roulishollandais;
First, in your
post #1148 you have completely missed my point in favour of making your own. Further, in your choice to parse the metaphorical expression, "99.99%" rather than try to understand what was being conveyed by the post you have demonstrated a complete absence of understanding of how flight safety works and why this industry is so remarkably safe and you have refused to engage in a pleasant dialogue which would have led to further discussion and perhaps even further comprehension.
My "99.99%" was a metaphor...a figure of speech indicating high, versus medium or low correlation between SOPs and their adherence, and the very high safety levels of our industry. You took this expression literally, applied mathematics to a metaphor and drew precise and entirely incorrect conclusions which have no basis in the kind of activities, processes and preventative strategies which bring about such high levels of safety in this industry. Should we briefly examine a counterexample, you take the
"ten to the minus ninth" standard and apply it to one variable, (my number of hours flying) and ridiculously try to extend such "chances" to the industry. That's not really how it all works, you see.
Your approach utterly fails to take into account this complex and effective safety system which is decades old and to which many engineers, human factors specialists, pilots' associations, manufacturers and airlines have immeasurably contributed and so, beyond a detail of what "99.99" means statistically, the point you are trying to make fails to make any contribution to a broader understanding of what is behind the millions of hours of unremarkable flight and why this accident has so captured the imagination and interest of so many.
Regarding your calculation of 7400ft, you have set up a straw man case which bears no relationship to the discussion at hand yet the outcome for your straw man argument, "7400ft" is applied to the case, again at hand. I don't know how you do that and still claim some correlation between the two but of course you are free to do as you please notwithstanding relevance to the discussion.
For your "model recovery" (which may have basis in fact but which, again, bears no relationship to the present exercise), you begin the recovery at FL100. If one approaches (
not enters) the stall at FL100, recovery may occur within your calculated altitude if the recovery from the approach-to-stall is handled smartly. In fact in simulator exercises, typical altitude loss using the "Approach to Stall" procedures was held to between 500 and 800ft depending on a number of factors. Further, I suspect that had these procedures been applied just prior to the apogee, (lowered pitch to 5deg below the horizon), TOGA thrust, respect the stall warning (in Alt law), the event may not have developed into a full stall. Once the AoA was increasing to 30 and 40 degrees, that procedure would NOT work and recovery from the stall would be necessary, which means pointing the nose down to between 15 and 20 degrees ND and accepting the extremely high rate of descent.
However, the simulator case at hand and our real case, AF447 was in full stall, and at FL100 was still descending at approximately 17000fpm with an AoA of 45deg. Your case and your argument is therefore wholly non-applicable; the aircraft is not going to recover in "7400ft".
You may pit your willingness to argue minutae such as "99.99%" against the experience of several here who know their stuff and against the numerous simulator exercises all of which run counter to your notions of recoverability. That, as you say, is your choice. But I submit that the issue here is not one of being right come what may but is one of understanding both the aircraft and high-altitude flight and what needs to be done by the crew to swiftly unload the wing to reduce the AoA below the stall when a transport aircraft is in a full stall at cruise altitudes.
It is completely incorrect to suggest that a fully-stalled airliner
at cruise altitudes of the kind we are discussing here will recover from such stall with a 7400ft loss of altitude from said altitude. An appreciation of the subtleties of this very dynamic set of circumstances would go a long way in support of a collegial exchange of views.
The only case in which your understanding may be marginally in accord with the facts is in strictly controlled flight test conditions where the approach to the stall is part of a test regime...note I said "Approach to the Stall" because NO ONE intentionally stalls a transport aircraft at any altitude any more, period. The Flight Test manual for these exercises states that such tests will be done at FL140 or higher. The one case which has occasionally been introduced here is the Perpignan case but this crew collectively decided to approach the stall test on final at 3000 AGL and rushed the process. The recommended height for such tests is for a reason, and the stuck AoA vane is one clear reason why.