state is changed from Cold and Dark > Turnaround, then 10 seconds later to Ready For TO). I doubt it would be an issue if only one aircraft state change was made every minute. We'll do some tests with this to see if we can break that logic and if so, prevent that from occurring in the future.
Mark - Just Flight