as-built configuration

An as-built configuration is the documented record of how a product, system, or asset was actually built and configured at the time of manufacture or release. It captures the real components, revisions, parameter settings, and approved deviations that were used, rather than the ideal or planned configuration from design or planning systems.

Core meaning in manufacturing and regulated environments

In industrial and especially regulated manufacturing (such as aerospace, medical devices, and defense), an as-built configuration commonly refers to:

• The complete list of parts, materials, and subassemblies used, with serial/lot numbers and revisions
• The routing actually followed, including operations performed and the resources used (machines, tools, fixtures)
• Process parameters and key settings as executed, where these are required for traceability
• Approved deviations, concessions, rework, and substitutions that differ from the original design or work order
• Links to inspection, test results, and nonconformance records associated with that specific build

The as-built configuration is typically captured and maintained by execution-layer systems such as MES, electronic travelers, or maintenance/asset systems, sometimes in coordination with ERP and PLM. It is a core element of traceability, genealogy, and digital thread initiatives.

As-built vs. other configuration views

Different lifecycle stages often maintain different views of configuration:

• As-designed configuration: The engineering intent managed in PLM or CAD systems (design BOM, design configuration). It describes what should be built.
• As-planned configuration: The manufacturable plan, usually in ERP/MRP and MES (manufacturing BOM, routing, planned work orders).
• As-built configuration: The factual record of what was actually built on the shop floor, including any approved departures from design or plan.
• As-maintained configuration: For in-service assets, the configuration after repairs, retrofits, and field modifications.

The as-built configuration is the authoritative reference when questions arise about which specific part revisions, lots, or processes were used on a particular unit or batch.

Operational use

In day-to-day operations, an as-built configuration typically appears as:

• A serial-level build record that ties finished units back to component serials/lots and process history
• Evidence for audits and investigations (for example, which aircraft or devices contain a given suspect lot)
• The basis for MRO and service decisions, where maintenance teams need to know exactly what is installed
• An anchor point for digital thread, linking design data, process data, quality data, and field performance

ERP, MES, and PLM integrations often revolve around keeping design and planning configurations aligned while ensuring the as-built configuration remains stable, traceable, and queryable over time.

Common confusion

• As-built vs. BOM: A bill of materials defines a structure of required parts. The as-built configuration is a historical, instance-specific record of which actual parts and revisions were used, plus execution details.
• As-built vs. as-designed: As-designed is the engineering specification. As-built is the realized outcome of manufacturing, including controlled differences.
• As-built configuration vs. documentation package: An as-built configuration is the structured configuration record. An as-built documentation package may include drawings, reports, and certificates, which reference or support the configuration record.

Context: ERP and aerospace MES

In aerospace ERP–MES integrations, ERP commonly owns planning data (as-planned BOMs, routings, and cost structures), while the MES or execution layer owns the detailed as-built configuration. Work orders, inventory, and completions are exchanged between systems, but the serial-level as-built configuration, including traceability and genealogy, is typically maintained within the MES and exposed back to ERP, PLM, and quality systems as needed.