A Structured and Comprehensive Air Vehicle Risk Assessment

In recent years, U.S. Army programs have leaned on the Department of Defense Standard Practice for System Safety (MIL-STD-882E) and commercial Aerospace Recommended Practices (SAE ARP4754A/ARP4761) to guide the implementation of System Safety processes in air vehicle design and sustainment. System Theoretic Process Analysis (STPA) adds to safety requirement capture and provides a unique pathway to integrating Human Factors Engineering and Cybersecurity assurance with System Safety. As part of the U.S. Army's Future Attack Reconnaissance Aircraft (FARA) program, Bell is implementing a novel blended approach that combines techniques from MIL-STD-882E, SAE ARP4754A/4761, and STPA to improve the overall performance of the System Safety process. The result is a more complete hazard identification process, a more thorough risk assessment (including identification of causal factors), a richer set of hazard control requirements, and a more contextual traceability to verification test cases. The Blended System Safety Framework (BSSF) is shown to be straightforward and results in the streamlined development of airworthiness artifacts while maintaining full traceability to content and framework source requirements.