---
title: "Aerospace & Defense"
description: "Comprehensive traceability for DO-178C, DO-254, and safety-critical systems development."
---

## Overview

Aerospace and defense software development operates under some of the most stringent regulatory requirements in any industry. TracerTM provides the robust traceability infrastructure needed to meet DO-178C, DO-254, MIL-STD-498, and other critical standards while maintaining the agility required for modern development practices.

### Key Challenges in Aerospace Development

**Regulatory Compliance**
- DO-178C requires complete bidirectional traceability from system requirements through verification
- DO-254 mandates hardware design assurance with full traceability
- RTCA/EUROCAE standards demand comprehensive documentation and audit trails
- MIL-STD-498 requires configuration management and change control

**Safety-Critical Requirements**
- Software Design Assurance Levels (DAL) A through E dictate rigor levels
- Catastrophic failure modes (DAL-A) require maximum traceability coverage
- Multiple verification methods must be tracked per requirement
- Independence requirements for verification activities

**Long Development Cycles**
- Programs span 5-15 years with evolving requirements
- Personnel changes require knowledge preservation
- Certification evidence must remain valid across updates
- Baseline management across multiple software versions

**Multi-Party Collaboration**
- Prime contractors, subcontractors, and suppliers
- Customer oversight and approval workflows
- Independent verification and validation (IV&V) teams
- Certification authorities (FAA, EASA, military agencies)

TracerTM addresses these challenges with built-in support for aerospace workflows, audit trails, and certification evidence generation.

---

## DO-178C Compliance with TracerTM

DO-178C (Software Considerations in Airborne Systems and Equipment Certification) is the primary standard for airborne software. TracerTM supports all traceability objectives defined in DO-178C.

### Objective Achievement

**Table A-3: High-Level Requirements to System Requirements**
```bash
# Create bidirectional traceability from system to high-level requirements
rtm link create \
  --from "SYS-REQ-001" \
  --to "HLR-001,HLR-002,HLR-003" \
  --type "derives_from" \
  --rationale "System requirement decomposition per DO-178C"

# Verify complete traceability
rtm matrix generate \
  --from-type "system_requirement" \
  --to-type "high_level_requirement" \
  --output compliance/A3-traceability.pdf
```

**Table A-4: High-Level Requirements to Low-Level Requirements**
```bash
# Link high-level to detailed design requirements
rtm link create \
  --from "HLR-001" \
  --to "LLR-001,LLR-002,LLR-003,LLR-004" \
  --type "derived_to" \
  --metadata '{"dal": "A", "verification_method": "review_analysis"}'

# Generate coverage report for certification
rtm report coverage \
  --source "HLR" \
  --target "LLR" \
  --dal-level "A" \
  --format "DO178C-A4"
```

**Table A-5: Low-Level Requirements to Source Code**
```bash
# Link requirements to implementation
rtm link create \
  --from "LLR-001" \
  --to "src/flight_control/altitude_hold.c:function:maintain_altitude" \
  --type "implemented_in" \
  --commit-hash "abc123" \
  --metadata '{"complexity": "medium", "reviewed_by": "john.smith@aerospace.com"}'

# Track code coverage for requirement
rtm link create \
  --from "LLR-001" \
  --to "TEST-LLR-001-001,TEST-LLR-001-002" \
  --type "verified_by" \
  --metadata '{"mc_dc_coverage": "100%", "statement_coverage": "100%"}'
```

**Table A-6: Source Code to Executable Object Code**
```bash
# Link compilation artifacts for configuration management
rtm link create \
  --from "src/flight_control/*.c" \
  --to "build/release/v2.1.0/flight_control.elf" \
  --type "compiled_to" \
  --metadata '{"compiler": "GCC 9.3.0", "optimization": "-O2", "checksum": "sha256:def456"}'
```

**Table A-7: Verification Cases to Requirements and Code**
```bash
# Create comprehensive test traceability
rtm link create \
  --from "TEST-HLR-001" \
  --to "HLR-001" \
  --type "verifies" \
  --metadata '{"method": "test", "coverage_type": "normal_range"}'

rtm link create \
  --from "TEST-HLR-001" \
  --to "src/flight_control/altitude_hold.c" \
  --type "exercises" \
  --metadata '{"branch_coverage": "95%", "path_coverage": "88%"}'
```

### Design Assurance Level (DAL) Management

TracerTM supports DAL-specific workflows and verification requirements:

```bash
# Configure project with DAL-A requirements (most stringent)
rtm project create "Fly-By-Wire Flight Control System" \
  --metadata '{
    "dal": "A",
    "certification_basis": "DO-178C",
    "verification_independence": "required",
    "mc_dc_coverage_required": true,
    "structural_coverage_required": true
  }'

# Define DAL-specific verification requirements
rtm item create \
  --type "verification_requirement" \
  --title "MC/DC Coverage for All Safety-Critical Functions" \
  --description "All software functions assigned DAL-A must achieve 100% MC/DC coverage" \
  --metadata '{"dal": "A", "objective": "A-7.1.7"}'
```

**DAL-Specific Verification Methods:**

| DAL Level | Requirements-Based Testing | Structural Coverage | Verification Independence |
|-----------|---------------------------|---------------------|---------------------------|
| A         | Required                  | MC/DC               | Required                  |
| B         | Required                  | Decision            | Highly Recommended        |
| C         | Required                  | Statement           | Recommended               |
| D         | Required                  | N/A                 | Optional                  |
| E         | N/A                       | N/A                 | N/A                       |

```bash
# Generate DAL-A compliance matrix
rtm matrix generate \
  --dal-level "A" \
  --include-coverage-metrics \
  --include-review-status \
  --output "certification/DAL-A-Compliance-Matrix.pdf"
```

---

## Safety-Critical Software Development Workflows

### Requirements Development and Decomposition

**System Safety Assessment (SSA) Integration:**

```bash
# Import system hazard analysis results
rtm import \
  --format "aerospace" \
  --source "safety_analysis/FHA-results.csv" \
  --type "failure_condition"

# Link failure conditions to derived safety requirements
rtm link create \
  --from "FC-001:Loss_of_Altitude_Hold" \
  --to "SAFE-REQ-001" \
  --type "mitigated_by" \
  --metadata '{"severity": "catastrophic", "probability": "extremely_remote"}'
```

**Derived Requirements Tracking:**

DO-178C requires tracking derived requirements (those not traceable to higher-level requirements):

```bash
# Mark requirement as derived
rtm item update "LLR-042" \
  --metadata '{"derived": true, "justification": "Implementation constraint for memory management"}'

# Link to design constraint that necessitated derivation
rtm link create \
  --from "LLR-042" \
  --to "DESIGN-CONSTRAINT-003" \
  --type "derived_from_constraint" \
  --rationale "Required to meet 100ms timing constraint on limited hardware"

# Ensure derived requirements get upward reviewed
rtm workflow start \
  --item "LLR-042" \
  --workflow "derived_requirement_review" \
  --reviewers "safety_engineer,systems_engineer"
```

### Verification and Validation Workflow

**Multi-Method Verification:**

Many aerospace requirements require multiple verification methods:

```bash
# Requirement verified by both test and analysis
rtm link create \
  --from "HLR-023:Maximum_Bank_Angle_Limit" \
  --to "TEST-HLR-023-001" \
  --type "verified_by" \
  --metadata '{"method": "test", "environment": "iron_bird"}'

rtm link create \
  --from "HLR-023:Maximum_Bank_Angle_Limit" \
  --to "ANALYSIS-HLR-023" \
  --type "verified_by" \
  --metadata '{"method": "analysis", "tool": "MATLAB/Simulink", "version": "R2023a"}'

# Verify completeness
rtm query \
  --type "high_level_requirement" \
  --filter "verification_methods.count < 1" \
  --output "unverified_requirements.json"
```

**Independent Verification:**

```bash
# Track independent verification activities
rtm link create \
  --from "TEST-DAL-A-001" \
  --to "HLR-001" \
  --type "independently_verifies" \
  --metadata '{
    "performed_by": "iv_and_v_team",
    "independent_from": "development_team",
    "completion_date": "2024-03-15"
  }'
```

### Configuration Management Integration

**Baseline Management:**

```bash
# Create formal baseline for certification
rtm baseline create \
  --name "Build 2.1.0 - Certification Baseline" \
  --items "all" \
  --freeze true \
  --metadata '{
    "certification_milestone": "FAA DER Review",
    "approved_by": "chief_engineer",
    "approval_date": "2024-06-01",
    "configuration_index": "CI-2.1.0"
  }'

# Track changes against baseline
rtm report changes \
  --baseline "Build 2.1.0" \
  --current "main" \
  --impact-analysis true \
  --output "certification/change-impact-report.pdf"
```

**Problem Report Traceability:**

```bash
# Link defects to requirements and verification
rtm link create \
  --from "PR-1234:Altitude_Hold_Oscillation" \
  --to "HLR-015,LLR-089,TEST-LLR-089-002" \
  --type "affects" \
  --metadata '{
    "severity": "major",
    "detected_phase": "integration_test",
    "root_cause": "timing_issue"
  }'

# Track regression test suite
rtm link create \
  --from "PR-1234:Altitude_Hold_Oscillation" \
  --to "REGTEST-PR-1234" \
  --type "prevented_by" \
  --metadata '{"added_to_regression_suite": "2024-04-10"}'
```

---

## Requirements to Test Case Traceability for Certification

### Test Coverage Requirements

**Structural Coverage Analysis:**

```bash
# Import coverage data from test execution
rtm import \
  --format "gcov" \
  --source "coverage/gcov-output.json" \
  --link-to-tests true

# Generate structural coverage report by DAL level
rtm report coverage-analysis \
  --by-dal-level \
  --mcdc-analysis \
  --decision-coverage \
  --statement-coverage \
  --output "certification/structural-coverage.pdf"
```

**Requirements Coverage Matrix:**

```bash
# Generate comprehensive coverage matrix for certification package
rtm matrix generate \
  --rows "high_level_requirement" \
  --columns "test_case,review,analysis" \
  --show-coverage-metrics \
  --highlight-gaps \
  --format "aerospace_compliance" \
  --output "certification/requirements-verification-matrix.xlsx"
```

### Test Procedure Development

**Test Case Derivation:**

```bash
# Create test cases from requirements
rtm item create \
  --type "test_case" \
  --title "Verify Altitude Hold Engagement" \
  --description "Test that altitude hold mode engages within 500ms of pilot command" \
  --metadata '{
    "test_level": "integration",
    "test_environment": "iron_bird",
    "dal": "A",
    "expected_coverage": "MC/DC"
  }'

# Link to requirements under test
rtm link create \
  --from "TEST-HLR-001" \
  --to "HLR-001,HLR-002" \
  --type "verifies" \
  --metadata '{"verification_method": "normal_range_test"}'
```

**Test Results Traceability:**

```bash
# Import test execution results
rtm import \
  --format "junit" \
  --source "test_results/integration_tests_2024-06-15.xml" \
  --link-to-requirements true

# Track certification test witnessing
rtm item update "TEST-EXECUTION-001" \
  --metadata '{
    "witnessed_by": "FAA DER",
    "witness_date": "2024-06-15",
    "witness_signature": "witnessed",
    "official_record": "Test Report TR-2024-015"
  }'
```

---

## Audit Trail Requirements

### Change Control and Traceability

DO-178C requires comprehensive change tracking and justification:

```bash
# Enable audit trail for all certification artifacts
rtm project configure \
  --audit-trail enabled \
  --track-all-changes true \
  --require-change-justification true

# Record requirements change with full justification
rtm item update "HLR-015" \
  --title "Altitude Hold Mode - Updated Bank Angle Limit" \
  --change-request "CR-2024-045" \
  --rationale "Customer requested reduction from 45° to 35° for passenger comfort" \
  --impact-analysis '{
    "affected_llr": ["LLR-089", "LLR-090"],
    "affected_tests": ["TEST-HLR-015-001", "TEST-HLR-015-002"],
    "affected_code": ["src/flight_control/altitude_hold.c"],
    "regression_testing_required": true,
    "certification_impact": "retest_required"
  }'
```

**Review and Approval Workflow:**

```bash
# Configure multi-level approval for safety-critical changes
rtm workflow create "safety_critical_change_approval" \
  --stages "peer_review,safety_review,chief_engineer_approval,customer_approval" \
  --metadata '{
    "applicable_to": "dal_a_and_b",
    "minimum_reviewers_per_stage": 2,
    "independence_required": true
  }'

# Track review completion
rtm workflow status "HLR-015" \
  --workflow "safety_critical_change_approval" \
  --output-format "certification_record"
```

### Certification Data Package Generation

```bash
# Generate complete certification package
rtm export \
  --format "certification_package" \
  --include-all-artifacts \
  --baseline "Build 2.1.0" \
  --output "certification/Certification-Data-Package-v2.1.0.zip" \
  --contents '{
    "requirements_documents": true,
    "traceability_matrices": true,
    "test_procedures": true,
    "test_results": true,
    "review_records": true,
    "problem_reports": true,
    "configuration_index": true,
    "tool_qualification": true
  }'
```

---

## Real-World Examples and Workflows

### Example 1: Flight Control System Development

**Scenario:** Developing a digital flight control system for a commercial aircraft (DAL-A).

**Step 1: Import System Requirements**

```bash
# Import from DOORS or other requirements tool
rtm import \
  --format "doors_ng" \
  --source "requirements/FCS-System-Requirements.csv" \
  --type "system_requirement"

# Tag with appropriate metadata
rtm query --type "system_requirement" | \
  xargs -I {} rtm item update {} \
    --metadata '{"system": "FCS", "dal": "A", "certification_basis": "DO-178C"}'
```

**Step 2: Decompose into High-Level Requirements**

```bash
# Create HLR from system requirements
rtm item create \
  --type "high_level_requirement" \
  --title "Pitch Axis Control Laws" \
  --description "The FCS shall implement pitch axis control laws per ARP-4754A" \
  --metadata '{"parent_system_req": "SYS-FCS-001", "dal": "A"}'

# Link to parent
rtm link create \
  --from "SYS-FCS-001" \
  --to "HLR-FCS-001" \
  --type "derived_to"
```

**Step 3: Detailed Design and Low-Level Requirements**

```bash
# Create LLRs from design
rtm item create \
  --type "low_level_requirement" \
  --title "Pitch Rate Feedback Gain" \
  --description "Pitch rate feedback gain shall be 0.5 rad/s per degree of stick deflection" \
  --metadata '{
    "parent_hlr": "HLR-FCS-001",
    "dal": "A",
    "verification_method": "test_and_analysis"
  }'

rtm link create \
  --from "HLR-FCS-001" \
  --to "LLR-FCS-001,LLR-FCS-002,LLR-FCS-003" \
  --type "derived_to"
```

**Step 4: Implementation and Code Traceability**

```bash
# Link to source code
rtm link create \
  --from "LLR-FCS-001" \
  --to "src/flight_control/pitch_axis.c:45-67" \
  --type "implemented_in" \
  --metadata '{"function": "calculate_pitch_command", "cyclomatic_complexity": 8}'

# Track code reviews
rtm link create \
  --from "src/flight_control/pitch_axis.c" \
  --to "CODE-REVIEW-FCS-001" \
  --type "reviewed_in" \
  --metadata '{
    "reviewers": ["senior_engineer_1", "senior_engineer_2"],
    "review_date": "2024-05-10",
    "findings": 0
  }'
```

**Step 5: Verification**

```bash
# Create comprehensive test suite
rtm item create \
  --type "test_case" \
  --title "Pitch Rate Feedback Normal Range" \
  --description "Verify pitch rate feedback within normal operating envelope" \
  --metadata '{"test_level": "software_integration", "dal": "A"}'

rtm link create \
  --from "TEST-FCS-001" \
  --to "LLR-FCS-001" \
  --type "verifies"

# Import coverage results
rtm import \
  --format "gcov_mcdc" \
  --source "coverage/pitch_axis_coverage.json" \
  --link-to "LLR-FCS-001"
```

### Example 2: Software Update Impact Analysis

**Scenario:** A critical defect requires updating certified software. Full impact analysis needed.

```bash
# Document the problem
rtm item create \
  --type "problem_report" \
  --title "PR-2024-089: Uncommanded Roll in Turbulence" \
  --description "Flight test revealed uncommanded roll oscillation in severe turbulence" \
  --metadata '{
    "severity": "critical",
    "safety_impact": "potential_loss_of_control",
    "dal": "A"
  }'

# Identify affected requirements
rtm graph analyze \
  --from "PR-2024-089" \
  --depth 5 \
  --direction "upstream" \
  --output "impact_analysis/pr-2024-089-upstream.json"

# Find all downstream impacts
rtm graph analyze \
  --from "LLR-ROLL-015" \
  --depth 10 \
  --direction "downstream" \
  --include-types "code,test,review,artifact" \
  --output "impact_analysis/pr-2024-089-downstream.json"

# Generate impact report for certification
rtm report impact-analysis \
  --problem-report "PR-2024-089" \
  --baseline "Build 2.1.0" \
  --format "DO-178C" \
  --output "certification/PR-2024-089-Impact-Analysis.pdf"
```

---

## Best Practices for Aerospace Traceability

### 1. Establish Traceability Early

Begin traceability activities during requirements development, not as a certification afterthought:

```bash
# Create project template with aerospace standards built-in
rtm project create "New Avionics System" \
  --template "aerospace_do178c" \
  --dal-level "A" \
  --enable-workflows \
  --enable-audit-trail
```

### 2. Maintain Bidirectional Traceability

Always create links in both directions to enable both forward and backward traceability:

```bash
# Good: Bidirectional linking
rtm link create --from "HLR-001" --to "LLR-001,LLR-002" --type "derived_to"
rtm link create --from "LLR-001,LLR-002" --to "HLR-001" --type "derived_from"

# Or use bidirectional flag
rtm link create --from "HLR-001" --to "LLR-001" --bidirectional
```

### 3. Use Consistent Metadata

Standardize metadata across the project for reporting and filtering:

```bash
# Define project metadata schema
rtm project configure --metadata-schema '{
  "dal": ["A", "B", "C", "D", "E"],
  "verification_method": ["test", "review", "analysis", "demonstration"],
  "review_status": ["not_reviewed", "in_review", "approved", "rejected"],
  "certification_status": ["not_certified", "in_process", "certified"]
}'
```

### 4. Automate Where Possible

Integrate TracerTM with your development pipeline:

```bash
# In CI/CD pipeline
# 1. Run tests and collect coverage
pytest --cov=src --cov-report=json

# 2. Import coverage results
rtm import --format gcov --source coverage.json --link-to-requirements

# 3. Check coverage thresholds
rtm report coverage-check \
  --dal-level A \
  --mcdc-threshold 100 \
  --fail-on-gap

# 4. Generate updated traceability matrix
rtm matrix generate --format pdf --output artifacts/matrix.pdf
```

### 5. Regular Audits and Gap Analysis

Schedule periodic traceability audits:

```bash
# Monthly traceability health check
rtm audit run \
  --check-broken-links \
  --check-unverified-requirements \
  --check-missing-metadata \
  --check-unapproved-changes \
  --output "audits/monthly-audit-$(date +%Y-%m).json"

# Generate gap report
rtm report gaps \
  --baseline "current" \
  --format "executive_summary" \
  --output "reports/traceability-gaps.pdf"
```

### 6. Tool Qualification

If using TracerTM as part of the certification process, consider tool qualification:

```bash
# Generate tool qualification package
rtm tool-qualification \
  --standard "DO-330" \
  --tool-category "TQL-5" \
  --include-validation-tests \
  --output "tool_qualification/TracerTM-DO-330-Package.zip"
```

### 7. Training and Documentation

Maintain project-specific traceability guidelines:

```bash
# Generate project traceability handbook
rtm project export-handbook \
  --include-workflows \
  --include-templates \
  --include-examples \
  --output "documentation/Traceability-Handbook.pdf"
```

---

## Compliance Checklist

Use this checklist to ensure DO-178C traceability compliance:

- [ ] All high-level requirements traced to system requirements
- [ ] All low-level requirements traced to high-level requirements
- [ ] All source code traced to low-level requirements
- [ ] All requirements have defined verification methods
- [ ] All requirements verified by test, review, or analysis
- [ ] Structural coverage meets DAL-specific objectives (MC/DC for DAL-A)
- [ ] Derived requirements identified and justified
- [ ] All changes tracked with rationale and impact analysis
- [ ] Baselines established and configuration-controlled
- [ ] Review and approval records maintained
- [ ] Tool qualification completed (if applicable)
- [ ] Certification data package generated and reviewed

```bash
# Run automated compliance check
rtm compliance check \
  --standard "DO-178C" \
  --dal-level "A" \
  --baseline "Certification-Build-2.1.0" \
  --output "certification/compliance-checklist.pdf"
```

---

## Additional Resources

- **DO-178C**: Software Considerations in Airborne Systems and Equipment Certification
- **DO-254**: Design Assurance Guidance for Airborne Electronic Hardware
- **ARP-4754A**: Guidelines for Development of Civil Aircraft and Systems
- **DO-330**: Software Tool Qualification Considerations
- **FAA Order 8110.49**: Software Approval Guidelines

For TracerTM-specific aerospace support:
- Contact: aerospace-support@tracertm.com
- Sample projects: `rtm project clone aerospace/flight-control-example`
- Training materials: https://docs.tracertm.com/training/aerospace
