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 an FAI is performed, it is not just measuring the physical part—it is 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. The AS9102 aerospace standard is often adopted 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 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 This prevents validating outdated designs.

Form 2: product accountability (the inputs)

Function: This step carefully validates that the fundamental composition of the product is correct before considering 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: It must be remembered 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. What has not been systematically mapped cannot be confidently verified.

Tagging: A unique number must be carefully assigned to every dimension, geometric tolerance, and text note on the engineering drawing.
Mapping: A corresponding verification row must be created in Form 3 for each of those assigned numbers.
Measuring: The actual measured variable data must be recorded (e.g. “3.05 mm”), rather than simply writing “OK” or “Pass.”
- Exception: “Pass” should only be used 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. The Range (Min/Max) should be recorded or all four values thoughtfully listed on the form. Measuring just one hole and assuming the rest are identical must be avoided.

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), a Delta FAI must be performed. Only the specific characteristics affected by that change need to be verified.
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, a Delta FAI should be executed 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 a failed characteristic is identified on Form 3, the line must be paused. The parts must not be shipped. The underlying process must be fixed and a new FAI run.