13 maintenance and alterations on specific aircraft, engines, and related components.
Second, operators must include their maintenance practices, policies, and procedures, usually found in a General Maintenance Manual (GMM), Maintenance Policies and Procedures Manual, or similar document. Both kinds of information, the product-specific and the operator’s general policies and procedures manuals, are part of the operator’s manual system required by parts 121 and 135. When preparing its maintenance manual, and in accordance with § 43.13(c), the operator may designate the manufacturer’s manuals as its own, develop its own maintenance information (operator-developed maintenance or inspections must be traceable to standards acceptable to the Administrator), or use some combination of the two. However, once its manual is FAA accepted under § 43.13(c), the operator is required to comply with its terms.
15.1.4 Operators may generally change their maintenance manuals in accordance with their procedures without obtaining prior FAA acceptance. These changes, however, must be acceptable to the FAA.
15.2 Section 43.13 Compliance. If an operator is following its maintenance manual under § 43.13(c), the operator will be in compliance with § 43.13(a) and (b). However, if the Administrator notifies an operator that a procedure in its manual is unacceptable under § 43.13(c), the carrier would no longer be authorized to use that procedure or process until the issue is resolved. Many operators have adopted procedures in their maintenance manuals to evaluate proposed changes to existing manufacturers’ service documents. The procedures used for evaluation may be inadequate or in need of revision if they do not provide manual procedures acceptable to the Administrator. An operator’s procedures must ensure that changes (and continue-in-service conditions) result in an airworthy aircraft. These changes (or variations) may involve the use of a different maintenance procedure, such as a temporary repair, an equivalent part substitution, inspection technique, or revising repair or allowable damage limit, including those in an SRM. In some cases, revising a limit results in an aircraft and/or article being approved for return to service without a repair having been performed.
15.3 Manual Changes. Operators typically process changes to their maintenance manual through their engineering organizations or may contract the services of others to process changes on their behalf. This includes documenting the damage, condition, or contemplated action; conducting a technical analysis to determine whether the change would comply with the pertinent airworthiness standards (e.g., parts 25, 33, etc.); and classifying the changed maintenance action or continue-in-service condition, which could include a major or minor repair. If the change is classified as major, the Administrator or designee must approve the technical and substantiating data. (Refer to §§ 121.379 and
135.437.) If the change is classified as minor, an operator should perform and document an engineering analysis in accordance with the procedures in the operator’s maintenance manual, appropriate to the complexity of the situation.
15.4 Contract Maintenance Functions. Some operators may authorize other entities to perform maintenance functions on their behalf in accordance with the operator’s procedures and manuals. These operators must have procedures in their maintenance manuals governing the manner in which these contract functions are carried out, and
14 i nclude appropriate documentation and internal approval. (Refer to §§
121.368 ,
121.369(a)(10), 135.426 , and 135.427(a)(1).)
16 EVALUATING PROPOSED CHANGES TO SERVICE DOCUMENTS.
16.1 General. Before an operator or other person acting on their behalf may change a repair design, limit, or other procedure in an SRM or other service document, the following three requirements must be met. First, the change must be processed in accordance with procedures in the operator’s maintenance manual, and result in methods, techniques, and practices traceable to standards acceptable to the Administrator (refer to §§ 43.13(c),
121.367, and 135.425). Second, the change must be shown to comply with the relevant airworthiness standards and documented. Compliance with these standards will establish that the aircraft and/or article will be returned to its original or properly altered condition in accordance with procedures in the operator’s manual that comply with § 43.13(c).
Third, major repairs or alterations must be done in accordance with technical data approved by the Administrator (refer to §§ 121.379 and 135.437). Any new maintenance process must be documented in the operator’s manual (refer to § 43.13(c)).
16.2 Manual Procedures. The operator’s manual procedures should be sufficiently detailed to allow anyone revising the manual to differentiate between minor editorial changes or substantive changes affecting maintenances practices. Changes to the baseline maintenance practices must be acceptable to the Administrator (refer to § 43.13(c)).
Procedures should also provide for a continuous loop of timely information and communications among the operators, FAA principal inspector (PI), responsible Aircraft Certification Service office, designees, and the manufacturer, as appropriate. The procedures to evaluate proposed changes to content contained in service documents should be included in the operator’s manual and should contain the following elements:
16.2.1 A procedure for ensuring only appropriately qualified and experienced personnel will make the engineering determinations required. Operators with no engineering department should have a process to assure DER services utilized under part 183 are qualified and hold Aircraft Certification Service office authorizations to produce the data.
16.2.2 A procedure for determining whether the proposed change requires FAA approval because it affects an AD, CMR, AL, minimum equipment list (MEL), maintenance program tasks, intervals, etc., and if the change requires FAA approval, procedures for obtaining that approval.
16.2.3 A procedure for determining whether the proposed change is minor or major. If the change would result in a major repair or alteration, procedures to obtain FAA approval of the data supporting the change. (Refer to §§ 121.379 and 135.437.) Operators should have a process written in their manual for this determination.
16.2.4 A procedure for developing technical and substantiating data, which includes the following (also see paragraphs 16.4 through 16.6 below.):
• A documented review to determine if the available technical data is sufficient to proceed with the proposed change.
• A documented process of consulting with the manufacturer, as appropriate. Such consultation brings together the best available knowledge and experience in the areas of design, production changes, and operations to ensure a well-designed repair.
• A procedure for obtaining additional substantiating data, as necessary.
• A procedure for documenting and substantiating compliance with pertinent airworthiness regulations, including citing the specific 14 CFR part(s) for which compliance has been determined. This should be accomplished through tests, analyses, and/or computations appropriate to the complexity of the change being proposed.
Note: In each case, the procedures must identify the airworthiness standards that are applicable to the change and provide for documenting that the change results in an airworthy aircraft.
• A procedure for documenting the substantiation process.
16.2.5 The method of notification/reporting to PIs of changes accomplished, as appropriate.
16.2.6 For other persons performing these functions on behalf of an operator, a method of coordinating with the operator.
16.2.7 A method of retaining the records of each action consistent with the recordkeeping requirements of 14 CFR.
16.3 Evaluating the Proposed Change. When determining whether a contemplated change from an existing service document is minor or major, the focus should be the change’s effect on the capability of the aircraft to remain airworthy after the change. For example, a structural repair performed in accordance with an SRM may call for a specific size fastener, fastener edge margin, finish, corrosion treatment, or similar method, technique, or practice. This may also pertain to a change to data not listed in any SRM or other manufacture data (i.e., a repair developed by a designee or operator engineering staff). In evaluating a proposed change (such as using an oversized fastener or a different finish than specified in the SRM), the analysis should address whether the change (including its effect on the repair and the aircraft configuration) will result in a change to the alteration or repair defined in § 1.1. This is because the FAA only considered the configuration of the aircraft with the repair described in the repair instructions when it previously approved the technical data supporting that repair in the SRM. This evaluation should be made within the scope of the definitions of part 1.
16.4 Showing Compliance With the Relevant Airworthiness Standards. Changes to aircraft maintenance programs shall ensure the aircraft meets the original airworthiness certification or other acceptable standards. Section 43.13(b) specifies these requirements.
Operators must document changes with traceability to new processes. Manual procedures must ensure evaluations consider the effect of changes to aircraft or articles relative to
16 allowable wear and limits. The procedures must consider previous changes (approved or acceptable) during revision of maintenance practices. Taken separately or in combination, each maintenance practice incorporated to an aircraft, cannot compromise the airworthiness. The interrelationships of multiple revisions to methods, techniques, or practices in the program shall be evaluated during each maintenance practice revision.
Failure to assess all maintenance practices (e.g., when the DAH, the FAA, or the designee is unaware of specific configuration), multiple alterations, repairs, or changes in maintenance practices on the same individual aircraft or aircraft fleet may affect the aircraft’s airworthiness. It is the operator’s responsibility to manage aircraft airworthiness configuration control.
Note: Other items to consider are the effects of the change on other requirements such as ALs, ADs, and life-limited parts. The following procedure (see paragraph 16.6 below) will help operators evaluate whether appropriate technical and substantiating data exists to accomplish the proposed change. The nature and extent of the data required to substantiate the change will vary according to the complexity of the change and the other factors described below.
16.5 Initial Assessment.
16.5.1 Description of the Affected Aircraft and/or Article. This description should include, but is not limited to:
• Nomenclature.
• Part number.
• Assembly number.
• Serial number(s), if applicable.
• Make and model of the aircraft and/or article.
• If known or as appropriate: hours or cycles, time-in-service, time since new, time since last maintenance action.
16.5.2 Description of the Discrepancy or Contemplated Change. A complete description of the damage, discrepancy, or change should include, but is not limited to:
• Specific location on the aircraft and/or article.
• Type (e.g., corrosion, limit exceeded, cracks, dents).
• Extent and/or dimensions.
• Associated, hidden, and/or adjacent discrepancies, damage, or alteration(s).
• Previous maintenance action(s) or disposition(s) thereof, or alteration(s) at or adjacent to the affected area(s) or part(s).
• Cause, if known (e.g., environmental, accidental, design).
16.5.3 Review Existing Data. As appropriate, review and document existing information
(e.g., applicable maintenance documents, procedures, or process specifications) to determine whether it applies to the proposed change.
16.5.4 Circumstances in Which Additional Data Are Required. Situations in which further data collection and analysis are required (refer to § 43.13) include, but are not limited to:
• Instances where no methods, techniques, and practices are specified in the applicable service document, or the existing condition is beyond allowable limits or repair tolerances.
• Performing an action in a different manner than prescribed by manufacturers’ service documents.
• Using maintenance or alteration data intended for a specific product, on a like product. In this case, a documented evaluation of product differences may be necessary to determine the degree to which the data is applicable.
• Substitution of materials or processes.
• Identifying that an AD applies to the product in the area of the damage, discrepancy, or contemplated change. This may require an AMOC.
• Discovering that the area of the damage, discrepancy, or contemplated change has been defined as a primary structure or will create a Principal Structural Element (PSE) (refer to § 25.571).
• Identifying that a CMR applies in the area of the damage, discrepancy, or contemplated change.
• Identifying that the aircraft and/or article has an AL. Items identified as having ALs require the responsible Aircraft Certification Service office’s approval to change.
16.6 Data Development.
16.6.1 Technical Qualifications. The operator’s procedures should prescribe the steps for reviewing, approving, and overseeing engineering authorizations, and specifying the minimum qualifications (particularly knowledge of applicable airworthiness standards) for the individuals engaged in these activities. These procedures should identify an individual who is responsible for the process, can delegate final engineering approval authority, and has the following qualifications if requiring the services of a designee:
1. The designee is qualified under part 183 and has the authorizations (codes) to perform the specific engineering function; or
2. The designee has:
• Similar qualifications or meets requirements described in FAA Order 8100.8, Designee Management Handbook;
• A thorough working knowledge of the applicable airworthiness standards of 14 CFR;
• At least 1 year of satisfactory experience in processing engineering work, in direct contact with the FAA for type certification or major repair/alteration approval; and
• At least 8 years of aeronautical experience, which may include the 1 year of processing engineering work described above.
16.6.2 Technical Data. Technical data development is the first part of the process in revising an operator’s manual, in accordance with § 43.13(c). The data needed to substantiate changes to in-service or alternate items to be installed on the aircraft may be derived from manufacturer information or developed by personnel as described in paragraph 16.6.1. In any case, the technical data must support that the condition of the article or product will be at least equal to its original or properly altered condition (with regard to aerodynamic function, structural strength, resistance to vibration and deterioration, and other qualities affecting airworthiness).
16.6.2.1 Assessment. As appropriate to the change being considered, the operator must assess the functions, interactions, environment, and consequence of the aircraft and/or article’s failure. The assessment must determine the extent of analysis and the expertise needed to develop technical data to comply with the airworthiness regulations.
16.6.2.2 This assessment may include, but is not limited to:
• Functional information describing how the aircraft and/or article functions within the assembly, how the assembly functions within the system, and/or how the system functions within the product.
• Operating environment of the product.
• Interaction with other systems and consequences of failure that could be most influenced by the maintenance, disposition, or alteration resulting from the proposed change. Consider the most probable effect on its ability to perform its intended function.
• Effect of the maintenance, alteration, or continued in-service condition on the aircraft’s ability to meet the airworthiness standards specified in its type certification basis, including its operational characteristics or performance.
16.6.2.3 Methods, Techniques, and Practices. After the technical data is developed to support the change, an operator must write the methods, techniques, and practices to implement the change. These methods, techniques, and practices should establish detailed work instructions, inspection criteria (incoming or initial, in-process, and/or final inspections), and a description of or reference to processes and instructions. These methods, techniques, and practices are written to implement the change based on the technical data. For example, processes and instructions could include:
1. Heat-treating, surface treatment, blending, and welding.
2. Consideration of specialized processes on engine hardware, such as, not limited to:
• High-pressure turbine (HPT) blade repair (especially single crystal alloys).
• Low-pressure turbine (LPT) blade repair.
• Subjecting engines and parts thereof to specialized processes
(e.g., acid stripping, ultrasonic cleaning, etc.) outside of the manufacturer’s ICA.
3. Continuous inspection requirements and/or future maintenance action requirements; and
4. Acceptance of condition without further specific maintenance action.
17 RETENTION OF RECORDS. The continued in-service processes of aircraft maintenance in accordance with § 43.13(c) must be documented in an operator’s manual in accordance with §§ 121.135 and 135.21. Because the operator is responsible for the continuing airworthiness of aircraft affected by their changes, it should retain these records for a sufficient period. These records may need to be used as reference material in addressing possible airworthiness concerns related to a repair or alteration.
18 AC FEEDBACK FORM. For your convenience, the AC Feedback Form is the last page of this AC. Note any deficiencies found, clarifications needed, or suggested improvements regarding the contents of this AC on the Feedback Form.
We sley L. Mooty Acting Deputy Executive Director, Flight Standards Service
Appendix A A-1 APPENDIX A. ASSESSING 14 CFR PART 43, § 43.13 APPLICABILITY A.1 The flowchart from the prior version of this advisory circular (AC) was for the purpose of major and minor determinations: repairs, alterations, and continued-in-service conditions.
This AC, as stated in paragraph 1, is about the information in an operator’s manual in accordance with § 43.13(c). Unless otherwise notified by the Administrator, for operators in 14 CFR part 121; part 129, § 129.14(b)(3); and part 135, § 135.411(a)(2) using the special provisions of § 43.13(c), your manual constitutes an acceptable means of compliance with § 43.13.
A.2 With this revision, we are clarifying that changes to FAA-approved data, in the case of major repairs or alterations, renders that data no longer FAA-approved, regardless of the nature of that data change. If using approved data for minor repairs or alterations, changing of the data does not require FAA approval.
Appendix A Is § 43.13(c) Applicable?
Start Are you a part 121, No- 129, or 135 operator holding OpSpecs?
Are Refer to you required Part 121 Subpart L
•NO by OpSpecs to and §§ 129.14(b)(3) provide a and 135.411(a)(2) CAMP?
Yes Section 43.13(c) is not applicable;
you must follow Section 43.13(c) applies. Compliance with § 43.13(a) and (b) § 43.13(a) and (b) is achieved by following the procedures specified in your manual.
When not otherwise restricted (e.g., § 43.16), your manual procedures may be derived from Original Equipment Manufacturer (OEM) manuals and instructions for End continued airworthiness (ICA) and further revised according to the procedures specified in your manual. All revisions must be appropriately substantiated. Your revisions to FAA-approved data must be approved by the FAA prior to the aircraft's return to service when FAA-approved data is required.
End Applicability A-2
Appendix A Manual Content in Support § 43.13(c) Operator's manual required by §§ 121.133 and 135.21 (refer to AC 120-16) Instructions for the Technical Data that Administration, Describe Maintenance Administrative Policies Management, and Standards, Methods, and Procedures Accomplishment of the Techniques, and (refer to AC 120-16) Maintenance Program? Procedures (refer to AC 120-16) (refer to AC 120-16) Procedures within this portion of the manual will prescribe...
...how to revise.
...content in this manual I Separate sections are typical but not required. The operator's manual should include all information indicated above.
Under the provisions of § 43.13(c) and requirements of §§ 121.135 and 135.23, you must:
1. Describe this process in your manual, and
2. Follow the process when making revisions.
Doing so constitutes an acceptable means of compliance with § 43.13.
A-3
Appendix A Applying § 43.13(a) Start From Substantiation Is work performed as specified in OEM manual or -No- ICA, or other acceptable methods, techniques, and practices?
Yes Is all maintenance, alterations, or preventive maintenance performed using -No- tools, equipment, and test apparatus in accordance with accepted industry practices?
Yes Tooling, special equipment, or No- test apparatus used as recommended by the OEM or equivalent?
Yes Go to Go to § 43.13(b) Substantiation A-4
Appendix A Applying § 43.13(b) From § 43.13(a) Work performed and materials used as specified -No- in OEM manual or ICA, or other acceptable methods, techniques, and practices?
Y Yes You must consider will work performed aerodynamic function, and materials used structural strength, No- resistance to vibration be at least equal to its original or properly altered and deterioration, and other qualities affecting condition?
airworthiness Yes Revise your manual according to established procedures End Go to Substantiation A-5