Originally Posted by
A0283
@FCeng84 - I really appreciate your effort to help clarify a number of issues. Hope Boeing will elaborate on this in the end ;-)
For me there is a difference between an "AoA increase" and a "positive AoA rate". Hope you can clarify that during your further explanations.
I was wondering if you were talking about "positional feedback" with MCAS or "force feedback" or both. In another explanation you exclude the "positional".
If you use the cutout and remove the power you disable MCAS ... which would put you outside the 'normal' certified envelope... do I read that correctly? ... With MCAS aimed at the NNC part of things, using the cutout appears to push you in yet again an other area, and outside certification?... Or is that a wrong interpretation?
Please excuse that I don't recall the context for "AoA increase" and "positive AoA rate". Can you point me in the right direction for that?
MCAS acts only to move the stabilizer an increment in the airplane nose down direction and then (if AOA decreases below the MCAS activation AOA threshold and the pilot has not provided an electric trim command) to take that increment of stabilizer out (i.e., run the stab airplane nose up the same amount). I don't see how this translates to "positional feedback" or "force feedback".
I think your last paragraph above gets at the issue of hazard levels, hazard mitigations, and availability of those mitigations. MCAS is implemented to address a handling qualities deficiency. The hazard level of not having MCAS drives the requirement for MCAS availability. Any failure that renders MCAS inoperative or leads to MCAS behavior for which the crew is expected to deactivate MCAS must have a probability that is low enough to permit loss of MCAS.