Hi Andrew, With all due respect, I understand SD causes and effects quite well. In fact I had to in order to develop the device that can prevent it. In essence, the only reason I am aware of that a pilot becomes disorientated is due to the loss of visual cues to the brain. I have never heard of a pilot becoming disorientated under normal flight with a clear horizon. Maybe an exception would be staring at terra firma during a spin! My questions were asking "has SD been essentially solved with modern day "glass cockpits", or is it still a major cause of loss of control? Put more simply, my device allows a pilot in IMC to see the horizon thus preventing SD. The device has no relationship to the aircraft systems or the pilot's ability. Considering the present technically advanced aircraft art (glass cockpits) , would my device be more beneficial in preventing SD? joe