To address technical challenges and accelerate civil aviation applications of advanced rotorcraft, a systems engineering approach was adopted. An input-process-output (IPO) model was developed for airworthiness theory and critical technology research. Key elements including inputs, enablers, control factors, activities, and outputs were defined and systematically interpreted. The results demonstrate that the development of advanced rotorcraft is jointly constrained by airworthiness standards and technical limitations, which exhibit a co-evolutionary development trend. Through this approach, the mapping relationships between airworthiness requirements and technical specifications are deconstructed. The IPO model achieves integrated information processing and standardized output generation for airworthiness and technical requirements, providing actionable references for conceptual development of advanced rotorcraft systems.