Compliance matrix
Compliance matrix evidence review for aircraft modifiers
A compliance matrix evidence review checks that each row of your STC matrix ties a certification-basis requirement to a stated means of compliance and to a document that still substantiates it. It is run for aircraft modifiers by an outside reviewer before a submittal goes to the authority, before a finding response is filed, or when a design change reopens closed rows. The review looks for uncovered requirements, means that no data supports, and citations that point at a superseded revision. You get a gap list, an evidence map keyed to each row, and a suggested order for closing the open items.
When this review is needed
- A submittal package is being assembled and the matrix is the index the authority will read first.
- The project office issued a finding against matrix coverage and a response is due on a fixed date.
- A design change touched a subsystem and nobody has confirmed which matrix rows it reopened.
- The program inherited a matrix from an earlier phase and its citations were never re-checked against the current data.
The problem
The matrix is the one document that promises full coverage, so it is also the document the authority uses to find holes. Rows accumulate over a program: a means of compliance gets assigned early, the supporting test slips, the citation stays pointing at a plan that was never executed. By submittal time the matrix reads as complete while several rows rest on evidence that does not exist yet or has moved under a new revision.
What gets reviewed
- Every certification-basis requirement mapped to at least one matrix row, with no basis paragraph left unaddressed
- The stated means of compliance for each row checked against what the cited evidence actually is
- Citation currency confirmed so no row points at a superseded report, drawing, or analysis revision
- Rows marked closed cross-checked against the document that is supposed to close them
- Derived and changed requirements confirmed to have their own rows rather than being folded silently into others
- Open, deferred, and to-be-determined rows collected into one honest list of what is not yet substantiated
What gets validated
- Each basis paragraph in the certification basis appears against at least one matrix row
- The means of compliance named on a row matches the type of evidence the citation resolves to
- Every cited report, drawing, or analysis number resolves to the revision currently under configuration control
- A row shown as closed is backed by a document that contains the finding it claims
- The set of open rows in the matrix equals the set of gaps carried in the program's own tracking
Evidence normally required
- The current compliance matrix in its working format
- The certification basis and any issue papers or special conditions in force
- The document register that resolves each citation to a controlled revision
- The means-of-compliance approach agreed with the authority for the project
- The program's own open-item or finding tracker for reconciliation
Common discrepancies
- Basis paragraphs that no row addresses, so a requirement has no assigned means at all
- Rows whose means of compliance is a test or analysis that the cited document does not contain
- Citations pointing at a revision that a later change already superseded
- Rows carried as closed in the matrix while the same item is still open in the program tracker
What is at stake
A matrix that overstates coverage draws findings that stall the whole package, because the authority cannot separate the rows that are genuinely closed from the ones that only look closed. Each round of clarification adds weeks, and a single citation to a retired revision can put otherwise sound rows back into question.
Move from findings to resolution
Identify gaps against the means of compliance.
How the work runs
Load the basis and the matrix
Set the certification basis, issue papers, and special conditions against the current matrix so coverage can be measured row by row.
Resolve every citation
Follow each row's reference to the controlled document and confirm the evidence type matches the stated means of compliance.
Reconcile against the tracker
Compare the matrix's open and closed rows with the program's own open-item list and surface every disagreement.
Deliver the gap list and order
Hand over the uncovered, unsupported, and stale rows with an evidence map and a closure sequence.
What the buyer receives
- A gap list naming each uncovered requirement, unsupported means, and stale citation
- An evidence map that ties every matrix row to the controlled document that substantiates it
- A suggested closure order that clears blocking rows before the ones that depend on them
Who uses the output
- STC program managers deciding whether the matrix is ready to leave the building
- Certification engineers preparing the response to a coverage finding
- Engineering leads reallocating effort toward the rows that actually block submittal
How the work fits into the transaction or program
The matrix sits at the center of the data package, indexing the certification plan on one side and the underlying reports on the other. This review reads it against both, so the coverage the plan promised and the evidence the reports hold line up before an authority reads the same rows.
Start with a single asset
Confirm requirements trace through verification.
Jurisdiction-specific considerations
Under FAA practice the matrix indexes to the 14 CFR basis and any issue papers, while an EASA package keys the same coverage to the certification basis and its certification review items. The review checks the matrix against whichever basis governs the project rather than assuming the two authorities read a row the same way.
Regulatory limits
This is an evidence check on the modifier's own matrix. It does not make compliance findings, does not issue or recommend any approval, and does not determine airworthiness. Those determinations remain with the authority and its delegated engineers.
What this review does not cover
- Writing or re-authoring the compliance matrix itself
- Generating the missing test, analysis, or inspection evidence a row lacks
- Any communication with the authority on the modifier's behalf
Specific to this review
- The most common defect is not a missing row but a present row citing evidence that was never produced, which reads as coverage until someone opens the reference.
- Derived requirements are where matrices quietly lose coverage, because they arrive after the basis is set and often never get their own row.
- A citation can be correct on the day it was written and wrong a month later, since a later revision of the same report can drop the exact section the row relied on.
- Matrix and tracker drift apart because closing a row and closing a tracker item are two separate manual steps that different people often perform.
Sources
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. FAA type certification process, certification basis establishment, and compliance findings.
SAE International. Development assurance process at aircraft and system level, including requirements capture and validation.
Frequently asked questions
Do you rewrite the matrix or just report on it?
The review reports. It returns a gap list, an evidence map, and a closure order keyed to your existing rows, so your team keeps ownership of the matrix and edits it from findings it can trace.
Can you review the matrix while some evidence is still open?
Yes. Open rows are expected mid-program. The value is separating rows that are genuinely closed from rows that only look closed, so the open set you carry forward is accurate.
Relevant glossary terms
Related pages
Where this fits
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