For any transport category, turbine-powered airplane with a type certificate issued after January 1, 1958, regardless of whether the maximum take-off gross weight is a result of an original type certificate or a later design change, and with a maximum take-off gross weight greater than 75,000 pounds, or with a maximum take-off gross weight less than 75,000 pounds for which a limit of validity of the engineering data that supports the structural maintenance programme is required, its operator shall incorporate into its maintenance programme the airworthiness limitations containing the above limit of validity, and shall implement such maintenance programme with CAA’s approval.The airworthiness limitations in the preceding paragraph shall be implemented pursuant to Attachment 18-1.Attachment 18-1 Transport category airplane widespread fatigue damage inspection compliance requirements and limit of validity.pdf