First Article Inspection (FAI)
Why the first article is measured, how AS9102 works, and what to verify
First Article Inspection verifies that the manufacturing process produces parts that meet the drawing — before production runs. The first article is measured against every drawing characteristic (dimensions, GD&T, finish, threads, material), documented per AS9102 format for aerospace or equivalent internal formats, and approved as the process baseline. FAI is the difference between shipping a batch and shipping a gamble.
1. Why FAI matters
A drawing says what the part must be; the process determines what it is. FAI catches the systematic issues — wrong tool radius, misunderstood datum, shrinkage error — before 500 parts inherit them. It also freezes the process: after FAI approval, changes require re-approval.
For machined, printed and molded parts the FAI is a one-time gate per drawing revision; stamped/die-cast parts re-FAI on tool changes and major process changes.
2. The AS9102 form structure
AS9102 uses three forms: Form 1 — part number, revision, supplier, PO and material lot traceability; Form 2 — every drawing characteristic measured, with method, result and tolerance; Form 3 — material, special processes and characteristic accountability.
Aerospace FAI includes dimensional, material (chemistry/mechanical) and special-process (anodize, heat treat, welding) verification; the responsible engineer signs accountability. Non-aerospace FAI uses the same logic in a lighter format.
3. What to check on the report
Verify the drawing revision matches, every characteristic has a measured value (not “OK” without data), critical features (position at MMC, flatness, threads) show method and result, and the material cert lot ties to the parts. Question gaps: unmapped characteristics mean unverified risk.
Review the CMM program and datum scheme match the drawing; a beautiful report measuring the wrong datum is worthless.
4. FAI in your workflow
Request FAI on production orders and on first runs of a new revision; the platform ships the FAI with the order and stores it in the order record. Use FAI results to set incoming inspection frequency: stable FAI history → skip-lot inspection; drift → tighten.
Keep FAI with the PPAP/quality file for audits; it is the evidence that your supplier controls the process, not just the parts.
Quick reference
| Form | Content | Purpose |
|---|---|---|
| Form 1 | Part, PO, supplier, material lot | Traceability |
| Form 2 | Every characteristic measured | Conformance evidence |
| Form 3 | Material + special processes | Process verification |
| Sign-off | Engineering accountability | Release authority |
| Re-FAI trigger | Revision, tool, process change | Process re-baseline |
Sources & references
- AS9102 Rev C — FAI aerospace
- AIAG PPAP — Automotive equivalent
- Xometry Learning Center — FAI Guide (public engineering reference)