ECCAIRS Aviation Ontology¶

The ECCAIRS (European Co-ordination Centre for Accident and Incident Reporting Systems) taxonomy is the European standard for aviation safety occurrence reporting. This page explains its structure, key domains, and how it's used in Aletheia.

What is ECCAIRS?¶

ECCAIRS is maintained by the European Union Aviation Safety Agency (EASA) and provides:

• Standardized terminology for reporting aviation occurrences
• Hierarchical classification of events, causes, and factors
• Interoperability across EU member states and international bodies
• Historical consistency for trend analysis across decades

Origin and Adoption¶

Users: National aviation authorities, airlines, airports, air navigation service providers, aircraft manufacturers, and safety investigators across 30+ countries.

Ontology Structure¶

The ECCAIRS taxonomy is organized around a central concept: Occurrence.

Root Concept: Occurrence¶

An Occurrence is any aviation safety-related event, including:

• Accidents (with injuries or substantial damage)
• Serious incidents (near-accidents)
• Incidents (safety-relevant events)
• Occurrences without safety effect

Everything in the ontology relates back to an Occurrence.

Key Domains¶

The ontology branches into six major domains:

                              Occurrence
                                  │
        ┌─────────┬───────┬───────┼───────┬───────┬─────────┐
        ▼         ▼       ▼       ▼       ▼       ▼         ▼
    Aircraft  Aerodrome  ANS   Air Space Events  Risk    Separation
        │         │       │               │       │
        ▼         ▼       ▼               ▼       ▼
     Crew     Runway   Sector         Factors  Assessment
     Engine   Vehicle  ATM Staff
     ...      FOD      ...

Domain Details¶

1. Aircraft Domain¶

Everything related to the aircraft involved in an occurrence.

Aircraft (abstract)
├── Engine
├── Propeller
├── Flight Crew Member
│   └── Flight Crew Licenses
├── Other Personnel on board
├── Incapacitation
├── Aircraft Fire Suppression
├── Floatation Devices
├── GPWS warning and reaction
├── Control and Monitoring Unit
├── Other Aircraft Recording Devices
├── Part Information
├── Search Difficulties
└── Weather Briefing

Key attributes: - Aircraft type and model - Registration - Operator - Flight phase - Damage level

Example:

"Embraer ERJ-195 (CS-TTW) operated by TAP Air Portugal" → Aircraft: ERJ-195, Registration: CS-TTW, Operator: TAP Air Portugal

2. Aerodrome Domain¶

Airport and ground infrastructure elements.

Aerodrome General (abstract)
├── Runway
├── Vehicle
├── Foreign Object (FOD)
├── Narrative
└── Note

Key attributes: - Airport name and ICAO code - Runway identifier - Surface condition - Lighting status

Example:

"Runway 26R at Paris CDG (LFPG) was contaminated with standing water" → Airport: Paris CDG, ICAO: LFPG, Runway: 26R

3. Air Navigation Service Domain¶

Air traffic control and navigation services.

Air Navigation Service (abstract)
├── Sector
│   └── ATM staff
│       ├── ATM ratings
│       │   └── ATM endorsements
│       └── HERA Error
│           └── Contextual Condition
├── ATM recording devices
├── Narrative
└── Note

Key attributes: - Sector identifier - Controller qualifications - Human error factors (HERA model)

Example:

"Controller in Barcelona ACC sector was handling 15 aircraft" → Sector: Barcelona ACC, ATM Staff: Controller

4. Events Domain¶

Classification of what happened during the occurrence.

Events (abstract)
└── Descriptive Factor
    └── Explanatory Factor

Event categories include: - Airborne events (turbulence, icing, bird strike) - Ground events (runway incursion, ground collision) - Technical events (system failure, structural issue) - Operational events (crew decision, procedure deviation)

Example:

"Aircraft encountered severe clear air turbulence at FL380" → Event: Turbulence, Severity: Severe, Altitude: FL380

5. Risk Assessment Domain¶

Safety analysis and risk classification.

Risk Assessment (abstract)
└── Risk Assessment RPAS/UAS

Risk categories: - Severity (Accident, Serious Incident, Incident) - Probability assessment - Safety barriers effectiveness

6. Potential Factors Domain¶

Causal and contributing factors analysis.

Potential Factors and Safety Issues (abstract)
└── Potential Explanatory Factor

Factor types: - Primary cause - Contributing factors - Human factors - Organizational factors - Environmental factors

Class Statistics¶

The full ECCAIRS ontology contains:

Core Classes (Non-Value)¶

Value Classes¶

Enumerated values for coded fields:

Using ECCAIRS in Aletheia¶

Loading the Ontology¶

# Convert ECCAIRS XML to TTL (if not already done)
python use_cases/aviation_safety/eccairs_taxonomy/eccairs_parser.py \
  "use_cases/aviation_safety/eccairs_taxonomy/Eccairs Aviation 7.0.0.1.xml" \
  -o use_cases/aviation_safety/ontology/eccairs_aviation.ttl

# Load ontology to graph
aletheia build-ontology-graph \
  --use-case aviation_safety \
  --knowledge-graph eccairs

Viewing the Ontology Graph¶

# Count classes by type
redis-cli GRAPH.QUERY eccairs \
  "MATCH (n:Entity)
   WHERE NOT n.name CONTAINS 'Values'
   RETURN n.ontology_type, count(*)
   ORDER BY count(*) DESC"

# View hierarchy
redis-cli GRAPH.QUERY eccairs \
  "MATCH (child)-[r:RELATES_TO {name: 'SUBCLASS_OF'}]->(parent)
   WHERE NOT child.name CONTAINS 'Values'
   RETURN parent.name, child.name
   LIMIT 20"

Building Knowledge Graph with ECCAIRS¶

aletheia build-knowledge-graph \
  --use-case aviation_safety \
  --knowledge-graph aviation_safety \
  --schema-mode graph-hybrid \
  --ontology-graph eccairs

Semantic Alignment Examples¶

The ontology enables consistent extraction:

Benefits for Aviation Safety Analysis¶

1. Cross-Report Consistency¶

All incident reports use the same terminology: - "CAT" → Clear Air Turbulence (standardized) - "CFIT" → Controlled Flight Into Terrain (standardized) - "FOD" → Foreign Object Debris (standardized)

2. Trend Analysis¶

Query patterns across years:

MATCH (o:Occurrence)-[:HAS_EVENT]->(e:Event {type: 'Turbulence'})
WHERE o.date >= '2020-01-01'
RETURN o.year, count(o) as incidents
ORDER BY o.year

3. Regulatory Compliance¶

Reports align with EASA requirements: - All mandatory fields captured - Standard classifications applied - Audit-ready format

4. International Interoperability¶

ECCAIRS data can be shared with: - ICAO (International Civil Aviation Organization) - FAA (US Federal Aviation Administration) - National authorities worldwide

Source Files¶

Further Reading¶

• EASA ECCAIRS Portal
• EU Regulation 376/2015
• Ontology Integration Guide
• Aviation Safety Demo