Key Concepts and Terminology in DO-178C: A Comprehensive Guide

DO-178C A comprehensive guide


DO-178C, the standard for Software Considerations in Airborne Systems and Equipment Certification, establishes the guidelines for software certification in the aviation industry. To navigate the complexities of DO-178C, it is crucial to understand its key concepts and terminology. In this comprehensive guide, we will explore the essential concepts and terminology in DO-178C, providing insights and explanations to help software developers, certification engineers, and aviation professionals ensure compliance and successful software certification in airborne systems.

Design Assurance Level (DAL)

Design Assurance Level (DAL) is a critical concept in DO-178C. It categorizes the criticality of software functions in airborne systems, ranging from Level A (most critical) to Level E (least critical). Each DAL level corresponds to specific safety objectives and requirements, guiding the rigor and depth of processes and activities throughout the software development lifecycle. Understanding the assigned DAL is essential for tailoring the certification activities to the criticality of the software components.

Item Development Assurance Level (IDAL)

The Item Development Assurance Level (IDAL) is synonymous with the Software Level in DO-178C. It aligns with the DAL and determines the criticality and associated processes for a specific software item or component. The IDAL guides the level of scrutiny, documentation, and verification required to achieve compliance for each software item.


Traceability plays a crucial role in DO-178C by establishing clear relationships between certification artifacts and requirements. It ensures that each requirement is well-connected to design elements, source code modules, test cases, and test results. This bidirectional traceability enhances transparency and facilitates the demonstration of compliance by ensuring that every requirement is properly addressed, implemented, verified, and validated. Additionally, traceability proves valuable in managing changes, conducting impact analysis, and ensuring comprehensive verification coverage.

Software Configuration Index (SCI)

The Software Configuration Index (SCI) is a comprehensive and structured listing of all software configuration items involved in a project. It encompasses various components such as software requirements, design elements, source code modules, and associated documentation. The SCI provides an organized overview of the software components, highlighting their relationships and interdependencies. It serves as a robust foundation for effective configuration management, facilitating tasks such as version control, traceability, and maintaining consistency throughout the software lifecycle. The SCI plays a vital role in ensuring efficient configuration management practices and supporting overall software integrity and reliability.

Verification and Validation

Verification and validation are integral processes in DO-178C to ensure the correctness and quality of the software. Verification activities confirm that the software satisfies its specified requirements, while validation activities evaluate the software’s performance against its intended functions and safety objectives. Verification includes activities such as inspections, reviews, and testing at various levels, including requirements-based testing, structural coverage analysis, and interface testing. Validation encompasses system-level testing, integration testing, operational scenario testing, and other relevant activities. Proper execution of verification and validation activities is crucial to ensuring the reliability, safety, and compliance of the software.

Independence and Separation of Responsibilities

DO-178C emphasizes the importance of independence and separation of responsibilities in the software certification process. Independence ensures objectivity in verification and validation activities. For objectives that require independence, the person verifying the item (e.g., requirement or source code) should not be the same person who authored it. This separation of responsibilities enhances the credibility and reliability of the certification process by avoiding biases and conflicts of interest.

Software Configuration Management (SCM)

Software Configuration Management (SCM) is a critical component of DO-178C, focusing on the management and control of software configuration items (SCIs) throughout the software development life cycle. SCM ensures that the software components are properly identified, documented, version-controlled, and baselined to maintain integrity and consistency.

SCM establishes a systematic approach to identify and define software configuration items (SCIs) within a project. SCIs encompass requirements, design elements, source code modules, test cases, and associated documentation. Clear identification of SCIs is crucial for traceability and managing changes effectively.

SCM facilitates version control to manage different iterations of software components. It ensures that the appropriate versions of SCIs are used during development, verification, and validation activities. Version control helps in tracking changes, comparing different versions, and maintaining a history of revisions.

SCM establishes baselines to capture a specific configuration of software components at a particular point in time. Baselines provide a reference for further development, verification, and validation efforts. They help ensure that the software components remain consistent and can be accurately reproduced as needed.


In this comprehensive guide, we have explored the key concepts and terminology in DO-178C, providing valuable insights into software certification in airborne systems. Understanding these concepts is essential for ensuring compliance and successfully navigating the complexities of DO-178C.

By comprehending the Design Assurance Level (DAL) and Item Development Assurance Level (IDAL), stakeholders can determine the criticality of software components and tailor their development, verification, and validation processes accordingly. The importance of traceability cannot be overstated, as it establishes clear connections between certification artifacts and requirements, ensuring transparency, compliance, and effective change management.

The Software Configuration Index (SCI) serves as a foundation for configuration management and traceability, providing a comprehensive overview of software components and their relationships. Verification and validation play pivotal roles in confirming the correctness and reliability of the software and ensuring adherence to safety objectives and performance expectations.

DO-178C emphasizes the significance of independence and separation of responsibilities, fostering objectivity in the verification and validation processes. Lastly, Software Configuration Management (SCM) ensures the proper identification, version control, baselining, and change management of software components throughout the software development lifecycle.

By embracing these key concepts and utilizing the appropriate terminology, stakeholders can enhance their understanding of DO-178C and execute software certification in airborne systems more effectively. Achieving compliance and ensuring the safety of airborne systems requires a comprehensive approach that encompasses critical considerations and adherence to industry best practices.

With this comprehensive guide, you are equipped with the knowledge and insights necessary to navigate the complexities of DO-178C. By embracing these key concepts and terminology, you can confidently approach software certification in airborne systems, contributing to the overall safety and reliability of aviation software.

Key Concepts and Terminology in DO-178C: A Comprehensive Guide
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