design change

A design change is a controlled modification to an approved product, component, software, or system design. It typically alters one or more design artifacts such as drawings, models, specifications, bills of material, software code, or interface definitions, and is managed through a formal engineering and configuration control process.

Scope and characteristics

In industrial and regulated manufacturing environments, a design change generally includes:

• Updates to engineering drawings, 3D models, or CAD data
• Revisions to requirements, specifications, or performance criteria
• Changes to materials, components, or part geometry
• Software or firmware updates that affect function, safety, or interfaces
• Configuration changes to assemblies, systems, or product variants

A design change is differentiated from routine process adjustments because it affects what the product is, not just how it is built. It is normally documented via engineering change requests (ECRs), engineering change orders (ECOs), deviation or concession processes, or similar mechanisms within PLM, PDM, or QMS systems.

Operational meaning in manufacturing

Operationally, design changes trigger coordinated updates across multiple systems and workflows, for example:

• Revising controlled documents such as drawings, specifications, and work instructions
• Updating BOMs and routing in ERP/MES to reflect new parts or operations
• Adjusting inspection plans, FAI packages, and quality records
• Assessing impact on tooling, fixtures, NC programs, and test equipment
• Updating maintenance, overhaul, and repair instructions in MRO environments

In standards such as AS9100 and similar quality frameworks, design changes are expected to be risk-assessed, reviewed, approved by authorized functions, and fully traceable. This includes clear identification of affected configurations, effective dates or serial/batch cut-ins, and linkage to verification and validation evidence.

Design change and risk management

In regulated sectors like aerospace and defense, design change is closely tied to risk management and configuration control. Typical practices include:

• Evaluating potential impacts on safety, reliability, and compliance before approval
• Reviewing downstream effects on suppliers, fielded assets, and MRO organizations
• Ensuring alignment between design data in PLM and execution data in MES/ERP
• Maintaining an audit trail of rationale, approvals, and implementation status

For in-service products, design changes may drive service bulletins, retrofit campaigns, or updated maintenance instructions, and must be coordinated with continuing airworthiness and configuration management of fielded units.

What a design change is not

To avoid confusion, a design change usually does not include:

• Minor shop-floor process tweaks that do not affect fit, form, function, or approved requirements
• Temporary repair deviations or concessions applied to individual units without altering the baseline design
• Administrative document edits that do not modify technical content

However, if a process or repair change alters product requirements, interfaces, or performance, it often must be promoted and controlled as a formal design change.

Common confusion

• Design change vs. process change: A design change affects the product definition (what is built). A process change affects how the approved design is manufactured or inspected. In practice they interact, but they should be controlled and documented distinctly.
• Design change vs. configuration change: A configuration change is any modification to the defined state of a product or system. A design change is one of the main mechanisms that drives configuration changes and updates the controlled baseline.
• Design change vs. deviation/concession: A deviation or concession typically allows a one-time or limited departure from design requirements for specific units. A design change modifies the requirements themselves for future units or configurations.