Airworthiness Directives; Austro Engine GmbH Engines

The FAA is adopting a new airworthiness directive (AD) for certain Austro Engine GmbH (Austro) Model E4 and E4P engines. This AD was prompted by reports of engine failures and an investigation where cracks were discovered on the pistons. This AD requires repetitive borescope inspections (BSIs) for cracks on the pistons, and, if necessary, removal from service and replacement of the piston, and a fuel sample analysis for water contamination and, if contamination is found, replacement of the high-pressure pump (HPP), injectors, and fuel rails. The FAA is issuing this AD to address the unsafe condition on these products.