AD FAA-2013-0661

We are adopting a new airworthiness directive (AD) for Schempp-Hirth Flugzeugbau GmbH Model Duo Discus T gliders. This AD results from mandatory continuing airworthiness information (MCAI) issued 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 the instructions provided to inspect the propeller hub and blades are insufficient for detecting cracks and/or other damage, and other operating instructions provided by the flight and maintenance manual are incorrect and insufficient. We are issuing this AD to require actions to address the unsafe condition on these products.