787 encounters more problems

[TopTup]

AK, I'll have a bash at it....

First and foremost, [crudely] TO/GA is a pitch mode whereby attitude and thrust are used to achieve what you have asked from the aircraft. Appreciate that and half your battle is won.

At >50 if TO/GA is not already active A/T is inhibited until reaching 400 ft altitude (you have manual thrust control). At 80 kts pushing TO/GA disarms LNAV and VNAV, nothing more, nothing less. At 100 kts a barometric snapshot of the ambient conditions is taken and applied (to assist in engine parameters DESPITE what you have entered into the FMC). So, for the competent 777 pilot you should be also checking the top left hand side of your MFD at 100 kts to confirm TAS appears to verify all is working well, just as you do engine parameters and a "80 knots" call. The 777 FMC is smart. Too smart for some who do not understand what it is telling you or what it is doing, hence overuse of FLCH or the complete inability to use V/S or "understand" VNAV.......VNAV activates the inputs the "pilot" selected to the FMC but corrects for pressure alt, etc as well as both real and predicted winds. For assumed T/O conditions control speeds are determined at the actual temperature, not what you/we the pilots want to tell the aircraft it is.

For whatever reason you want MCT on your 777:
Firewall the thrust levers, but be prepared for what you have just asked the aircraft to do for you. The EEC monitors thrust settings but DOES NOT relieve the pilot from monitoring engine parameters him/herself. If conditions are encountered during the takeoff where additional thrust is required [windshear] the crew should not hesitate to manually advance thrust levers to maximum takeoff thrust. Thrust levers should not be advanced beyond the fixed derate limit unless conditions are encountered during a takeoff where additional thrust is needed on both engines [again, windshear]. A thrust increase during an engine failure could lead toward loss of direction control. (All paraphrased from the FCOM/FCTM).

Advancing the thrust levers removes all derates and assumed temp factors.

So, I read all this to say that Boeing tell us to use the automation, know, understand and comprehend what the automation is doing and when you want to be a pilot again, know, understand and comprehend what you are doing. (A fast becoming rare attribute). Taking manual control will remove derates and the assumed temp considerations and the engines will give all they can with respect to ambient conditions, ie without cooking themselves.

Hey, where and if I'm wrong then tell me! The day we stop (wanting) to learn is the day we should put the wings away. I can just as easily misinterpret things but this is how I appreciate thrust management on the 777.