Key takeaway
Approval of a new design does not prove every unit contains it. Record the effectivity boundary and the evidence of incorporation separately.
Ask about a unit, not the latest drawing
A product archive can contain an approved drawing and still lack the evidence needed to describe an older unit. An engineering change may apply from a serial number, a production lot, a date or a defined retrofit. Choose the actual unit and configuration question first. An evaluation of historical decisions needs the design that applied then, not simply the most recent file exported today.
NASA’s configuration-management guidance separates proposing and approving a change from incorporating it and verifying implementation. It also describes status accounting for current and historical configurations, proposed changes and waivers. Those distinctions support this records review. They are NASA engineering guidance, not a requirement that every private manufacturer adopt the following ledger or a clearance to disclose design content.
A change crosses the production boundary
In this hypothetical assembly archive, drawing D17 revision A applies through unit U099. Change C8 approves revision B for U100 onward. Unit U098 later receives a separately recorded retrofit. Unit U101 has an authorized deviation for one feature. Unit U102 has a traveler reference but no retained incorporation evidence. The example’s effectivity and deviation rules are invented review inputs, not engineering instructions.
The completed ledger preserves the different histories. U098 does not become revision B on its original build date merely because it was retrofitted later. U101 needs its deviation alongside the B baseline. U102 remains unresolved. The table gives the configuration owner concrete questions without declaring whether any unit is safe, compliant or fit for service.
| Unit | Applicable history in the illustration | Evidence decision |
|---|---|---|
| U099 | Original build under D17-A | Retain A baseline and build record |
| U100 | C8 makes D17-B applicable | Link B approval and recorded incorporation |
| U098 | Built under A; later retrofit F3 | Keep original and later states with separate dates |
| U101 | B baseline; authorized deviation V2 | Retain deviation scope; do not rewrite baseline |
| U102 | B expected; traveler link only | Hold configuration claim pending incorporation evidence |
Give effectivity its own fields
Create fields for approved change identifier, affected configuration item, old and new revision, application boundary and change authority. Preserve the basis of that boundary: serial range is different from date of approval. If a change has several boundaries for different assemblies, retain each relationship rather than collapsing them into a single effective date. Explain whether the record describes designed, built, modified or inspected configuration.
For U098, a useful answer contains two dated states and the link to F3. A later assembly record may establish that a retrofit occurred without retaining every original inspection. Document that limitation. An alias assigned for external preparation must preserve the internal distinction between units and assemblies, but the alias does not create permission to disclose their configuration.
NASA’s technical-data management guidance addresses identification, review controls, access and distribution as distinct planning topics. For this proposed ledger, give the configuration owner a focused retrieval exercise: start at U098’s original build, find D17-A, follow retrofit F3 and identify the later recorded state. Then start at F3 and confirm which unit it concerns. Record the exact document versions used and what could not be retrieved. A link that opens only the current drawing fails this historical question even if the filename appears correct. The exercise tests the retained evidence; it does not resolve U102’s missing incorporation record.
Handle deviations without silently changing the design
NASA distinguishes an authorized waiver from a change to the baseline. For an internal archive review, retain the deviation or waiver identifier, authority, affected unit or range, limited feature and any stated expiry or follow-up. Use your organization’s actual terminology; different organizations may use deviation and waiver differently. Do not infer authorization from a technician note saying an alternative was fitted.
The hypothetical V2 applies only to U101. A data-preparation operator must not propagate it to U102 because both units share a production week. Nor should an approved drawing replace the built record when they disagree. Configuration review should preserve the discrepancy, identify which evidence was checked and assign the responsible engineer to resolve the specific boundary.
Keep design authority and reuse authority separate
A build or change approval concerns the product. An external evaluation concerns the proposed recipient and use of information about that product. Customer drawings, supplier specifications, tolerance details and licensed software exports can need separate authority. Begin with metadata describing revision coverage, effectivity fields and known gaps; keep restricted design attachments in the approved company environment.
Use inventory to describe the retained configuration history and rights review to organize component-level questions. The completed internal decision for this example is to describe U099–U101 with their stated histories, flag U102 as unresolved and hold drawings pending permission review. If the evaluator needs actual dimensional content, that becomes a new sample request. VOID can coordinate a named, permissioned introduction while that broader record and license decision remains with the owner.