Summary
The FAA proposes to supersede Airworthiness Directive (AD) 2023-20-03, which applies to certain Austro Engine GmbH Model E4 and E4P engines. AD 2023-20-03 requires repetitive engine oil analysis for aluminum content outside the acceptable limits and, if necessary, replacement of the pistons, piston rings, con-rods assembly, and crankcase or, as an alternative, replacement of the engine core. Since the FAA issued AD 2023-20-03, the manufacturer identified errors in the lists of affected engines and provided updated information, which prompted this proposed AD. This proposed AD would retain the requirements of AD 2023-20-03, add compliance times for additional affected engine serial numbers, and remove certain engine serial numbers from the applicability of the existing AD. The FAA is proposing this AD to address the unsafe condition on these products.