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Prerequisites

Before evaluating post-mitigation RPN, ensure you have:

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Step 1: Open the Final Risk Evaluation View

  1. Open your SFMEA or DFMEA risksheet document.
  2. From the view selector, choose 5. Final Risk Evaluation.
This view focuses on the Final Ranking section, showing post-mitigation occurrence, detection, and the computed post-mitigation RPN (postmitigationRPN).
Switch to 7. Risk Summary to display pre- and post-mitigation RPN columns side by side. This view is ideal for design reviews and certification evidence packages.

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Step 2: Set Post-Mitigation Occurrence

For each failure mode row where mitigations have been implemented:
  1. Click the Post-Mitigation Occurrence cell (postmitigationFMOccurrence field).
  2. Select a value from 1–5 reflecting the reduced failure frequency after controls are applied.
ScoreMeaning
1Extremely unlikely — control eliminates failure path
2Remote — significant frequency reduction achieved
3Occasional — partial reduction, residual exposure remains
4Probable — minor improvement only
5Almost certain — control ineffective
Both postmitigationFMOccurrence and postmitigationDetection default to 0. A field left at 0 produces an RPN of 0, which may be misread as “no risk” rather than “not yet evaluated.” Always set both fields explicitly before closing the review cycle.

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Step 3: Set Post-Mitigation Detection

  1. Click the Post-Mitigation Detection cell (postmitigationDetection field).
  2. Select a value from 1–5 reflecting how reliably the failure can be detected after verification methods are in place.
Lower scores indicate better detection (1 = almost certain detection by BITE or test). Higher scores indicate weak or no detection path.

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Step 4: Review Computed Post-Mitigation RPN

The commonRpnNew formula computes the post-mitigation RPN automatically: 
Post-Mitigation RPN = Severity × Post-Mitigation Occurrence × Post-Mitigation Detection
The result is stored in the postmitigationRPN field. Color coding updates immediately: diagram The row header color (rowHeaderRpnNew) updates to match, giving you an instant visual scan of residual risk across the entire risksheet.

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Step 5: Act on High Residual RPN

For any failure mode where post-mitigation RPN remains > 30:
  1. Review whether the linked risk control tasks are fully Verified (not just Implemented).
  2. Consider adding additional controls, design changes, or increasing detection capability.
  3. Escalate to a program review — high residual RPN requires documented justification or design rework.
The fmSeverity field is fixed — only occurrence and detection scores can be improved by risk controls. A catastrophic failure condition (Severity = 5) requires detection score ≤ 2 to achieve RPN ≤ 10.

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Step 6: Verify the Mitigation Chain

Switch to View 6 (or the Mitigations view) to confirm that each risk control task is linked correctly:
  • Risk Control task status is Verified
  • Linked design or system requirements are present (sysReq / desReq back-links)
  • At least one test case is linked through those requirements
This chain — Failure Mode → Risk Control → Requirement → Test Case — is required evidence for ARP 4761 and DO-254 compliance.
The exact view numbers and column labels may vary between SFMEA and DFMEA risksheet instances. Confirm view naming in your deployed risksheet configuration.

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Verification

You should now see:
  • Post-mitigation RPN values populated for all evaluated failure modes
  • Row header colors reflecting green (≤10), amber (11–30), or red (>30) residual risk
  • No failure mode rows with postmitigationRPN = 0 remaining in unreviewed state
  • The Risk Control Effectiveness report (available from the Reports section) showing pre/post RPN comparison across all components

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See also

Code: .polarion/pages/spaces/_default/Requirements Traceability Summary/page.xml, Verification Validation Summary/page.xml, Risk Control Effectiveness Report/page.xml, System Decomposition Report/page.xml, FMEA Coverage Report/page.xml, Classification Consistency Report/page.xml, System FMEA Report/page.xml, System Structure Navigator/page.xml (0.56) · modules/RiskTemplates/SubSystem-FMEATemplate/attachments/risksheet.json (0.48) · .polarion/nextedy/models/rtm.yaml (0.45) · modules/Risks/DFMEA-CMP-PSU/attachments/risksheet.json (0.39) · modules/RiskTemplates/DFMEATemplate/attachments/risksheet.json (0.38) · datasets/sol-aero-ui-walkthrough/summary.md, navigation.md, dashboards/home-dashboard.md, dashboards/role-dashboards.md, dashboards/standards-compliance.md, risksheet-views/risksheet-views.md, work-item-types/data-model.md (0.38) · modules/RiskTemplates/PFMEATemplate/attachments/risksheet.json (0.37) · modules/RiskTemplates/System-FMEATemplate/attachments/risksheet.json (0.36) · .polarion/pages/spaces/_default/Safety Assessment Summary/page.xml, Common Cause Analysis Report/page.xml, Security Threat Assessment/page.xml, Hara Risk Matrix Report/page.xml (0.36) · .polarion/pages/scripts/velocity/nextedy_solutions.vm (0.35)