Crossunder & bsevenfour:
The B777 A/T reduces thrust to idle at c.25R in normal operation.
The stall protection modes are not active below 100R on approach or below 400' AAL on takeoff, interestingly. This effectively means there is an un-annunciated 'Landing Mode', very similar to the Airbus one...
As for the argument about 'hard' and 'soft' envelope protection, I tend to side (very slightly) with the Airbus philosophy (even though I fly a Boeing!). The most oft-quoted example is the 'need-to-pull-a-bit-harder-to-get-over-the-mountain-bugger-it-won't-let-me' scenario. As CFIT is still one of the largest killers, it would seem to be the most relevant, also.
Take aircraft A & B. A has full (hard) envelope protection, B makes it difficult, but possible, to go outside the protection.
In aircraft A, once you get the dreaded "Whoop Whoop", full back-stick commands TOGA thrust and a computed trajectory to maximise the obstacle clearance potential. No thought required.
In B, you press the buttons and pull back. How hard? Well, if your AoA is too low you will hit the mountain. Too high and your gradient will suffer and you hit the mountain as well. You do have some flight director guidance but I can't find an explanation as to what it is. Chances are you won't get it right if it is a marginal escape as you most likely are flying at night/in IMC so can't see the obstacle (otherwise why are you trying to hit it?)
The point I am trying to make is that I would rather have a bunch of computers recalculating my optimum 'escape vector' hundreds of times a second and keeping the wing just on the performance 'sweet spot', than to try and figure all that out myself. I would rather have spare capacity to work out where the **** we were and what to do about it!
Last edited by FullWings; 8th September 2004 at 17:54.