Summary
We propose to adopt a new airworthiness directive (AD) for Alexander Schleicher, Segelflugzeugbau Model ASK 21 gliders. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as inadequate guidance for spin training operations. We are issuing this proposed AD to require actions to address the unsafe condition on these products.