When does a tooling change require a partial FAI?

A tooling change requires a partial First Article Inspection when the change can affect a product characteristic, the process used to create or control that characteristic, or the inspection evidence used to accept it. In AS9102-style aerospace practice, the trigger is not simply that a tool changed. The trigger is whether the tooling change could invalidate part of the prior FAI or affect fit, form, function, producibility, or verification of design characteristics.

This is site-specific and program-specific in practice. Customer requirements, internal procedures, delegated authority, criticality of the feature, and the history of the process can all make the requirement stricter than the baseline standard.

Common tooling changes that can trigger a partial FAI

• A new, replaced, reworked, or substantially repaired fixture, jig, mold, die, mandrel, drill template, forming tool, trim tool, or bonding tool that locates, forms, constrains, or creates product features.
• A tooling change that alters datums, clamping, nesting, alignment, sequence of operations, tool offsets, or the relationship between features.
• A change to CNC workholding, NC tooling strategy, machine setup, or toolpath support that can affect dimensional results.
• A change to inspection tooling, gaging, CMM program, measurement method, or acceptance setup when it affects how FAI evidence is generated.
• A tool move to another machine, cell, site, supplier, or process route when the production method is no longer equivalent.
• A customer, drawing, purchase order, quality clause, or program plan that explicitly requires partial FAI after certain tooling events.

When a tooling change may not require partial FAI

Routine maintenance, calibration, replacement of consumables, or like-for-like replacement of standard cutters, inserts, bushings, or wear items does not usually require a partial FAI by itself if the validated process remains equivalent and no design characteristics are affected. That conclusion should not be informal. It should be supported by documented change review, inspection results where appropriate, and the applicable internal procedure.

A common mistake is to treat tooling maintenance as automatically exempt. A repaired tool that shifts a datum, changes springback, alters hole location, changes bondline thickness, or affects repeatability may need partial FAI even if the part revision did not change.

How much of the FAI is repeated?

A partial FAI should cover the affected characteristics, not necessarily the entire part. The scope should include characteristics directly produced by the tool and any linked or downstream characteristics that could be affected by the tooling change. For example, a fixture change that affects hole pattern location may also affect edge distance, mating alignment, positional tolerance, or assembly fit.

The scope should be defined from the drawing, model, ballooned characteristics, routing, control plan, special process dependencies, and inspection plan. If the affected boundary is uncertain, many quality organizations choose a broader partial FAI scope rather than relying on an undocumented engineering judgment.

System and recordkeeping implications

In brownfield environments, the decision is rarely contained in one system. PLM may hold the released design, MES may hold the routing and work instructions, QMS may hold the change record and FAI package, ERP may hold part and supplier records, and maintenance systems may hold tool repair history. If those systems are not well integrated, the organization needs manual controls to ensure the tooling change is visible to quality planning and inspection.

Do not rely only on part revision status. A partial FAI can be required even when the drawing revision is unchanged, because the manufacturing or inspection method changed. The defensible record is the traceable link between the tooling change, the risk assessment, the affected characteristics, the partial FAI results, and any customer or internal approvals required by the program.

Practical decision rule

Ask this directly: could the changed tool affect how any design characteristic is made, located, constrained, measured, or accepted? If yes, a partial FAI is usually required or should at least be formally evaluated. If no, document why the prior FAI remains valid and retain the evidence under normal change control.