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Before You Begin

Ensure you have an existing FHA document with classified failure conditions — the top events in your fault tree should correspond to catastrophic or hazardous failure conditions identified during FHA. You will need access to the Risks space in your Polarion project.

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Steps

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1. Create the FTA Module

  1. Navigate to the Risks space in your project sidebar.
  2. Click Create Document and select the FTA Template from the Nextedy solution templates.
  3. Name the document following the convention: <System Name> - Fault Tree Analysis (for example, FCC System - Fault Tree Analysis).
  4. Confirm creation. The document opens with the FTA risksheet pre-loaded.
The exact location of the Create Document action and template selector may vary depending on your Polarion configuration and role permissions.

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2. Define the Top Event

  1. In the FTA risksheet, add the first row at the Top Event level (level 1).
  2. Set the work item type to failureCondition.
  3. Enter the failure description — for example, Loss of Flight Control.
  4. Set the Classification field to the ARP 4761 severity level: Catastrophic, Hazardous, Major, Minor, or No Safety Effect.
  5. Set the DAL Allocation (A–E) derived from the classification.
  6. Set the Flight Phase to identify when this failure condition can occur.
  7. Enter the Probability Target — the quantitative failure rate objective aligned to your DAL allocation.

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3. Add Intermediate Events and Gate Logic

  1. Add child rows beneath the top event at level 2 (intermediate events).
  2. For each intermediate event, select the Gate Type that describes the failure logic:
diagram
Gate TypeColorLogic
ANDBlueAll inputs must occur simultaneously
ORRedAny single input triggers the event
InhibitOrangeConditional — input triggers only when condition is met
K-of-NPurpleExactly K of N inputs must occur
  1. Continue adding rows at level 3 for Basic Events — the fundamental, indivisible causes at the lowest level.
To connect your fault tree to the bottom-up FMEA analysis:
  1. Open a basic event row and navigate to the Links panel.
  2. Add a causeOf link pointing to the corresponding failureCondition in your FHA document.
  3. For failure mode propagation chains, use the causes link role to connect failureMode items from your SFMEA or DFMEA documents to intermediate events in the fault tree.
If your FHA failure conditions are already classified and linked to safety requirements via allocatesTo, the fault tree basic events can inherit DAL and probability targets from that chain — reducing manual re-entry.

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5. Use the Four Risksheet Views

Switch between views using the view selector at the top of the risksheet:
  • Full Tree — complete hierarchy with all columns
  • Top Events — summary of root failure conditions and their classifications
  • Gate Summary — focused view on gate types and logic structure
  • Probability View — quantitative failure rate targets and DAL allocations

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6. Complete Probability Targets

For each basic event, enter the allocated Probability Target consistent with ARP 4761:
ARP 4761 SeverityProbability Category
CatastrophicExtremely Improbable
HazardousExtremely Remote
MajorRemote
MinorReasonably Probable
The FTA risksheet configuration inside each module instance is an independent copy of the template. If the solution template is updated by your administrator, existing FTA documents are not automatically updated. Re-create or manually update instance risksheet.json files when template changes are deployed.
The K-of-N gate type appears in the gate renderer but may not yet be available in the gate type enumeration for your installation. If it does not appear in the dropdown, use an OR gate and document the K-of-N constraint in the event description field.

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Verification

You should now see an FTA document in the Risks space with a structured tree of failureCondition work items organized by level, gate types assigned to intermediate events, probability targets set for basic events, and traceability links connecting to your FHA and FMEA documents. Open the Gate Summary view to confirm that all intermediate events have a gate type assigned.

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See Also

Code: .polarion/tracker/fields/workitem-link-role-enum.xml (0.59) · modules/RiskTemplates/FTATemplate/attachments/risksheet.json (0.58) · .polarion/nextedy/models/rtm.yaml (0.57) · 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 (0.56) · .polarion/tracker/fields/workitem-type-enum.xml (0.53) · modules/RiskTemplates/PSSATemplate/attachments/risksheet.json (0.53) · .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 (0.53) · .polarion/pages/spaces/Requirements/Home/page.xml, Design/Home/page.xml, Risks/Home/page.xml, Testing/Home/page.xml, Risks/FMEA Reports/page.xml, Documentation/Home/page.xml, Documentation/Powersheet Help Redirect/page.xml, RiskTemplates/Home/page.xml (0.53) · modules/RiskTemplates/System-FMEATemplate/attachments/risksheet.json (0.52) · modules/RiskTemplates/CCATemplate/attachments/risksheet.json (0.51)