Implementing Model-Based Design for Flight Critical Applications

Triumph Engine Control Systems has been successfully developing Level A (flight critical/catastrophic hazard level) software to RTCA DO-178B for over 20 years for helicopter and fixed-wing aircraft. In order to meet rising customer and business demands, the company is investing in software development tools and techniques to improve cycle-time and reduce overall costs by incorporating RTCA DO-331 Model-Based Development and Verification while also utilizing a new company process that is built around the MathWorks® and Simulink® toolsets. The paper notes that the use of graphical models to represent requirements has the advantages of non-ambiguity and allows for simulation to support validation of requirements and verification of the implementation. The paper describes how the company has created standards and automated processes to enable the MathWorks tools users to follow a prescribed and consistent workflow process that meets the Triumph Engine Control Systems standards and objectives. The complexities of traceability, the interplay of system and software requirements, and the overall notion of verification via simulation are discussed relative to the toolset. The paper explains that through the use of the new structured approach to Model-Based Development and verification, Triumph Engine Control Systems has begun to yield cost and cycle time improvements without impacting quality or safety; further improvements are expected as the process expands and matures.