Yes, the feedback forces overcome the pump output so there is a sudden "jolt" and temporary loss of control. We used to be required to demo it to studes going through the basic rotary course at Shawbury. Goodness knows what it did to the airframe, as it didn't feel pleasant! We used to go into a steep high speed descent and pull up quite hard, whereupon the aircraft "kicked" more nose up and rolled a little, which actually helped the recovery. It would be quite difficult to see this in normal ops, as it was really at the "extreme of manoeuvre".
Apologies for thread drift - I'm certain it was also possible to get close to main rotor jackstall in the military Puma. I displayed that aircraft for a while and sometimes the old girl registered her displeasure by suddenly vibrating hard, again in fairly extreme circumstances (high speed pull up, etc). The recovery was just to back off the collective pitch and/or reduce the extremity of manoeuvere, just as in the Gazelle. However, a pilot flying on normal squadron ops would have to be very hamfisted to reach those limits.
As for the two display pilots who achieved the impossible by hitting the tail rotor blades against the tail pylon...... "LSH", I think, might remember one of those occasions quite well
