Straight-up C is not at all suitable for safety-critical software. C plus various bolt-on tools for static analysis and the like can be usable, but is always going to be less effective (IMO) than a unified language where every tool is working according to the same rules.

There might be a few legitimate use cases for C, but I've seen people pick it for the wrong reason so often (and using C because "it would be performant" is entirely invalid IME).