Promotion recommendation
I move that jpete, Probationary PPRuNer, be promoted immediately to Newby 1st class, with Elephant stamp and Star. Seconders? Ah. I see Thread Boss has already done that in effect.
Thank you jpete, for a wonderful tool. I hadn’t grasped the full power of Googles’ ‘site:’ prefix, and was only using it simplisticly to search my counties’ sites.
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Thanks also all you others, who responded to my ISUS search query (ICUS sic). I drove the first steam age A320s for a bare 100 hrs or so, and I see the pneumatics are as always. However, I was mostly interested to discover the degree of autonomy that the new digital S/B 'A/H' has.
I twice suffered loss of all driven flight instruments, (not on the 'bus!) once a total shut-down for 8-10 mins, and the other more insidiously with both the ADI & HSI freezing in place with no warnings at all, both in dark-night. I therefore used to be somewhat paranoid about finding out how long each type that I flew could last on battery power, after loss of all electrics (had once), and would develop an Apollo 13 like power-down procedure, until all that was left was the 3A (IIRC) S/B AH, a torch, and the SB pneumatic gauges, radio sched call each 30 mins, from the one (motorbike rated) 20 A.H. NiCad battery in the belly, just in case I lost all elects again. With 3 hours max to the nearest available, highly desirable. I also frequently practiced hand flying on cruise to 'freshen up,’ and was always very manually current.
This preamble is to say that, given the 'bus’s zero stick-feedback, zero throttle-feedback, and non-amplified vertical attitude tape response (as, say, the Concord had in cruise), the thought of hand flying the A320 on cruise was a bridge too far for me. To return to the thread: Even given that hand-flying is actually only providing joystick like CWS inputs in Airbus's FBW logic, and far too coarse for the delicate inputs needed at high altitude, I cannot see how any line pilot, and possible even any test-rated pilot could hand fly this extreme initial jet upset, the cause of which remains a mystery I understand.
My interest in the ISIS was actually related to the soundness of the attitude display, whether it’s attitude reference is integrally sourced as the original A320s were, or whether the ISIS is dependent on external reference in any way. The manufacturers specifications make no mention of this. If the ISIS *is totally independent in attitude, it does seem odd that there appears to have been no flight guidance reference made to it, at least discussed. In such an upset, I would have been glued to it, regardless of all other indications.
But then, who can discuss realistically the forces in the interior of a Cb, except those who have done so and survived, usually with hairy stories?
In regard to PJ2’s comment: “..never saw the "slight increase"!” (a pitch-up) PJ2, it certainly existed in the climb. In every previous type I flew when possible I used to hand-fly to TOC. Constant refresh of cp movement/mach tuck, etc. That went out on the 320, with the pitch up. It was approx 0.2 deg/sec, which required approx 10 g nose down force applied to the top curve of the side stick to neutralize. (A gentle little-finger pressure.) Somewhere on file I have copies of the two (typewritten) letters I wrote to Airbus directly, requesting an explanation for the apparent external force being applied in CWS, which could compound a situation if a pilot chose to rely on CWS in some situation. Seems it may have been the 1g at increasing altitude effect. I never did heard back from Airbus.
In the meantime I go back to exploring the implications of RetiredF4's eye opening post (his~her reference to Ostawiri & Naik’s post stall study of the NACA 44x airfoil lift curves specifically) which has chilling implications which I find quite disturbing.
In memory.