  Safety-critical system's failure or malfunction can cause loss of human lives
or damage to the physical environment; therefore, continuous safety assessment
is crucial for such systems. In many domains this includes the use of Safety
assurance cases (SACs) as a structured argument that the system is safe for
use. SACs can be challenging to maintain during system evolution due to the
disconnect between the safety analysis and system development process. Further,
safety analysts often lack domain knowledge and tool support to evaluate the
SAC. We propose a solution that leverages software traceability to connect
relevant system artifacts to safety analysis models, and then uses these
connections to visualize the change. We elicit design rationales for system
changes to help safety stakeholders analyze the impact of system changes on
safety. We present new traceability techniques for closer integration of the
safety analysis and system development process, and illustrate the viability of
our approach using examples from a cyber-physical system that deploys Unmanned
Aerial Vehicles for emergency response.
