Airworthiness Directives; Austro Engine GmbH Engines

The FAA is adopting a new airworthiness directive (AD) for certain Austro Engine GmbH Model E4 and E4P engines. This AD was prompted by reports of engine failures and the determination that certain batches of cap screws, installed on the inner main bearing positions of the engine, were manufactured at the lower end of the material strength tolerance. This AD requires replacing certain cap screws with a part eligible for installation and prohibits installing certain cap screws on any inner main bearing position of any engine. This AD also prohibits installing certain engine cores on any engine unless certain requirements are met. The FAA is issuing this AD to address the unsafe condition on these products.