Stress,
Flight controls are not my specialty but I note you said it's a turbine Dak. Is your pilot familiar with the turbine version? If radial piston engines are replaced by turbines, a lot of gyro stabilisation from all that rotating machinery is lost and handling effected. As an example, look at the CL415 versus the old 215 - most of all that extra ironmongery on the wings & tail is just adding back in the stability lost in the engine change.