• Airworthiness inspections, including instructions covering procedures, standards, responsibilities, and authority of inspection personnel.
15.1.2 Additional maintenance manual requirements are in 14 CFR §§ 121.367, 121.369,
135.425, and 135.427. These rules also require the operator to follow its manual when performing maintenance, preventive maintenance, and alterations. Operators must substantiate and incorporate changes to methods, techniques, or practices into their maintenance program, as required in 14 CFR § 43.13. A maintenance manual generally includes two basic kinds of information:
1. The first is product-specific and consists of the methods, techniques, and practices for performing maintenance and alterations on specific aircraft, engines, and related components.
2. The 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.
15.1.3 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 14 CFR parts 121 and 135. When preparing its maintenance manual, and in accordance with 14 CFR § 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 14 CFR § 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. However, the manuals must be updated (refer to 14 CFR §§ 121.133 and 135.21) and these changes must be acceptable to the FAA as outlined in 14 CFR § 43.13 prior to returning an aircraft to service.
15.2 Section 43.13 Compliance. If an operator is following its maintenance manual under 14 CFR § 43.13(c), the operator will be in compliance with 14 CFR § 43.13(a) and (b).
However, if the Administrator notifies an operator that a procedure in its manual is unacceptable under 14 CFR § 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 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., 14 CFR 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 14 CFR §§ 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 include appropriate documentation and internal approval (refer to 14 CFR §§ 121.368,
121.369(b)(10), 135.426, and 135.427(b)(10)).
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:
1. 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 14 CFR §§ 43.13(c), 121.367, and 135.425).
2. Second, the change must be shown to comply with the relevant airworthiness standards and documented. Compliance with these standards will establish that the aircraft or article will be returned to its original or properly altered condition in accordance with procedures in the operator’s manual that comply with 14 CFR § 43.13(c).
3. Third, major repairs or alterations must be done in accordance with technical data approved by the Administrator (refer to 14 CFR §§ 121.379 and 135.437). Any new maintenance process must be documented in the operator’s manual (refer to 14 CFR § 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 14 CFR § 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
15 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.
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 14 CFR §§ 121.379 and 135.437). Operators should have a process written in their manual for this determination. AC 43-210 and Order 8300.16 address major repair and alteration data; however, the AC and order may not be all inclusive and cover everything that can be a major repair or alteration.
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 in manual procedures per paragraph 16.2.
• 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 change to manual procedures per paragraph 16.2.
• 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, or computations appropriate to the complexity of the change being proposed.
Note: In each case, the manual procedures must identify the airworthiness standards that are applicable to the change and provide for documenting that the change results in an airworthy aircraft as required in 14 CFR §§ 21.31 and 43.13.
• A procedure for documenting the substantiation process.
16.2.5 The method of notification or 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 manufacturer 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 14 CFR § 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 14 CFR part 1. The FAA allows minor deviations from approved data. A deviation or minor change from approved data must be such that the condition of the aircraft, airframe, aircraft engine, propeller, or appliance worked on will at least equal to its original or properly altered condition (refer to 14 CFR § 43.13(b)).
16.4 Showing Compliance With the Relevant Airworthiness Standards. Changes to aircraft maintenance programs shall ensure the aircraft meets the original airworthiness certification or would be at least equal to its original or properly altered condition.
Title 14 CFR § 43.13(b) specifies these requirements. Operators must document changes in the manual with traceability to new processes. Manual procedures must ensure evaluations consider the effect of changes to aircraft or articles relative to 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 (refer to 14 CFR §§ 121.363, 121.369, 121.373, 135.413, 135.427, and 135.431). 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 or Article. This description should include, but is not limited to:
• Nomenclature.
• Part number.
• Assembly number.
• Serial number(s), if applicable.
• Make and model (M/M) of the aircraft 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 or article.
• Type (e.g., corrosion, limit exceeded, cracks, dents).
• Extent or dimensions.
• Associated, hidden, 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 14 CFR § 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 14 CFR § 25.571 and AC 25.571-1).
• Identifying that a CMR applies in the area of the damage, discrepancy, or contemplated change.
• Identifying that the aircraft 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.
16.6.2 Technical Data. Technical data development is the first part of the process in revising an operator’s manual, in accordance with 14 CFR § 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 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. This assessment may include, but is not limited to:
• Functional information describing how the aircraft or article functions within the assembly, how the assembly functions within the system, 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.
16.6.2.2 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, 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 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 14 CFR § 43.13(c) must be documented in an operator’s manual in accordance with 14 CFR §§ 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.
L eisha Bell for Hugh J. Thomas Executive Director, Flight Standards Service
Appendix A A-1 APPENDIX A. ASSESSING 14 CFR § 43.13 APPLICABILITY A.1 The flowchart from the original 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 14 CFR § 43.13(c). Unless otherwise notified by the Administrator, for operators in 14 CFR part 121 and §§ 129.14(b)(3) and 135.411(a)(2) using the special provisions of 14 CFR § 43.13(c), your manual constitutes an acceptable means of compliance with 14 CFR § 43.13.
Appendix A Is 14 CER § 43.13(c) Applicable?
Start -No or 135 operator holding OpSpecs? Are you a 14 CFR part 121, 129, Referto 14 CFR Are you required by OpSpecs part 121 subpart L to provide a CAMP? and §§ 129.14(b)(3) and 135.411(a)(2) Title 14 CFR § 43.13(c) is not applicable;
you must follow 14 CFR § 43.13(a) and (b) Title 14 CFR § 43.13(c) applies. Compliance with 14 CFR § 43.13(a) and (b) is achieved by following the procedures specified in your manual. When not otherwise restricted (e.g., 14 CFR § 43.16), End your manual procedures may be derived from Original Equipment Manufacturer (OEM) manuals and 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 14 CFR § 43.13(c) Operator's manual required by 14 CFR §§ 121. 133 and 135.21 (refer to AC 120-16) Instructions for the Technical Data that Administration, Describe Maintenance Administrative Policies and Procedures Accomplishment of the Management, and Standards, Methods, 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 ' Separate sections are typical but not required. The operator's manual should include all information indicated above.
Under the provisions of 14 CFR § 43.13(c) and requirements of 14 CFR §§ 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 14 CFR § 43.13.
A-3
Appendix A Applying 14 CFR § 43.13(a) Start From Substantiation Is work performed as specified in OEM No manual or ICA, or other acceptable methods, techniques, and practices?
Is all maintenance, alterations, or preventive maintenance performed using No tools, equipment, and test apparatus in accordance with accepted industry practices?
Tooling, special equipment, or test apparatus used as recommended by the OEM or equivalent?
Yes Go to 14 CFR Go to § 43.13(b) Substantiation A-4
Appendix A Applying 14 CFR § 43.13(b) From 14 CFR § 43.13(a) Work performed and materials used as No specified in OEM manual or ICA, or other acceptable methods, techniques, and practices?
You must consider Will work performed aerodynamic function, and materials used structural strength, NO be at least equal to its original resistance to vibration and deterioration, and or properly altered condition? other qualities affecting airworthiness res Revise your manual according to established procedures End Go to Substantiation A-5