U.S. Department of Transportation Federal Aviation Administration Advisory Circular Subject: Alternative Methods of Compliance Date: 09/14/16 Initiated By: AIR-140 AC No: 39-10
This advisory circular (AC) presents guidance for persons seeking approval of an alternative method of compliance (AMOC) to an airworthiness directive (AD). This AC also provides answers to common questions regarding AMOCs.
If you have any suggestions for improvements or changes, you may use the template provided at the end of this AC.
Richard E. Jennings Acting Manager, Design, Manufacturing, & Airworthiness Division Aircraft Certification Service
CONTENTS Paragraph Page i
Chapter 1. General Information1-1
Purpose. ......................................................................................................................... 1-1 1.1 Audience. ...................................................................................................................... 1-1 1.2 Effective Date. .............................................................................................................. 1-1 1.3 Background. .................................................................................................................. 1-1 1.4 Definitions..................................................................................................................... 1-1 1.5 Discussion. .................................................................................................................... 1-2 1.6
Chapter 2. When an AMOC Is Necessary2-1
General. ......................................................................................................................... 2-1 2.1 AD-Mandated Instructions............................................................................................ 2-1 2.2 Frequently Asked Questions From AMOC Requesters. ............................................... 2-1 2.3
Chapter 3. The AMOC Proposal3-1
General. ......................................................................................................................... 3-1 3.1 Requirements for an AMOC Proposal. ......................................................................... 3-1 3.2 Who Approves an AMOC? ........................................................................................... 3-2 3.3 Where to Submit. .......................................................................................................... 3-3 3.4 AMOC Submittal Methods. .......................................................................................... 3-3 3.5 The AMOC Response. .................................................................................................. 3-3 3.6
Chapter 4. Other AMOC Considerations4-1
General. ......................................................................................................................... 4-1 4.1 Global AMOCs (AMOCs of General Applicability). ................................................... 4-1 4.2 Returning Aircraft to Service. ....................................................................................... 4-2 4.3 Revoking an AMOC. .................................................................................................... 4-3 4.4 Foreign Registered Aircraft. ......................................................................................... 4-3 4.5 Military Commercial Derivative Aircraft. .................................................................... 4-4 4.6 24/7 AMOC Support. .................................................................................................... 4-4 4.7 Sharing AMOCs with Design Approval Holders. ........................................................ 4-4 4.8 AMOCs for Appliances Including TSO-Approved Articles. ....................................... 4-4 4.9 AMOCs for Rotable or Unserialized Parts. .................................................................. 4-5 4.10
CONTENTS Paragraph Page ii Previously Approved AMOCs. ..................................................................................... 4-5 4.11
Appendix A LIST of AcronymsA-1
Appendix B Related FAA PublicationsB-1
Appendix C Advisory Circular Feedback InformationC-1
1-1 CHAPTER 1. GENERAL INFORMATION
1.1 Purpose.
1.1.1 This advisory circular (AC) provides the following information:
1.1.1.1 Guidance for persons seeking approval of an alternative method of compliance (AMOC) to an airworthiness directive (AD).
1.1.1.2 Answers to common questions, such as when an AMOC is necessary, changes that may require an AMOC, and how to document AMOC approval after completion.
1.1.2 This guidance is derived from Federal Aviation Administration (FAA) and industry experience with AMOCs. Although it is not mandatory, implementation of any or all aspects of this AC will enhance the AMOC process, facilitate continued compliance with an AD, and reduce the potential for delays caused by incomplete AMOC proposals.
1.2 Audience.
This AC is for anyone who wishes to propose an AMOC to the FAA. The AC is also for owners/operators who choose to comply with an AMOC.
1.3 Effective Date.
The effective date for this AC is XX/XX/XX.
1.4 Background.
In August 2002, the FAA added amendment 39-9474 to Title 14 of the Code of Federal Regulations (14 CFR) part 39. The amendment incorporated several standard provisions previously included in individual ADs. One standard provision specified that an AD applies to a product even if the product had been modified, altered, or repaired in the area addressed by the AD. Another standard provision identified procedures for asking the FAA to approve AMOCs to an AD.
1.5 Definitions.
For the purposes of this AC, the following definitions are used:
1.5.1 Airworthiness Directive.
A final rule of the following types of rulemaking documents issued by the FAA pursuant to part 39, including supersedures and corrections to those documents:
Final rule after notice of proposed rulemaking (NPRM) or supplemental NRPM (SNPRM);
1-2 Final rule, request for comments (commonly referred to as an Immediately Adopted Rule (IAR), No-Notice Final Rule (NFR), or Federal Register Version of an Emergency AD (FRV)); or Emergency AD.
1.5.2 Alternative Method of Compliance.
An AD contains the required method for resolving an unsafe condition in an aircraft, aircraft engine, propeller, or appliance. An AMOC provides an acceptable level of safety for a different method, other than the one specified in the AD, to address the unsafe condition.
1.5.3 Change in Compliance Time.
As authorized by § 39.19, anyone may propose a change to the compliance time stated in the AD if the proposal provides an acceptable level of safety.
Note: This AC uses the general term “AMOC” to define an FAA-approved alternative method of compliance to the specific requirements of an AD or a change in the compliance time.
1.5.4 Global AMOC.
A global AMOC is sometimes referred to as an “AMOC of general applicability,” a term used in some bilateral agreements. A global AMOC applies to two or more operators; it can be used to obtain an AMOC for multiple serial numbers or makes and models specified in an AD.
1.5.5 Product.
An aircraft, aircraft engine, propeller, or appliance.
1.5.6 Responsible Office.
The office within the FAA’s Aircraft Certification Service (AIR) that is responsible for approving AMOCs for a particular AD. Each AD identifies the responsible office.
1.5.7 Service Bulletin (SB).
Document used to convey service information (such as modifications or inspections) to owners/operators of products.
1.6 Discussion.
1.6.1 The FAA issues an AD when an unsafe condition is found to exist in a product and is likely to exist or develop in other products of the same type design.
1.6.2 The actions specified in an AD are intended to detect, prevent, resolve, or eliminate the unsafe condition. Those actions can either be written directly into the rule portion (“body”) of the AD, or into another document, such as an SB, that can be referenced in
1-3 the AD body and incorporated by reference in the AD. Compliance with the portions of an SB that are incorporated by reference in an AD is mandatory.
1.6.3 An AMOC is required if an owner/operator cannot comply or wants to propose a different way to comply with the actions specified in an AD. Chapter 2 of this AC provides some questions and answers about when an AMOC is necessary.
1.6.4 The reasons an AMOC may be necessary or desirable include, but are not limited to, the following:
1.6.4.1 To accomplish AD actions in a way that better suits an owner/operator’s business processes;
1.6.4.2 Because an owner/operator devises another way of addressing the unsafe condition;
1.6.4.3 Because an owner/operator wishes to adjust the compliance time stated in an AD;
1.6.4.4 Because existing modifications, alterations, or repairs to a product make compliance with AD procedures difficult or impossible;
1.6.4.5 To use later revisions of service documents specified in an AD;
1.6.4.6 Because a superseding AD invalidates previous AMOCs to the original AD; or
1.6.4.7 To address errors in the service document.
1.6.4.8 To address errors in the AD.
Note: For an error in an AD, an AMOC can be an expeditious way to alert the public of the error and the correction. However, the AD will be superseded to eliminate the error in the regulation and ensure the broadest availability of the correction .
2-1 CHAPTER 2. WHEN AN AMOC IS NECESSARY
2.1 General.
This chapter provides information useful for determining when an AMOC may or may not be required. It is not intended to be all inclusive. For circumstances or situations not covered in this chapter, contact your local principal inspector (PI), your local Flight Standards District Office (FSDO), your local Certificate Holding District Office (CHDO), or the responsible office listed in the AD.
2.2 AD-Mandated Instructions.
Each AD contains instructions on the actions necessary to resolve an unsafe condition.
Sometimes those instructions are included in the AD itself; at other times, the instructions are contained in a design approval holder’s (DAH) service information, which is incorporated by reference in the AD. If you desire to deviate from the mandated instructions as written, you must propose an AMOC to the FAA.
2.3 Frequently Asked Questions From AMOC Requesters.
2.3.1 Service Documents in ADs.
2.3.1.1 Question: I converted the AD and the referenced instructions in the referenced service document to an in-house fleet campaign notice, an engineering change order, or individual work cards. Do I need an AMOC?
Answer: No, as long as you transfer the AD language to your own in-house instructions and those instructions precisely represent all of the AD requirements and compliance times.
2.3.1.2 Question: I complied with the referenced instructions in the service document revision referenced in the AD before the AD was issued. Do I need an AMOC?
Answer: Maybe. If the AD specifically allows previously accomplished work, you do not need an AMOC. If the AD is silent on previously accomplished work or it is unclear whether the work done before the AD was issued is acceptable, an AMOC is required.
2.3.1.3 Question: Do I need an AMOC if I accomplish the instructions in a later version of the DAH service document than what was mandated in the AD?
Answer: Yes, any deviations to the technical requirements of the specific document that are required to be accomplished by the AD will need an AMOC. Therefore, if the DAH did not obtain a global AMOC approval for the later version of the service document, you must apply for
2-2 an AMOC. Contact the DAH or FAA responsible office to determine whether the DAH obtained a global AMOC for the service document revision.
2.3.1.4 Question: The instructions in the mandated service document incorporated by reference in the AD call for a specific fastener on my aircraft. May I substitute another fastener?
Answer: No. You cannot use a different fastener (or any part, material, or process) from what is specifically mandated in an AD without obtaining an AMOC, unless the procedures in the AD (or service information that was incorporated by reference) permit substitution. If you substitute another fastener without an AMOC, you violate § 39.7 each time you operate the aircraft.
2.3.1.5 Question: The AD requires me to perform actions in a service document by a certain date. The service document recommends a date that is later than required by the AD. I want to perform the actions at the later date, pursuant to the service document. Do I need an AMOC?
Answer: Yes. Pursuant to § 39.27, AD requirements override any other language in service documents. You would have to propose an AMOC and substantiate that a change in compliance time similar to that referenced in the service document provides an acceptable level of safety.
The service document alone is inadequate substantiation.
2.3.1.6 Question: The AD requires that I accomplish specific instructions in an SB. Those instructions require actions from a manual, and the manual requires actions from a standard practice manual. My operating procedure differs from the standard practice manual. Do I need an AMOC to continue using my operating procedure?
Answer: Yes. You must accomplish the specific instructions in the SB specified in the AD, including any second- or third-tier documents required to complete the actions. However, if the specific instructions in the SB use flexible language (refer to AC 20-176) to refer to the secondor third-tier documents, then an AMOC may not be required.
2.3.2 Changes in the Area Addressed by ADs.
2.3.2.1 Question: I previously repaired my aircraft structure in the area now addressed by the AD. The repair affects my ability to perform the AD.
Must I obtain an AMOC for the AD?
Answer: Yes. Pursuant to § 39.17, if a change to a product affects your ability to accomplish the actions required by the AD in any way, you must request FAA approval of an AMOC. Unless you can show the change eliminated the unsafe condition, your proposal should include the specific actions you propose to address the unsafe condition.
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2.3.2.2 Question: During the last AD inspection, I found a crack the AD warned about. I obtained an approved repair from the aircraft DAH, which differs from the repair mandated by the AD. Do I need an AMOC for the repair?
Answer: Yes. You must comply with the specific requirements of the AD. Therefore, you or the DAH must apply for and obtain an AMOC if any action differs from the specific requirements of the AD.
2.3.2.3 Question: The AD requires that I visually inspect for cracks. However, the previous owner/operator installed a repair doubler that prevents me from inspecting. I am attempting to accomplish the AD inspection. Do I need an AMOC?
Answer: Yes. Whenever you cannot comply with the specific requirements of an AD, you must seek an AMOC. In this case, you must either devise a new method to inspect the area identified in the AD, or show that the repair reinforces the area and redistributes the loads, so an inspection is no longer required. In either case, you must request and obtain an AMOC to ensure compliance with the AD.
2.3.2.4 Question: The AD requires that I perform an eddy current inspection of a structural area. There is a repair doubler behind the area that interferes with the eddy current readings, making them uncertain. Do I need an AMOC for this AD?
Answer: Yes. You need an AMOC any time a repair, modification, or alteration interferes with the ability to obtain proper results from a required inspection. This is true when the results of the required inspection are questionable, even though you can physically perform the inspection.
2.3.2.5 Question: A structural modification required by an AD was accomplished on my aircraft. I have to do a repair in the region previously modified by this AD for a specific reason (such as corrosion, accidental damage, or cracks). Do I need to apply for an AMOC to install this repair?
Answer: Yes. Any change or modification to the configuration mandated by an AD requires an AMOC.
2.3.3 Removing and Replacing Appliances.
2.3.3.1 Question: The applicability section of an AD lists an appliance I previously removed from my aircraft. Is an AMOC required for the aircraft?
Answer: No. You do not need an AMOC when the AD applicability statement applies to an appliance and you no longer have the appliance installed.
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2.3.3.2 Question: The applicability section of an AD lists an appliance installed on my aircraft. I cannot accomplish the actions in the AD because I previously modified, deactivated, or partially removed the appliance.
Do I need an AMOC?
Answer: Yes. Whenever you cannot comply with the specific requirements of an AD, you must seek an AMOC. Pursuant to § 39.15, the AD still applies to the appliance even though it was modified, altered, or repaired, including deactivation or partial removal.
2.3.3.3 Question: The AD says I must install a specific version of software. I did that. Now I have received a later version of the same software from the DAH. Do I need an AMOC to install this later version?
Answer: Yes. You will need an AMOC to install any version other than the version specifically referenced in the AD.
2.3.3.4 Question: An AD applies to a technical standard order (TSO)-approved article. The DAH has received an AMOC for changes to the article. Do I need an additional AMOC to install the modified article into my aircraft?
Answer: No. You do not need an additional AMOC to install the article into the aircraft. The installation, however, may require additional approval. The AMOC approval letter will identify this as a limitation.
2.3.4 Superseding ADs.
2.3.4.1 Question: An AD supersedes another AD applicable to my aircraft. I had received an AMOC for a different inspection procedure from what the original AD called out. Is my AMOC still valid?
Answer: It depends on the superseding AD.
If the superseding AD includes a provision that AMOCs to the original AD inspection are approved as an AMOC to the superseding AD inspection, your AMOC is still valid for the superseding AD inspection.
If the superseding AD does not include such a provision, your AMOC is not valid for the superseding AD inspection and you must propose a new AMOC if you cannot comply with the superseding AD compliance actions.
Note: If you have any question concerning compliance with the superseding AD, contact the responsible office.
2.3.4.2 Question: An AD that applies to my aircraft was superseded, adding a mandatory terminating action. It includes a provision that AMOCs to the inspection methods, approved in accordance with the original AD, are approved as AMOCs to the inspection methods in the superseding AD.
2-5 Can I perform the AMOC inspection instead of accomplishing the terminating action?
Answer: No. Even if an AMOC is still valid, it is only valid for the specific paragraphs of the AD as listed in the AMOC response, not for the superseding AD as a whole. An AMOC inspection may be an acceptable alternative to the mandated inspection (if the superseding AD allows it), but not for the mandated terminating action (which is likely to be in a different paragraph of the AD). The mandatory terminating action must still be done within the compliance time specified in the superseding AD.
2.3.5 Parts Approved via Parts Manufacturer Approval (PMA).
Question: The AD calls for installing a specific part number as the corrective action.
There is a PMA-approved replacement for the part listed in the AD. Do I need an AMOC to install the PMA part?
Answer: Yes. Unless the PMA part number is listed in the AD as an acceptable alternative, you need an AMOC to install any part number other than the one listed in the AD.
2.3.6 AD Compliance Before Delivery.
2.3.6.1 Question: The DAH (or production approval holder [PAH]) delivered my aircraft with AD status records (indicating compliance with all applicable ADs). Do I still need to get AMOCs for these ADs?
Answer: No. AMOCs are not necessary if the AD status records show that the aircraft complies with all of the applicable ADs. Note that there might be recurring or terminating AD actions that are not yet due. To continue operating the aircraft, you are responsible for complying with these actions before they become due.
2.3.6.2 Question: I just received my aircraft, but cannot get an AD status record from the DAH (or PAH). AD XXXX-XX-XX applies to the aircraft. Do I need to take action?
Answer: Yes. Before flying the aircraft, you must either comply with the AD as written, or obtain and implement your own AMOC.
2.3.7 Typographical Errors.
Question: Do I need an AMOC if the service instructions referenced by the AD have an obvious typographical error? For example, it states to use lint-free clothes (when it should have identified lint-free cloths)?
Answer: Yes. In cases of typographical errors in either the AD or service instructions, you must apply for an AMOC. The FAA will approve these types of requests as global AMOCs because a typographical error affects all parties subject to the AD.
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2.3.8 Required for Compliance.
Question: Do I need an AMOC if I can accomplish the intent of the compliance action in the service instructions? For example, the service instructions state to use a 20-gallon bucket, but I only have a 50-gallon bucket to rinse the part.
Answer: Maybe. Starting June 2011, some DAHs are adopting the “required for compliance” (RC) notation whereby the critical steps of an SB are identified with a notation of “RC”.
If the SB incorporates this notation, and— If the task is identified as RC, you must request an AMOC to deviate from this task; or If the task is not identified as RC, you may deviate from the specific task using accepted methods in accordance with an operator’s maintenance or inspection program without an AMOC, provided the RC steps, including substeps and identified figures, can still be done as specified, and the airplane can be put back in an airworthy condition.
If the SB does not incorporate the RC notation, and the task is in the mandated portion of the SB, you must request an AMOC to deviate from the requirements in the service instructions.