This paper presents a selective regression testing approach for testing proper failure mitigation in safety-critical systems. Based on changes to the models used for test generation, it classifies tests as obsolete, retestable, and reusable. It also defines a process for generating new tests based on partial regeneration. It takes advantage of the phased approach of the original method that starts with behavioral and mitigation model, determines points of failure in the behavioral test suite and weaves mitigation into it to create a safety-mitigation test suite. This Black-Box selective regression-testing approach is illustrated using a Railroad Crossing Control System.