Considerations Related to UK CAA – MCAI (Mandatory Continuing Airworthiness Information)

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Sofema Online (SOL) looks at the process for managing MCAI within the UK CAA as part of the UK CAA / EASA Bilateral Agreement Technical Implementation Procedures (TIP).


International Civil Aviation Organization (ICAO) defines MCAI as “mandatory requirements for the modification, replacement of parts, or inspection of aircraft and amendment of operating limitations and procedures.”

» An Airworthiness Directive (AD) is one type of such information. ICAO requires that member States have a system to maintain the airworthiness of aeronautical products on their registry. As part of this system, States publish and exchange MCAI.

Unsafe Condition and MCAI

The Technical Agents (UK CAA or EASA Competent Authority) will perform the following activities for the civil aeronautical products for which they function as the authority discharging the SOD responsibilities:

» Issuing MCAI whenever the Technical Agent determines that an unsafe condition exists in a civil aeronautical product and is likely to exist or develop on a product of the same type design.

» This may include civil aeronautical products which develop unsafe conditions as a result of other products being installed on them. The content of MCAIs should include, but are not limited to, the following:

o Make, model, and serial numbers of affected civil aeronautical products;

o Description of the unsafe condition, reasons for the mandatory action, and its impact on the overall aircraft and continued operation;

o Description of the cause of the unsafe condition (e.g. stress corrosion, fatigue, design problems, quality control, suspected unapproved part);

o The means by which the unsafe condition was detected;

o Corrective actions and corresponding compliance times; and

o A list of the relevant manufacturer’s service information including reference number, revision number, and date;

» Issuing a revised MCAI to introduce an alleviation to the previously issued MCAI or issuing a superseding MCAI whenever any previously issued MCAI is found to be incomplete or inadequate and does not fully correct or properly mitigate the unsafe condition;

» In the case of emergency MCAIs, ensuring that the VA is notified prior to publication, when possible;

» Advising and assisting the VA on the appropriate actions to take in the issuance of its own MCAI;

Note - UK CAA maintains a web-based database of MCAI that can be accessed by the VA at the following locations:

» For the CAA: CAA publication CAP747 and its associated website:

» For EASA: AD publishing tool:

The Certificating Authority (CA) will share information on any change that affects operating limitations, life limits, or any other airworthiness limitations, to include manual changes and changes to certification maintenance requirements.

» These changes should be promptly sent to the Validating Authority (VA) in order to ensure the continued operational safety of affected aircraft.

o The Technical Agents may treat a reduced life limit as an unsafe condition and may accordingly issue an MCAI.

o The Technical Agents may also issue an MCAI for other limitation changes when considered as an unsafe condition

o The VA may either issue its own MCAI or adopt the CA’s MCAI in order to address all unsafe conditions on affected civil aeronautical products that have been certified, approved, or otherwise accepted by the VA.

Note - For certain cases of an unsafe condition related to production or maintenance, EASA may issue an Emergency Conformity Information (ECI) instead of an AD. Both ECI and AD are EASA-issued MCAI under Annex 8 to the Chicago Convention.

Alternative Methods of Compliance (AMOC) to an AD

EASA-approved AMOCs related to EASA ADs applicable to EU SOD products or STCs are automatically considered to be UK CAA approved, provided the related EASA AD has been adopted by the UK CAA or the UK CAA issued an AD with no deviations from the EASA AD.

UK CAA-approved AMOCs related to UK CAA ADs applicable to UK SOD products or STCs are separately approved by EASA.

»When issuing its approval EASA will give full consideration to the UK CAA-approved AMOC provided the related UK CAA AD has been adopted by EASA.

» When issuing its approval of the UK CAA AMOC, EASA should focus on areas where EASA standards deviate from UK standards in a way that may impact the mitigation measures applied by the UK CAA.

» EASA will rely on the UK CAA to support this process to the fullest extent.

Next Steps

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