Glossary

Dimensional inspection

Dimensional inspection measures part features against specified dimensions and tolerances.

Quality, Compliance and Traceability First Article Inspection (FAI) in Aerospace Manufacturing and Regulated Supply Chains Inspection and Sampling (AQL)

Dimensional inspection is the process of measuring the physical features of a part, assembly, or product and comparing the results with specified dimensions and tolerances. It confirms whether measured characteristics such as length, diameter, hole location, flatness, profile, or angle are within the limits defined by an engineering drawing, model, specification, or control plan.

In manufacturing, dimensional inspection is commonly used for incoming inspection, in-process checks, final inspection, and first article inspection. Results may be recorded as measured values, pass/fail outcomes, or characteristic-level data tied to a drawing balloon, operation, lot, serial number, or inspection plan. Common tools include calipers, micrometers, gauges, height stands, optical systems, and coordinate measuring machines.

Dimensional inspection is closely related to geometric dimensioning and tolerancing, metrology, and measurement system analysis. It should not be confused with visual inspection, which focuses on observable conditions, or functional testing, which checks whether an item performs as intended. A dimensional result may support quality records and traceability, but it does not by itself establish broader product conformity beyond the measured requirements.

In most aerospace plants, Quality owns the FAI process, but day-to-day coordination is often handled by a quality engineer, FAI coordinator, or program quality role. Manufacturing engineering, planning, inspection, supply chain, and document control usually contribute evidence and approvals.

What should be resubmitted during a partial FAI?

During a partial FAI, resubmit the FAI records needed to prove the changed or affected characteristics, not the entire original package by default. At minimum, identify the reason for the partial FAI, reference the prior accepted FAI, and provide objective evidence for the affected requirements. Customer flowdowns may require more.

What KPIs should be tracked to monitor FAI performance?

FAI performance should be measured with a balanced set of cycle-time, quality, documentation, review, and change-impact KPIs. Speed alone is a weak measure; in AS9102 and regulated environments, traceability, completeness, and controlled disposition matter as much as throughput.

How should aerospace manufacturers handle nonconformances discovered during FAI?

Nonconformances found during FAI should be controlled through the normal nonconforming material and quality system process, not informally corrected to make the FAIR pass. The FAIR should reflect the actual result, with disposition, approvals, corrective action, and any required partial or full FAI rerun handled under contract and QMS controls.

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