3.5 First article inspection (AS9102)

A proper First Article Inspection (FAI) is not merely a quick check of a “golden sample”; it is a comprehensive, deep-dive validation of the entire manufacturing process. When we perform an FAI, we are not just measuring the physical part—we are actively auditing the process that created it. If the first unit off the line is an anomaly or barely passes, the subsequent production run will likely yield frustrating levels of scrap. We often adopt the AS9102 aerospace standard for this because it enforces a rigorous, unambiguous method of documentation that protects both the manufacturer and the customer.

The three-form architecture

The formal FAI Report (FAIR) is structured around three specific logic gates. These forms should be completed sequentially and should never be combined or rushed.

Form 1: part number accountability (the identity)

Function: This form clearly connects the physical part sitting on your desk to the specific drawing revision and the active Purchase Order.
Guideline: If the Revision level stated on Form 1 does not perfectly match the Revision level on both the engineering drawing and the PO, the FAI is considered void. This prevents us from validating outdated designs.

Form 2: product accountability (the inputs)

Function: This step carefully validates that the fundamental composition of the product is correct before we worry about its shape.
Scope: It covers raw materials (e.g. specific resins or steel alloys), Special Processes (e.g. Anodizing, Heat Treating, or critical Soldering), and Functional Tests.
Guideline: If a required Plating Certificate of Conformance (CoC) is missing from the supplier, Form 2 fails. Consequently, the entire FAI must be paused or rejected, regardless of how perfect the part’s dimensional accuracy might be.

Form 3: characteristic accountability (the geometry)

Function: This is the detailed dimensional audit. Every single feature on the engineering drawing must be “Ballooned” (numbered) and measured.
Guideline: Remember that global notes (such as “Break all sharp edges” or “Unless otherwise specified…”) are also considered critical characteristics. They must be ballooned and explicitly verified, not just glossed over.

The “ballooning” protocol

Thorough inspection always requires structured indexing. You simply cannot confidently verify what you have not systematically mapped.

Tagging: Carefully assign a unique number to every dimension, geometric tolerance, and text note on the engineering drawing.
Mapping: Create a corresponding verification row in Form 3 for each of those assigned numbers.
Measuring: Record the actual variable data you measured (e.g. “3.05 mm”), rather than simply writing “OK” or “Pass.”
- Exception: You should only use “Pass” for attribute data (for example, verifying a note that states “Color must be Black”).

Pro-Tip: If a dimension is called out as “4x M3 Holes,” that constitutes one balloon, but it actually requires four distinct physical measurements. You should record the Range (Min/Max) or thoughtfully list all four values on the form. Do not measure just one hole and assume the rest are identical.

Trigger logic: when to repeat FAI (delta FAI)

An FAI is not intended to be a static, one-time event; it represents a continuous state of process compliance. That state can easily be broken or reset by changes on the floor.

Re-Validation Guidelines:

When there is an Engineering Change (a Revision update), perform a Delta FAI. You only need to verify the specific characteristics affected by that change.
When production of a specific part lapses for >2 Years (24 Months), a Full FAI is usually required. Process stability relies on continuous operation; tooling degrades, and tribal knowledge fades over time.
When the manufacturing source, process, or location changes (e.g. moving production from CNC Machine A to CNC Machine B), a Delta FAI is necessary to prove the new setup is capable.
When a natural disaster occurs or major tooling repairs are performed, you should execute a Delta FAI to re-baseline the equipment.

Final Checkout: First article inspection (AS9102)

Control Point	Guiding Principle
Data Integrity	Form 3 should always record the actual measured values, avoiding generic “Pass/Fail” entries for variable dimensions.
Traceability	Form 2 must link directly to specific Lot or Batch numbers. Generic Material Certs without traceability often lead to Rejections during an audit.
Completeness	100% of the ballooned items must be measured and recorded. A single missing data point renders the entire FAI Incomplete.
Validation	The FAI should be verified by a Quality Engineer (independent of the operator who built it). “Self-signed” FAIs by the machine operator are generally considered invalid.
NC Handling	If you identify a failed characteristic on Form 3, pause the line. Do not ship the parts. Fix the underlying process and run a new FAI.