It is acknowledged that Airworthiness Limitation Section (ALS) of the Instructions for Continued Airworthiness is an approved document, part of the Type Design, which is itself part of and approved through the Type Certificate.
Being part of the Type Certificate, any change to the ALS shall be handled according to the Part 21 Subpart D “Changes to Type-Certificates and Restricted Type-Certificates” requirements.
EASA interpretation of Part 21.A.91 requirement and associated Guidance Material has, up to now, always been to consider any change to the Type Certificate which alters the ALS, as major.
This interpretation might be seen as too restrictive and the industry has collected and it is ready to propose cases of ALS changes which can be classified as minor and approved using DOA privileges.
