... until outside envelope, where you are into test-pilot territory or even beyond.
Not necessarily, esp. if only in pitch... (gawd

, many were stalling and recovering gliders and even powered aircraft before they had a full driving licence. I'm sure some were recovering from spins even).
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I find it quite incredible that so many are suggesting (albeit frequently doing it between the lines), that the aircraft may have been irrecoverable once fully stalled soon after reaching the apogee.
It's a fairly conventional aerod. design, and I see no reason we should start comparing it to a 'T' tailed a/c operating with an aft c.g.
The fact it stayed at a stable AoA (probably determined by the THS setting) and just rocked its wings (+/- 20° max), maintained a reasonable airflow and forward speed component, make me think all was definitely not lost until say, at a guess, 25 > 20,000 ft.
It's for this reason that I banged on loudly earlier about an well positioned AoA instrument, with
green and
red areas a bit like the revcounter in many cars, and about insistance on above average manual flying skills, for any aircrew going for a commercial license.
One other thing, and I know this will not be accepted immediately by all Airbus cockpit crew ..
I am not convinced that the airbus sidestick design is optimum for all situations (I'll leave it at that for now!).