Airworthiness Directives; Stemme GmbH Gliders

Official abstract: The FAA proposes to adopt a new airworthiness directive (AD) for all Stemme GmbH (Stemme) Model Stemme S 12 gliders. This proposed AD was prompted by reports of fuel leaking around certain copper sealing rings within the fuel system. This proposed AD would require repetitive visual checks of the fuel system for fuel leakage, and replacement of the affected copper sealing ring. This proposed AD would also prohibit the installation of affected parts. The FAA is proposing this AD to address the unsafe condition on these products.