DO-178B, Software Considerations in Airborne Systems and Equipment Certification, is the primary set of guidelines employed by the aerospace industry to create safe and reliable software. This guidance for software development was published and developed by Radio Technical Commission for Aeronautics (RTCA) and European Organization for Civil Aviation Equipment (EUROCAE).
DO-178B defines five Design Assurance Levels – A, B, C, D, and E; where Level A is the most rigorous.

• Level A : Catastrophic - Failure may cause a crash.
• Level B : 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.
• Level C : Major - Failure is significant, but has a lesser impact than a Hazardous failure (for example, leads to passenger discomfort rather than injuries).
• Level D : Minor - Failure is noticeable, but has a lesser impact than a Major failure (for example, causing passenger inconvenience or a routine flight plan change).
• Level E : No Effect - Failure has no impact on safety, aircraft operation, or crew workload.

DO-178B describes the suggested lifecycle processes for software from requirements through development and verification. The processes are divided into five distinct areas including Planning, Development, Verification, Configuration Management and Quality Assurance. Some of the processes in DO-178B include:

• Requirements-based software development
• Requirements-based software verification
• Independent peer review of software products
• Independent peer review of test cases and test procedures
• Robustness and out of range testing
• Structural coverage analysis
• 100% traceability from requirements to testing

DO-178B requires the following life cycle data:

• Plan for Software Aspects of Certification (PSAC)

• Software Development Plan (SDP)
• Software Verification Plan (SVP)
• Software Configuration Management Plan (SCMP)
• Software Quality Assurance Plan (SQAP)

• System requirements
• Software requirements standards
• Software design standards
• Software code standards

• Software Requirements Data (SRD)
• Software Design Description (SDD)
• Source code
• Executable object code

• Software Verification Cases and Procedures (SVCP)
• Software Verification Results (SVR)

• Software Configuration Index (SCI)
• Software Life Cycle Environment Configuration Index (SECI)

• Software Quality Assurance Records (SQAR)
• Software Accomplishment Summary (SAS)