Explainer
ICA for STC Holders: What the FAA Expects
The Order
Guidance Written for the Reviewer
The duty itself is short. 14 CFR 21.50(b) applies to the holder of a design approval, “including either a type certificate or supplemental type certificate,” where application was made after 28 January 1981. The holder must furnish at least one complete set of instructions for continued airworthiness (ICA) to the owner at delivery or at the first standard airworthiness certificate for the affected aircraft, whichever is later, and must make the instructions and every change to them available to anyone required to comply with them. For the general picture, see our explainer on instructions for continued airworthiness.
What the rule does not say is how the FAA decides that an STC's ICA are acceptable. That is the job of FAA Order 8110.54A, “Instructions for Continued Airworthiness Responsibilities, Requirements, and Contents.” It was signed on 23 October 2010, replaced the 2005 order of the same number, and is listed by the FAA as Active. It is written for the Aircraft Certification Service and Flight Standards staff who review ICA, and it describes itself as supplementing 21.50(b), the 1529-series sections of Parts 23, 25, 27, and 29, and their appendixes. It is not a regulation, but it is the clearest statement of what a reviewer has been told to expect from an STC applicant.
One point from the Order is worth knowing before you start. An STC on an older aircraft still owes ICA for what it changes, “even though it was not required by the original certification basis.” The FAA looks at the date of the application for the design approval, not the age of the aircraft.
Scope
Cover What the Change Touches
An STC does not have to rewrite the aircraft's maintenance data. Order 8110.54A says ICA for a new or amended STC “should cover only the items changed or affected by the design change,” and that ICA limited to the affected change are considered complete under 21.50(b). Its own example is a GPS installation: it does not need to address the engine, but the submitted ICA must include all applicable items from the regulations for the installation, appropriate information about the antenna and its installation, and, if the GPS is critical to operations, requirements for periodic performance checks.
Note the word affected. The Order says the scope includes other systems, parts, or areas of the aircraft, so an installation that adds electrical load, changes a structural area, or alters a procedure elsewhere pulls those items into the ICA too. Your engineering change list is the starting point; the maintenance consequences of that list are the real scope.
Layering is the other issue. The Order recognizes that ICA from separate STCs, PMA parts, and major alterations can pile up on one aircraft, so a maintainer has to research which data applies to a given configuration. It asks each applicant to assess the existing ICA and then either propose supplementary instructions or state that the existing ones remain adequate. For how the receiving side copes, see our guide to small-fleet technical publications.
No Change to ICA
The Impact Assessment Route
Some design changes do not alter the maintenance picture at all. For an STC, the Order allows the applicant to submit an impact assessment to the aircraft certification office (ACO). The assessment has to show that the project “does not change any information, procedures, process, requirements, or limitations in the current ICA or maintenance documentation.” The original design approval holder's ICA then still apply. After the assessment, the applicant submits either recommended changes or a statement that the existing ICA apply.
The FAA records the outcome. Where an impact assessment shows no change, the Order tells the ACO to put a statement on the design approval document, and for an STC recommends placing it below the Limitations and Conditions section, so the record shows the FAA reviewed the assessment and found no additional changes needed.
Two cautions follow from the Order. First, the assessment depends on the documents it was checked against. A holder that writes supplementary ICA is responsible for keeping them applicable if the ICA they were based on change, and the Order gives two ways to do that: specify the documents and revision levels the assessment is based on, or keep monitoring them and issue revised supplements as needed. Second, the Order says ICA submitted for an approval must carry the Airworthiness Limitations section statement from the applicable regulations even when the design approval does not affect that section, to document that the section was reviewed. Our explainer on the Airworthiness Limitations section covers what that statement is and why it is binding.
Review
What a Reviewer Looks For
The ACO approves the Airworthiness Limitations section and decides whether the rest of the ICA is acceptable, with concurrence from an aircraft evaluation group (AEG) on the maintenance content. The Order tells ACOs to warn applicants early that review can take up to 30 calendar days from a complete submission, including reference documents, and tells the AEG inspector to send written concurrence within 30 calendar days of receiving the ICA. Treat that as a planning input, not a promise, and leave room for a round of comments.
Several expectations in the Order are easy to miss on a first STC:
- Product-specific data. ICA “must be specific to the product, not general.” The Order says applicants often lean on standard practices or on the FAA's general inspection and repair advisory material, which it calls acceptable only where no manufacturer instructions exist. A standard practices manual can support a task but is not acceptable as the complete set.
- An early document list. The applicant should list the documents that will make up the complete set as early as practical and submit it for FAA concurrence, along with the program for distributing changes.
- Agreed format and media. Applicants should propose the format or standard and the media before developing ICA. The Order points to ATA iSpec 2200, GAMA Specification No. 2, and S1000D as sample formats. Manuals must be in English and have a way of recording updates, such as a list of effective pages and a record of revisions.
- A principal manual. With more than one document, one describes the others and how to use them, and is the one used for day-to-day maintenance. The Airworthiness Limitations section goes there.
- Judgment beyond the checklist. The Order supplies checklists in appendixes A to G and says they are not all-inclusive; reviewers are told to use their best judgment when deciding whether an ICA is complete.
Some FAA reviews are delegated. The Order notes that a designee or delegated organization may not be able to accept every aspect of added or changed ICA, in which case the ACO, and possibly the AEG, must become involved.
Content Standard
Which Appendix Sets the Contents
The Order does not replace the content rule for your aircraft. Each certification part points ICA at its own appendix, and the STC's ICA are judged against the one that applies:
- Part 23 airplanes: Appendix A
- Section A23.4 sets out the Airworthiness Limitations section and its prominent FAA-approval statement. Level 4 airplanes carry some extra items, such as electrical loads and special repair methods.
- Part 25 airplanes: Appendix H
- H25.1 to H25.5: general, format, content, the Airworthiness Limitations section, and EWIS instructions.
- Part 27 and Part 29 rotorcraft: Appendix A to each part
- The same shape: general, format, content, and an Airworthiness Limitations section (A27.4 and A29.4).
The appendixes share a structure. Section 1 of each says the ICA for an aircraft must include those for each engine and propeller or rotor, each required appliance, and the interface information for them, and that if a supplier provides none, the aircraft's ICA must carry the information essential to continued airworthiness. It also requires the applicant to submit to the FAA a program showing how changes to the ICA, made by the applicant or by manufacturers of installed products and appliances, will be distributed. For a transport airplane's full list of contents, see the general ICA explainer.
When ICA Are Not Ready
The Incomplete-ICA Statement
Sections 23.1529, 25.1529, 27.1529, and 29.1529 all allow ICA to be incomplete at certification if a program exists to complete them before the first airplane or rotorcraft is delivered or receives a standard certificate of airworthiness, whichever is later. Order 8110.54A tells the ACO how to handle that for a design approval, an STC included.
The default is that the FAA should not normally issue the approval before it has concurred with the ICA or the assessment. If it must, the ACO approves a completion program that has at least a list of every part of the ICA affected or required by the change, a detailed schedule for completing and submitting them, and a memo to the right office that a standard airworthiness certificate cannot be issued. It also adds a statement to the type certificate data sheet or the STC's Limitations section:
“Instructions for Continued Airworthiness are incomplete. The aircraft will be eligible for return to service when the ICA is complete and accepted.”
The practical meaning, in the Order's words, is that “an aircraft can be modified, but cannot return to service until we accept the complete ICA.” Once the FAA accepts them, the statement can come off. For an STC the responsible Flight Standards office is told that return to service is delayed until the ICA are complete. A customer who has paid for an installation will care about that date, so the schedule in the program is a commitment worth planning around.
After Approval
Changes, Distribution, and Who Gets Them
The duty continues after the certificate is issued. The Order tells the ACO, with AEG concurrence, to review the applicant's program for distributing the first release and later changes, including the media and how soon after a change it will go out. Changes may go to owners on paper, in electronic form, or through web access, and web access also needs a way to tell owners on record that a change is available. Whatever the method, the owner can ask for a paper copy, and the holder must furnish it.
Revisions that do not come with a new design approval, such as those driven by service bulletins or by errors found in operation, follow a second program. The holder submits them to the FAA for review while sending them to owners, so that accurate ICA are available at once. The exception is the Airworthiness Limitations section and certification maintenance requirements: changes to those must be FAA-approved before they are distributed. Our piece on keeping service bulletins and revisions current covers the same problem from the user's side.
Beyond owners, 21.50(b) requires the holder to make ICA available to any other person required to comply with them. The Order narrows when that is enforced: the requester must be a repair station or operating certificate holder currently rated for the product and required by the regulations to comply with the ICA, or an individual working for the owner or operator under a Part 65 mechanic certificate. A person who qualifies is also entitled to the changes. The Order also says the intent was to let owners and operators manage their own maintenance, not to give anyone entering the repair business a right to repair manuals. Read the rule and the Order text for your own position.
Checklist
Preparing STC ICA, in Order
A working sequence drawn from the Order and the rule. It is not a substitute for the Order text or for your certification office's direction on your project.
- Find the baseline. List the manuals and revisions that already cover the aircraft you are changing, because everything you write is measured against them.
- Map what the change touches. Include other systems, parts, or areas affected by the change, not only the new equipment.
- Decide between a supplement and a statement. If the baseline ICA still holds, prepare the impact assessment. If not, write supplementary instructions for the differences.
- Make it specific to the product. A pointer to general practices is not enough on its own.
- Address the Airworthiness Limitations section, even if the answer is that nothing in it changes.
- Agree the format and media with the FAA early, and name the principal manual if there is more than one document.
- Write the change-distribution program: media, who receives changes, and how soon.
- Record the baseline revisions your assessment relied on, and decide how you will notice when they change.
For where ICA sit among the other manuals an aircraft carries, see what an aircraft maintenance manual is. For the sample formats the Order mentions, see ATA iSpec 2200 and S1000D.
FAQ
Questions We Hear
Does an STC need instructions for continued airworthiness?
Yes, where application was made after 28 January 1981. 14 CFR 21.50(b) puts the duty on the holder of a design approval, "including either a type certificate or supplemental type certificate," and Order 8110.54A says the date of application decides it, not the original certification basis. An STC on an older aircraft still needs ICA for the areas it changes. That can be a short supplement, or a documented finding that the existing ICA still apply.
How much of the aircraft do STC ICA have to cover?
Order 8110.54A says ICA for a new or changed STC "should cover only the items changed or affected by the design change," and that ICA covering only the affected change are complete under 21.50(b). Its example is a GPS installation, which does not need to address the engine but does need the antenna and its installation and, if the GPS is critical to operations, periodic performance checks. "Affected" can reach other systems, parts, or areas of the aircraft.
What is an ICA impact assessment?
It is the applicant's written finding that the design change does not alter any information, procedures, process, requirements, or limitations in the current ICA or maintenance documentation. Order 8110.54A lets an STC applicant submit it to the certification office, along with either recommended changes or a statement that the existing ICA apply. For an STC, the Order recommends the FAA place a statement below the Limitations and Conditions section showing it reviewed the assessment.
What does "Instructions for Continued Airworthiness are incomplete" on an STC mean?
Order 8110.54A says the FAA should not normally issue a design approval before it has concurred with the ICA or the assessment. If it must, it approves a completion program: a list of the ICA parts affected, a detailed schedule, and a statement in the certificate data sheet or the STC's Limitations section reading "Instructions for Continued Airworthiness are incomplete. The aircraft will be eligible for return to service when the ICA is complete and accepted." The aircraft can be modified but cannot return to service until the complete ICA are accepted.
Is Order 8110.54A a regulation?
No. It is FAA guidance written for the staff who review ICA, in the Aircraft Certification Service and Flight Standards, and it says it supplements 14 CFR 21.50(b) and the 23.1529, 25.1529, 27.1529, 29.1529, 31.82, 33.4, and 35.4 rules and their appendixes. The FAA's orders index lists it as Active, issued 23 October 2010. It shows how reviewers are told to judge a submission, so it is a good guide to what to expect, but your project's certification basis and your certification office govern what you actually have to do.
Who has to receive an STC holder's ICA and later changes?
21.50(b) requires one complete set to the aircraft owner at delivery or at the first standard airworthiness certificate for the affected aircraft, whichever is later, and availability of the instructions and every change to anyone required by the regulations to comply with them. Order 8110.54A adds that the owner can always ask for paper, and that a repair station rated for the product, or a mechanic working for the owner under a Part 65 certificate, can be entitled to the ICA and its changes. Read the rule and your contract for the details that apply to you.
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