An approach to allow safety requirements to be efficiently decomposed , traced , and validated

ARP 4754A and ARP 4761 are international standards for the avionics domains. ARP 4761 provides a guidance for the safety assessment process, while the ARP 4754A prescribes close interactions between the safety assessment process and system development process in order to capture safety requirements imposed on the design. According to the ARP 4754A, the safety requirements should be carefully traced and validated. A phase of the safety assessment process is the FHA (Functional Hazard Analysis) and the high-level safety requirements are derived. ARP 4754A indicates that the safety requirements obtained from the FHA phase should be allocated and validated, but the standard only indicates " What " should be done, but not " How " to do it. Hence, when developing an avionic system, an ad-hoc method must be provided to allocate and validate the safety requirements. Thesis work is focused on providing a systematic approach to allow safety managers jointly with designers to decompose, allocate and validate the safety requirements. Furthermore, the proposed approach is aligned with the ARP 4754A and DOORS tool, including how to decompose and validate the safety requirements in the system development process. This way will reduce the necessity to provide an ad-hoc method each avionic systems, and overcome the lacking methodology. Finally, a safety-critical system developed by SAAB is used as case study to validate the proposed approach. 3 Acknowledgements First of all, I would like to thank my family, which they gave me the big opportunity to study abroad and to have this wonderful experience. I am most grateful to Kristina Forsberg, to give me a great opportunity to do the thesis work in SAAB AB. Which I had a wonderful experience in the company, and I met nice " colleagues ". I would like to thank my supervisor, Barbara Gallina, for her patience and support during the entire thesis period. I would like to thank my examiner, Kristina Lundqvist. Without her, I never had the opportunity to know the safety-critical systems engineering field and interest in it. more for a great time that we spent together during my stay in Västerås.