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Core FHA Tasks

Identify Failure Conditions — Discover what can go wrong at the system level. Learn to elicit failure conditions from system functions, organize them by flight phase, and document their effects on aircraft safety and operations. Classify Failure Effects and Severity — Assign severity classifications (Catastrophic, Hazardous, Major, Minor, No Effect) based on failure condition effects. Understand the ARP 4761 severity scale and why classification drives certification scope. Assign DAL to Failure Conditions — Allocate Design Assurance Levels (DAL A through E) to each failure condition. Learn how classification and probability targets determine the rigor and cost of downstream development and verification activities. Link Safety Requirements to Failure Conditions — Trace failure conditions to safety requirements that prevent or mitigate them. Establish the safety requirement traceability chain that proves compliance to your failure condition classification.

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Why FHA Matters

diagram FHA is the top-level safety analysis—your entry point to the V-Model. Every failure condition you identify flows downward through SFMEA (system-level failure modes) and DFMEA (component-level failure modes), and upward through requirements and verification. Classification mistakes here compound through the entire program; correctness here prevents rework downstream.

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Before You Start

  • System definition — You have defined system functions and boundaries
  • Flight phases — You understand the aircraft’s operating envelope (takeoff, cruise, landing, etc.)
  • Safety standards — Your project follows ARP 4761 (or ARP 4754A for system development assurance)
  • Risk document — You have created an FHA risksheet in Polarion
Functional Hazard Assessment requires cross-functional involvement: systems engineering, safety, certification, and sometimes customers. Plan for review cycles and stakeholder sign-off at each classification milestone.
Code: modules/RiskTemplates/FHATemplate/attachments/risksheet.json (0.61) · modules/RiskTemplates/DFMEATemplate/attachments/risksheet.json (0.53) · .polarion/tracker/fields/failureCondition-phase-enum.xml (0.44) · 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 (0.44) · .polarion/nextedy/models/rtm.yaml (0.42) · .polarion/tracker/fields/failureCondition-custom-fields.xml (0.41) · modules/RiskTemplates/SubSystem-FMEATemplate/attachments/risksheet.json (0.40) · .polarion/tracker/fields/workitem-type-enum.xml (0.40) · .polarion/nextedy/sheet-configurations/DO-178C Objectives Compliance Matrix.yaml (0.40) · .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 (0.39)