RetiredF4
First I'm cautious concerning the extent of reality of present flight sims concerning stall behaviour and reaction of the sim on flight control inputs in this untested flight regime.
Me too. But it seemed reasonable.
The pitch response with manual trim is fairly gentle as one can only move the trim wheel about 90° at a time in the practical sense, before having to move your hand back and grip the trim wheel again (not like the Boeings with the fold out hand crank)
Winnerhofer
Disable AutoTrim in all Laws bar Normal as this is will force crew to be in the loop.
Actually that doesn't put the crew any more in the loop, as the SS remains a gload/pitch rate demand input, and gives no information to the crew as to the relationship between the stab and the elevator (like a conventionally controlled airplane way out of trim would) Neutral SS still would command essentially 1g—even though it may take full elevator to do so (if the stab is way off ).
A good example of this is a fault where autotrim fails, but manual trim is still functional. In this case the airplane appears to fly just fine, but the crew (directed by the non-normal procedure) must view the flight control page on the Systems Display-SD) and trim for neutral elevator. When this is happening, there is no feel change in the airplane, but as the stab position changes the elevator deflection necessary to maintain the commanded pitch response (i.e., 1g) changes accordingly. Obviously as the airplane slows for approach, the crew must continue this procedure, for if the didn't they run the risk of "running out of elevator" near landing as the elevator may (unbeknownst to the crew) be near full up just to maintain the approach trajectory (1g)and not have any excess for the flare.
In alternate law, as the airplane approaches stall speed, the pitch law incorporates "stabilities",which when you get right down to it is changing to direct law in pitch and allowing the natural pitch stability of the airplane to become evident. The speed at which this occurs is not indicated. The trim stops—if it didn't then the stability would not be evident!
The unfortunate part of this is (for AF447 type situations) is that indicated airspeed is required to make that change over (not just AOA). So, one must assume that in the case of invalid airspeed the SS remained a g/rate demand input.
MrSnuggles
I read some posts ago that maybe Bonin was afraid of an overspeed situation. While that is a serious concern I can not see it was in any way applicable here.
It shows Bonin's state of unawareness of the state of the airplane. The pitch had been up, they'd climbed nearly 3000 feet, the stall warning was sounding for almost a minute, Robert had been telling him to "go back down", yet he had apparently confused the significant stall buffetting with Mach buffet- as he remarked that he thought they had "some crazy speed" and at one point deployed the speedbrakes though Robert told him right away not to. The supercritical airfoil makes it easier and more efficient to go M.84, but harder and therefore less of a hazard to get to M 1.0 - without the Mach tuck threat of 707 days.