stpa-step3-unsafe-control-actions

Unsafe control actions in STPA are control commands that could lead to a hazard if provided, not provided, or executed with wrong timing or duration. The Skill systematically identifies these four action types for each control action across safety-critical automotive, cybersecurity, and medical device contexts.

To identify unsafe control actions, apply the STPA 4-type analysis to each control action collected in Step 2. The Skill guides you through Not Provided, Provided, Wrong Timing, and Wrong Duration scenarios, generating a prioritized UCA table that links each action to hazards, severity, and likelihood.

Yes, STPA hazard identification works for medical device controllers, automotive braking systems, and authentication services. The Skill applies the 4-type unsafe control action analysis to safety-critical control architectures across these domains to capture domain-specific hazards.

The best way to prioritize hazards during STPA Step 3 is to generate a structured UCA analysis table. The Skill links each unsafe control action to its corresponding hazard, severity, likelihood, and detectability requirements, providing template-driven prioritization criteria for your safety analysis.

Yes, you need the control actions collected in STPA Step 2 before analyzing unsafe actions. The Skill takes these previously identified control actions and applies the 4-type analysis to systematically uncover unsafe scenarios across your safety-critical system contexts.

Manual STPA analysis is error-prone and time-consuming because applying the 4-type analysis to every control action across multiple contexts requires extensive tracking. The Skill automates this structured analysis, ensuring consistent coverage of Not Provided, Provided, Wrong Timing, and Wrong Duration scenarios.