Final rule · 2026-22785

Airworthiness Directives; Lycoming Engines

The FAA is superseding Airworthiness Directive (AD) 2026-17- 10, which applied to Lycoming Engines (Lycoming) Model O-235, O-540, and IO-540 engines with a certain piston pin installed. AD 2026-17-10 required replacement of the affected piston pin with a part eligible for installation and, for certain engines, oil change and visual inspection of the engine oil filter, oil pressure screen, and oil suction screen for metal particulates. AD 2026-17-10 also prohibited the installation of an affected piston pin on any engine. Since the FAA issued AD 2026-17-10, the manufacturer has identified additional Lycoming Model engines that are subject to the unsafe condition, and the FAA determined the need to clarify the definition for an "affected piston pin," and include corrective action for engine models that were not listed in the manufacturer's service material. This AD requires replacement of the affected piston pin with a part eligible for installation and, for certain engines, oil change and visual inspection of the engine oil filter, oil pressure screen, and oil suction screen for metal particulates. This AD also prohibits the installation of an affected piston pin on any engine. This AD also expands the applicability to include additional affected engines with a certain piston pin installed. The FAA is issuing this AD to address the unsafe condition on these products.