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2.4 Required Sections. As technology in aviation evolves, traditional pages may become digital sections or subsections of flowing text. As such, content may be presented and tracked differently in digital format compared to print. The following MMEL-based elements must be in an operator’s MEL, but may be presented according to the operator’s style and system output capabilities. The MMEL format outline contains eight sections, six of which must be in the operator’s MEL:
2.4.1 Table of Contents. The table of contents includes a sequential list of all the content in the MEL, by section, subsection, paragraph, or title, and includes the corresponding location identifier or page identification. The format may vary based on the operator’s manual system preferences.
2.4.2 L og of Revisions. The log of revisions contains the revision identification (usually a number) and the date of the revision. It may also contain a list of the revised pages, a block for the initials of the person posting the change, and additional enhancements for use by the operator. The format may vary based on the operator’s manual system preferences.
2.4.3 D efinitions . A list of definitions of terms used in MMELs and MELs is found in MMEL PL-25. For operator MELs, certain MMEL definitions may be edited or may be omitted if the element is not used in the operator’s MEL. MEL definitions will be tailored, as appropriate, including content and format, dependent upon the aircraft operator’s make/model (M/M) of aircraft, type of installed items, and specific operation.
However, the intent of the definition must be the same and cannot be less restrictive than the MMEL.
2.4.4 P reamble . The standard MMEL preamble should be reproduced verbatim in each MEL, should not be modified, and should comply with the policy requirements included in FAA MMEL PLs. Operators conducting part 91K, 121, 125, or 135 operations should use the preamble included in MMEL PL-34, MMEL and MEL Preamble.
2.4.5 Control Page. The control page is meant for tracking the status of the MEL to ensure currency and applicability to a specific aircraft. It includes a revision record, which lists the date of each page of the operator’s MEL. It may also be used as a means of conveying FAA approval of the MEL. At a minimum, the control page will contain:
• The operator’s name;
• A listing of all pages in the MEL (including the date of each page’s revision);
• The MMEL revision number on which the MEL is based; and
• A signature block containing space for the signature of the POI (required only if this page is used as a means of conveying FAA approval of the MEL).
2.4.6 MMEL ATA or Joint Aircraft System/Component (JASC) Coded Sections. Each MEL contains the MMEL ATA or JASC coded sections, as appropriate to the operator’s and aircraft manufacturer’s nomenclature.
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2.5 Optional Sections.
2.5.1 C over Page. The cover page format and information ma y be the same as the MMEL at the operator’s discretion. If a cover page is used, the operator should include the MMEL revision on which the MEL is based. The operator may also include additional information in the control page at the operator’s discretion.
2.5.2 Highlights of Change Page. This page summarizes the changes made by the operator in each revision.
Note: T he operator may include additional information sections in addition to the ones listed.
3-1 CHAPTER 3. MINIMUM EQUIPMENT LIST (MEL)—CONTENT
3.1 MEL Contents. In addition to the required MEL format items, an operator’s MEL includes specific content based on the items installed on the operator’s aircraft. Except for those instances specified by policy, an operator’s MEL should incorporate the phraseology used in the MMEL to ensure clarity and standardization.
3.2 Air Transport Association of America (ATA) or Joint Aircraft System/Component (JASC) Coded Sections. The use of the term “coded sections” refers to either the JASC Code Table or the ATA Specification 100 code. The MEL ATA/JASC coded system sections include a list of individual items in the aircraft, together with requirements for operation when the items are inoperative. Each system sequence may be further broken down into individual item numbers along with repair interval categories.
3.2.1 System and Sequence Item Numbers. Operators should use the ATA or JASC system sequence numbering system. The ATA numbering system provides an industry-wide standard for numbering aircraft systems and is relevant for all aircraft. The alternate format for aircraft system coding is the JASC.
3.2.2 I ndividual Item Numbers.
1. Individual item numbers are not required to match ATA/JASC system and sequence item numbers. An operator may use its own numbering system to identify individual items within a given ATA/JASC code group, as appropriate.
2. A triple asterisk (***) below the system number in column 1 of an MMEL indicates that an item has been installed on some models of a particular aircraft make/model/series (M/M/S). Operators omit the triple asterisk symbol in their MEL and use a system sequence number when the item is installed on one or more of the operator’s aircraft.
3. An MMEL item that is not listed in an operator’s MEL is not subject to MEL relief and must be fully operative at takeoff in accordance with § 91.213.
4. An operator’s MEL limitations, conditions, and restrictions may never be less restrictive than the MMEL. However, an operator may add limitations or increase restrictions for a particular item if they are more restrictive that those required by the MMEL.
5. Operators typically list an MEL item exactly as it is in the MMEL. If an MMEL uses a generic term to describe a particular item, an operator may use different terminology, provided the operator’s terminology is recognizable and easily identified with the corresponding MMEL item.
6. If an MEL item contains multiple components, the operator may choose to list the components separately following the item in the MEL.
7. Operators may not list duplicate items or items that are listed individually elsewhere in the MMEL.
8. Individual components of an MMEL or MEL item may not be listed as NEF.
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3.3 Repair Categories. Each item listed in an MEL (excluding NEF items or administrative control items (ACI)) should include a repair category designator as depicted in the MMEL. Repair categories represent the maximum time interval during which an item may be inoperative. When an item becomes inoperative and the operator defers repair, the aircraft may not be operated beyond the specified period until repairs are made. The requirement to comply with repair categories are included in the operator’s Operations Specification (OpSpec)/Management Specification (MSpec) D095, Minimum Equipment List (MEL) Authorization. Maximum repair time intervals are delineated by repair categories “A,” “B,” “C,” and “D.” Operators may adopt repair intervals that are more restrictive than the MMEL, but may not use a repair category that is less restrictive than the MMEL. Unless exercising an extension as listed in Chapter 5, MEL Management Program Requirements, operators using an MEL should ensure that repairs of deferred inoperative items are accomplished prior to expiration of the repair intervals established by the following letter designators:
3.3.1 R epair Category A. This category item must be repaired within the interval specified in the “Remarks or Exceptions” column of the aircraft operator’s MEL. For repair intervals specified in consecutive calendar days or flight days, the day of discovery is excluded.
For all other time intervals (e.g., flights, flight legs, cycles, hours), the repair interval begins at the point when the item is deferred in accordance with the aircraft operator’s MEL.
3.3.2 R epair Category B. In accordance with § 91.213 and OpSpec/MSpec D095, this category item must be repaired within 3 consecutive calendar days (72 hours), excluding the day of discovery. For example, if it were recorded at 10 a.m. on January 26, the 3-day interval would begin on January 27 and end at 23:59:59 on January 29.
3.3.3 R epair Category C. In accordance with § 91.213 and OpSpec/MSpec D095, this category item must be repaired within 10 consecutive calendar days (240 hours), excluding the day of discovery. For example, if it were recorded at 10 a.m. on January 26, the 10-day interval would begin on January 27 and end at 23:59:59 on February 5.
3.3.4 R epair Category D. In accordance with § 91.213 and OpSpec/MSpec D095, this category item must be repaired within 120 consecutive calendar days (2,880 hours), excluding the day of discovery.
3.4 Number of Items Installed. The “Number Installed” column of an MEL lists the number (quantity) of the specified item installed on the aircraft. This number typically represents the aircraft configuration used to develop the aircraft MMEL.
3.4.1 Variable Number Installed. A dash (-) for number installed indicates a variable number of the installed item. Use of a “-” is common in fleet MELs where aircraft of the same make and model (M/M) have differing numbers of specific items. Additionally, operators may use a “-” if it is impractical to show the actual number of the specific items (e.g., light bulbs, light-emitting diodes (LED)) installed on the aircraft.
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3.4.2 Items Listed on the MMEL But Not Installed on the Aircraft. An operator’s MEL does not have to list items included in the MMEL but not installed on the operator’s aircraft.
For number continuity in an MEL, operators may choose to:
1. Omit the item from the MEL altogether and renumber the individual items within an ATA category as necessary to provide continuity. Individual item numbers in an MMEL are not necessarily ATA/JASC code numbers but could be sequential item numbers within an ATA/JASC category; or
2. List the item in the MEL and show the “Number Installed” as zero (0). In this case, the “Number Required for Dispatch” would also be zero (0), and the remark “Not Installed” would be noted under “Remarks or Exceptions.” In this case, the repair category designators are omitted.
3. Omit the item from the MEL, but not renumber the subsequent items to keep the same numbering as the MMEL. For example, jumping from 21-21-01 to 21-21-03, and omitting 21-21-02.
4. Other alternatives may be proposed by an operator to their FAA Certificate Management Team (CMT).
3.5 Number Required for Dispatch. The “Number Required for Dispatch” column of an MEL reflects the minimum number of items required, provided the conditions specified in the “Remarks or Exceptions” are met. The number of items required for dispatch may differ from what is required in the MMEL under the following conditions:
1. The item is listed in the MMEL as optional, is not installed on the operator’s aircraft, or is installed on the operator’s aircraft but is not required in all operations. In this case, a zero (0) may be shown as the number required for dispatch.
2. The “Number Required for Dispatch” is followed by a “-” in the MMEL.
3. Where the MMEL shows a dash “-” required for dispatch, the MEL should reflect the actual number required for dispatch. Fleet configuration differences and the dispatch requirements will be specified in the “Remarks or Exceptions” column.
4. The number required for dispatch in the MEL cannot be less restrictive than the MMEL.
3.6 Remarks or Exceptions. The “Remarks or Exceptions” column of the MMEL includes the Maintenance (M) and Operations (O) indicators, a statement permitting operation with a specific number of inoperative items and their associated provisos. To accommodate a variety of operators and operating rules, MMELs contain intentionally general “Remarks or Exceptions” for items required by 14 CFR for a particular type of operation, or for items that require specific procedures when inoperative. The MMEL may list a specific number of items that may be inoperative or may state “any in excess” of a number. “Remarks or Exceptions” in an operator’s MEL may not be general. Each operator’s MEL will expand the MMEL “Remarks or Exceptions” to include specific 14 CFR compliance requirements and detailed procedures for operating with the inoperative item(s). Listing the 14 CFR regulation (e.g., § 121.643) in the operator’s
3-4 MEL is optional so long as the compliance requirements are listed. MEL “Remarks or Exceptions” that list references to other manuals containing MEL procedures within the operator’s manual system is an acceptable alternative. The “Remarks or Exceptions” column may be blank or may include a statement permitting operation with a specific number of items inoperative. The statement may include provisos for such operations and appropriate notes. If the MMEL remarks are blank, the aircraft operator’s MEL may, at the operator’s discretion, incorporate the text, “May be inoperative.”
3.7 MEL Remarks and Exceptions Defined. The operator’s MEL will expand on MMEL general “Remarks or Exceptions” and will include specific procedures to enable compliance with applicable operating requirements. The following phrases are examples of MMEL general “Remarks or Exceptions”-specific conditions that should be expanded in the operator’s MEL “Remarks and Exceptions” when the particular item is inoperative.
The FAA may not approve an MEL that includes provisos with general statements such as:
• “May be inoperative provided procedures do not require its use.”
• “May be inoperative or missing if alternate procedures are established and used.”
• “May be inoperative unless required by 14 CFR” or “As required by 14 CFR.”
3.8 MEL Proviso Stipulations Should Be Specific. An operator’s MEL contains specific procedures, requirements, and conditions that apply when a particular item is inoperative.
The operator is responsible for ensuring that the MEL contains enough information to adequately and safely address operations with the item inoperative. The information is assessed by the FAA as part of the approval process.
3.9 (M) and (O) Procedures. The presence of (M) and (O) indicators in the MEL indicates that a specific procedure is required to be accomplished.
3.9.1 (M ) Procedures . This symbol indicates a requirement for a specific maintenance procedure that must be accomplished prior to operation with the listed item inoperative.
Normally, these procedures are accomplished by maintenance personnel. However, other personnel may be qualified and authorized to perform certain functions under 14 CFR part 43. Procedures requiring specialized knowledge or skill, or requiring the use of tools or test equipment, should be accomplished by maintenance personnel.
1. T he operator is responsible for ensuring that all (M) procedures are accomplished in accordance with the operator’s MEL program and applicable maintenance regulations.
2. As part of the review and approval process, the FAA may ask the operator to include additional instructions within the provisos to ensure that deferral procedures will continue to provide an Acceptable Level of Safety (ALoS).
3. The (M) procedures may be fully depicted in the operator’s MEL or in another manual. If a procedure is contained in another manual, the MEL should provide specific reference to the current version of that manual. MEL (M) procedures are
3-5 subject to FAA review and validation to ensure they are adequate for the relief sought.
3.9.2 (O) Procedures. The (O) indicator stipulates an operations procedure intended to be followed for planning purposes or for operating with a deferred item. These procedures may be required for flight planning purposes and are normally accomplished by the flightcrew; however, other personnel may be qualified and authorized to perform certain functions (e.g., an inoperative Global Positioning System (GPS) unit requiring the flight plan to revert to following airways may be submitted by the flightcrew or a qualified dispatcher). Additionally, procedures may have to be developed for MEL items that affect the aircraft weight and balance (W&B), dispatch, or passenger/cargo loading
(e.g., procedures for additional personnel such as those involved with aircraft load control).
1. The (O) procedures may be fully depicted in the operator’s MEL or in another manual. If a procedure is contained in another manual, the MEL should provide specific reference to the current version of that manual. MEL (O) procedures are subject to FAA review and validation to ensure they are adequate for the relief sought.
2. During the MEL review and approval process, the operator may have to include additional instructions in its provisos to ensure that deferral procedures provide an ALoS.
3. The operator is responsible for accomplishing all (O) procedures in accordance with its MEL program.
3.9.3 Operator Developed (M) and (O) Procedures. Operators should develop procedures that appropriately address the type of operation conducted. The procedures can be more restrictive than the MMEL but can never be less restrictive than the MMEL.
3.10 Provisos. Provisos are terms, conditions, or limitations that the operator must comply with to operate an aircraft with an inoperative item. Provisos are listed in the “Remarks or Exceptions” column of an MEL and, if more than one proviso applies to a given item, are listed by a number or a lowercase letter. For example, a proviso may allow an item to be inoperative provided the aircraft is not operated in Extended Operations (ETOPS); or a proviso may require that an aircraft only be operated under visual flight rules (VFR) when a particular item is inoperative. In the operator’s MEL, the phrase “As Required by 14 CFR,” or any similar statements from the MMEL, will be replaced with the specific regulatory references or conditions under which an item may be inoperative.
3.11 Notes. Notes provide additional information for crewmember or maintenance consideration. Notes are used to identify applicable material, which is intended to assist with compliance, but do not relieve the aircraft operator of the responsibility for compliance with all applicable requirements. Additional notes may be amended, deleted, or added to the MEL by the aircraft operator, as appropriate, but must remain within the scope of this definition. Notes are not a part of the provisos.
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3.12 Definitions. MMEL PL-25 provides a list of definitions for use in MMELs and MELs .
For MELs, certain MMEL definitions may be edited or may be omitted if the element is not used in the operator’s MEL. MEL definitions will be tailored, as appropriate, including content and format, dependent upon the aircraft operator’s M/M of aircraft, type of installed items, and specific operation. However, the intent of the definition must be the same and cannot be less restrictive than the MMEL.
3.13 R eferences. The operator should research regulatory requirements in detail to develop the appropriate deferral limitations and conditions. Clarification of specific regulatory requirements will be included in each related proviso. Appendix A of MMEL PL-25 contains a list of regulatory references by ATA section. Operators may use MMEL PL-25 to identify the appropriate terminology to use in their MEL. An operator may include a reference to their FAA-approved or FAA-accepted manual that contains the procedure(s) required to address a particular MEL item. The MEL may only reference FAA-approved or FAA-accepted manuals. The following conditions apply when referencing manuals:
1. Manual reference(s) will be preceded by either a proviso(s) or specific instruction(s) defining the action required. A single proviso or specific instruction may have more than one manual reference associated with it.
2. Manual references will direct the reader to use the current revision of the subject manual. Actual revision level/date of the manual is not required to be listed in the MEL.
3. The operator’s MEL management program and manual system should include procedures for notifying the FAA when references within the MEL have changed. All changes to procedures in the MEL require an MEL revision and FAA approval of the MEL revision.
4. The proviso or specific instruction and manual reference in the MEL is considered the means of compliance for MEL purposes when the MEL is approved by the FAA.
Each procedure referenced is either FAA-approved or FAA-accepted, depending on the status of the manual referenced. For example, for “Remarks or Exceptions” which contain procedures, an operator could include a proviso or specific instruction to secure or isolate an item in accordance with a specific chapter, section, task, or paragraph of the referenced manual. The instructions and the reference to the manual is the means of compliance.
Note: A change to any procedure listed in an MEL (in the event that an operator lists procedures in the MEL instead of providing references to other approved or accepted manuals) will be evaluated and approved as part of the MEL revision.
References in the MEL to maintenance procedures contained in an approved or accepted manual may contain language such as “Deactivate and lock start valve in the closed position according to current version of AMM 80-12-14-201A.” Such language will be approved as part of the original submission of the MEL and will remain approved as long as the reference is valid. An operator may make changes to the referenced AMM procedure without subsequent MEL approval. The FAA does not need to reapprove an MEL as a result of a change in a procedure in a referenced approved or accepted manual.
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3.14 Specific 14 CFR Requirements. “As required by 14 CFR” or any similar statement is prohibited in an operator’s MEL. MEL deferrals based on MMEL items that may be inoperative “unless required” by 14 CFR will contain specific details of the relevant regulatory requirements. For example, an MMEL general “Remarks or Exceptions” for distance measuring equipment (DME) states “As required by 14 CFR.” An acceptable MEL “Remarks or Exceptions” would be “May be inoperative provided flight remains below FL 240.”
4-1 CHAPTER 4. MEL RELIEF FOR ITEMS INSTALLED AFTER TYPE
CERTIFICATION
4.1 General. The aircraft design approval holder (DAH) determines the configuration of the aircraft, the items installed, and the official parts listed during the initial aircraft type certification process conducted at the time of manufacture. Any subsequent installation or removal of items may be accomplished only through a Supplemental Type Certificate (STC), an Engineering Order (EO), a Field Approval, or other FAA-approved methods (as appropriate).
4.2 Operator NEF Items or Administrative Control Items (ACI). Items listed on an operator’s NEF program and ACIs are excluded from the requirements for evaluation, as listed in this chapter.
4.3 MMEL Items and MEL Items. For an item to be listed in an operator’s MEL, it should first be listed in the MMEL, as the MMEL is the basis for an operator’s MEL. (The only exceptions are MEL relief added through an MMEL PL with a Global Change (GC) designation or an Aircraft Evaluation Division (AED) approval letter, as these are considered addendums to the MMEL.)
4.3.1 Example. If an operator wants to add an item to its MEL, such as a flight management system (FMS) or an autopilot, then that item should first appear in the applicable aircraft’s MMEL as “FMS” or “Autopilot.”
4.3.2 Ite ms Not L isted in an MMEL. An operator may petition the AED to add items to the applicable aircraft’s MMEL through the Flight Operations Evaluation Board (FOEB) process. This may be accomplished through the operator’s responsible Flight Standards office or directly to the responsible AED office. An operator should be prepared to provide the information that the FOEB will need for this evaluation. See the list of needed items found in paragraph 4.6.
4.4 STC. A design change to a TC is often done with an STC. Ideally, MMEL/MEL relief can be evaluated during the STC certification when this is requested by the STC applicant.
4.4.1 Evaluation of MEL Relief During STC Certification. To obtain MMEL/MEL relief, the STC applicant involved in the certification of an STC should submit a request for relief in accordance with the FOEB MMEL Agenda Coordination Process (refer to FAA Order 8900.1, Volume 8, Chapter 2, Section 3, Flight Operations Evaluation Board, and AC 21-40, Guide for Obtaining a Supplemental Type Certificate). This submission should be made early in the certification process to allow MMEL/MEL evaluation concurrent with the certification process. Requests for relief subsequent to the completion of the certification process can delay the availability of MMEL/MEL relief for an item.
4.4.2 MME L PL. MMEL PL-109, Supplemental Type Certificate (STC) MMEL/MEL Relief Process, provides amended guidance regarding MMEL/MEL relief for items installed on an aircraft that affected the aircraft’s type certificate (TC) and to any change to the TC when MMEL/MEL relief is sought. Flight Standards updated this policy to allow
4-2 operators to work with their responsible Flight Standards office to obtain relief for unevaluated STC items as described in this chapter. Operators are no longer required to petition the STC or design holder for relief.
4.5 Adding Relief for Items Installed After Type Certification. STCs issued without concurrent AED evaluation may be granted relief by request from the operator to the FAA. Additional information may be found in Order 8900.1, Volume 4, Chapter 4, Section 3, MEL Re quirements for 14 CFR Parts 91K, 121, 125, 125 LODA, and 135 Operations. STCs already listed by STC number in the applicable aircraft MMEL or in an AED approval letter may be added to the operator’s MEL through the normal revision process without further evaluation. However, a principal inspector (PI) may coordinate with the AED during this process, as needed. Using the normal revision process found in Chapter 9, MEL Revi sions, of this AC, an operator may add relief for items to its MEL through any of the following solutions:
4.5.1 MMEL Specifically Lists the Relief. Where the MMEL lists the specific STC number
(e.g., ST00733SE) or identifies the specific design change nomenclature (other than STCs), an operator may add the relief to its MEL.
4.5.2 Design Change Approval Letters. Upon evaluation and approval of a design change, the AED will submit an approval letter directly to the FAA’s DRS. Operators may access these approval letters at https://drs.faa.gov/ under “MELs and AED Guidance Documents,” “STC Relief Approval Letters.” The approval letter will contain the allowed relief, including conditions and provisos, along with remarks or exceptions. Approval letters will be dated and have revision numbers. Operators may amend their MEL(s) with the relief for the STC(s) in accordance with the AED approval letter. Paper copies of the AED approval letter are also acceptable in lieu of the DRS database.
4.5.3 MEL Relief T hrough MMEL PL With GC Designation. Operators may add relief into their MEL(s) for an STC through an MMEL PL with a current GC designation. However, upon the AED evaluation of the item (if an evaluation is conducted), operators may have to amend or remove previously approved relief in their MEL(s). See Chapter 9 for additional information on GC.
4.5.4 Responsible Flig ht Standards Office’s Relief Evaluation. If the proposed relief is not covered by one of the three solutions immediately above and the MEL item is listed generically in the MMEL, the item may be evaluated by the responsible Flight Standards office. Additional information may be found in Order 8900.1, Volume 4, Chapter 4, Section 3. To add MEL relief using this method, the following points should be considered:
1. T he basic item needs to be found in the applicable aircraft’s MMEL (e.g., FMS, autopilot, passenger seat). If not, the AED must complete the evaluation.
2. The operator’s Safety Management System (SMS) (as applicable) reveals that the proposed relief does not present a hazard to the operator’s use of the relief.
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3. The PIs conducting the evaluation may consult with the STC holder, AED, Original Equipment Manufacturer (OEM), and other stakeholders during their evaluation of the operator’s proposal.
4. If the item was previously evaluated by the AED and relief was not granted, the item is not eligible for evaluation by the responsible Flight Standards office.
5. If the PI believes a hazard exists with the operator’s proposal, the item is not eligible for relief.
4.6 Items Needed for Evaluation of Design Changes. Each proposed operator MEL relief item should have accompanying supporting justification before it will be considered. The information needed by the FAA allows a thorough evaluation of the risk associated with operating the aircraft with the item inoperative. The FAA may reject an item proposal if the justification information is inadequate. At a minimum, the following information should accompany all item proposals:
1. The title and number of the proposed MMEL item;
2. A brief description of the system and its intended functions;
3. A summary of the proposed MMEL relief;
4. A brief description of intent;
5. The effect of dispatching a flight with this inoperative item;
6. The operating rule(s) that requires the item to be operative, as applicable;
7. The transfer of function when the item is inoperative;
8. The next most critical failure;
9. The effect on increased flightcrew workloads (including risk mitigations);
10. The certification requirements for the item;
11. Any conflicts with Airplane Flight Manual (AFM) limitations, procedures, or Airworthiness Directives (AD);
12. If the item affects or is required to accomplish an emergency procedure;
13. The effect on aircraft capability in an emergency;
14. Maintenance (M) and Operations (O) procedures required for the proposed dispatch condition;
15. Any information that adds support to the proposal (e.g., wiring diagrams, schematic drawings, or STC documents); and
16. Any other information requested by the FAA before or during the evaluation.