First Article Inspection (FAI): What It Is and How to Run One

First article inspection (FAI) is the complete, documented verification of the first part produced by a new or changed manufacturing process, checking every dimension, note, and specification on the drawing before regular production is allowed to start. Instead of sampling a few characteristics, an FAI measures all of them once, to prove that the process, tooling, programs, and instructions can actually produce a conforming part.

What first article inspection covers

A full FAI verifies three things at once. First, the product: every dimensional characteristic, material callout, surface finish, and marking requirement on the drawing. Second, the process: that the part was made using the intended machines, tooling, and work instructions, not a hand-tuned workaround. Third, the documentation: that certificates, test reports, and inspection records exist and match. In aerospace, the AS9102 standard defines the three FAI forms (part accountability, product accountability, and characteristic accountability), and many other industries borrow that structure.

When an FAI is required

• A brand new part number goes into production.
• An engineering change alters fit, form, or function.
• Tooling is replaced, reworked, or moved to another machine or site.
• The manufacturing process or sequence changes materially.
• Production has lapsed for a long period (AS9102 uses two years) and the process must be re-proven.

A partial FAI is common after smaller changes: only the characteristics affected by the change are re-verified.

The FAI process step by step

1. Balloon the drawing: number every characteristic so each one can be traced to a measurement.
2. Build the first article under normal production conditions, with production tooling and operators.
3. Measure every ballooned characteristic with calibrated equipment and record actual values, not just pass or fail.
4. Verify materials and special processes through certificates and test reports.
5. Disposition any failures, fix the cause, and re-run the affected characteristics.
6. Approve, file the report, and release the process to production.

Worked example: a 42-characteristic FAI

Suppose a machined bracket has 42 ballooned characteristics. The first article passes 39 and fails 3: two hole positions are out by 0.04 mm against a 0.02 mm true position tolerance, and one surface finish reads Ra 3.4 against a 3.2 limit. That is a 7.1 percent characteristic failure rate (3 of 42). The team traces the hole positions to a fixture clamping issue and the finish to a worn insert, corrects both, and re-measures only those 3 characteristics. The FAI report then shows 42 of 42 conforming with actuals recorded for each. Without the FAI, those two systematic errors would have appeared in every production part.

FAI vs PPAP

FAI proves one part and the process that made it. A PPAP (Production Part Approval Process) is broader: it is an automotive approval package that can include capability studies, gauge R&R, FMEA, and a control plan alongside dimensional results. See our comparison of first article inspection vs PPAP for when each applies.

Common FAI mistakes

• Building the first article under special conditions (senior operator, slowed feeds) that production will never repeat.
• Recording pass or fail instead of measured values, which hides how close characteristics sit to their limits.
• Treating the FAI as a one-time gate and never re-running it after tooling or process changes.
• Ignoring measurement capability: a gauge that cannot repeat within the tolerance makes the FAI meaningless.

After the FAI: keeping the process in spec

An FAI proves the process can make a good part on day one. Keeping it that way is a monitoring problem: capability drifts as tools wear and settings creep. Ongoing statistical process control and acceptance sampling catch drift between FAIs, and real-time production monitoring shows when equipment behavior changes after the first article was approved. Fabrico gives manufacturers that continuous view: live production and OEE data plus maintenance records on the same equipment, so quality engineers can see what changed since the process was proven.

Frequently Asked Questions

Who performs a first article inspection?

Usually the supplier's quality team measures and documents the first article, and the customer reviews or witnesses the results. Some customers require an independent inspector or a source inspection at the supplier's site before shipment is allowed.

Does an FAI replace routine inspection?

No. An FAI is a one-time, full verification of a new or changed process. Routine production still needs its own inspection plan, typically a mix of in-process checks, sampling, and SPC defined in the control plan.

How long does a first article inspection take?

It depends on the number of characteristics and the measurement equipment available. A simple part with 20 characteristics may take a few hours; a complex machined part with hundreds of ballooned dimensions and special process verifications can take days, so plan FAI time into new product schedules.

Want production and maintenance data that shows exactly what changed since your process was approved? Book a Fabrico demo.