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Quality Process Guide
First Article Inspection (FAI): What It Is, What Buyers Receive, and Why It Matters
· Quality Process Guide
When a buyer places a first production order, the question is always the same: are the parts actually built to drawing? First article inspection — FAI — is the documented answer. It is a formal verification that the first units off a production process conform to every requirement on the engineering drawing before a full run is released.
This guide explains what a first article inspection covers, how it differs from PPAP, which standard governs it in aerospace contexts, and what documentation a supplier should hand over when FAI is complete. At the bottom, there is a short section on how VNcontX runs FAI on CNC machined parts — part of our broader quality management process that covers every order from incoming material to final shipment authorization.
What Is a First Article Inspection (FAI Inspection)?
A first article inspection — also called an FAI inspection or 1st article inspection — is a structured review of the first part — or small sample from the first production run — against the engineering drawing and any referenced specifications. The goal is to confirm that the manufacturing process, tooling, and setup can consistently produce a part that meets all dimensional, material, and finish requirements before volume production begins.
FAI is not a random sample audit and it is not the same as incoming inspection on a repeat order. It applies specifically at the start of a new part number, after a design change, after a process change, or after a supplier change. In each of those cases, the production baseline has shifted and needs to be re-confirmed with objective evidence.
The term “first article” refers to the part itself — a physical unit produced under production-representative conditions. The inspection report is the documentation that records all measurement results against drawing requirements, with pass/fail notation for each characteristic.
First article inspection is a process qualification, not a product acceptance step. It confirms that the production method is capable of making the part correctly — not just that one specific unit happened to be within tolerance.
AS9102: The Aerospace FAI Standard
In aerospace manufacturing, first article inspection is governed by AS9102, published by SAE International and aligned with EN 9102 in Europe. The standard defines three forms that make up a complete FAI package:
AS9102 also requires that the inspection be performed on a part produced using production tooling, production processes, and production personnel — not a hand-finished sample built outside the normal workflow. The representative production environment requirement is what gives the FAI its value as a process confirmation.
Outside aerospace, most industrial buyers reference the same three-form structure informally, even when AS9102 is not explicitly required. The logic is the same regardless of industry: drawings, materials, and dimensions all need documented sign-off before volume starts.
FAI vs PPAP: What Is the Difference?
PPAP — Production Part Approval Process — is the automotive industry’s equivalent of FAI. Both exist to confirm production readiness before a volume run ships. The difference is in scope and paperwork depth.
| FAI (AS9102) | PPAP (AIAG) | |
|---|---|---|
| Industry origin | Aerospace / defense | Automotive (OEM supply chain) |
| Governing standard | AS9102 / EN 9102 | AIAG PPAP Manual (4th ed) |
| Submission levels | Full / partial / re-validation | Levels 1–5 (Level 3 most common) |
| Process capability data | Not explicitly required in standard | Required — Cpk / Ppk per characteristic |
| FMEA / control plan | Not part of standard FAI | Required at Level 3+ |
| Sample size | Typically 1–5 parts | Minimum 30 parts for Cpk studies |
| When triggered | New part, design change, process change, supplier change | Same triggers — plus new production location |
For most industrial and medical device buyers, FAI (without full PPAP) is sufficient for CNC machined parts. The key deliverables are the same: material traceability, dimensional conformance, and a record that the part was inspected against the current drawing revision.
If your quality system requires PPAP with Cpk studies, confirm this with your supplier before order placement — PPAP requires a larger sample population and additional documentation that adds lead time.
What a First Article Inspection Report Should Contain
A compliant FAI package for CNC machined parts covers the following items. If a supplier’s report is missing any of these, ask before approving the first article.
- Drawing identification — part number, revision, date of drawing used
- Material certificate (CoC) — alloy grade, heat/lot number, chemical and mechanical properties
- All dimensional characteristics measured, with nominal, tolerance, actual, and pass/fail columns
- Measurement method noted per characteristic — caliper, CMM, surface profilometer, thread gauge
- GD&T callouts measured individually — flatness, perpendicularity, true position each recorded separately
- Surface finish measurement data (Ra) where specified on drawing
- Finishing or coating confirmation — anodize class, passivation standard, plating thickness if applicable
- Inspection date and inspector identification
- Supplier sign-off with part serial/trace number linking report to physical part
For a step-by-step review framework covering all 47 checkpoints across documentation, dimensional, GD&T, material, surface finish, and process records, see the 47-point FAI checklist for CNC parts.
When you receive an FAI report, verify the drawing revision on the report matches the revision you sent. A common error is FAI performed against an outdated rev — the measurements may all pass, but they’re proving conformance to the wrong requirement.
When First Article Inspection Is Required
FAI is not just for new part numbers. The following events each require a fresh first article — a repeat order does not automatically carry over the previous FAI approval if any of these conditions have changed.
- New part number being introduced to production for the first time
- Engineering change — any drawing revision that modifies a dimension, tolerance, or material specification
- Process change — different machine, different cutting tool, change in setup or fixturing
- Supplier change — moving a part from one subcontractor to another, even using the same drawing
- Extended production gap — most quality systems define this as 12–24 months of inactivity, though the buyer may set a shorter threshold
- Non-conformance disposition that modifies the accepted baseline
For low-volume precision work — prototype runs, pre-production builds, and early design validation — FAI on the first unit serves a second purpose: it gives the design team dimensional feedback they can use to confirm tolerances are achievable before committing to a larger order.
How VNcontX Runs First Article Inspection on CNC Orders
Every order shipped from our Bình Chánh facility includes a full FAI report — not as an option, and not on request. The inspection runs on a Zeiss Contura CMM or Mitutoyo coordinate measuring equipment depending on part geometry. Surface finish is measured with a Mitutoyo SJ-210 profilometer. All results are recorded in a CMM dimensional report delivered in PDF with the shipment.
The report documents each callout on the drawing individually. GD&T features — true position, perpendicularity, flatness, runout — are each measured and recorded with actual deviation, not simply noted as “within tolerance.” Material certificates (CoC) from our stock suppliers are attached as a separate page in the same PDF package.
Our facility holds ISO 9001:2015 certification. Process capability is tracked with Cpk ≥ 1.67 as the minimum threshold on precision features. If a characteristic measures outside tolerance on the first article, production stops — the part is reworked or re-machined and a corrected FAI is issued before any order ships.
Frequently Asked Questions
Related Technical Resources
Every VNcontX Order Ships with a Full FAI Report
CMM dimensional data, material CoC, and finish confirmation — included as standard, not on request.
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duc.nguyen@vncontx.com ·
