AML STC expansion
Means-of-compliance mapping for an AML STC model-list expansion
This work builds the means-of-compliance map that ties every requirement in the certification basis to the method chosen to show compliance and the evidence that carries it. It supports equipment and avionics suppliers adding aircraft models to an existing approved model list, and runs before the expansion package reaches the authority. The map is checked line by line so that a stated means always has a real evidence path behind it, not an intention. You get a gap assessment, an evidence-linked compliance map, and a closure plan the STC holder can work through ahead of formal review.
When this review is needed
- New aircraft models are being added to an approved model list and each requirement needs a stated means confirmed against real evidence.
- The original compliance approach was written for the launch model and has to be re-justified for a different installation environment.
- An authority has asked how compliance is shown for the added effectivity and the answer must resolve to documents.
- Program management wants the compliance method fixed before verification effort is spent chasing the wrong evidence.
The problem
A means-of-compliance map inherited from the original STC reads as complete until you test each row against the expanded effectivity. Requirements that were satisfied by similarity on the launch model may need fresh test or analysis on a new airframe, and a method stated in a column does not prove the evidence exists. Suppliers often discover mid-review that a means was assigned but never actually produced the document it points to.
What gets reviewed
- Every certification-basis requirement for the added models mapped to a specific means of compliance
- The evidence artifact behind each stated means identified and confirmed to exist
- Requirements satisfied by similarity re-examined against the new installation environment
- Means that changed between the original model and the added effectivity flagged and re-justified
- The compliance map reconciled to the certification basis so no requirement is left without a method
- Open rows sequenced into a closure plan the STC holder can execute before submission
Scope this review
Tell us the asset, the event, and the evidence in scope, and we will outline a focused first engagement.
Identify what is missing against the means of compliance.
What gets validated
- Each requirement carries a means of compliance that is appropriate to the requirement and the added effectivity
- Every stated means resolves to a named evidence artifact rather than an intention to produce one
- Compliance-by-similarity claims hold for the new installation and not merely for the launch model
- The map covers the full certification basis with no requirement left unmapped
- Changed means between original and expanded effectivity are re-justified and traceable
Evidence normally required
- The certification basis and applicable special conditions for the added models
- The existing means-of-compliance map from the original AML STC
- The compliance checklist and any prior authority correspondence on method
- Test, analysis, and similarity evidence held for the launch model
- The installation description and environment for each added aircraft model
Common discrepancies
- A requirement mapped to compliance by similarity that no longer holds on the added airframe
- A stated means pointing to a report that was planned but never issued
- Requirements introduced by the added effectivity that the inherited map never addressed
- A method column filled in without the certification basis reference that would justify it
What is at stake
A compliance map with a stated method and no evidence behind it stalls formal review the moment a reviewer follows the row to its source. Each unbacked means becomes a finding, and findings raised late cost far more to close than the same gap caught while the package is still in the supplier's hands. The expansion slips, and the aircraft models waiting on it stay off the approval.
How the work runs
Pull the basis and the inherited map
Assemble the certification basis for the added models and the means-of-compliance map from the original STC.
Test each means against the expansion
Confirm every stated method still holds for the added effectivity, with similarity claims checked against the new installation.
Trace method to evidence
Follow each row to its named artifact and flag any means with no real evidence path.
Sequence the closure
Build a plan that clears the open rows before the package moves into formal review.
What the buyer receives
- A gap assessment listing each requirement whose means or evidence is missing or weak
- An evidence-linked means-of-compliance map covering the full expanded effectivity
- A closure plan sequencing the open rows before the package enters formal review
Who uses the output
- STC holders confirming the compliance approach is defensible before they submit
- Certification leadership deciding where fresh test or analysis is unavoidable
- Program managers scoping the remaining compliance work against the schedule
How the work fits into the transaction or program
The map is the spine the rest of the expansion package hangs from. It sets which requirements need fresh evidence and which carry over, so it runs ahead of the requirements trace, the verification evidence, and every qualification report. Everything downstream reconciles back to the method fixed here.
Start with a single asset
Reduce finding cycles by checking the package first.
Jurisdiction-specific considerations
An AML STC accepted by the FAA and validated toward EASA can face different expectations on how a means of compliance is stated and substantiated. The map notes where a method that satisfies one authority may need additional justification for the other, so the same expansion does not have to be reworked twice.
Regulatory limits
This work builds and checks the compliance map. It does not select an acceptable means on the authority's behalf, make a compliance finding, or grant any approval. Those decisions rest with the authority reviewing the expansion.
What this review does not cover
- Producing the underlying test or analysis evidence a stated means depends on
- Making the formal compliance finding for any requirement
- Negotiating the certification basis or special conditions with the authority
Specific to this review
- A means-of-compliance map fails most often at the similarity rows, because a claim true for the launch model quietly breaks on a different airframe.
- The map is where an expansion's real cost becomes visible: it exposes which carried-over methods still need fresh test or analysis.
- A stated means with no evidence behind it is worse than an empty row, because it hides the gap until a reviewer follows the trail.
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. 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.
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
Can we reuse the original STC's compliance map for the new models?
Parts of it, but not wholesale. The map has to be re-tested against the added effectivity: requirements satisfied by similarity on the launch model may need fresh test or analysis on a different airframe, and any requirement introduced by the new installation was never in the original map. We confirm each row before it carries forward.
Relevant glossary terms
Related pages
Where this fits
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