Many years ago in a galaxy far,far away:
Yes you can control the AC , but there will be feedback. The controls do not lock. Reduce power, roll to level or otherwise unload the AC.
The aircraft is completely controllable unless you are pulling so much "G" that you are way out of the flight envelope.
I am referring to an AS350D or AS350B, the AS355F1 has a limit light to advise you when you has arrived at the "G" limit due to the dual hyd system.
Long time ago but I recall the limit was 2 G.
We used to demonstrate this, very carefully, in training.
As I say that was a long time ago later models of the AC may well be more difficult to control - I don't know.
"Very interesting subject with the following comments and questions: So If I understand, with a `Jack stall’ condition you cannot move the controls, meaning during this time the aircraft is not controllable. If the aircraft is designed up to a 2g or 3 gs depending on loading, It should also be maneuverable within the designed envelope. Are helicopters required to have a G meter to prevent this occurrence? Does this design characteristic meet the intent of Part 27 or 29-141 and 143? Have the manufacturers and the certifying agencies missed something in the certification process"