Dear @Andre.White,
Indeed it looks like a blade-edgewise instability. I was first expecting a physic instability, but given the every other time step oscillation when the model first goes unstable, I’m now wondering if it is a numerical instability. What does these time series look like if you drop DT by an order of magnitude–from 0.025 to 0.0025 s?
Does the model remain stable if you disable the blade-edgewise DOF (EdgeDOF = False)?
Again, does the parked simulation also go unstable when using steady, uniform wind rather than full-field turbulence?
Best regards,