A safety-critical system is any system whose failure could put people, equipment, or operations at risk. In aviation, examples include avionics, flight controls, braking systems, and sensors that help crews make fast decisions. These systems must work reliably under stress, because even a small error can have serious consequences.
In cyber security, safety-critical systems deserve extra attention because an attack does not need to cause a total outage to be dangerous. A false reading, delayed output, configuration change, or corrupted update can be enough to affect safety. Defenses focus on integrity, strong access control, tamper resistance, careful patching, testing, logging, and clear maintenance procedures. Teardowns and inspections help defenders understand how hardware is built and where trust depends on software, wiring, or calibration.