CERTON’s DO-178B Software Considerations in Airborne Systems & Equipment Certification

For nearly a decade, CERTON has provided services and solutions to customers across the Aerospace Industry from General Aviation to Space Flight focused on certification of Airborne Software compliant with RTCA/DO-178B Software Considerations in Airborne Systems & Equipment guidelines. CERTON can work closely with you to ensure successful TSO and/or Type Certification during any phase of the software project lifecycle under DO-178B.

DO-178B Design Assurance Level (DAL)

For systems and equipment using software to fulfill a safety related aircraft function, the FAA Advisory Circular 20-115B cites RTCA/DO-178B as a means of compliance to the Federal Aviation Regulations (FARs) Part 21, 23, 25, 27, 29 and 33. The FAA defines RTCA/DO-178B as a means, but not the only means, of compliance to the FARs. It is an extremely rare exception that an alternative means of compliance is used for software in avionics applications.

In order to certify safety-critical airborne software using the RTCA/DO-178B guidelines, the system safety assessment process will identify the applicable DAL according to the five failure conditions categories necessary for safe operation identified in the table below.

DAL	Condition
Level A	Catastrophic
Software that would cause or contribute to a failure of the system function resulting in conditions that would prevent continued safe flight and landing.
Level B	Hazardous/Severe-Major
Software that would cause or contribute to a failure of the system function resulting in reducing the capability of the aircraft or the ability to the crew to cope with adverse operating conditions so that there would be a large reduction in safety margins of functional capabilities.
Level C	Major
Software that would cause or contribute to a failure of the system function resulting in reducing the capability of the aircraft or crew with adverse operating conditions that would create a significant reduction in safety margins or functional capabilities, a significant increase in crew workload, possibly including injuries.
Level D	Minor
Software that would cause or contribute to a failure of the system function which would involve crew action that are well within their capabilities that causes slight reductions in safety margins or functional capabilities and slight increase in crew workload.
Level E	No Effect (DO-178B Objectives Do Not Apply)
Software that would cause or contribute to a failure of the system function which has no affect the operational capability of the aircraft or increase workload.

CERTON has the expertise to develop and certify airborne software for any DAL using the RTCA/DO-178B guidelines for compliance and Certification Authority approval. Click here to view several CERTON projects for DO-178B Software that shows our DAL experience.

The CERTON DO-178B Compliant Model

CERTON DO-178B Compliant Model The DO-178B Software Development Lifecycle is made up of six main phases, Project Planning Phase, Validation & Verification Phase, Requirements Phase, Design & Architecture Phase, Implementation & Integration Phase, and Delivery Phase. Each phase in the software development lifecycle consist of guidelines and activities to achieve compliance with the certification objectives that need to be filled in order for phase completion.

In CERTON's model of the DO-178B Software Development Lifecycle, the Validation & Verification Phase encompasses activities during all of the development phases once the plans have been approved by a Certification Authority (FAA, EASA, ANAC, Transport Canada, etc.). This is the key to successfully managing the risk on a DO-178B project and the V&V team members should contribute to the development of these plans that will affect the entire program as it evolves.

Software Development projects that fall victim to schedule and budget overruns can almost always be attributed to not having a trained and experienced V&V team in place early and actively involved during all phases of the software lifecycle. DO-178B projects are requirements based, and CERTON has the expertise and experience to contribute valuable input related to System Requirements, High Level Requirements, and Low Level Requirements Design and Architecture that will support streamlined implementation and integration, V&V, and Delivery. Errors in the Requirements, Design and Architecture have to be identified and resolved as they are created by the Development team early in the project. Otherwise, the inevitable consequence of detection by V&V after implementation and integration is complete rework from the top all the way down. These avoidable errors become very costly to a program with milestone deadlines, such as First Flight (SOF), Type Inspection Authorization (TIA), and Certification.