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Understanding DO-254 and Solutions to Facilitate Compliance wwww.mentor.com 7 Tool assessment and qualification can happen one of three ways: 1. Independent Output Assessment, where another independent tool or method validates the results of the tool. 2. Relevant History, where the tool has been previously used and shown to provide acceptable results. 3. Tool Qualification, which requires establishing and executing a plan to confirm that the tool produces correct outputs for its intended application on the particular project seeking compliance. Regardless of these classifications, the task of tool assessment falls upon the airborne applicant or integrator who propose the method of tool assessment as part of the DO-254 planning and documentation. The certification agency or its representative (in the United States, this would be the DER) will determine if the proposed method of compliance is adequate for the development process. A tool vendor cannot assess or qualify their own tools and the FAA does not provide blanket approval for use of any tools in DO-254 projects. For more information on this topic, refer to the companion whitepaper entitled "Assessing the ModelSim and Questa Tools for Use in DO-254 Projects" available at www.mentor.com/go/do-254 . SOLUTIONS TO FACILITATE DO-254 COMPLIANCE PLANNING The purpose of planning is to have a project team thoroughly think through aspects of the development process that will demand DO-254 compliance, document how compliance will be achieved, have this documentation reviewed and accepted by a certification authority, and then to have this information (in the form of a PHAC and the other planning documents) guide all the program activities. This process can break down in a number of ways, including when team members are not trained on DO-254 compliance. Training is more than purchasing RTCA/DO-254 and making it required reading. Many other factors, policy documents, and industry opinions have shaped the accepted and best-practice methods of compliance. The best way to learn all of this is to take DO-254 compliance training from a well-qualified trainer. (Mentor Graphics offers scheduled and on-demand, public, private and customized training classes on DO-254 compliance. For more information, visit www.mentor.com/training_and_services/training/courses/fpga_pld/236322.) Another challenge of this phase is writing the plans themselves. Some companies provide templates that can help simplify the process. Another possibility is finding others within an organization that has already developed plans and leverages their work. Alternatively, simply look at the guidance in DO-254 section 10.1.1, which provides a clear outline of what needs to be included in a PHAC document. Supplement this by looking at section 3.1 "Activities for Stage of Involvement #1 – Planning Review" in the Job Aid, to prepare for the planning review audit. HARDWARE DESIGN PROCESSES DO-254 hardware design processes encompass development activities from requirements capture through production transition: REQUIREMENTS CAPTURE (INCLUDING MANAGEMENT AND TRACEABILITY) Requirements define the intended function of a device, and as stated earlier (from the CFRs), a DO-254- compliant process ensures that a device performs its intended function. So the first step in requirements- driven flow is capturing the requirements. In addition to simply capturing requirements, system requirements allocated to a hardware item must be reviewed (validated), managed (to control changes and their impact), and traced to the pertinent design and verification activities. Likewise, derived requirements, or those derived from design decisions throughout the process, must go through these same processes and additionally have a feedback mechanism to the system safety engineers for validation at that level as well.

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