Unsafe Control Actions
From Leveson, STAMP handbook, an unsafe control action is a control action that, in a particular context and worst-case environment, will lead to a hazard. It can be one of four types:
- Not providing the control action leads to a hazard.
- Providing the control action leads to a hazard.
- Providing a potentially safe control action but too early, too late, or in the wrong order.
- The control action lasts too long or is stopped too soon (for continuous control actions, not discrete ones).