They should be linked indirectly first, and directly only where the manufacturing context justifies it.
In practice, a FAIR is usually evidence that a part revision and its approved manufacturing process were demonstrated under a defined configuration. That means the primary link should normally be to the part number, revision, site or work center context, routing or process version where relevant, and the work order, lot, or first production run that generated the FAIR evidence. Serialized units should then inherit that relationship through genealogy and as-built records, rather than each serial number carrying a standalone FAIR record as if the FAIR were unique to that unit.
If you attach FAIRs directly to every serialized part with no effectivity logic, you usually create duplication, confusion during revision changes, and weak auditability. If you never associate serialized units to the FAIR context at all, you lose traceability when someone asks which FAIR supported a shipped serial number and whether later process or design changes broke that linkage.
Link the FAIR record to the part number and revision.
Link it to the manufacturing definition in effect at the time, such as routing version, operation set, inspection plan, tooling set, or approved method, if your systems can represent that cleanly.
Link it to the originating production context, typically work order, traveler, batch, or the first serialized unit or units produced under that configuration.
Store effectivity dates or change-state boundaries so the system can determine when the FAIR is valid, superseded, or potentially impacted.
Link each serialized part to its as-built genealogy, which should include the work order, operation history, material lots, inspection results, and revision state. That genealogy is what lets you infer which FAIR package applies.
Where a customer, internal quality process, or system design requires a direct serial-level pointer, use a reference link from the serial record to the governing FAIR identifier. But that serial-level link should still point back to a controlled FAIR object with revision and effectivity, not to a loose document attachment.
At minimum, the combined ERP and MES landscape should be able to answer these questions reliably:
Which FAIR package supports this part number and revision?
Which work order, lot, or first-run serials generated the FAIR?
Which serialized units were built under the same approved configuration?
What change events would require review, partial update, or new first article activity?
Can the FAIR references be traced to the exact inspection results, material certs, and process records used as evidence?
If the system cannot answer those questions without manual reconstruction from PDFs, shared drives, and tribal knowledge, the linkage is too weak for a regulated aerospace environment.
Direct linkage at the serialized-part level can make sense when:
The first article was executed on one or a small number of specific serial numbers and those units are important as reference builds.
The product has highly individualized configuration, making lot or family-based inheritance unreliable.
Customer requirements or internal procedures expect a serial-level evidence chain.
The ERP or MES supports serial effectivity and controlled document associations well enough to avoid duplicate maintenance.
Even then, the FAIR should still be managed as a controlled quality object with status, supersession, and change history. A plain file attached to a serial record is usually not enough.
In many aerospace plants, ERP owns the item, revision, order, and serial master while MES, QMS, or a separate FAI tool holds the execution details and FAIR package. In that case, do not force one system to become the source of truth for everything unless you are prepared for significant revalidation, migration effort, and disruption.
A more durable pattern is:
ERP holds the serialized item master and order context.
MES holds execution, genealogy, and inspection transactions.
QMS or FAI software holds the FAIR object and approval workflow.
Integration links them through stable identifiers such as part number, revision, work order, operation, lot, serial number, and FAIR ID.
This is less elegant than a single-platform model, but it is often more realistic in qualified environments with legacy systems, limited downtime windows, and long asset lifecycles. Full replacement strategies often fail here because the qualification burden, validation cost, integration complexity, and operational risk are higher than expected.
Using document attachments instead of controlled object relationships.
No revision or effectivity model, so obsolete FAIRs still appear valid.
Serial numbers exist in ERP, but execution evidence sits in MES with no reliable key mapping.
Partial FAI, delta FAI, or process-change triggers are managed outside the system and never reflected in linkage status.
Operators or quality staff manually enter FAIR references, creating inconsistency across serial records.
One FAIR is treated as permanently valid even after tooling, source, routing, or design changes.
Use a controlled FAIR record linked to part revision and manufacturing context, then relate serialized units through work order and genealogy. Add direct serial references only when needed for effectivity clarity or customer traceability. The best model is the one your ERP, MES, QMS, and document controls can sustain under change control, with validated integrations and clear ownership of master data.
No single linkage pattern is correct for every plant. The right answer depends on how you manage revisions, serial effectivity, first article triggers, and system interoperability. But as a rule, FAIRs should support serialized traceability through a governed data model, not through ad hoc file attachments or one-off manual links.
Whether you're managing 1 site or 100, Connect 981 adapts to your environment and scales with your needs—without the complexity of traditional systems.
Whether you're managing 1 site or 100, C-981 adapts to your environment and scales with your needs—without the complexity of traditional systems.
