Summary
The FAA proposes to supersede airworthiness directive (AD) 2018-07-16 which applies to all Austro Engine GmbH model E4 and E4P diesel piston engines. AD 2018-07-16 requires initial and repetitive replacement of the waste gate controller and the control rod circlip. Since the FAA issued AD 2018-07-16, Austro Engine GmbH developed a modification of the waste gate control-rod fail-safe bridge and spring- loaded circlip that terminates the need for repetitive replacement of the waste gate controller and the control rod circlip. This proposed AD would retain the requirements of AD 2018-07-16 and requires engine modification by installing a waste gate control-rod fail-safe bridge and new spring-loaded circlip that terminates the initial and repetitive replacement requirements of AD 2018-07-16. The FAA is proposing this AD to address the unsafe condition on these products.