Short answer
A first article inspection (FAI) is documented, objective evidence that your production process can make a part that meets every requirement on the drawing and in the purchase order. In aerospace it follows AS9102, which uses three forms:
- Form 1, part number accountability: the part, its revision and any sub-assemblies.
- Form 2, product accountability: raw materials, special processes and functional tests, with their certifications.
- Form 3, characteristic accountability: every design characteristic, numbered on a ballooned drawing, with its requirement and measured result.
What is a first article inspection for?
An FAI verifies the process, not just one part. The first article has to be made with the same machines, tooling, programs, methods and materials you'll use in production. A hand-finished prototype that happens to measure well proves nothing about the next 500 parts.
That is why customers ask for a new FAI when something about the process changes, even if the drawing hasn't.
When is an FAI required?
AS9102 calls for a full FAI on the first production run of a new part. After that, a full or partial (delta) FAI is required when something changes that could affect fit, form or function, including:
- A change in the design characteristics of the part.
- A change in manufacturing source, process, inspection method, location of manufacture, tooling or materials.
- A change to a numerical control program, or moving it to another machine or media.
- A natural or human-caused event that may affect the manufacturing process.
- A lapse in production of two years, unless the customer specifies a different period.
A partial FAI covers only the characteristics affected by the change. The forms should say clearly why it's partial and which characteristics were re-verified.
What goes on each AS9102 form?
| Form | Purpose | Typical contents |
|---|---|---|
| Form 1 | Part number accountability | Part number and name, drawing revision, serial or lot number, organization and supplier codes, whether the FAI is full or partial and why, sub-assembly part numbers, sign-off |
| Form 2 | Product accountability | Each raw material, special process (heat treat, plating, NDT, painting) and functional test, with specification, supplier, certificate of conformance number and whether the supplier is approved where required |
| Form 3 | Characteristic accountability | One line per characteristic: balloon number, reference location, characteristic designator, requirement with tolerance, measured result, the tooling or gauge used, and any nonconformance reference |
How to balloon a drawing
Ballooning means numbering every requirement on the drawing so each one appears exactly once on Form 3. The most common failure is missing characteristics, so be thorough:
- Every dimension and its tolerance, including basic dimensions used by GD&T controls.
- Every geometric tolerance in its feature control frame, with its datum references.
- Surface finish, edge breaks, thread callouts and hole callouts, each as its own characteristic.
- Every drawing note and flag note, including general notes in the title block, such as default tolerances and "break all sharp edges".
- Requirements from specifications the drawing references, such as a plating thickness or a marking method.
Number in a consistent order, for example clockwise from the top left of each sheet, and record the sheet and zone for each balloon so a reviewer can find it.
How should results be recorded?
- Variable characteristics get the actual measured value, in the drawing's units. "OK" or a tick is not a result for a dimension.
- Attribute characteristics, such as a note or a visual requirement, can be recorded as conforming, with the method of verification.
- Record the gauge or method for each characteristic, and make sure every instrument used was calibrated and capable of the tolerance.
- Anything out of tolerance needs a nonconformance reference and a disposition before the FAI is complete.
Why FAI packages get rejected
- Missing characteristics: usually notes, general tolerances or requirements buried in referenced specs.
- Revision mismatch: the FAI was done to a different drawing or purchase order revision than the one on the order.
- Material or process certificates that don't match: wrong specification, wrong heat or lot, or a special process from a source the customer hasn't approved.
- Unusable results: "OK" for dimensions, missing units, or results that can't be traced to a calibrated gauge.
- Not representative of production: the part was made on a different machine, program or method than production will use.
FAI checklist
- Confirm the drawing and purchase order revisions, and the customer's FAI requirements and forms.
- Make the first article on the production process, with production tooling and programs.
- Balloon every characteristic, note and referenced requirement.
- Collect material, special process and test certificates and check them against the specifications.
- Measure and record actual values with calibrated, capable gauges.
- Disposition any nonconformance before sign-off.
- Complete Forms 1, 2 and 3, review the package independently, then sign and submit.
Frequently asked questions
Is a first article inspection the same as PPAP?
No. FAI under AS9102 is the aerospace standard for verifying the first production part. PPAP (Production Part Approval Process) is the automotive equivalent from AIAG and is broader: it also covers process flow, FMEA, control plans, measurement system analysis and capability studies.
Can an FAI be done on a prototype?
Not a valid one. The first article has to be produced with the production process, tooling and methods. A prototype inspection can be useful, but it doesn't satisfy AS9102.
What is a partial or delta FAI?
A partial FAI re-verifies only the characteristics affected by a change, such as a new revision, a new machine or a new material source. It still needs Forms 1 to 3, with the reason for the partial FAI stated.
When does an FAI need to be repeated?
When the design, the manufacturing source, process, location, tooling, materials or NC program change in a way that could affect fit, form or function, after an event that may affect the process, or after a two-year lapse in production unless the customer specifies otherwise.