First Article Inspection (FAI) is the formal verification process confirming that the first production unit of a new or changed part meets all design and engineering requirements before serial production is authorized.
FAI is a proactive quality gate: it catches manufacturing and process issues at the very first unit, rather than after thousands of non-conforming parts have been produced. The investment in a thorough FAI pays dividends by preventing costly escapes and customer returns.
The process follows AS9102 in aerospace (EN 9102 in Europe), PPAP in automotive, and similar standards in defense and medical device industries. All share the same underlying principle: 100% verification of every characteristic on the first production article.
Upon successful completion, the customer issues FAI approval (sometimes called "Part Approval" or "Production Readiness Clearance"), authorizing the supplier to proceed with series production and deliveries.
Concrete example
A new hydraulic manifold enters production. The supplier performs FAI: balloons 340 characteristics, measures each one, submits Form 3 with actual values, provides Cpk data for 18 CCs, and obtains written approval from the prime before shipping the first production batch.