Microprocessor Evaluations for Safety - Critical , Real - Time Applications : Authority for Expenditure No . 43 Phase 3 Report

Department of Transportation in the interest of information exchange. The United States Government assumes no liability for the contents or use thereof. The United States Government does not endorse products or manufacturers. Trade or manufacturer's names appear herein solely because they are considered essential to the objective of this report. This document does not constitute FAA certification policy. Consult your local FAA aircraft certification office as to its use. This report discusses the findings concerning safety issues in using today's commercial off-the-shelf (COTS) microprocessors on aircraft. The report addresses the applicability of RTCA/DO-254 to microprocessors, documents potential safety concerns when using modern COTS microprocessors on aircraft, and proposes potential approaches for addressing these safety concerns. The research was performed in multiple phases with participation from avionic system developers (BAE Systems, The Boeing Company, Lockheed Martin, and Smiths Aerospace) and Federal Aviation Administration organizations responsible for aircraft safety research and development. Phase 1 established the project scope and identified the research parameters, as well as reviewed the available literature and surveyed microprocessor users to identify the issues and potential solutions associated with the use of COTS microprocessors in regulated, safety-critical applications. Phase 2 developed the project objectives and found an approach to work toward the solution of these issues and the achievement of these objectives. Phase 3, documented in this report, evaluated the proposed approach and continued the development of processes, services, and prototype tool development. Phase 4, depending heavily on industry experience, will attempt to determine if new approaches can be developed to ensure system safety and provide more effective methods to accumulate safety evidence for certification while reducing the time and cost to develop and certify complex systems. These results will be documented in a Microprocessor Selection and Evaluation Handbook to facilitate application to real-time, safety-critical applications. The Microprocessor Evaluations Project researched methods to assess commercial off-the-shelf (COTS) microprocessors for safety-critical aerospace applications. Neither RTCA/DO-254 nor RTCA/DO-178B documents specify how microprocessors should be ensured. This project investigated assessment criteria and safety concerns for microprocessors and developed methods and procedures to (1) permit the safe, economical qualification of microprocessor applications with complex, nondeterministic architectures, (2) select microprocessors for safety-critical aerospace applications that can be proven to be safe, and (3) provide input to the Federal Aviation Administration for regulations and policy development regarding the design and test of COTS microprocessor components. Authority for Expenditure (AFE) No. 43 Phase 3 used …