Overview
The CCA Risksheet organizes common cause events using a 3-level hierarchy:
Column Structure
| Column Name | Type | Description |
|---|---|---|
| Zone/Area | System Element | Identifies the system zone, area, or location where the common cause could originate |
| Analysis Type | Enumeration | Type of common cause analysis: ZSA (Zonal), PRA (Particular Risk), or CMA (Common Mode) |
| Event Description | Text | Description of the potential common cause event |
| Affected Functions | Link | References to system functions or subsystems that could be affected |
| Failure Modes | Link | References to related failure modes from SFMEA/DFMEA documents |
| Potential Effects | Text | Consequences of the common cause event affecting multiple items |
| Risk Assessment | Enumeration | Initial risk level (High/Medium/Low) based on probability and severity |
| Corrective Actions | Link | References to risk controls or design changes to prevent or mitigate the common cause |
Analysis Type Color Coding
The CCA Risksheet uses color coding to distinguish between the three required analysis types, enabling quick visual scanning:| Analysis Type | Color | Abbreviation | Purpose |
|---|---|---|---|
| Zonal Safety Analysis | Indigo | ZSA | Identifies common causes originating from a specific zone (e.g., lightning, heat, vibration in a physical location) |
| Particular Risk Analysis | Red | PRA | Analyzes risks particular to a specific function or failure mode that could propagate through dependencies |
| Common Mode Analysis | Teal | CMA | Identifies design or operational scenarios where multiple failures occur from a single root cause |
Hierarchy and Organization
The CCA Risksheet implements a 3-level hierarchy:Level 1: Zone/Area
The top level groups events by physical location or logical area within the system. Examples:- Electrical compartment
- Flight deck
- Engine bay
- Software subsystem
- Power distribution network
Level 2: Analysis Type
Each zone contains events organized by the three analysis types (ZSA, PRA, CMA). ARP 4761 requires all three perspectives to be analyzed for comprehensive common cause coverage.Level 3: Common Cause Event
Individual events are listed at the lowest level, each with:- Event description
- Affected functions/failure modes
- Potential effects across the system
- Risk assessment
- Corrective actions or preventive measures
Views
The CCA Risksheet provides four specialized views to support different analysis workflows:Full Analysis View
Displays all columns and all hierarchy levels, enabling comprehensive review of common cause events across all analysis types.By Zone View
Groups events primarily by zone, allowing safety engineers to focus on location-based common causes and their cross-system effects.By Analysis Type View
Organizes events by ZSA/PRA/CMA type, supporting focused analysis of each methodology and cross-checking for gaps.Actions View
Focuses on corrective actions, displaying:- Event description
- Assigned responsibility (owner)
- Action status (Open/In Progress/Complete)
- Linked risk controls
- Verification evidence
Risk Type and Work Items
| Property | Value | Description |
|---|---|---|
| Risk Type | commonCauseEvent | The primary work item type used in the CCA Risksheet |
| Work Item Hierarchy | 3 levels | Zone → Analysis Type → Event |
| Task Type | riskControl | Corrective actions and preventive measures linked via mitigates role |
Configuration Details
The following details are based on the CCA template structure. Verify specific column properties, formula definitions, and cell styling rules in the Risksheet configuration UI.
Row Header Coloring
The row header background color is applied based on the analysis type:Analysis Type Selection
The Analysis Type column is typically configured as an enumerated picker with three valid values:Linked Items
| Link Role | Source | Target | Cardinality | Purpose |
|---|---|---|---|---|
affects | commonCauseEvent | function, failureMode | Many | Functions or failure modes impacted by the common cause |
mitigates | riskControl | commonCauseEvent | Many | Risk controls that prevent or mitigate the common cause |
Key Workflow Patterns
1. Creating a Common Cause Analysis
- Decompose the system into zones or areas using system element hierarchy
- For each zone, create one set of ZSA events (zone-specific common causes)
- Create PRA events analyzing particular risks from subsystem interdependencies
- Create CMA events identifying design weaknesses or operational scenarios with multiple failure modes
- Link each event to affected functions and failure modes from SFMEA/DFMEA
- Assign risk assessments and corrective actions
2. Linking to System FMEA
Common cause events discovered during CCA analysis should be:- Cross-referenced in the System SFMEA as potential downstream risks
- Allocated to subsystem SFMEAs for detailed failure mode analysis
- Traced back to design requirements for verification and validation
- Tracked through risk controls until closure
3. Verification and Closure
Corrective actions are tracked as risk control tasks with:- Description of the preventive or mitigating measure
- Responsible engineer assignment
- Verification method (design review, analysis, test)
- Closure evidence from verification documents
Related Documents
The CCA analysis supports and connects to other safety assessment documents in the Aerospace Safety Solution:- FHA Risksheet Configuration Reference — Functional Hazard Assessment (first step)
- SFMEA Risksheet Configuration Reference — System and Subsystem FMEA
- DFMEA Risksheet Configuration Reference — Design FMEA (component level)
- FTA Risksheet Configuration Reference — Fault Tree Analysis (failure logic)
- Safety Assessment Concept Guide — Understanding the ARP 4761 process
Visual Reference: CCA Analysis Type Matrix
ZSA focuses on where common causes can originate (physical zones). PRA examines what particular design or operational risks could cause cascading failures. CMA investigates how multiple failures can occur from single root causes. Together, they provide comprehensive common cause coverage required by ARP 4761.
Source References (dev)
Source References (dev)
Code:
modules/RiskTemplates/CCATemplate/attachments/risksheet.json (0.70) · modules/Risks/COMPLIANCE-001/module.xml, modules/Risks/MIL-STD-882E-HTS-001/module.xml, modules/Risks/SEC-THREAT-001/module.xml, modules/Risks/SFMEA-SUB-001/module.xml, modules/Risks/SFMEA-SUB-002/module.xml, modules/Risks/SFMEA-SUB-003/module.xml (0.59) · .polarion/polarion-project.xml, .polarion/context.properties, .polarion/security/user-roles.xml, .claude/PROJECT.md, TODO.md (0.58) · modules/RiskTemplates/RiskControlPlanTemplate/attachments/risksheet.json (0.58) · 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 (0.57) · modules/RiskTemplates/SSATemplate/attachments/risksheet.json (0.57) · modules/RiskTemplates/PSSATemplate/attachments/risksheet.json (0.56) · modules/RiskTemplates/HazardTrackingTemplate/attachments/risksheet.json (0.53) · modules/RiskTemplates/DFMEATemplate/attachments/risksheet.json (0.52) · modules/RiskTemplates/SecurityThreatTemplate/attachments/risksheet.json (0.52)