I feel a slow urge coming on to pull out what's left of my university course notes ("stability and control" was supposedly my 'final' subject, got me my first job on Concorde systems).
"Aircraft pitched up to and beyond stall AoA, THS trimmed to fully nose-up, SS - and presumably elevator - being held NU, plus TOGA"
Seems to have been a 'nice and stable' configuration, all the way down.
I wouldn't call it a "deep stall", but it was certainly 'stable'. Why?
From my own very limited flight training - a long time back...., I still remember a full 'power-on' stall, mushing through the air nose-up, but going down at a rate of ft/min.... (sounds familiar?). Throttle back, stick forward, and the conditions keeping us in that 'semi-stable' state were gone, and the nose would drop, and we were back to a more normal state of flight.
Sure, a Piper Cub and an A330 are not the same aircraft.
I would have hoped these pilots had been treated to at least a few "power-on stalls" during their 'ab initio' training, and somehow have retained the memory.... as even I have.
Seems I'm wrong....