A vehicle safety case may show it to be acceptably safe to be driven on a road, but conclude that it may be unsuited to driving on rough ground, or with an off-center load for example, if there would then be a greater risk of danger e.g. a loss of control or an injury to the occupant.
A safety case should be revisited when an existing product is to be re-purposed in a new way, if this extends beyond the scope of the original assessment.
[4] Safety Cases are becoming more popular on civil/commercial aircraft and Department of Defense (DoD) weapon systems as complexity and criticality increase.
Functional behavior is often better understood, expressed and defended when graphically displayed every step of the way in MBSE vs. traditional development with enormous paperwork that is very difficult to correlate into an effective Safety Case.
Upfront articulation of Arguments (rationale and claims) to be used and (2) independent review to verify and validate.
A well balanced Safety Case must also allow for special safety directed verification, such as testing of credible failure conditions, testing of malfunctions to observe predicted safe states and planned behavior, fault insertion for expected functionality under worse case conditions, failure immunity to ensure system ignores corruption and rogue threats, and off nominal or modified conditions, out of bounds, and other type test results to prove safety requirements are met outside normal operation.