CS MMEL.110 MMEL purpose

ED Decision 2014/004/R

The MMEL is a document that lists the items which may be temporarily inoperative, associated with special operating conditions, limitations or procedures, as applicable, for a specific aircraft type or model.

GM1 MMEL.110 MMEL purpose

ED Decision 2014/004/R

AIRCRAFT TYPE

An MMEL document may cover more than one aircraft type provided that benefits on commonality can be taken and the applicability of each item is clearly indicated.

GM2 MMEL.110 MMEL purpose

ED Decision 2014/004/R

NON-SAFETY-RELATED ITEMS

(a) All items not included in the list are required to be operative unless they are considered to be non-safety-related items.

(b) Non-safety-related items include those items related to the convenience, comfort, or entertainment of the passengers and equipment that is used only on ground for maintenance purpose. Convenience, comfort, or entertainment of the passengers may include items such as galley equipment, movie equipment, stereo equipment, overhead reading lamps. Additional guidance is provided in GM1 ORO.OPS.MLR.105(a).

(c) Non-safety-related items need not be included in the MMEL, unless so desired by the applicant.

CS MMEL.115 Types of operation

ED Decision 2014/004/R

The MMEL covers all the types of operation for which the aircraft type or model is certified.

CS MMEL.120 Format and content of the MMEL

ED Decision 2014/004/R

(a) The MMEL is written in a format acceptable to the Agency.

(b) Each MMEL contains the following:

(1) Approval status, including date of approval and effective date.

(2) A preamble, containing considerations on the purpose and limitations, utilisation, multiple inoperative items, rectification interval extension, definitions and, if appropriate, clarifying notes which adequately reflect the scope, extent and purpose of the list.

(3) The list of items, including for each item:

—             the rectification interval category;

—             the number installed or a dash symbol, as applicable;

—             the number required or a dash symbol, as applicable;

—             the operational procedure symbol, as applicable;

—             the maintenance procedure symbol as applicable;

—             placarding indications, as applicable; and

—             any associated conditions and limitations, including the intent and periodicity for the accomplishment of the operational and maintenance procedure, as applicable.

GM1 MMEL.120 Format and content of MMEL

ED Decision 2014/004/R

GENERAL

(a) The MMEL should normally be written in a ‘five-column format’. Refer to examples in GM2 MMEL.120. Other paper or electronic formats are accepted provided they are clear and unambiguous.

(b) The MMEL should contain: cover page, revision history, detailed summary of changes at last revision, list of effective pages, and table of contents within the administrative control pages at the beginning of the MMEL, or equivalent information should be made available in the case of MMEL in other than paper format.

(c) A model of acceptable preamble can be found in GM5 MMEL.120.

(d) Each item listed in the MMEL should be described and identified in accordance with the Air Transport Association (ATA) specification 100 or 2200 code system. Consistency of terminology and identification means should be maintained, as far as possible, among aircraft documentation. Where appropriate, the MMEL should contain means to identify applicability of items.

(e) Where a Message Oriented approach is used, the messages displayed may be listed in place of the item title in the relevant section, as this will be considered as a representation of the item(s) affected. Number installed and number required are not applicable for such an approach.

(f) Rectification interval may be identified through a reference to another item.

(g) Number installed and number required may not be listed if not practical and not relevant for dispatch determination.

(h) Where there is a requirement for a specific maintenance procedure, then an (M) symbol should be included as part of the MMEL entry to indicate this. Where there is a requirement for a specific operational procedure, then an (O) symbol should be included as part of the MMEL entry to indicate this.

(i) When a maintenance procedure is associated to an MMEL item, a dispatch condition, identifying the intent of the procedure (e.g. deactivation of an equipment), should be included in the associated item, as far as practicable.

(j) References to where the content of the operational and maintenance procedures is available should be included in the MMEL.

(k) A decision on whether the necessary procedure can be assigned as an (O) or an (M) should be based on which is the most appropriately qualified trade to carry out the procedure and which trade would normally carry out such a task in their line of duty, based on the intended types of operation normally performed by the aircraft. On this basis deactivation and securing tasks should normally be assigned an (M) while procedures based on operation of equipment should normally be assigned an (O).

(l) The periodicity for the accomplishment of the procedures should be clarified either in a generic manner in the MMEL preamble or specifically in the associated dispatch conditions. Maintenance deactivation procedure should normally be performed once prior to the first flight under the associated item. Maintenance verification procedures periodicity may vary and should therefore be clarified in the MMEL. Operational procedures should normally be performed or acknowledged by the flight crew members before each flight, unless otherwise specified.

(m) Placarding instructions are provided as part of the dispatch conditions or in a generic manner in the preamble to inform the crew members and maintenance personnel of the item condition, to the extent practicable.

(n) Unless it is specifically allowed by the MMEL, an inoperative item should not be removed.

GM2 MMEL.120 Format and content of MMEL

ED Decision 2014/004/R

FIVE-COLUMN FORMAT EXAMPLE

MASTER MINIMUM EQUIPMENT LIST

GM3 MMEL.120 Format and content of MMEL

ED Decision 2014/004/R

MESSAGE ORIENTED FORMAT EXAMPLE

GM4 MMEL.120 Format and content of MMEL

ED Decision 2014/004/R

ELECTRONIC FORMAT EXAMPLE

Placard

O May be inoperative

GM5 MMEL.120 Format and content of MMEL

ED Decision 2020/012/R

MMEL PREAMBLE

(SPECIMEN)

EUROPEAN UNION AVIATION SAFETY AGENCY

MASTER MINIMUM EQUIPMENT LIST

(AIRCRAFT TYPE)

PREAMBLE

Introduction

The following is applicable for operators subject to Commission Regulation (EU) No 965/2012 of 5 October 2012 - Air Operations. Paragraph 1.3.2 of Annex II (essential requirements for airworthiness) of Regulation (EU) 2018/1139 (the ‘Basic Regulation’) requires that all equipment installed on an aircraft required for type certification or by operating rules shall be operative. However, paragraph 2(c)(iii) of Annex V (essential requirements for air operations) to the Basic Regulation also allows the use of a Minimum Equipment List (MEL) where compliance with certain equipment requirements is not necessary in the interests of safety under all operating conditions. Experience has shown that with the various levels of redundancy designed into aircraft, operation of every system or installed items may not be necessary when the remaining operative equipment can provide an acceptable level of safety.

Purpose and limitations

This Master Minimum Equipment List (MMEL) is developed by the applicant and holders of the (Supplemental) Type Certificate and approved by the European Union Aviation Safety Agency to improve aircraft use, and thereby, to provide more convenient and economic air transportation for the public. This MMEL includes those items related to airworthiness, air operations, airspace requirements and other items that EASA finds may be inoperative, while maintaining an acceptable level of safety through appropriate conditions and limitations; it does not contain obviously required items such as wings, flaps, and rudders. In order to maintain an acceptable level of safety, the MMEL establishes limitations on the duration of, and conditions for, operation with inoperative items. Unless specifically allowed by this MMEL, an inoperative item may not be removed from the aircraft.

This MMEL includes items identified by a '#'-symbol or provided in a dedicated list, which have been based only on European operational requirements, using associated guidance developed by EASA. If the applicable operational requirements differ from the European operational requirements, then for the approval of the MEL, the items in the MMEL could be adapted to the applicable operational requirements, provided that is permitted by the State of the operator.

In such a case, the MEL content is still considered to be in conformity with the content of this MMEL.

Utilisation

The MMEL is the basis for the development of individual operator’s MEL which take into consideration the operator’s particular aircraft equipment configuration and operational conditions. An operator’s MEL may differ in format from the MMEL, but shall not be less restrictive than the MMEL. The individual operator’s MEL, when approved, allows operation of the aircraft with inoperative items of equipment for a certain period of time until rectification can be accomplished.

The MEL cannot deviate from Airworthiness Directives, or any other additional mandatory requirements. It is important to remember that all items related to the airworthiness and the operational regulations of the aircraft not listed on the MMEL shall be operative.

Suitable conditions and limitations in the form of placards, maintenance procedures, crew operating procedures and other restrictions as prescribed in this MMEL shall be specified in the MEL to ensure that an acceptable level of safety is maintained. It is important that rectifications be accomplished at the earliest opportunity.

When an item is discovered to be inoperative, it is reported by making an entry in the continuing airworthiness record system or the operator’s technical log, as applicable. Following sufficient fault identification, the item is then either rectified or deferred following the MEL or other approved means of compliance acceptable to the competent authority and the Agency prior to further operation. MEL conditions and limitations do not relieve the operator from determining that the aircraft is in a condition for safe operation with items inoperative.

Prior to operation with any item inoperative acceptance by the crew is required in accordance with the continuing airworthiness management procedures.

Operators shall establish a controlled and sound rectification programme including the parts, personnel, facilities, procedures and schedules to ensure timely rectification.

Operators should include guidance in the MEL to deal with any failures which occur between the commencement of the flight and the start of the take-off.

When developing the MEL, compliance with the stated intent of the preamble, definitions and the conditions and limitations specified in this MMEL is required.

Multiple inoperative items

Operators are responsible for exercising the necessary operational control to ensure that an acceptable level of safety is maintained. The exposure to additional failures during continued operation with inoperative items shall also be considered. Wherever possible, account has been taken in this MMEL of multiple inoperative items. However, it is unlikely that all possible combinations of this nature have been accounted for. Therefore, when operating with multiple inoperative items, the inter-relationships between those items and the effect on aircraft operation and crew workload shall be considered.

Rectification interval extension

[The operator may be permitted, by its competent authority, to extend the rectification intervals of the MEL.

This MMEL has been evaluated taking into account a one-time extension of the rectification intervals of category B, C and D.]

(The above statement in [] is applicable only if demonstrated during the MMEL review process)

DEFINITIONS AND EXPLANATORY NOTES

[In addition to a preamble arranged and worded along the lines of this Specimen, the MMEL should contain, as part of the preamble, sufficient definitions and explanatory notes to provide the user (this is primarily the operator when compiling the MEL) with a full and proper understanding of the intent and purpose of the items it contains.

While many of the definitions used will be common to all MMELs, others will be specific to particular or individual aircraft types. (Supplemental) TC holders should ensure, when preparing the MMEL, that all relevant definitions are included. Also explanatory notes should be provided in sufficient detail wherever the intent and purpose of a term or phrase or abbreviation etc. is necessary or advisable.]

1. ‘Airplane/Rotorcraft Flight Manual’ (AFM/RFM) means the document required for type certification and approved by the Agency. The AFM/RFM for the specific aircraft is listed on the applicable Type Certificate Data Sheet.

2. ‘Alternate procedures are established and used’ or similar statement, means that alternate procedures (if applicable), to the affected process, must be drawn up by the operator as part of the MEL approval process, so that they have been established before the MEL document has been approved. Such alternate procedures are normally included in the associated operations (O) procedure.

3. ‘Any in excess of those required by regulations’ means that the listed item is required by applicable legislation (e.g. Part OPS, Single European Sky legislation or the applicable airspace requirements) must be operative and only excess items may be inoperative. When the item is not required, it may be inoperative for the time specified by its rectification interval category. Whenever this condition is used in the MMEL, the applicable regulations for the intended flight routes and the resulting dispatch restrictions need to be clarified at the operator’s MEL level.

4. ‘As required by (operational) regulations’ means that the listed item of equipment is subject to certain provisions (restrictive or permissive) expressed in the applicable legislation (e.g. regulation Air Operations, Single European Sky legislation or the applicable airspace requirements). When the equipment is not required, it may be inoperative for the time specified by its rectification interval category.

5. ‘Calendar Day’ means a 24-hour period from midnight to midnight based on either UTC or local time, as selected by the operator. All calendar days are considered to run consecutively.

6. ‘Combustible Material’ means the material which is capable of catching fire and burning. In particular: if a MEL item prohibits loading of combustible (or flammable or inflammable) material, no material may be loaded except the following:

1) Cargo handling equipment (unloaded, empty or with ballast);

2) Fly away kits (excluding e.g. cans of hydraulic fluid, cleaning solvents, batteries, capacitors, chemical generators, etc.);

Note: If serviceable tyres are included, they should only be inflated to a minimum pressure that preserves their serviceability; and

3) Inflight service material (return catering — only closed catering trolleys/boxes, no newspapers, no alcohol or duty free goods).

7. ‘Commencement of flight’ is the point when an aircraft begins to move under its own power for the purpose of preparing for take-off.

8. ‘Considered Inoperative’ as used in the dispatch conditions, means that item must be treated for dispatch, taxiing and flight purposes as though it were inoperative. The item shall not be used or operated until the original deferred item is repaired. Additional actions include: documenting the item on the dispatch release (if applicable), placarding, and complying with all remarks, exceptions, and related MMEL provisions, including any (M) and (O) procedures and observing the rectification interval.

9. Dash ‘#’ in column 2 (Rectification Interval), or its equivalent in an MMEL, means that the rectification interval is not specified at the level of that item, but rather that it is specified in another MMEL item that is referred to as part of the dispatch conditions (e.g. item B is considered to be inoperative).

10. ‘Day’ or ‘Daylight’ means the period between the beginning of morning civil twilight and the end of evening civil twilight relevant to the local aeronautical airspace; or such other period, as may be prescribed by the appropriate authority.

11. ‘Day of discovery’ means the calendar day that a malfunction was recorded in the aircraft maintenance record/log book.

12. ‘Extended overwater flight’ means a flight where the aeroplane is operated over water at a distance, away from land suitable for making an emergency landing, that is greater than:

(1) the distance covered in 120 minutes at cruising speed, or 400 NM, whichever is the lesser, in the case of aeroplanes that are capable of continuing the flight to an aerodrome with the critical engine(s) becoming inoperative at any point along the route, or with planned diversions; or

(2) for all other aeroplanes, the distance covered in 30 minutes at cruising speed, or 100 NM, whichever is the lesser.

13. ‘Flight’, for the purposes of this MMEL, means:

—             for aeroplanes: the period of time between the moment when an aircraft begins to move under its own power, for the purpose of preparing for take-off, until the moment the aircraft comes to a complete stop on its parking area, after the first landing.

—             for helicopters: the period of time between the moment when the rotor of the helicopter starts to turn for the purpose of taking off, until the moment when the rotor is stopped after the helicopter finally comes to rest at the end of the flight.

14. ‘Flight Day’, a 24-hour period from midnight to midnight based on either UTC or local time, as selected by the operator, during which at least one flight is initiated for the affected aircraft. ‘ETOPS’ or ‘ER operations’ refers to extended range operations of a two-engine airplane as defined by Part-SPA.

15. ‘Icing Conditions’ means an atmospheric environment that may cause ice to form on the aircraft or in the engine(s) as defined in the AFM/RFM.

16. ‘If installed’ means that the item is either optional or is not required to be installed on all aircraft covered by the MMEL.

17. ‘Inoperative’ means that the item does not accomplish its intended purpose or is not consistently functioning within its approved operating limits or tolerances.

18. ‘Is not used’ in the provisions, remarks or exceptions for an MMEL item may specify that another item relieved in the MMEL ‘is not used’. In such cases, crew members should not activate, actuate, or otherwise utilise that item under normal operations. It is not necessary for the operators to accomplish the (M) procedures associated with the item. However, operations-related provisions, (O) procedures must be complied with. An additional placard must be affixed, to the extent practical, adjacent to the control or indicator for the item that is not used to inform crew members that an item is not to be used under normal operations.

19. ‘Intended flight route’ corresponds to any point on the route including diversions to reach alternate aerodromes required to be selected by the operational rules.

20. ‘Item’ means component, instrument, equipment, system or function.

21. ‘(M)’ indicates a requirement for a specific maintenance procedure which 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 authorised to perform certain functions. The satisfactory accomplishment of all maintenance procedures, regardless of who performs them, is the responsibility of the operator. Appropriate procedures are required to be published as part of the Operator’s Manual or MEL.

22. ‘Master Minimum Equipment List’ means a document approved by the Agency that establishes the aircraft equipment allowed to be inoperative under conditions specified therein for a specific type of aircraft.

23. ‘Maximum distance from an adequate aerodrome for two-engine aeroplanes’ as defined in SPA.ETOPS and CAT.OP.AH.140.

24. ‘Minimum Equipment List’ means a document established as per paragraph 5(c) of Article 30 of Regulation (EU) 2018/1139 and approved by the competent authority, in accordance with ORO.MLR.105 of Annex III (Part-ORO) to Regulation (EU) No 965/2012, that authorises an operator to dispatch an aircraft with aircraft equipment inoperative as per CAT.IDE.A/H.105 of Annex I (Part-CAT) to Regulation (EU) No 965/2012 or NCC.IDE.A/H.105 of Annex VI (Part-NCC) to Regulation (EU) No 965/2012 under the conditions specified therein.

25. ‘Notes’ provide additional information for flight crew or maintenance consideration. Notes are used to identify applicable material which is intended to assist with compliance, but do not relieve the operator of the responsibility for compliance with all applicable requirements. Notes are not a part of the dispatch conditions.

26. ‘Number Installed’ is the number (quantity) of items normally installed in the aircraft. This number represents the aircraft configuration considered in developing this MMEL. Should the number be a variable (e.g. passenger cabin items), or not applicable, a number is not required; a ‘-’ is then inserted.

Note: Where the MMEL shows a variable number installed, the MEL should reflect the actual number installed, as far as practical.

27. ‘Number required for dispatch’ is the minimum number (quantity) of items required for operation provided the conditions specified are met. Should the number be a variable (e.g. passenger cabin items) or not applicable, a number is not required; a ‘-’ is then inserted.

Note: Where the MMEL shows a variable number required for dispatch, the MEL should reflect the actual number required for dispatch, as far as practical, or an alternate means of configuration control approved by the competent authority.

28. ‘-’ in the Number Installed Column (respectively Number Required for Dispatch Column) indicates a variable number (quantity) of the item installed (respectively item required) or not applicable.

Note: Where the MMEL shows a variable number installed, the MEL should reflect the actual number installed, as far as practical.

29. ‘(O)’ indicates a requirement for a specific operational procedure which must be accomplished in planning for and/or operating with the listed item inoperative. Normally these procedures are accomplished by the flight crew; however, other personnel may be qualified and authorised to perform certain functions. The satisfactory accomplishment of all procedures, regardless of who performs them, is the responsibility of the operator. Appropriate procedures are required to be published as a part of the operator’s manual or MEL.

Note: The (M) and (O) symbols are required in the operator’s MEL.

30. ‘Operating minima’ means the set of requirements associated to operations requiring a specific approval (refer to Part-SPA).

31. ‘Operative’ means that the system and/or component can accomplish its intended purpose and consistently functions normally within its design operating limit(s) and tolerance(s). When an MMEL item specifies that an item of equipment must be operative, it does not mean that its operational status must be verified; the item is to be considered to be operative unless it is reported or known to be malfunctioning. When an MMEL item specifies that an item of equipment must be verified as being operative, it means that it must be checked and confirmed as being operative at the interval(s) specified for that MMEL item. When an MMEL item specifies that an item of equipment must be verified, but no interval is specified, verification is only required at the time of deferral.

32. ‘Placarding’ Each inoperative item must be placarded, as applicable, to inform and remind the crew members and maintenance personnel of the item’s condition.

Note: To the extent practical, placards should be located adjacent to the control or indicator for the item affected; however, unless otherwise specified, placard wording and location will be determined by the operator.

33. ‘Rectification intervals’ Inoperative items or components, deferred in accordance with the MEL, must be rectified at or prior to the rectification intervals established by the following letter designators:

Category A

No standard interval is specified. However, items in this category shall be rectified in accordance with the conditions stated in the MMEL.

(i) Where a time period is specified in calendar days or flight days, the interval excludes the day of discovery.

(ii) Where a time period is specified other than in calendar days or flight days, it shall start at the point when the defect is deferred in accordance with the operator’s approved MEL.

Category B

Items in this category shall be rectified within three (3) calendar days, excluding the day of discovery.

Category C

Items in this category shall be rectified within ten (10) calendar days, excluding the day of discovery.

Category D

Items in this category shall be rectified within one hundred and twenty (120) calendar days, excluding the day of discovery.

34. ‘Remarks or Exceptions’ include statements either prohibiting or allowing operation with a specific number of items inoperative, provisos (conditions and limitations), notes, (M) and/or (O) symbols, as appropriate for such operation.

35. ‘Required Cabin Crew Seat’ is a seat in the aircraft cabin which meets the following conditions:

1) Where the certification of the cabin requires this seat to be occupied by a qualified cabin crew member as specified in the Operations Manual;

2) This seat is a part of the station to which a qualified cabin crew member is assigned for the flight; and

3) The qualified cabin crew member assigned to the station is a member of the minimum cabin crew designated for the flight.

36. Triple Asterisk ‘***’ means an item which is not required by the regulations, but which may have been installed on some models of aircraft that are covered by this MMEL. This item may be included on the aircraft operator’s MEL after it has been determined that the item has been installed on one or more of the aircraft operator’s aircraft. The triple asterisk symbol, however, must not be carried forward into the aircraft operator’s MEL. It should be noted that the use of this symbol does not provide the authority to install or remove an item from an aircraft.

37. ‘Visible Moisture’ means an atmospheric environment containing water in any form that can be seen in natural or artificial light; for example, clouds, fog, mist, rain, sleet, hail, or snow.

Issue No: MMEL/2

CS MMEL.125 Operational and Maintenance Procedures

ED Decision 2014/004/R

Accomplishment instructions for the operational and maintenance procedures identified in the MMEL by the associated symbols are developed and validated by the applicant.

GM1 MMEL.125 Operational and maintenance procedures

ED Decision 2014/004/R

VALIDATION OF OPERATIONAL AND MAINTENANCE PROCEDURES

(a) Compliance with CS MMEL.125 does not require an individual review of every and each operational or maintenance procedure.

(b) A description of the validation methods for the operational and maintenance procedures has to be made available to the Agency upon request.

CS MMEL.130 Rectification Interval

ED Decision 2014/004/R

A rectification interval is established for each MMEL item in accordance with the following categories:

(a) Category A: No standard interval is specified; however, items in this category shall be rectified in accordance with the conditions stated in the MMEL.

(1) Where a time period is specified in calendar days or flight days, the interval excludes the day of discovery.

(2) Where a time period is specified other than in calendar days or flight days, it shall start at the point when the defect is deferred in accordance with the operator’s approved MEL.

(b) Category B: Items in this category shall be rectified within 3 calendar days, excluding the day of discovery.

(c) Category C: Items in this category shall be rectified within 10 calendar days, excluding the day of discovery.

(d) Category D: Items in this category shall be rectified within 120 calendar days, excluding the day of discovery. Items in this category meet the following criteria:

(1) the absence of the item does not adversely affect crew workload;

(2) the crew do not rely on the function of that item on a routine or continuous basis; and

(3) the crew’s training, subsequent habit patterns and procedures do not rely on the use of that item.

GM1 MMEL.130 Rectification Interval

ED Decision 2014/004/R

USE OF CATEGORY D

The rectification interval category D is normally used for MMEL items of an optional nature such as items installed in excess of the applicable certification and operational requirements.

GM2 MMEL.130 Rectification Interval

ED Decision 2014/004/R

RECTIFICATION INTERVAL EXTENSION

(a) The MMEL should highlight in its preamble when rectification interval extensions have been considered in the development of the MMEL.

(b) Where quantitative analysis forms part of the justification, rectification interval and rectification interval extensions, if any, should be considered in this analysis (see CS MMEL.145 and GM1 MMEL.145(d)).

GM3 MMEL.130 Rectification Interval

ED Decision 2014/004/R

RECTIFICATION INTERVAL FOR ‘REFERED TO’ ITEM

When an MMEL item is referring to another MMEL item or another document where a rectification interval is provided, the rectification interval does not need to be specified. In such case, a dash symbol may be used.

GM4 MMEL.130 Rectification Interval

ED Decision 2020/012/R

If a time period is specified in flight hours for an item whose rectification interval category is A, the flight hours that are counted as part of that period should start at the commencement of taxiing prior to the first flight for aeroplanes and at the start of the rotation of the rotor for helicopters under the associated MEL item.

Issue No: MMEL/2

CS MMEL.135 Rectification Interval Extension

ED Decision 2014/004/R

The MMEL preamble indicates if extension of the rectification intervals of category B, C and D is applicable.