Airworthiness Directives; Lycoming Engines
Key claim: The FAA is requiring aircraft operators to replace certain defective piston pins and inspect engine oil systems across an expanded list of Lycoming engine models to prevent engine damage or failure.
Abstract
(Rule · Transportation Department, Federal Aviation Administration) 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.
Why this matters
This final rule extends mandatory maintenance requirements to additional Lycoming engine models, broadening the operators covered by the earlier directive. Piston pin replacement and oil-system inspections address a defect that can cause engine damage or failure; the finding expands an existing safety requirement rather than introducing a new regulatory approach.