Gazelle `hyd`on/off` switch was always on the collective,so hands were on cyclic and collective,feet on pedals....
Why should it yaw to the right as the lever came up..?
were the accumulators charged correctly...? if they were ,then it should be a soft changeover..?
Was the aircraft engineer cleared to do rotor running..? It is not unknown for a Gazelle to get ground resonance...