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UK Civil Aviation Regulations

These are published by the CAA on our UK Regulations pages. EU Regulations and EASA Access Guides published by EASA no longer apply in the UK. Our website and publications are being reviewed to update all references. Any references to EU law and EASA Access guides should be disregarded and where applicable the equivalent UK versions referred to instead.

Minimum Equipment Lists (MEL) and Master Minimum Equipment Lists (MMEL)

ORO.MLR.105 specifies the requirements for producing a Minimum Equipment List (MEL) from the Master Minimum Equipment List (MMEL).

For Air Navigation Order (ANO) operators, ANO 2016 Article 78 applies and a formal Permission is issued by the CAA.

Submitting the MEL for approval

The operator should submit the:

  • the MEL for approval; together with
  • the associated MMEL - which must be confirmed by the operator to be the latest version; and
  • the MEL Compliance Statement.

This submission should be emailed to: npa@caa.co.uk.

The MEL is reviewed jointly by the assigned Flight Operations Inspector, Airworthiness Surveyor and Operational Support Officer.


ORO.MLR.105 (a) states “A minimum equipment list (MEL) shall be established as specified under point 8.a.3 of Annex IV to Regulation (EC) No 216/2008, based on the relevant master minimum equipment list (MMEL) as defined in the data established in accordance with Regulation (EU) No 748/2012.” To determine which MMEL should be used:

1. Where the latest MMEL (or other OSD document) was accepted by EASA on or before 31 December 2020 this should be used as the source document. Any subsequent amendment after 31 December 2020 will need to be:

       a. Approved by the UK CAA, or

       b. Accepted or validated under the terms of a bilateral arrangement with the Certificating Authority.

Example: An EASA approved MMEL for a Bombardier product issued prior to 31 December 2020 is automatically accepted as part of the (EU) savings legislation as if it was issued by the UK CAA. Any subsequent amendment after this date will need to be accepted or validated under the terms of the UK-TCCA bilateral arrangement as the TCCA is the Certificating Authority for this product.

An EASA approved subsequent amendment is not accepted as EASA are not the primary certifying authority for this product.

2. Where there is not an EASA MMEL (or other OSD document) accepted by the EASA on or before 31 December 2020, a MMEL approved by UK CAA should be used as the source document. Any subsequent amendment will need to be:

           a. Approved by the UK CAA, or

           b. Accepted or validated under the terms of a bilateral with the Certificating Authority.

3. In the event that a MMEL has not been established as part of the operational suitability data for a particular type, the MEL may be based on the latest issue of the Type Certificate Holder’s MMEL approved by the Primary Certificating Authority. For Type Certificate Holders approved in the United States as the State of Design, this would be the FAA MMEL. The requirements of CS-MMEL must also be incorporated into the MEL (See GM1 ORO.MLR.105(a) for more information).

Note: Dependant on the classification of changes being incorporated into the MMEL, some bilateral arrangements allow automatic acceptance of the Certificating Authority’s approval. As a result, the UK CAA may not be aware of the amendment status of the latest MMEL source document. To determine if a change is acceptable to the UK CAA, the operator is responsible for obtaining confirmation from the Type Certificate Holder that the MMEL on which the operator MEL amendment is based has either been validated by the UK CAA, or accepted under the respective bilateral arrangement. The operator confirms this when completing the declaration on the MEL Compliance Document submitted with the MEL.

In the preamble, circumstances in which the flight crew can dispatch with an unserviceable item, must be specified. A system for determining whether items are non-safety related must also be developed and included in the MEL.

In addition a number of MMEL items for specific aircraft types are associated with UK certification requirements and need to be retained. This would be where there are notified UK national requirements as published in the aircraft Aircraft Flight Manual (AFM).

For certain types (e.g. Saab 340 or Falcon 20) the removal of the CAA generated MMEL and reversion to the Type Certificate Holder’s MMEL may have an effect on Rectification Interval Extensions (RIE). RIE allow operators to permit a one-time extension of the applicable RI category B, C or D, for the same duration as that specified in the MEL provided that the source MMEL allows RIE. RIE requires separate approval from the CAA and any application is reviewed jointly by the assigned FOI and AS. The application should be made in writing to the assigned FOI.

State emergency services helicopters

For the operation of state emergency services helicopters, the requirements for flight recorder standards are listed in the CAA Specification No. 23. The corresponding items for CVR, FDR and combination recorders in CS-MMEL, which perform similar functions, may be used as a guideline.

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