Originally Posted by
FE Hoppy
@JT
On out little E-Jets we've got an ATTCS system that will rapidly increase the thrust from a full 25% reduction to about 10% above Rated thrust. I've often wondered how that would look a kt or 2 above VMCG.
That would seem to violate part of FAR 25 Appendix I:
I25.4 Thrust Setting.
The initial takeoff thrust or power setting on each engine at the beginning of the takeoff roll may not be less than any of the following:
(a) Ninety (90) percent of the thrust or power set by the ATTCS (the maximum takeoff thrust or power approved for the airplane under existing ambient conditions);
That seems to be saying, at least as I read it, that the ATTCS delta should be 10% above the thrust set for that takeoff, not 10% above the Rated thrust. Whereas what you describe is more like 50% (75% rated to 110% rated).
Our equivalent system works, IIRC, on a delta to the set thrust, not a delta to the Rated thrust.