Delta FAI commonly refers to a partial or incremental First Article Inspection (FAI) that documents and verifies only the changes from a prior, approved baseline FAI. It is typically used in aerospace and other regulated manufacturing environments that follow AS9102 or similar requirements.
Instead of repeating a full FAI on an unchanged part, a Delta FAI focuses on characteristics, features, or process steps that are affected by a design change, process change, tooling change, supplier change, or other defined trigger. The intent is to show objective evidence that the impact of the change has been understood and that the affected characteristics still meet requirements.
What Delta FAI includes
In practice, a Delta FAI usually includes:
- Reference to the original, full FAI report used as the baseline
- Identification of the specific change drivers (for example, engineering change order, revised drawing, new machine or program)
- Updated ballooned drawings or characteristic listings limited to affected features
- Measurement results and inspection records only for the affected characteristics
- Updated process or routing references when manufacturing steps have changed
- Signoff and date stamps that clearly differentiate Delta FAI from the original submission
Delta FAIs can be recorded using the same forms or digital tools as a full FAI, with the scope and coverage clearly marked as incremental to an earlier report.
What Delta FAI is not
- It is not a full, start-to-finish First Article Inspection on every feature of the part.
- It is not intended to bypass FAI triggers that would require a full re-FAI, as defined by customer or standard-specific rules.
- It is not a generic in-process inspection; it is tied to configuration-controlled changes relative to a known baseline.
Operational use in manufacturing
On the shop floor and in quality systems, a Delta FAI typically appears as:
- An additional FAI package linked to the same part number and revision, but associated with a new change notice or revision level
- A focused inspection plan generated by MES, QMS, or FAI software containing only the impacted characteristics
- A referenced attachment in customer portals or FAI management tools (for example, a new Delta FAI submission in Net-Inspect that points back to an earlier FAI record)
Digital workflows often manage Delta FAI by versioning FAI records, preserving traceability between the original FAI and each incremental update so that auditors and customers can reconstruct the complete inspection history of a part or assembly.
Common confusion
- Delta FAI vs. full FAI: A full FAI covers all drawing characteristics and applicable requirements. A Delta FAI limits coverage to characteristics impacted by a defined change, with the original FAI serving as the baseline for everything else.
- Delta FAI vs. routine inspection: Routine in-process or final inspection may occur on every lot or shipment, but a Delta FAI is a formal, documented event tied to configuration changes and often controlled by customer or standard-driven criteria.
Context in AS9102 and aerospace
In aerospace, customer specifications or quality agreements often define when a new full FAI is required versus when a Delta FAI is acceptable. Organizations typically maintain procedures that:
- Define change events that trigger a Delta FAI (for example, drawing revision that affects only certain dimensions)
- Describe how to identify and document affected characteristics
- Ensure that both the original and Delta FAI records are retained and traceable for audits and customer review
Although the exact term “Delta FAI” may not be formally defined in every standard, it is widely used in industry practice to describe this incremental FAI approach.