Machinbird;
re, "PJ2 describes the proper effort as little more than a light squeeze on the stick if I remember correctly, although he also indicates that the aircraft is a bit goosey in roll in Alt 2 (my words, not his)."
That's just how I described it: light squeeze, if anything at all, and that's how the sim performed. Taking one's hand off the stick would have been by far the best decision and then gently correct the right roll with one small motion. Tough to do? You betcha. This is just hindsight.
Really, this initial roll and the few back-and-forths were entirely a non-event...in the sim one rolled back and forth a bit just like we see in the data, primarily because it is sensitive, but as Owain Glyndwr has stated and I completely agree based upon experience with hand-flying the airplane at cruise altitudes (in Normal Law), the PF learned quickly and got this bit of roll under control quite nicely.
The rolling response of the airplane is all but inconsequential to any of this including the initial, instant pitch-up. This pitch-up was instant, steady (uncorrected, unchallenged) and held for a relatively long time. It went from what may have been perceived as the "correct" response (to the UAS) to an urgent pull-up to arrest either the descent, or what may have been later assessed as an overspeed, (I think that notion is difficult to support). The lateral stick forces which produce the minor rolling we see in the data (+/- 8deg) are tiny but the half-pull (10deg NU IIRC) to produce such pitch-up requires a much stronger force - I don't think it is a result of 'being distracted'.
The eight degrees is nothing to be concerned over, nor are the back-and-forths; such minor gyrations don't lead to a complete loss of control, and he got it under control. Now, over thirty-five degrees bank at that point would be something to comment upon.
I've never understood the fascination with this initial roll and subsequent minor PIO. There's just nothing in it - it's what the airplane would do with just a bit of lateral stick and he very quickly got it right. But it doesn't stall the airplane.
While it has generally been agreed that the sim cannot - does not reproduce aircraft behaviour at and post stall, nor does it behave wildly and unexpectedly in the stall and subsequent descent if one keeps the stick back. The stall is however quite recoverable, taking about 20,000ft or so. The positive lift from the THS even at 13deg NU and the elevators 30deg UP has been acknowledged as contributing to a ND tendency which, if full ND stick is applied AND HELD, with pitch at 15-18deg ND until the airplane is clearly flying again, (rapid increase in CAS, disappearance of buffet, increasing wind noise), the stall is exited before FL200. That's the sim, (Level D). I am not an engineer but my pilot instincts tell me that below FL200, opportunity for a successful recovery rapidly reduces, mitigated only by the thicker air. It would take very aggressive action on the controls to do so and we're just not trained to do that. That means the guy at the controls at that very late point in the event would be of a mindset that recognizes only one way out with seconds to decide..., "15deg nose down, 15,000ft away from earth doing 18,000fpm down is my only chance" and that capacity to think and do that is, I expect, rare.
After all situational awareness was lost and reassessing what had occurred just prior to the apogee, (meaning, why the airplane couldn't be in a high-speed condition given its initial pitch up after stable flight), the loss of energy & post-stall entry became extremely difficult to assess and respond to. there just isn't the instrumentation to tell you that and I firmly believe that an AoA indicator would not have saved this flight at that point. It may have up to the apogee but the psychology of perception/assessment/agreement rapidly changed after the descent began.
The recurring stall warning was a sad happening in an extremely complex and impossible-to-assess set of circumstances but that occurred very late into the descent, (about FL200 to 180) where recovery was rapidly becoming impossible even with extremely aggressive actions.
Last edited by PJ2; 20th March 2012 at 06:10.