AS9102 Rev C keeps the core expectation that a full First Article Inspection (FAI) establishes the baseline configuration and verification of a part or assembly. Partial and delta FAIs are controlled variants of that baseline, not shortcuts or alternatives to doing a full FAI when it is required.
What is a partial FAI in AS9102 Rev C?
In AS9102 Rev C, a partial FAI is performed when an existing, previously accepted FAI remains largely valid, and only the affected characteristics, processes, or design elements are re-verified. The standard allows this when specific changes occur, and a full FAI is not technically necessary.
Typical triggers for a partial FAI (subject to customer and internal procedures) include:
- Design change that affects only some characteristics (for example, selected dimensions, materials, or notes)
- Change in manufacturing process, method, machine, or location that does not invalidate the entire original FAI
- Change in source of a critical material or special process, but not the complete part configuration
- Correction of a nonconformance where the fix only affects defined features or operations
Key points under Rev C:
- You must have a valid baseline FAI for the part number (or configuration) before you can rely on a partial FAI.
- Only the changed or affected characteristics are re-inspected, but the documentation must clearly show what was re-verified and why.
- Forms 1, 2, and 3 must still provide complete traceability back to the approved FAI and to the applicable design definition and revision.
- Customer-specific flowdowns or contract requirements may override internal decisions and force a full FAI even when a partial FAI would otherwise be allowed.
What is a delta FAI in AS9102 Rev C?
AS9102 Rev C uses the term delta FAI to describe the documented difference (or gap) between the original, approved FAI and the current configuration or condition being released. In practice, a delta FAI is usually realized as a partial FAI package with clear identification of what changed relative to the baseline.
Conceptually:
- The original FAI is your baseline verification and documentation set.
- The delta FAI shows exactly what is different and how the affected features, processes, or configurations have been re-verified.
Under Rev C, a delta FAI must:
- Identify the previously approved FAI it builds on (part number, dash number, configuration, and FAI report identification)
- Explicitly list the changes and affected characteristics, and map those to the re-inspection data
- Use Forms 1, 2, and 3 (or equivalent) to maintain continuity and traceability across configurations
- Be performed and controlled in accordance with internal procedures and customer requirements, including required approvals where applicable
When can partial or delta FAI be used instead of a full FAI?
AS9102 Rev C allows partial or delta FAI usage only when a full FAI already exists and is still valid for the unchanged portion of the part or assembly. In practice, this is heavily constrained by:
- Customer and prime requirements: Many primes or Tier 1 customers specify exactly when full vs partial/delta FAI is acceptable. These requirements can be stricter than AS9102.
- Change type and risk: Wide-ranging design changes, major process or equipment changes, or long production gaps may invalidate the earlier FAI, driving a full FAI.
- Internal risk assessment: Conservative organizations often choose a full FAI when there is uncertainty about the impact of changes, especially for safety-critical or key characteristics.
AS9102 Rev C does not guarantee that a partial or delta FAI is acceptable to your customer. It defines how to perform and document them when allowed. Contract, PO clauses, customer manuals, and quality agreements still control.
Documentation and system implications in brownfield environments
In most regulated aerospace operations, FAI and delta/partial FAI sit on top of a mixed stack of legacy MES, ERP, PLM, and QMS systems. AS9102 Rev C expects:
- Clear linkage between the original and partial/delta FAI records (FAI report IDs, part and configuration, date, reason for FAI, and change reference)
- Controlled change management so that design changes, ECOs, and routing/process changes are consistently reflected in the FAI scope
- Traceable ballooning and characteristic mapping so that only the correct affected items are treated as part of the delta or partial scope
Full replacement of existing FAI tools or Net-Inspect-style workflows is often risky in brownfield, long-lifecycle environments due to re-validation effort, downtime, integration complexity, and the need to preserve historical FAI lineage. Most plants layer digital FAI tools on top of existing PLM/MES/ERP, focusing on:
- Reliable import of current design definition and revisions
- Explicit tracking of which characteristics are in scope for each partial or delta FAI
- Audit-ready evidence showing that partial/delta decisions followed internal procedures and customer requirements
Practical cautions
- Do not treat partial or delta FAI as a shortcut to avoid a required full FAI; this is a common audit and customer finding.
- Always confirm customer-specific FAI rules before deciding that a partial or delta FAI is acceptable.
- Ensure your QMS procedures explain when to use partial/delta FAI, who approves, and how traceability to the baseline FAI is maintained across systems.
This answer is a high-level summary only. For exact wording and figures, refer directly to the AS9102 Rev C standard and applicable customer documentation.
