Are we perhaps talking different definitions of stick force gradients? In post 4 I referred to "pitch force gradient" after which I apologized and in post 9 suggested I should use the term "stick force gradient", which I then clarified to mean "change in stick force with a change in airspeed". Other than that, I've been very careful to indicate the gradient is with respect to speed.
I see this from FAR 25..
"(c) The average gradient of the stable slope of the stick force versus speed curve may not be less than 1 pound for each 6 knots"
Does my post 9 make sense now?
If not, then I offer the following:
Genghis, when I said thrust is reduced, I meant that the aircraft is to maintain level flight. I said this in para 1, but did not repeat it in para 2. By level I meant maintain altitude, though I realize that I did not state that. And hence airspeed must decrease. I was trying to take a simple case. But as to why it is necessary (other than the certification requirements) to have a 1 lb per 6 knot stick force change I can't understand. Surely the aircraft would be very easy to fly without this stick force gradient with respect to speed (maintain altitude, very slowly increase pitch as the speed drops, then maintain this new attitude for the assigned altitude, as the speed settles in at about 240 kias).
MFS mentions the Greek Falcon 900 accident, and though I haven't read it again recently, my memory tells me this was more of a stick force per inch of travel type of problem, or stick force per G. Not a changing of stick force per knot. I believe the falcon was at something like 330 kias, and if the speed was decreasing at the time, it was not the decreasing speed that gave the pilot difficulty.
Mr Tullarmarine, you ask "but how are you intending to exercise any sort of control over what the aircraft is doing .. ie other than just being along on a roller coaster ride ?"
I'd say simple. I adjust pitch up or down to maintain my assigned altitude, and adjust the throttle to maintain my assigned speed. If I'm asked to slow from 250 to 240 kias, I pull the levers back a tad and crosscheck. I don't see why I can't do this very easily with a zero stick force per knot gradient. Sounds sort of nice, like an auto trim system engaged.
You also mention the TP incident, but I do not see how stick force per knot is a player here. Sounds like control was difficult even while at a constant speed, so a changing stick force per knot should not have been the root of his problem (which was admittedly that the loading was outside the envelope.)
"Don't feel too bad about this stuff confusing you a tad". Yep, I'm confused