Modification status
Modification and STC status review inside the continuing-airworthiness source file
A modification status source review reads the modification and STC status report line by line against the continuing-airworthiness file behind it. For every claimed embodiment, the analyst asks whether the CAMO records actually show an applicable modification, an approval basis that covers this serial number, and evidence the work was done. Where the answer is no, the line goes on an exception list for the continuing-airworthiness manager. Teams commission it when the airworthiness status baseline is being set or when a status report has to survive outside scrutiny.
When this review is needed
- The status report lists STCs inherited from prior operators and nobody has confirmed they apply to this serial number.
- An avionics or cabin change was embodied under time pressure and the approval paperwork was to follow.
- The maintenance program must be revised for a modification and the CAMO needs certainty about what is actually installed.
- A lessor or buyer has asked for the substantiation behind specific modification lines before signing anything.
The problem
Modification status reports accumulate lines the way aircraft accumulate operators. Each transition imports someone else's claims, and a line that says embodied can rest on nothing more than the previous report saying the same thing. Effectivity is the usual casualty: an STC approved for the type is quietly assumed to cover this serial number, and the one document that would prove it was never in the file to begin with.
What gets reviewed
- Every embodiment line on the modification status report traced into the CAMO source records
- Approval basis identified for each modification: STC, approved data under 14 CFR 43, or the EASA equivalent
- Effectivity confirmed against the serial number, configuration, and any prerequisite modifications
- Accomplishment evidence located: work orders, certification statements, or release documentation
- ICA and maintenance-program consequences of each modification checked for follow-through in the file
- Removed or deactivated modifications verified as closed out rather than silently dropped
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What gets validated
- Each status line cites an approval document that exists in the file and matches the modification described
- Serial-number effectivity is demonstrated by the approval itself, an amendment, or a permission letter, never assumed from type applicability
- Accomplishment records name the aircraft, the date, and the performing organization consistently with the CAMO reports for that period
- Where a modification changed the maintenance program, the program reference in the file reflects it
- No status line rests solely on a prior operator's report with nothing underneath it
Evidence normally required
- The current modification and STC status report
- The CAMO source file: status reports, airworthiness-review notes, program references, and the open-item log
- Approval documents held for each modification, including any effectivity amendments
- Work orders or release paperwork evidencing embodiment where available
Common discrepancies
- An STC listed as embodied whose approval covers the type but was never extended to this serial number
- Embodiment claimed on the report while the only evidence in the file is the prior operator's identical claim
- A modification installed and later removed, with the removal missing from the status report entirely
- ICA obligations created by a modification that never appear in the maintenance-program references
What is at stake
An unsupported embodiment claim contaminates everything downstream of it. Maintenance-program tasks get added or omitted on the strength of a modification that may not be installed as described, ICA compliance cannot be demonstrated, and at transaction time each doubtful line becomes a negotiation item with a price attached. Authorities treat configuration claims without approval evidence as findings, not clerical issues.
Move from findings to resolution
Move from findings to a documented resolution path.
How the work runs
Index the status report
Number every embodiment line and record its claimed approval basis and date.
Trace each line to source
Search the CAMO file for the approval, the effectivity, and the accomplishment evidence behind each claim.
Classify the support
Mark each line supported, partially supported, or unsupported, with the specific missing element named.
Deliver and disposition
Hand over the exception list and walk the CAMO through recovery paths for the lines that matter most.
What the buyer receives
- A line-keyed exception list separating supported, partially supported, and unsupported status entries
- A gap register naming the missing document for each unsupported line and where it is likely recoverable
- A corrected working view of modification status the CAMO can adopt into its baseline
- A short brief for management on the lines that carry transaction or program risk
Who uses the output
- Continuing-airworthiness managers setting or defending the airworthiness status baseline
- Engineering staff who maintain the program and need to trust the configuration it assumes
- Asset and fleet managers answering counterparty questions about specific modification lines
How the work fits into the transaction or program
Modification status sits between the logbook chain and the configuration records: the logbooks say when work happened, the equipment list says what is installed today, and this review confirms the approval and substantiation story connecting the two. Its exceptions typically feed both the equipment-list review and the maintenance-program update queue.
Jurisdiction-specific considerations
FAA-registered aircraft carry the field-approval and 14 CFR 21 STC lineage, where AC 21-40 style permission letters and effectivity amendments matter. EASA-managed aircraft answer to Part 21 minor and major change classifications under Regulation 748/2012, and the airworthiness review will expect the classification trail. Aircraft that changed register mid-life often hold approvals valid under one system and unrecognized under the other, which the review flags explicitly.
Regulatory limits
This is a records verification, no more. It does not approve modifications, reclassify changes, issue or validate STCs, or determine airworthiness. Findings describe what the file supports; deciding what to do about an unsupported line remains with the operator, the CAMO, and where applicable the authority.
What this review does not cover
- Physical configuration survey to confirm what hardware is actually installed
- Preparation or procurement of new approval data for unsupported modifications
- Judgment on the technical adequacy of the modifications themselves
Specific to this review
- Effectivity failures outnumber missing-embodiment failures in practice, because approvals travel by type while aircraft trade by serial number.
- A status report that has passed several lease transitions unamended is itself a warning sign; healthy reports change as removals and deactivations occur.
- Cabin and connectivity modifications generate the densest exception clusters, since they are installed fast, revised often, and documented last.
- One recovered approval document frequently clears several status lines at once when a modifier bundled changes under a single project.
Sources
U.S. Government (eCFR). Maintenance recordkeeping content and approval-for-return-to-service requirements, including 43.9, 43.11, and Appendix B.
U.S. Government (eCFR). Type certificates, STCs (Subpart E), TSO authorizations (Subpart O), PMA (Subpart K), and export airworthiness approvals (Subpart L).
Federal Aviation Administration. STC application process, certification basis, and continued airworthiness obligations of an STC holder.
European Union / EASA. EASA design and production certification, STCs, ETSO authorizations, and EASA Form 1 release.
U.S. Government (eCFR). Records an owner or operator must keep, including total time in service, current status of life-limited parts, and AD compliance.
Frequently asked questions
Does the review confirm what is physically installed on the aircraft?
No. It confirms what the records support. A physical survey answers the installed-hardware question; this review answers whether the paper trail behind the status report would hold up to an airworthiness reviewer or a counterparty. The two are complementary, and unexplained disagreement between them is itself a finding.
Relevant glossary terms
Related pages
Where this fits
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