ALTHOUGH the first certification or the Jetstream is to be to B.C.A.R. Section K and F.A.R. Part 23, it has always been intended that full airline standards will be maintained and ultimately certification to Section D, and Part 25 will be obtained. From the point of view of static strength these standards differ little and will have a minor effect only on the structural design. The spirit of the full airline requirements, however, is aimed at long life and fail safe philosophies, and this has been foremost in the thought behind Jetstream's structure. The design crack‐ free life is 40,000 flights (30,000 hours) with the additional aim of a fail safe primary structure. The long crack‐free life will be obtained by restricting the working and fluctuating stresses to values decided for each component by its own spectrum of load cycles. Fail safe primary structure is achieved by the duplication of members, alternative load paths, ‘catchers’, or by effective crack stoppers.