ORO.MLR.105 Minimum equipment list

GENERAL

(a)The Minimum Equipment List (MEL) is a document that lists the equipment that may be temporarily inoperative, subject to certain conditions, at the commencement of flight. This document is prepared by the operator for their own particular aircraft taking account of their aircraft configuration and all those individual variables that cannot be addressed at MMEL level, such as operating environment, route structure, geographic location, aerodromes where spare parts and maintenance capabilities are available, etc., in accordance with a procedure approved by the competent authority.

(b)The MMEL, as defined in the mandatory part of the operational suitability data established in accordance with Commission Regulation (EU) No 748/2012, is developed in compliance with CS-MMEL or CS-GEN-MMEL. These Certification Specifications contain, among other, guidance intended to standardise the level of relief granted in MMELs, in particular for items that are subject to operational requirements. If a MMEL established as part of the operational suitability data is not available and items subject to operational requirements are listed in the available MMEL without specific relief or dispatch conditions but only with a reference to the operational requirements, the operator may refer to CS-MMEL or CS-GEN-MMEL guidance material, as applicable, to develop the relevant MEL content for such items.

NON-SAFETY-RELATED EQUIPMENT

(a)Most aircraft are designed and certified with a significant amount of equipment redundancy, such that the airworthiness requirements are satisfied by a substantial margin. In addition, aircraft are generally fitted with equipment that is not required for safe operation under all operating conditions, e.g. instrument lighting in day VMC.

(b)All items related to the airworthiness, or required for the safe operation, of the aircraft and not included in the list are automatically required to be operative.

(c)Equipment, such as entertainment systems or galley equipment, may be installed for passenger convenience. If this non-safety-related equipment does not affect the airworthiness or operation of the aircraft when inoperative, it does not require a rectification interval, and need not be listed in the operator's MEL, if it is not addressed in the MMEL. The exceptions to this are as follows:

(1)Where non-safety-related equipment serves a second function, such as movie equipment being used for cabin safety briefings, operators should develop and include operational contingency procedures in the MEL in case of an equipment malfunction.

(2)Where non-safety-related equipment is part of another aircraft system, for example the electrical system, procedures should be developed and included in the MEL for deactivating and securing in case of malfunction. In these cases, the item should be listed in the MEL, with compensating provisions and deactivation instructions if applicable. The rectification interval will be dependent on the secondary function of the item and the extent of its effect on other systems.

(d)If the operator chooses to list non-safety-related equipment in the MEL, not listed in the MMEL, they should include a rectification interval category. These items may be given a ‘D’ category rectification interval provided any applicable (M) procedure (in the case of electrically supplied items) is applied.

(e)Operators should establish an effective decision making process for failures that are not listed to determine if they are related to airworthiness and required for safe operation. In order for inoperative installed equipment to be considered non-safety-related, the following criteria should be considered:

(1)the operation of the aircraft is not adversely affected such that standard operating procedures related to ground personnel, and crew members are impeded;

(2)the condition of the aircraft is not adversely affected such that the safety of passengers and/or personnel is jeopardised;

(3)the condition of the aircraft is configured to minimise the probability of a subsequent failure that may cause injury to passengers/personnel and/or cause damage to the aircraft;

(4)the condition does not include the use of required emergency equipment and does not impact emergency procedures such that personnel could not perform them.

AMENDMENTS TO THE MEL FOLLOWING CHANGES TO THE MMEL — APPLICABLE CHANGES AND ACCEPTABLE TIMESCALES

(a)The following are applicable changes to the MMEL that require amendment of the MEL:

(1)a reduction of the rectification interval;

(2)change of an item, only when the change is applicable to the aircraft or type of operations and is more restrictive.

(b)An acceptable timescale for submitting the amended MEL to the competent authority is 90 days from the effective date specified in the approved change to the MMEL.

(c)Reduced timescales for the implementation of safety-related amendments may be required if the Agency and/or the competent authority consider it necessary.

MEL FORMAT

(a)The MEL format and the presentation of items and dispatch conditions should reflect those of the MMEL.

(b)The ATA 100/2200 Specification numbering system for MEL items is preferred.

(c)Other formats and item numbering systems may be used provided they are clear and unambiguous.

MEL PREAMBLE The MEL preamble should:

(a)reflect the content of the MMEL preamble as applicable to the MEL scope and extent;

(b)contain terms and definitions used in the MEL;

(c)contain any other relevant specific information for the MEL scope and use that is not originally provided in the MMEL;

(d)provide guidance on how to identify the origin of a failure or malfunction to the extent necessary for appropriate application of the MEL;

(e)contain guidance on the management of multiple unserviceabilities, based on the guidance given in the MMEL; and

(f)contain guidance on placarding of inoperative items to inform crew members of equipment condition, as appropriate. In particular, when such items are accessible to the crew during flight, the control(s) and indicator(s) related to inoperative unit(s) should be clearly placarded.

SCOPE OF THE MEL The MEL should include:

(a)The dispatch conditions associated with flights conducted in accordance with specific approvals held by the operator in accordance with Part-SPA.

(b)Specific provision for particular types of operations carried out by the operator in accordance with ORO.GEN.310 and with ORO.AOC.125.

EXTENT OF THE MEL The operator should include guidance in the MEL on how to deal with any failures that occur between the commencement of the flight and the start of the take-off. If a failure occurs between the commencement of the flight and the start of the take-off, any decision to continue the flight should be subject to pilot judgement and good airmanship. The pilot-in-command/commander may refer to the MEL before any decision to continue the flight is taken.

SCOPE OF THE MEL

(a)Examples of special approvals in accordance with Part-SPA may be:

(1)RVSM,

(2)ETOPS,

(3)LVO.

(b)Different types of operations carried out by the operator in accordance with ORO.GEN.310 and with ORO.AOC.125:

(1)crew training,

(2)positioning flights,

(3)demonstration flights.

(c)When an aircraft has installed equipment which is not required for the operations conducted, the operator may wish to delay rectification of such items for an indefinite period. Such cases are considered to be out of the scope of the MEL, therefore modification of the aircraft is appropriate and deactivation, inhibition or removal of the item should be accomplished by an appropriate approved modification procedure.

PURPOSE OF THE MEL The MEL is an alleviating document having the purpose to identify the minimum equipment and conditions to operate safely an aircraft having inoperative equipment. Its purpose is not, however, to encourage the operation of aircraft with inoperative equipment. It is undesirable for aircraft to be dispatched with inoperative equipment and such operations are permitted only as a result of careful analysis of each item to ensure that the acceptable level of safety, as intended in the applicable airworthiness and operational requirements is maintained. The continued operation of an aircraft in this condition should be minimised.

GM1 ORO.MLR.105(e);(f) Minimum equipment list

RECTIFICATION INTERVAL (RI) The definitions and categories of rectification intervals are provided in CS-MMEL.

RECTIFICATION INTERVAL EXTENSION (RIE) — OPERATOR PROCEDURES FOR THE APPROVAL BY THE COMPETENT AUTHORITY AND NOTIFICATION TO THE COMPETENT AUTHORITY

(a)The operator’s procedures to address the extension of rectification intervals and ongoing surveillance to ensure compliance should provide the competent authority with details of the name and position of the nominated personnel responsible for the control of the operator’s rectification interval extension (RIE) procedures and details of the specific duties and responsibilities established to control the use of RIEs.

(b)Personnel authorising RIEs should be adequately trained in technical and/or operational disciplines to accomplish their duties. They should have necessary operational knowledge in terms of operational use of the MEL as alleviating documents by flight crew and maintenance personnel and engineering competence. The authorising personnel should be listed by appointment and name.

(c)The operator should notify the competent authority within 1 month of the extension of the applicable rectification interval or within the appropriated timescales specified by the approved procedure for the RIE.

(d)The notification should be made in a form determined by the competent authority and should specify the original defect, all such uses, the reason for the RIE and the reasons why rectification was not carried out within the original rectification interval.

RECTIFICATION INTERVAL EXTENSION (RIE) Procedures for the extension of rectification intervals should only be applied under certain conditions, such as a shortage of parts from manufacturers or other unforeseen situations (e.g. inability to obtain equipment necessary for proper troubleshooting and repair), in which case the operator may be unable to comply with the specified rectification intervals.

OPERATIONAL AND MAINTENANCE PROCEDURES

(a)The operational and maintenance procedures referenced in the MEL should be based on the operational and maintenance procedures referenced in the MMEL. Modified procedures may, however, be developed by the operator when they provide the same level of safety, as required by the MMEL. Modified maintenance procedures should be developed in accordance with Commission Regulation (EU) No 1321/2014.

(b)Providing appropriate operational and maintenance procedures referenced in the MEL, regardless of who developed them, is the responsibility of the operator.

(c)Any item in the MEL requiring an operational or maintenance procedure to ensure an acceptable level of safety should be so identified in the ‘remarks’ or ’exceptions’ column/part/section of the MEL. This will normally be ‘(O)’ for an operational procedure, or ‘(M)’ for a maintenance procedure. ‘(O)(M)’ means both operational and maintenance procedures are required.

(d)The satisfactory accomplishment of all procedures, regardless of who performs them, is the responsibility of the operator.

OPERATIONAL AND MAINTENANCE PROCEDURES

(a)Operational and maintenance procedures are an integral part of the compensating conditions needed to maintain an acceptable level of safety, enabling the competent authority to approve the MEL. The competent authority may request presentation of fully developed (O) and/or (M) procedures in the course of the MEL approval process.

(b)Normally, operational procedures are accomplished by the flight crew; however, other personnel may be qualified and authorised to perform certain functions.

(c)Normally, maintenance procedures are accomplished by the maintenance personnel; however, other personnel may be qualified and authorised to perform certain functions in accordance with Commission Regulation (EU) No 1321/2014.

(d)Operator's manuals may include the OM, the continued airworthiness management organisation manual (CAME) or other documents. Operational and maintenance procedures, regardless of the document where they are contained, should be readily available for use when needed for the application of the MEL.

(e)Unless specifically permitted by a maintenance procedure, an inoperative item may not be removed from the aircraft.

OPERATIONAL AND MAINTENANCE PROCEDURES — APPLICABLE CHANGES

(a)Changes to the operational and maintenance procedures referenced in the MMEL are considered applicable and require the amendment of the maintenance and operating procedures referenced in the MEL when:

(1)the modified procedure is applicable to the operator’s MEL; and

(2)the purpose of this change is to improve compliance with the intent of the associated MMEL dispatch condition.

(b)An acceptable timescale for the amendments of maintenance and operating procedures, as defined in (a), should be 90 days from the date when the amended procedures referenced in the MMEL are made available. Reduced timescales for the implementation of safety related amendments may be required if the competent authority considers it necessary.

OPERATION OF AN AIRCRAFT WITHIN THE CONSTRAINTS OF THE MMEL — OPERATOR’S PROCEDURES FOR THE APPROVAL BY THE COMPETENT AUTHORITY

(a)The operator’s procedures to address the operation of an aircraft outside the constraints of the MEL but within the constraints of the MMEL and ongoing surveillance to ensure compliance should provide the competent authority with details of the name and position of the nominated personnel responsible for the control of the operations under such conditions and details of the specific duties and responsibilities established to control the use of the approval.

(b)Personnel authorising operations under such approval should be adequately trained in technical and operational disciplines to accomplish their duties. They should have the necessary operational knowledge in terms of operational use of the MEL as alleviating documents by flight crew and maintenance personnel and engineering competence. The authorising personnel should be listed by appointment and name.

OPERATION OF AN AIRCRAFT WITHIN THE CONSTRAINTS OF THE MMEL — OPERATOR’S PROCEDURES FOR THE APPROVAL BY THE COMPETENT AUTHORITY Procedures for the operation of an aircraft outside the constraints of the MEL but within the constraints of the MMEL should only be applied under certain conditions, such as a shortage of parts from manufacturers or other unforeseen situations (e.g. inability to obtain equipment necessary for proper troubleshooting and repair), in which case the operator may be unable to comply with the constraints specified in the MEL.