Abstract: he structural designs of AD-series aircraft are described in detail,especially for AD-200 aircraft. Based on testing data a connective method with glue nails and toothed nails is recommended, which can solve the problem of connection between a metal joint and a honey-comb sandwich structure. The difficulty of direct connection between a metal structure and a honeycomb sandwich structure is solved by using a plywood transition structure. In addition,a set of reliable measure of fail-safe designs are proposed.

Key words: honeycomb structures, glass fibers, fail-safe system