What Is a First Article Inspection? A Practical Guide for OEM Buyers
What an FAI report contains, when one is required, how AS9102 formats it, and how FAI differs from a C of C.
IsoCNC Engineering Team
CNC Machining & DFM Engineers · Updated · 9 min read
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The Short Answer
A first article inspection (FAI) is a complete, documented verification that a production process can actually produce a part that meets every requirement on the drawing. If you have ever asked "what is a first article inspection and why is my supplier quoting it as a line item," the answer is this: it is the formal proof — not a promise — that the first part off a new setup conforms to 100% of the specified dimensions, materials, finishes, and special processes, with objective evidence attached to each one.
An FAI is not a visual check of the first piece. It is a structured inspection exercise in which every single drawing characteristic is measured, recorded, and compared against its specified value, and the results are compiled into a first article inspection report (FAIR) that both the supplier and the buyer sign off on. Once the FAI passes, the process is considered validated for that part number and revision — full inspection of every feature on every subsequent part is no longer necessary, because the process itself has been proven capable.
What an FAI Report Actually Contains
A proper first article inspection report has three core elements, formalized in the aerospace AS9102 standard (more on that below) but applicable to any precision part:
1. A ballooned drawing. Every dimension, note, tolerance, surface finish callout, and material requirement on the drawing is assigned a unique number — the "balloons." A drawing with 80 measurable characteristics gets 80 balloons. This creates a one-to-one map between the drawing and the results table, so nothing can be silently skipped.
2. A characteristic accountability table. For each ballooned characteristic, the report lists the specified requirement (value and tolerance), the actual measured result, the measuring equipment used, and a pass/fail disposition. Any characteristic that does not conform must be dispositioned — reworked, use-as-is with buyer approval, or rejected — before the FAI can close.
3. Supporting certifications. The dimensional results are only part of the package. A complete FAIR also attaches:
- Material certifications — the mill cert for the actual material lot used, traceable by heat number, proving the alloy and temper match the drawing callout.
- Special process certifications — certificates for any process performed to a specification: anodizing to MIL-A-8625, passivation to AMS 2700, heat treatment, plating, and so on, each traceable to the batch the part went through.
- Certificate of conformance (C of C) for the part itself, tying the serial or lot number to the drawing revision.
The depth of our own quality inspection capability — CMM measurement, surface and thread verification, documented results — exists precisely to support this kind of characteristic-level accountability.
When Is an FAI Required?
Buyers sometimes treat FAI as a one-time event, but the trigger conditions are broader. An FAI (full or partial/delta) is generally required when:
- A part is produced for the first time — the classic case. New part number, new supplier, or new production line.
- The drawing is revised. A delta FAI covers only the characteristics affected by the revision; unchanged characteristics carry over from the original report.
- The manufacturing process changes — new machine, new tooling, new fixture, a move to a different facility, or a change in a special process source. Anything that could affect the outcome invalidates the assumption that the old FAI still represents the process.
- There is a lapse in production. AS9102 uses a two-year lapse as the trigger for re-validation, and many OEMs adopt the same convention: if the part has not been made in over two years, the process must be re-proven.
- A nonconformance history demands it — repeated escapes on a part often lead buyers to require a fresh FAI after corrective action.
The common thread: an FAI validates a process, not just a part. Change the process inputs, and the validation no longer stands.
AS9102: The Standard Format, Explained
AS9102 is the aerospace industry's standard for first article inspection, published by SAE and used throughout the aviation, space, and defense supply chain — it is the FAI companion to the AS9100 aerospace quality management framework. Even if your parts are not aerospace, AS9102 is worth understanding because it is the most mature, widely recognized FAI format in precision manufacturing, and many medical, automotive, and industrial buyers borrow it directly.
The standard defines three forms:
| AS9102 Form | Name | What it captures |
|---|---|---|
| Form 1 | Part Number Accountability | Part identity, drawing revision, serial/lot numbers, and indexes of sub-assemblies and detail parts |
| Form 2 | Product Accountability | Raw material, special processes, and functional testing — with certificate numbers and traceability |
| Form 3 | Characteristic Accountability | The ballooned-characteristic table: designed requirement vs. actual result, with measurement tooling and nonconformance references |
A few practical points about AS9102 that buyers should know. First, "full" versus "partial" FAI is defined in the standard — a partial FAI must reference the original FAI it amends. Second, AS9102 requires that the part used for the FAI come from the actual production run, using production tooling and processes — not a hand-finished lab sample. Third, every characteristic on the drawing must be accounted for, including notes; if a characteristic cannot be measured, it still must be listed with an explanation of how conformance was verified.
FAI vs. C of C vs. Full Inspection — Three Different Things
These three documents are routinely confused, and the confusion costs buyers real money:
- A certificate of conformance (C of C) is a statement, signed by the supplier, that the parts conform to the purchase order and drawing. It carries no measurement data. It is an attestation, appropriate for lower-risk parts and repeat orders of a validated part.
- An FAIis a one-time (per trigger) deep validation of the entire process, with measured evidence for every characteristic. It answers: "Can this process make this part correctly?"
- Full (100%) inspection is ongoing: every part in every lot is measured on specified characteristics. It answers: "Did every individual part come out right?" It is far more expensive per part and is typically reserved for safety-critical features or processes that are not yet stable.
The normal economics: pay for one FAI up front, then rely on sampling or final inspection per lot, backed by a C of C. Full inspection is what you pay for when the FAI approach cannot carry the risk.
What Buyers Should Ask a Supplier For
Whether you are qualifying a new machining supplier or launching a new part, a few pointed questions separate shops with real inspection infrastructure from shops that treat FAI as paperwork:
- Will the FAIR include a ballooned drawing and measured results for every characteristic — including notes and finish callouts — or only "critical" dimensions? (The right answer is every characteristic; "critical only" is a red flag unless you explicitly scoped a partial FAI.)
- What equipment will be used, and is it calibrated? CMM measurement with calibrated gauges is the baseline expectation; ask for the equipment list on Form 3.
- Are material certs and special-process certs included and lot-traceable, with heat numbers that match the material actually used?
- What triggers a delta FAI in your system? A supplier who can answer this crisply has a real FAI process; one who cannot will surprise you when a drawing revision ships without revalidation.
- Is there an FAI charge, and is it one-time? FAI cost is legitimate — the ballooning, setup, and measurement time is real — but it should be a defined, one-time-per-trigger charge, not a recurring line item.
A supplier's certifications and quality management framework tell you whether these answers are backed by a system or by good intentions — it is fair to ask what quality standards the shop's processes are built around, and to verify the inspection equipment exists. Our certifications and quality page describes the quality framework our inspection documentation is produced under.
Putting FAI Into Your Next RFQ
The cleanest way to get a good FAI is to specify it in the RFQ: name the format (AS9102 or your own template), state that material and special-process certs must be included and lot-traceable, and define the delta-FAI triggers for revisions. That removes all ambiguity about scope and cost before the first chip is cut. If you are sourcing precision machined parts and want FAI documentation scoped correctly from the start, review our quality inspection capabilities and upload your drawing through the instant quote portal — note your FAI requirement in the order comments and we will confirm the format, triggers, and documentation package with the quote.
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