You do get an audible "DUAL INPUT DUAL INPUT" warning and some lights though [1]. It is never allowable to make sidestick inputs unless you are the single desig

You do get an audible "DUAL INPUT DUAL INPUT" warning and some lights though [1]. It is never allowable to make sidestick inputs unless you are the single designated "pilot flying", but people can sometimes break down under stress of course. [1] https://safetyfirst.airbus.com/app/themes/mh_newsdesk/documents/archives/dual-side-stick-inputs.pdf https://safetyfirst.airbus.com/app/themes/mh_newsdesk/docume...