# 2026-22785: FAA Orders Engine Pin Swaps to Keep Pistons From Misbehaving 2026-22785, Airworthiness Directives; Lycoming Engines, is a Federal Register rule from Transportation Department, Federal Aviation Administration published 2026-11-09, effective 2026-11-24; PRIA reads it as touching household money (as of 2026-11-11). - Canonical: https://policyrisk.com/federal-register/2026-22785 - As of: 2026-11-11 - Plain-text twin of the page above; the HTML and this file carry the same facts. ## Facts - Document number: 2026-22785 - Title: Airworthiness Directives; Lycoming Engines - Type: Rule - Agencies: Transportation Department; Federal Aviation Administration - Citation: 91 FR 70781 - Published: 2026-11-09 - Effective: 2026-11-24 - Comments close: not stated - Significant: no - Touches household money: yes - Regulation identifier numbers: 2120-AA64 - Last updated: 2026-11-11 ## In one line FAA Orders Engine Pin Swaps to Keep Pistons From Misbehaving ## Summary If you own or work with Lycoming O-235, O-540, or IO-540 engines, listen up! The FAA is updating rules to replace certain piston pins that could cause engine trouble, plus check oil parts for metal bits. These changes start November 24, 2026, and might cost some time and money but keep your engines safe and sound. ## Abstract 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. ## Effects PRIA read - Mandatory piston-pin replacement: cost, high. If you own or operate Lycoming engines listed in the AD with piston pin P/N LW-13445 manufactured between January 7, 2021 and December 15, 2025 (or if the manufacture date is unknown), you must replace the affected piston pin with a part eligible for installation. The AD requires replacement per Ly… - Immediate oil change and inspection deadline: cost, medium. Effective November 24, 2026, Group 1 and Group 2 engines (except Group 2 engines with ≥150 hours time-in-service (TIS) as of that date) must have an oil change and a visual inspection of the engine oil filter, oil pressure screen, and oil suction screen for metal particulates within 5 hours TIS aft… - Deadlines for piston-pin replacement by engine group: cost, medium. The AD sets group-specific replacement deadlines: Group 2 engines with ≥150 hours TIS as of November 24, 2026 must have affected piston pins replaced before further flight; Group 2 engines with <150 hours must replace within 25 hours TIS after November 24, 2026 or before reaching 150 total hours TI… - Ban on installing affected piston pins: benefit, low. Starting November 24, 2026, you may not install a piston pin defined as 'affected' (P/N LW-13445 manufactured January 7, 2021–December 15, 2025, or with unknown manufacture date) on any engine. The AD explicitly prohibits installation of those affected piston pins after the effective date. - Estimated compliance cost and fleet size: cost, high. The FAA estimates this AD affects 957 engines on U.S.-registered airplanes and estimates a per-engine compliance cost of $4,325 (25 work-hours × $85/hour = $2,125 labor plus $2,200 parts), for a total U.S. operator cost of $4,139,025. The FAA notes some costs may be covered under warranty by the ma… - Special flight permits limited by inspection results: mixed, low. Special flight permits may be issued to ferry aircraft for replacement work only if no metal particulates are found during the inspection required by the AD. For Group 2 engines not subject to the 5-hour inspection, an oil change showing no metal particulates is required before issuing a special fl… ## Related documents - [2026-15585](https://policyrisk.com/federal-register/2026-15585): Requirements for Interference-Tolerant Radio Altimeter Systems, 2026-07-31 - [2026-13440](https://policyrisk.com/federal-register/2026-13440): Enabling Supersonic Overland Flight, 2026-07-02 - [2026-13126](https://policyrisk.com/federal-register/2026-13126): Designation-Restrict the Operation of Unmanned Aircraft in Close Proximity to a Fixed Site Facility; Extension of Comment Period, 2026-06-30 - [2026-08943](https://policyrisk.com/federal-register/2026-08943): Designation-Restrict the Operation of Unmanned Aircraft in Close Proximity to a Fixed Site Facility, 2026-05-06 - [2025-04846](https://policyrisk.com/federal-register/2025-04846): Extension of the Prohibition Against Certain Flights in the Territory and Airspace of Libya, 2025-03-20 - [2025-03853](https://policyrisk.com/federal-register/2025-03853): Enforcement Policy Regarding “Drug and Alcohol Testing of Certificated Repair Station Employees Located Outside of the United States; Corre…, 2025-03-11 ## Sources - [2026-22785 on federalregister.gov](https://www.federalregister.gov/documents/2026/11/09/2026-22785/airworthiness-directives-lycoming-engines) - [2026-22785 as published (PDF)](https://www.govinfo.gov/content/pkg/FR-2026-11-09/pdf/2026-22785.pdf) ## Related - [Previous: 2026-22781, Technical Corrections of Commercial Space Transportation Regulations](https://policyrisk.com/federal-register/2026-22781) - [Next: 2026-22788, National Emission Standards for Hazardous Air Pollutants: Polyvinyl Chloride an…](https://policyrisk.com/federal-register/2026-22788) - [All Federal Register documents](https://policyrisk.com/federal-register) Source: PRIA, https://policyrisk.com/federal-register/2026-22785 (as of 2026-11-11).