October 16, 2013

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The What and Why of “DO-178B” in Avionics Software

Overview of DO-178B
DO-178B, produced by the Radio Technical Commission for Aeronautics Inc. (RTCA), is the corporate acknowledged standard worldwide for regulating safety in the integration of aircraft systems software.

The strict title DO-178B doesn’t say much. Its official title is “Software Considerations in Airborne Systems and Equipment Certification.”

The purpose of this blog is to provide information about the  standard for software development in aircraft systems.

Before an aircraft system can be positioned, it must pass an “airworthiness” authorization held by regulatory organizations such as the Federal Aviation Administration (FAA) or the European Aviation Safety Agency (EASA), and DO-178B is recognized as the standard for the certification of the software portion of an avionics system.

The development processes is the main concern of DO-178B. As a result, certification to DO-178B specifications involves the delivery of numerous supporting documents and records. The  number of items needed for DO-178B certification, and the amount of information they must contain, is determined by the level of certification required.

Safety levels of DO-178B
DO-178B necessitates that all system requirements be mapped for one of the five aircraft software system safety levels mentioned below.

Level

Failure condition

Description of failure

A

Catastrophic

Avoids continued safe flight or landing, many serious damages

B

Hazardous/Severe

Potential serious damages to a small number of occupants

C

Major

Impairs aircrew efficiency, discomfort or possible injuries to occupants

D

Minor

Reduced aircraft safety margins, but well within crew competencies

E

No Effect

Does not affect the safety of the aircraft

DO-178B Processes
DO-178B is mainly divided into the five  following major processes:

  • Software Planning
  • Software Development
  • Software Verification
  • Software Configuration Management
  • Software Quality Assurance

DO-178B Process-wise expected document output
Every DO-178B process has a set of the following expected documents:

Process

Expected Document Output

Software Planning

Plan for Software Aspects of Certification (PSAC)
Software Development Plan
Software Verification Plan
Software Configuration Management Plan
Software Quality Assurance Plan

Software Development

Software requirements data (SRD)
Software design description (SDD)
Source code
Executable object code

Software Verification

Software Verification Cases and Procedures
Software Verification Results

Software Configuration Management

Software Configuration Index
Software Lifecycle Environment Configuration Index

Software Quality Assurance

Software quality assurance records (SQAR)
Software conformity review (SCR)
Software accomplishment summary (SAS)

Read more about aviation related software solutions,here.

References

http://en.wikipedia.org/wiki/DO-178B