The DO-178 is a document established to guide software considerations and equipment certification in airborne systems. The guidelines, jointly developed by RTCA and EUROCAE, are widely used in civil aerospace on a global scale.
What Is DO-178B?
DO-178B, Software Considerations in Airborne Systems and Equipment Certification, is a software jointly created by the Radio Technical Commission of Aeronautics Inc. (RTCA) SC-167 of the RTCA and WG-12 of European Organisation for Civil Aviation Equipment (EUROCAE). While EUROCAE published the ED-12B, RTCA published RTCA/DO-178B.
DO-178B software is recognized globally for regulating safety in airborne systems software. The Federal Aviation Regulations, Part 21, Subpart O outlines the requirement of the airworthiness certification process. DO-178B previously involved one of the mandatory certification requirements but requires other components to guarantee software safety. Although technically a guideline, DO-178B was the corporate standard for developing airborne systems software until it was replaced by DO-178C in 2012.
DO-178B involves five major processes: software planning, software development, verification, configuration management, and quality assurance. Each process must comply with the expected documented outputs outlined in the Federal Aviation Regulations requirements.
What Is DO-178C?
DO-178C is the primary document by which certification authorities, including the Federal Aviation Administration (FAA), European Aviation Safety Agency (EASA), and Transport Canada, approve commercial software-based aerospace systems. The document, called DO-178C/ED-12C was jointly produced by RTCA and EUROCAE.
After replacing the DO-178B in 2012, the DO-178C became the de facto approach for software in military avionics systems on a global scale. The FAA approved AC 20-115C in 2013, acknowledging the DO-178C as “acceptable means, but not the only means, for showing compliance with the applicable airworthiness regulations for the software aspects of airborne systems and equipment certification.”
DOC-178C guidance involves six key areas: planning, development, verification, configuration management, quality assurance, and certification liaison. Testing is one part of the overall DO-178C verification. Although it primarily involves development in the software life cycle, verification is a joint process that continues beyond the software life cycle. For instance, the planning stage of the DO-178C planning stage involves the development of a Software Verification Plan (SVP).
DO-178C Software Levels
The Software Level, commonly referred to as the Design Insurance Level (DAL) and the Item Development Assurance Level (DAL), is determined from the safety assessment process and hazard analysis by reviewing the effects of failure conditions in avionics systems. Failure conditions are categorized based on their effects on the aircraft, crew, and passengers.
Software Levels are divided into six groups: catastrophic, hazardous, major, minor, and no effect. Catastrophic failures may cause deaths and typically involve the loss of the aircraft. Hazardous failures have significant negative impacts on the safety and performance of the aircraft or reduce the ability of the crew to effectively operate the aircraft. Major failures significantly reduce the safety margin or increase the crew workload, resulting in passenger discomfort and/or minor injuries. Minor failures slightly reduce the safety margin or increase the crew workload, causing passenger inconvenience. No effect failures do not influence safety, aircraft operation, or crew workload.
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DO-178 training can help you learn the objectives for the software life cycle, descriptions and activities for achieving those objectives, and descriptions of evidence that indicate that those objectives have been satisfied.