Safe Architecture Design of Flight Control System for
eVTOL 2023-01-7101
Advanced flight control system, aviation battery and motor technologies are
driving the rapid development of eVTOL to offer possibilities for Urban Air
Mobility. The safety and airworthiness of eVTOL aircraft and systems are the
critical issues to be considered in eVTOL design process. Regarding to the
flight control system, its complexity of design and interfaces with other
airborne systems require detailed safety assessment through the development
process. Based on SAE ARP4754A, a forward architecture design process with
comprehensive safety assessment is introduced to achieve complete safety and
hazard analysis. The new features of flight control system for eVTOL are
described to start function capture and architecture design. Model-based system
engineering method is applied to establish the functional architecture in a
traceable way. SFHA and STPA methods are applied in a complementary way to
identify the potential safety risk caused by failure and unsafe control action.
PSSA with FTA assists to allocate safety requirements and modify the
architecture of flight control system. Through the practice of safety-oriented
architecture design of flight control system for eVTOL, safety requirements are
identified, and related modifications and design are implemented to optimize the
system architecture design. Comparing to the safety assessment method with only
ARP4761 methods, the combination of ARP4761 and STPA will extend the perspective
to deal with potential unsafety issues. Hazards caused by random failure and
incorrected control are all tackled. The work of this paper can serve as a
useful reference for the system safety assessment and architecture design for
eVTOL and airborne systems.