DO-178C Part 3 - Software Development in IBM ELM

With planning in place, the next challenge is execution. In a DO-178C project, software development is not only about turning requirements into design and code. Teams also need to show that those activities were controlled, reviewed, and kept traceable as the system evolved.

That is usually where the workload starts to grow. Requirements change, designs are refined, code is updated, and evidence has to keep up with each step. If those relationships are managed across separate tools or manual records, gaps appear quickly.

IBM Engineering Lifecycle Management (ELM) helps teams manage this in one connected environment. This article looks at how IBM ELM supports key DO-178C software development activities and what that means in day-to-day project work.

In practice, DO-178C expects teams to focus on three major parts of software development:
● Requirements Development
● Software Design
● Coding and Integration
Each step has strict objectives, such as:
● Consistent and traceable refinement of requirements
● Documented design that supports verifiable implementation
● Coding standards and conformance
● Traceability from requirements through design, source code, and tests
● Reviews that show correctness, consistency, and compliance
● Controlled changes and baselines

This is often the point where teams lose time. The issue is not understanding what DO-178C asks for. The issue is keeping requirements, design, implementation, and reviews aligned once the project is moving and changes start to accumulate.

IBM ELM consolidates all components into one structured system, allowing teams to stay compliant while still working efficiently.

📖 If your team is already using IBM ELM and needs a more controlled way to support DO-178C development, Softacus can help align requirements, workflows, traceability, and review practices with certification needs.

1. Software requirements set the direction for everything that follows. If they are unclear, weakly linked, or poorly controlled, problems spread into design, code, and verification. In ELM, DOORS Next allows teams to:
● Maintain high-level, derived, and low-level software requirements
● Use version-controlled modules for stable baselines
● Capture requirement attributes such as DAL level, safety tags, verification method, and priority
● Ensure every requirement is reviewed and approved before use
● Link requirements to design, model elements, change requests, and verification artifacts
This ensures complete traceability, which becomes essential for certification audits.

2. System and Software Design with Engineering Systems Design Rhapsody
DO-178C expects the design to be clear, consistent, and verifiable.
IBM Rhapsody supports model-based design (MBD), which DO-178C endorses when combined with the DO-331 supplement. It provides:
● Block diagrams, activity/state charts, and architecture views
● Automatic linking between requirements and design elements
● Model simulation to catch errors early
● Design consistency checks
● Generated documentation to support certification evidence
Design becomes fully traceable and systematically controlled, eliminating “whiteboard design” risks. 

3. Controlled Coding with Engineering Workflow Management (EWM)
Under DO-178C, coding is expected to happen within a controlled process. It is not enough to manage source code changes. Teams also need a clear record of why a change was made, who reviewed it, and how it connects to the rest of the lifecycle. EWM supports this by providing:
● Integrated source control with change sets
● Coding rule enforcement through custom process templates
● Linked work items for development tasks
● Code reviews before approval to maintain standards and control changes
● Linking development tasks to work items, so every step is tracked and connected.
This satisfies DO-178C objectives related to implementation reviews, consistency, compliance with standards, and controlled change.  

4. Maintaining Traceability Across Development Artifacts
Traceability is one of the hardest parts to maintain manually, especially once development is spread across multiple teams and artifacts.

Using global configurations, teams can link:

● Requirements to design

● Design to code

● Code to test cases

● Test cases to results

● Change requests to affected artifacts

IBM ELM makes these relationships visible and helps teams spot gaps early. That matters during audits, but it also matters much earlier, when engineers need to understand what a change affects and what still needs to be reviewed.

5. Supporting Iterative or Agile Development
DO-178C is often associated with sequential development, but the standard does not require a single delivery model. What matters is control, traceability, and evidence.

IBM ELM can support iterative or agile development by giving teams a way to manage work items, baselines, reviews, and verification activities without losing lifecycle discipline as the project moves forward.
IBM ELM enables:
●Agile work item tracking
● Iterative baselines
● Incremental growth of requirements, design, and code
● Sprint-based verification
All while retaining the strict traceability and evidence-capture requirements of DO-178C.

📖 Learn more about ELM on our Aerospace & Defence Solutions page 

1. Requirement Drift and Inconsistent Design
As requirements evolve, teams struggle to keep design aligned.

ELM Solution:

Impact analysis shows what changes affect which design elements or code components, keeping everything synchronized.  

2. Missing or Broken Traceability
Disconnected tools create gaps that auditors immediately flag.

ELM Solution:

Automated traceability links ensure that every requirement is connected to its design and code, with dashboards showing missing links. 

3. Code Not Linked to Certification Evidence
Code reviews, coding standards, and justification are often scattered.

ELM Solution:

EWM ties work items, reviews, and change sets directly to DO-178C artifacts, creating a clean audit trail. 

4. Manual Documentation Overload
Certification relies on documentation, and generating it manually is painful.

ELM Solution:

The suite automatically generates requirements reports, traceability matrices, design documentation, and change histories.

● Plan your development workflow in advance, specifying requirements refinement, design approvals, and review criteria.
● Use strict versioning and baselines — especially when approaching major milestones.
● Automate as much traceability as possible — avoid creating links manually when tools can assist.
● Integrate modeling and design reviews — Rhapsody simulations catch errors long before testing.
● Require peer reviews for all code changes — EWM makes this mandatory in the workflow.
● Leverage dashboards to track coverage and ensure nothing is missed.
Not only do these practices make compliance easier, but they also help teams produce software that’s safer and more trustworthy. 

IBM ELM provides the platform, but the real challenge is shaping it around the way a DO-178C project actually runs. That includes requirements structure, traceability rules, review flows, baselines, development change control, and the evidence teams need later.

Softacus helps aerospace and defence organizations configure IBM ELM so development work stays connected across requirements, design, implementation, and verification. The aim is to make the lifecycle easier to manage in practice, not just easier to describe in documents.

This is especially useful for teams that already use IBM ELM but need a setup that better supports certification-oriented engineering work.

DO-178C software development depends on more than technical output. Teams need to keep requirements, design, code, reviews, and change history aligned as the project evolves.

IBM ELM helps by giving those activities a shared structure. When the platform is set up well, teams can reduce manual coordination, maintain traceability more consistently, and prepare for audits with less rework.

For organizations using IBM ELM in aerospace or defence projects, the real value comes from turning the suite into a working compliance environment rather than a collection of separate tools.