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Prerequisites

  • An FHA risksheet document is open (e.g., “FCC System Functional Hazard Assessment (ARP 4761)”)
  • At least one failure condition row has been added to the risksheet
  • You have edit rights on the document

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Step 1: Locate the Classification Column

In the FHA risksheet, find the Classification column under the Classification header group. Each failure condition row has a classification cell that accepts one of five severity values. The column appears after the Failure Identification group (Failure Condition, Flight Phase, Effect Description).

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Step 2: Select the Severity Level

Click the Classification cell for the failure condition you want to classify. Select one of the five ARP 4761 severity levels from the dropdown:
ClassificationWhen to UseProbability TargetDAL
CatastrophicPrevents continued safe flight and landingExtremely Improbable (< 10⁻⁹)DAL A
HazardousLarge reduction in safety marginsExtremely Remote (< 10⁻⁷)DAL B
MajorSignificant reduction in safety marginsRemote (< 10⁻⁵)DAL C
MinorSlight reduction in safety marginsReasonably ProbableDAL D
No Safety EffectNo effect on aircraft safety—DAL E
Each level is color-coded in the risksheet: Catastrophic displays in red, Hazardous in orange, Major in yellow, Minor in green, and No Safety Effect in grey.

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Step 3: Set the Probability Target

In the Probability Target column (same Classification group), enter the required probability target that corresponds to the classification you selected. This value documents the design and verification objective for this failure condition.

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Step 4: Verify Automatic DAL Allocation

After selecting a classification, the DAL column (under the DAL Allocation group) updates automatically. The mapping is fixed per ARP 4761: diagram The DAL cell uses the same color scheme as the Classification cell, so the two columns will always display a matching color. diagram

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Step 5: Consider Flight Phase Context

Review whether the classification correctly reflects the Flight Phase already set for this failure condition. The same failure mode can receive different severity classifications depending on when during the mission it occurs — for example, loss of a navigation function is more severe during Approach than during Cruise. The seven flight phases are: Takeoff, Climb, Cruise, Descent, Approach, Landing, and Ground. If the flight phase is wrong, update it before finalizing the classification.
If you set a classification before selecting a flight phase, the classification may not accurately reflect worst-case conditions. Always confirm the flight phase first — it is a key input to determining whether a failure is Catastrophic or merely Hazardous.
Cross-check against known classifications to calibrate your judgments. For example, in the FCC System FHA: “Loss of pitch control authority” during Takeoff is Catastrophic (DAL A), “Erroneous airspeed indication” during Cruise is Hazardous (DAL B), and “Loss of autopilot engagement” during Cruise is Minor (DAL D). These provide a consistent reference baseline.
The DAL value is driven by the auto-formula from the Classification field. Manually overriding the DAL cell breaks the ARP 4761 mapping and can cause inconsistencies in downstream PSSA documents that inherit the DAL from the FHA.

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Step 6: Track Verification Status

After classification, confirm the Verification Status column (under the Verification group) is set appropriately:
  • Open — Classification recorded, no further action taken
  • In Progress — Safety requirement allocation underway
  • Completed ✅ — Linked safety requirements completed
  • Verified — Evidence collected and reviewed
For a freshly classified failure condition, the status should typically be Open until safety requirements are allocated.

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Verification

You should now see:
  • The Classification cell displays the selected severity level with its corresponding color
  • The DAL cell automatically shows the matching DAL level (same color)
  • The row header color reflects the severity classification
  • The Probability Target column contains the appropriate numerical target

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See Also

Code: .polarion/tracker/fields/failureCondition-classification-enum.xml (0.69) · modules/RiskTemplates/FHATemplate/attachments/risksheet.json (0.66) · 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 (0.64) · .polarion/nextedy/models/rtm.yaml (0.62) · modules/RiskTemplates/SubSystem-FMEATemplate/attachments/risksheet.json (0.60) · .polarion/tracker/fields/failureMode-custom-fields.xml (0.59) · .polarion/tracker/fields/failureCondition-phase-enum.xml (0.58) · modules/RiskTemplates/System-FMEATemplate/attachments/risksheet.json (0.58) · modules/RiskTemplates/PSSATemplate/attachments/risksheet.json (0.57) · modules/RiskTemplates/SSATemplate/attachments/risksheet.json (0.56)