I think a lot of the hydraulic problems mentioned above during high speed turns are not really hydraulic problems but retreating blade stall which causes a euro machine to flick right and a US machine to the left. For this reason when teaching steep turns, you get the student to turn the opposite way to the flick, so that if it goes wrong, you flick upright.
I well remember being number 5 in a tail chase in a S55 when the leader sped up close to vne and wrapped on lots of right bank. A few seconds later, trying to follow number 4, I was doing a steep turn to the left. Very worrying but not really a hydraulic problem.
Maybe the Gazelle had this happen?
