Originally Posted by Dartman
FLCH adjusts thrust to give you a rate of climb (or descent, as the case may be) to reach the selected altitude / level in 2 minutes. i.e. If you are descending 2000 FT, it will give you approximatly 500 FPM. 1000 FT / 250FPM, etc. The AP will adjust the thrust up to CLB, or IDLE, as the case may be to try and achieve this.
I don't fly the 777 but I call "rubbish" on all of that.
Not rubbish at all. That's exactly how FLCH works in the 777, although I think you'll find that a 2,000 ft descent in 2 minutes equates to 1,000 ft/min not 500 ft/min, etc!
If the thrust comes back to IDLE, the autothrottle then transitions to HOLD. It doesn't 'wake up' again unless another vertical mode engages. Therein lies the problem.