Very interesting subject whith 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 maneuvrable within the designed envelope. Are helicopters required to have a G meter to prevent this occurence? Does this design characteristic meets the intent of Part 27 or 29-141 and 143? Have the manufacturers and the certifying agencies missed something in the certification process?