A delta FAI under AS9102 is usually a partial FAI: it is triggered when a change could invalidate part of the original First Article Inspection. The partial FAI should cover the affected characteristics and supporting evidence, not necessarily repeat the entire FAI. The exact scope depends on the drawing change, process change, customer requirements, and whether the organization can justify which characteristics are affected.
Common AS9102 triggers include:
- Design changes, such as drawing revisions, specification changes, or model changes that affect design characteristics.
- Manufacturing source changes, including moving work to a different supplier, site, department, or manufacturing location when the change could affect conformity.
- Process changes, such as changes to manufacturing methods, special processes, inspection methods, or sequencing that may affect fit, form, or function.
- Tooling changes, including new, modified, refurbished, or replaced tooling that could affect product characteristics.
- NC program or media changes, where a CNC program, post-processor output, or translation to another media could affect the part.
- Material changes, including material type, form, source, or specification changes where product characteristics may be affected.
- Production lapse, commonly a lapse of two years or a shorter period if specified by the customer or program.
- Natural or man-made events that may adversely affect the manufacturing process, such as equipment damage, facility disruption, or other process-impacting events.
The important phrase is could affect. A change does not have to be proven to have caused a nonconformance before a partial FAI is considered. If the change can reasonably affect a design characteristic, process output, inspection result, or traceability basis, it should be evaluated through change control.
Delta FAI scope is not automatic
A delta FAI is not always a full restart. In many cases, only the changed or affected characteristics need to be reverified. However, the organization needs a defensible rationale for the scope. If the impact analysis is weak, auditors, customers, or delegated quality representatives may challenge why unaffected characteristics were excluded.
Customer requirements can also be stricter than the baseline AS9102 expectation. Some programs require customer approval before limiting the FAI scope, require a full FAI after certain source changes, or define shorter production-lapse thresholds. Contract, purchase order, drawing notes, and supplier quality clauses need to be checked before deciding the scope.
Where the trigger usually comes from
In a brownfield aerospace environment, the trigger may originate in several systems, not only the FAI tool:
- PLM may issue the drawing, model, specification, or bill-of-material revision.
- ERP may identify a supplier, routing, material, or production order change.
- MES may control the traveler, operation sequence, work instructions, inspection steps, or NC program reference.
- QMS may manage change requests, deviations, nonconformances, corrective actions, or customer approvals.
- Maintenance or equipment systems may show equipment events that affect process capability.
The failure mode is common: the drawing changes in PLM, the routing changes in ERP or MES, but the FAI record is not reassessed. That creates traceability risk. Integration helps, but it does not remove the need for ownership, validation, and a controlled impact assessment.
What should be documented
A partial FAI record should normally identify the original approved FAI, the reason for the delta, the affected characteristics, the evidence used to verify them, and the approval status. If characteristics are excluded, the rationale should be clear enough to survive internal review and customer scrutiny.
AS9102 does not make the decision risk-free. The organization still needs controlled procedures, trained reviewers, current configuration data, and customer-specific rule checks. When the impact is unclear, the safer operational practice is to escalate through quality and program change control rather than assume the original FAI remains valid.