STC continued airworthiness
STC program instructions for continued airworthiness support
This review prepares the Instructions for Continued Airworthiness that ship with an STC so they cover the configuration the modification actually introduces. A certification engineer runs it before submittal, once the maintenance tasks, limitations, and parts data are drafted. It reads the ICA against the approved design change, checking that every added or altered item has the maintenance, airworthiness limitations, and parts coverage an operator will need. You get a gap assessment, a trace map from the modification to its ICA coverage, and a closure plan for the instructions that lag the design.
When this review is needed
- A modification adds equipment or structure and the ICA has to give operators the tasks and limitations to maintain it.
- The design changed during the program and the ICA drafted against an earlier configuration has to catch up.
- The safety assessment produced airworthiness limitations that have to appear correctly in the ICA.
- The STC will be installed across an operator fleet and the ICA has to integrate with existing maintenance programs.
The problem
The ICA is the part of an STC an operator actually lives with after the modification is installed, and it is often drafted last, against a design that kept moving. A maintenance task that references a part the design revised, or an airworthiness limitation from the safety assessment that never made it into the limitations section, leaves the operator without the instructions the modification depends on. Because the ICA trails the design, it is where the package most often falls out of step with what was approved.
What gets reviewed
- Maintenance tasks covering the equipment and structure the modification introduces
- Airworthiness limitations carried correctly from the safety assessment into the ICA
- Parts data, including illustrated parts and interchangeability, for the added configuration
- Servicing, inspection, and troubleshooting coverage for the modified systems
- Integration points with the existing maintenance program the ICA supplements
- The ICA revision state against the approved design change
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
- Every item the modification adds or alters has a corresponding maintenance task or a rationale for none
- Airworthiness limitations from the safety assessment appear in the ICA limitations section
- Parts referenced in the ICA match the approved configuration's part numbers and revisions
- Inspection intervals and tasks are consistent with the certification basis and safety conclusions
- The ICA reflects the current approved design change, not an earlier drafting baseline
Evidence normally required
- The approved design change and its configuration definition
- The draft ICA, including maintenance tasks and the limitations section
- The airworthiness limitations derived from the safety assessment
- The parts data and illustrated parts information for the modification
- The existing maintenance program the ICA has to supplement
Common discrepancies
- A maintenance task referencing a part number the design revised after drafting
- An airworthiness limitation from the safety assessment missing from the ICA
- Added equipment with no servicing or inspection coverage in the instructions
- ICA revision state that trails the current approved configuration
What is at stake
ICA that lag the approved configuration leave operators maintaining a modification against instructions that do not match it, which surfaces at the first maintenance event and can ground the aircraft until the discrepancy is resolved. An airworthiness limitation omitted from the ICA is a compliance gap that follows the STC into every installation. Correcting the ICA after approval means revising an approved document across a fleet, which is slower than getting it right before submittal.
How the work runs
Map the modification
List everything the approved design change adds or alters that an operator will maintain.
Check task and parts coverage
Confirm each item has a maintenance task and correct parts data against the current configuration.
Verify the limitations
Trace airworthiness limitations from the safety assessment into the ICA limitations section.
Close the lag
Plan the ICA revisions that bring the instructions up to the approved design.
What the buyer receives
Who uses the output
- Certification engineers confirming the ICA cover the approved configuration
- Continued-airworthiness staff who will maintain the modification in service
- Program managers reconciling the ICA to a design that changed late
How the work fits into the transaction or program
The ICA is where the certification work becomes something an operator can maintain, so it has to catch up to the final approved configuration before submittal. This review reconciles the instructions to the design and the safety limitations, so the modification arrives in service with maintenance data that matches what was approved rather than an earlier draft.
Start with a single asset
Reduce finding cycles by checking the package first.
Jurisdiction-specific considerations
FAA and EASA both require ICA with an STC and both treat airworthiness limitations as approved data, so where the STC is validated across both, the review notes where the limitations section and task coverage have to satisfy a second authority's expectations.
Regulatory limits
The review confirms the ICA cover the approved configuration and carry the required limitations. It does not approve the ICA, set airworthiness limitations on an authority's behalf, sign a compliance finding, or determine that the maintenance program is adequate.
What this review does not cover
- Authoring the maintenance program the ICA supplements
- Setting airworthiness limitations on the authority's behalf
- Approving the ICA or signing the compliance finding that carries the STC
Specific to this review
- The ICA is usually drafted last against a design that kept changing, so it is the package's most common point of lag with the approved configuration.
- An airworthiness limitation dropped between the safety assessment and the ICA limitations section is a compliance gap that follows the STC into every installation.
- Correcting an ICA after approval means revising approved data across every aircraft the STC touched, which is far slower than reconciling it before submittal.
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.
RTCA. Environmental qualification test categories and procedures referenced by TSO and equipment qualification.
Frequently asked questions
Why is the ICA reviewed separately from the rest of the STC data?
The ICA is drafted against the design but has to reflect its final approved state, and because it is usually completed last it drifts from late changes more than any other artifact. Reviewing it on its own catches the tasks, parts, and limitations that fell out of step, before the modification reaches an operator relying on them.
Relevant glossary terms
Related pages
Where this fits
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