I want to know what I have to do to revalidate my CPL MEP IR and obviously to make sure its all EASA. Is it just a case of passing 3 skills tests to revalidate them at this stage or will I need to go back to ground school
The requirements are for you to complete training as needed to reach the required level of proficiency, then a combined MEP/IR Proficiency Check.
For the MEP/IR Proficiency Check, it's actually just one combined test to renew both your MEP and IR ratings. See FCL.625 for IR Renewal requirements (CAP 804, Section 4, Part G, Subpart 1, page 3) and FCL.740 for MEP Class Rating Renewal requirements (CAP 804, Section 4, Part H, Subpart 1, page 6). Simples!
You can then apply to the CAA for an EASA licence which will be returned as a lifetime EASA CPL(A) with valid MEP and IR ratings.
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