@AirRabbit
If you go back to the OP you will find it querying
FAA changes to "Va"
after the Airbus deal
I take this to mean the changes FAA made to their regulations as a result of NTSB pointing out the confusion that existed between Va used as a design speed and Va used as a manoeuvre speed.
If you check out the posts I cited earlier you will find that the FAA made changes to the definition of the latter, not to Va used as a design speed. Consequently I think that referring RH and CS to the latest definition of manoeuvre design speed won't help them - hence my reference to an earlier PPRuNe discussion.
@ Dozy
Not so much time to drain the systems Dozy, just that if the pipes are open to the atmosphere the working pressure drops to zero, so the remaining control surfaces will flop all over the place under whatever aerodynamic hinge moments they might experience.
I don't think we know anything about the subsequent gyrations and I would certainly not like to attempt any prediction - they were nowhere near stall when if happened so I don't see why it should develop an almost instantaneous flat spin - in fact a aircraft that size will not do anything much in a fraction of a second.