Owain Glyndwr, Rudderrudderrat, DozyWannabe thank you for your replies and inputs.
I subscribe to
“I'm away off with work.., so if I don't respond it's not because I'm ignoring people”
BEA doesn't remark any PIO because it wasn't.
Here is a quote from final report:
"When the autopilot disconnected, the roll angle increased in two seconds from 0 to +8.4 degrees without any inputs on the sidesticks. The PF was immediately absorbed by dealing with roll, whose oscillations can be explained by:
- A large initial input on the sidestick under the effect of surprise;
- The continuation of the oscillations, in the time it took to adapt his piloting at high altitude, while subject to an unusual flight law in roll (direct law)"
“Mayonnaise Stirring” is just normal and characteristic to any AB-FBW aircraft
https://www.youtube.com/watch?v=pJrLKLoJG_o#t=201
Simply, that type of input at cruise speed is overcontrol, not to be confused with PIO. Pitch input was too much either, then the aircraft ended up in coffin corner, at almost 38000 ft. THS moved at NU stop. So, at that point, they were already doomed. From there, any other excellent crew would end-up pancake on ocean surface.
See how the longitudinal stability works for a non FBW aircraft
“...et rapidement les choses revient normale”, "...and things quickly returned normal"
https://www.youtube.com/watch?v=WAiA6ep95Sc#t=1508
Also, it's interesting to revise an accurate tv reconstruction. Robert acknowledge verbally “STALL”, in CVR transcript is (!), that was at only 50 seconds after AP disconnect, 30 seconds later, nothing else matter, either with “mayonnaise stirring” or with an expert touch
Sometimes, we can not see the forest due to leaves:
https://www.youtube.com/watch?v=WAiA6ep95Sc#t=268