This paper combs and analyzes the airworthiness requirements related to the common mode issues of FBW flight control systems, innovatively establishes the “common mode cognitive-control certification process model for FBW flight control system” and proposes the review principles and certification considerations for the common mode issues, which helps to fully analyze, identify and determine possible common mode failures, propose independent design requirements and trade-off design solutions. By applying the model and certification consideration, the certification case of a complex electronic hardware error common-mode of an FBW flight control system was analyzed, the common mode factors and common mode failures were identified and confirmed, and the feasibility of each design solution was analyzed. The research results have guiding and reference significance for the certification and design of common mode issues of FBW flight control system and other complex systems.