Next-generation aviation safety: system-of-systems safety concept unveiled

A new safety concept based on the system-of-systems (SoS) perspective is proposed in a recent review paper published in Engineering, aiming to address the challenges of future civil aviation transportation system (CATS) safety management. With the expected growth in air traffic complexity, future CATS is evolving into a complex cyber-physical-social system, bringing new risks from scenarios like urban air mobility (UAM), new technologies, and new requirements.

The paper, authored by Daqing Li, Anzhuo Yao, and others, first reviews the evolution of aviation safety, which has gone through four generations. Each generation is characterized by different driving factors and safety improvements, but also faces new risks with the introduction of new technologies. For example, new introducing new technologies often results in a temporary decline in safety performance.

The complexity of aviation risks is analyzed from three aspects: emergence, diversity, and conflict. Risks can emerge from complex interactions within CATS, and are diverse in types, including human, machine, information, and management risks. The dynamic nature of CATS also makes risk spreading likely, resulting in conflicts in safety management.

To deal with these challenges, the concept of SoS safety is introduced, inspired by the human immune system. It includes three core elements: safety capability, safety logic, and safety architecture. Safety capabilities cover aspects such as risk perception, mitigation, and elimination, with elements like global awareness, collaborative orientation, intelligent decision-making, and agile response. The safety logic features a three line of defense design, aiming to control known risks, be aware of unknown risks, and explore underlying unknown risks. The safety architecture is modeled as a hypernetwork structure, consisting of a safety fundamental network, a safety collaboration network, and a safety decision network. Key technologies supporting SoS safety, such as model-based systems engineering (MBSE), digital engineering, and parallel management, are also discussed.

The development of SoS safety in CATS is predicted to progress in three phases. In the first phase, resilience management at the operational level is the core, aiming to enhance safety management. The second phase extends safety capabilities to the design end, enabling better adaptability to risks. In the third phase, with the advent of UAM and mixed operations, SoS safety aims to mitigate unknown risks through the integration of design and operation and the evolution of risk cognition.

The proposed SoS safety concept represents a paradigm shift in complex system safety study. It has implications for safety management, guiding the transformation from isolated system safety to SoS safety, from operational-process-only risk management to the integration of design and operation, and from “process & outcome-oriented” to “capability-oriented” safety management. Although the concept is introduced with civil aviation as an example, it can be applied to other large-scale complex systems. Future research should focus on validating the concept through testing and digital engineering, especially in emerging contexts like low-altitude operations and UAM.

The paper “Next Frontiers of Aviation Safety: System-of-Systems Safety,” authored by Daqing Li, Anzhuo Yao, Kaifeng Feng, Hang Zhou, Ruixin Wang, Ming Cheng, Hang Li, Dongfang Wang, Shuiting Ding. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.01.002. For more information about the Engineering, follow us on X (https://twitter.com/EngineeringJrnl) & like us on Facebook (https://www.facebook.com/EngineeringJrnl).