stpa-step3-unsafe-control-actions

Identifying unsafe control actions in STPA requires analyzing each control action against four hazard types: not provided, provided when not needed, wrong timing, and wrong duration. This reveals how specific control commands could trigger system hazards.

You identify unsafe control actions by evaluating control commands against four hazard types: not provided, provided when not needed, wrong timing, and wrong duration. This process requires detailed input on control actions and previously identified hazards to link failures correctly.

You need detailed input on the system's control actions and previously identified hazards. These inputs are required to map unsafe control scenarios—such as providing a command at the wrong time—directly to potential system failures.

STPA hazard identification works for autonomous vehicle braking systems by analyzing control actions like 'apply brakes' against unsafe conditions. It identifies hazards such as brakes not applied when needed or applied for the wrong duration, linking them to accident risks.

Unsafe control action analysis should be performed during the safety analysis phase of safety-critical systems development. It systematically identifies potential hazards associated with control actions, ensuring critical failure modes are not overlooked before implementation.