Lignes Directrices pour le Développement d'Aéronefs Civils et Systèmes (ARP4754A / ARP4754B)

ARP4754A Systems Engineering V-Model Architecture

Requirements Decomposition, DAL Allocation, and Verification & Validation

Central System: System Safety Assessment Core - ARP4754A / ED-79A Lifecycle Engine

Aviation Architecture Nodes

• Aircraft Functional Requirements Ingress
• Functional Hazard Assessment (FHA)
• Development Assurance (DAL) Allocator
• Preliminary System Safety (PSSA)
• Verification Cross-Reference Matrix (VCRM)

Architectural Layers & Protocol Stacks

• Aircraft-Level Functional Definition (Model-Based Systems Engineering (MBSE) / SysML v2 / Aircraft Function Trees): Decomposing mission requirements into aircraft-level functions and capturing boundary assumptions across mechanical, electrical, and avionic subsystems.
• Functional Hazard Assessment (FHA) (Failure Condition Severity Classification (Catastrophic, Hazardous, Major, Minor, No Effect)): Systematic identification of failure conditions, evaluating severity from Minor to Catastrophic, and establishing qualitative safety objectives.
• Development Assurance Level (DAL) Allocation (Independence Verification / Common Cause Prevention / DAL Allocation Tables): Assigning DAL A through DAL E to system functions, isolating critical functions through architectural segregation to prevent failure propagation.
• Verification & Validation (V&V) Tracking (DOORS Requirements Management / Traceability Matrix / Formal Proof Engines): Continuous validation that requirements are correct and complete, and formal verification through flight test, iron-bird simulation, and analysis.

Flight Telemetry Metrics: DAL A to E (Development Assurance Levels) | 100% (Bidirectional Traceability Coverage) | < 10^-9 (Catastrophic Failure Probability / Hr) | 5 Phases (ARP4754A Lifecycle V-Model Stages)