DO-178C is a certification standard for software used in airborne systems.
DO-178C concentrates on objectives for software life-cycle processes to assure the development of safe and reliable software for airborne environments.
DO-178C determines five safety levels by examining the effects of a failure condition in the system. Also known as the Design Assurance Level (DAL), the five safety levels are:
- Catastrophic – Failure may cause deaths, usually with loss of the airplane
- Hazardous – Failure has a large negative impact on safety or performance, or reduces the ability of the crew to operate the aircraft due to physical distress or a higher workload, or causes serious or fatal injuries among the passengers.
- Major – Failure significantly reduces the safety margin or significantly increases crew workload. May result in passenger discomfort (or even minor injuries).
- Minor – Failure slightly reduces the safety margin or slightly increases crew workload. Examples might include causing passenger inconvenience or a routine flight plan change.
- No Effect – Failure has no impact on safety, aircraft operation, or crew workload.
The objective-based nature of DO-178C allows a great deal of flexibility in regard to following different styles of software life cycle.
Once an activity within a process has been defined, it is generally expected that the project respect that documented activity within its process. Additionally, processes (and their concrete activities) must have well defined entry and exit criteria, according to DO-178C, and a project must show that it is respecting those criteria as it performs the activities in the process.
DO-178C exists because advances in software engineering technologies and methodologies since the release of DO-178B made consistent application of the DO-178 objectives difficult.
Subsequently, in 2012, DO-178C/ED-12C was released, which clarified details and removed inconsistencies from DO-178B, and which also includes supplements that provide guidance for design assurance when specific technologies are used, supporting a more consistent approach to compliance for software developers using these technologies.
DO-178C guidance also clarified some details within DO-178B so that the original intent could be better understood and more accurately met by developers.
The DO-178C standard should be at the forefront of any planning for new commercial software-based aerospace systems and follow the basic design assurance principle that you say what you are going to do before you do it.
Want to learn more? Tonex offers Advanced DO-178 Training Workshop, a 4-day course that covers the aspects of DO-178C guideline, as well as its supplementary standards. Participants are introduced to the philosophy, rationale, and history behind DO-178C and will learn about the methods and techniques required to develop and implement it in your organization.
Advanced DO-178C training workshop also covers the main notions behind DO-178B/C avionics certification. It also reviews the differences between DO-178B and DO-178C.
For more information, questions, comments, contact us.