When does a manufacturing process change trigger a new FAI?

A manufacturing process change triggers a new FAI, or more commonly a partial FAI, when the change could affect product characteristics or make the original First Article Inspection evidence no longer representative. The practical test is not whether the process name changed. It is whether the change could affect fit, form, function, material condition, special process results, dimensional characteristics, or the method by which conformity is demonstrated.

In AS9102-style aerospace environments, a process change does not automatically mean a full FAI on the entire part. A partial FAI is often appropriate when the affected characteristics can be clearly identified and traced. A full FAI may be required if the impact is broad, uncertain, customer-mandated, or the prior baseline is no longer reliable.

Common process changes that may trigger FAI activity

FAI impact should be assessed through formal change control. Common triggers include:

• Changing the manufacturing method, sequence, or routing in a way that could affect characteristics.
• Moving production to a different machine, line, cell, facility, or supplier when the move could affect results.
• Changing tooling, fixtures, dies, molds, jigs, or workholding that influence product geometry or repeatability.
• Changing CNC programs, machine parameters, additive manufacturing parameters, weld schedules, cure cycles, heat treat conditions, coating processes, or other controlled process settings.
• Changing material, material source, approved special process source, or subcontracted operation.
• Changing inspection methods or equipment when prior inspection evidence is no longer comparable or the measurement system has not been shown to be equivalent.
• Resuming production after a significant lapse, where customer requirements or internal procedures require FAI reassessment.

Changes that may not require a new FAI

Not every change to a traveler, work instruction, ERP routing, or MES operation record requires a new FAI. Administrative corrections, clearer operator wording, barcode changes, sequencing notes that do not affect the product, or system field cleanup may not trigger FAI by themselves.

That said, the burden is on the organization to document why the change does not affect the FAI baseline. In regulated environments, an undocumented assumption is weak evidence.

Partial FAI versus full FAI

A partial FAI is usually appropriate when the affected characteristics, operations, or clauses can be isolated. For example, a fixture change may require reinspection of dimensions controlled by that fixture, not necessarily every characteristic on the drawing.

A full FAI becomes more likely when the change affects the overall manufacturing approach, transfers production to a materially different environment, changes multiple interdependent operations, or creates uncertainty about which characteristics are affected. Customer contracts, engineering authority requirements, delegated source inspection rules, and internal procedures can also force a full FAI even when the technical impact appears limited.

System and evidence considerations

In brownfield plants, the FAI decision often depends on data spread across PLM, ERP, MES, QMS, inspection systems, and document control. A routing change in ERP may not show the actual work instruction revision used at the station. A PLM change may not automatically update the MES traveler. A QMS change request may not include enough manufacturing detail to determine FAI scope.

For that reason, FAI triggers should not rely on a single system flag unless the integrations, master data, revision controls, and approval workflows have been validated for that use. Many sites still need a controlled manual review by manufacturing engineering, quality, and sometimes the customer or design authority.

What should be documented

The change record should show what changed, which characteristics or operations are affected, whether a full or partial FAI is required, who approved the decision, and what evidence supports the conclusion. If no FAI is required, that rationale should also be recorded.

The main failure mode is treating FAI as a paperwork event after production has already moved. In a regulated manufacturing environment, the FAI impact assessment should happen before release of the changed process, not after parts are built and shipped.