Arc Skills / Safety
Review hazard mitigations and closure evidence
This task checks whether a named hazard control is implemented and verified on the build under review. Arc Skills returns a control-to-evidence matrix with a bounded recommendation for the authorized closure reviewer.
Use this skill
Use Arc Skills to review hazard-control closure evidence for the current product baseline. Follow each hazard through control claim, allocated requirement, implementation and test result.
Inputs:
- Hazard log, approved control and closure criteria.
- Current design/software versions and relevant changes.
- Test reports, deviations and residual-risk decisions.
Return supported, partial or unsupported evidence findings with exact configuration gaps. Distinguish evidence sufficiency from formal hazard acceptance.What you provide and what you get
| What you have | How it is used | What you get |
|---|---|---|
| Hazard and approved control | Defines claim to close | Control path |
| Current implementation baseline | Tests whether earlier results apply | Change-impact question |
| Execution and deviation records | Shows tested modes and unresolved anomalies | Evidence disposition |
A V3 inhibit test does not automatically cover V4 state logic
Illustrative engineering example.
Synthetic hazard H-7 credits service-mode heater command inhibition. Test T-4 passed on software V3. The current V4 release changed service-mode transition logic; no impact assessment or V4 test is attached.
| Control claim | Evidence/configuration | Assessment | Required closure record |
|---|---|---|---|
| Command inhibited in steady service mode | T-4 pass on V3 | Historical support only for exercised V3 mode | V4 change impact and targeted steady-state test |
| Command inhibited on entry to service mode | T-4 scope does not list transition | Unsupported for transition | Fault/transition test with recorded V4 output |
| Physical power interruption | Not part of approved C-1 control | Outside this closure claim | Keep separate architecture decision visible |
A V3 pass remains useful historical evidence, but the changed V4 state logic can affect the very transition that matters to the hazard. The closure reviewer needs a reasoned change-impact assessment and, where affected, a V4 execution record.
The table also prevents a narrower command-control claim from becoming a claim about physical power isolation. The first two rows are evidence assessments; neither accepts residual risk or closes H-7. A linked requirement or test name alone cannot substitute for the actual tested conditions and configuration.
Review the control at its tested boundary
- State hazard, credited control, modes and formal closure criterion.
- Trace implementation and each execution record to exact configuration.
- Compare changes, deviations and untested transitions with the control claim.
- Present evidence status and open actions to the authorized hazard owner.
Questions about this task
Can an old pass be reused after a change?
Possibly, if a documented impact analysis shows the changed design cannot affect the credited behavior. Otherwise obtain targeted current verification.
Who closes the hazard?
The project’s authorized safety process. This review reports evidence support and gaps; it does not accept residual risk.
Sources and further reading
- NASA Systems Engineering Handbook: Lifecycle, requirements, verification and technical-management guidance.
- NASA Fault Tree Handbook with Aerospace Applications: NASA-hosted guidance for fault-tree gates, cut sets and reliability block diagrams.