The Federal Aviation Administration has removed its earlier Lycoming piston pin airworthiness directive, AD 2026-17-10, and replaced it with AD 2026-22-13, which expands applicability to additional affected Lycoming engines with a certain piston pin installed. The final rule amends 14 CFR 39.13 and takes effect November 24, 2026. The Federal Register published it on November 9, 2026, as a final rule with request for comments, under Amendment 39-23515 and Docket No. FAA-2026-13797.
The directive applies to Lycoming engines listed in table 1 of the AD that have piston pin part number LW-13445 manufactured between January 7, 2021 and December 15, 2025. It also applies when a pin's manufacture date cannot be determined, but it does not apply if the current P/N LW-13445 pins were installed before January 7, 2021. The AD sorts affected engines into two groups by pin manufacture date. Group 2 engines have pins made from March 23, 2023 to December 15, 2025, or pins of unknown manufacture date, and Group 1 is every other affected engine. The FAA estimates the AD affects 957 engines installed on airplanes of U.S. registry.
The superseded AD 2026-17-10, issued August 28, 2026 (91 FR 55451), covered Lycoming Model O-235, O-540 and IO-540 engines with the pin installed. It required an eligible replacement part for the affected pin and, for certain engines, an oil change and visual inspection of the oil filter, oil pressure screen and oil suction screen for metal particulates. It also barred installing an affected pin on any engine, and it was prompted by several reports of pin failure that led to metal particulates in engine oil and engine failure.
What the new AD requires
Once effective, AD 2026-22-13 requires an eligible part to replace the affected piston pin on Lycoming engines that have it, and prohibits installing an affected pin on any engine. Certain engines also need an oil change, followed by a visual check of the oil filter, oil pressure screen and oil suction screen. Owners and operators of Group 1 and Group 2 engines must carry out the oil change and a visual inspection for metal particulates within 5 hours time in service after November 24, 2026. Group 2 engines with 150 or more hours time in service as of the effective date are excepted from that step. The FAA states the 5-hour oil change and inspection is an AD requirement that Lycoming MSB 667A does not contain.
If the inspection finds metal particulates, the affected pin must be replaced with an eligible part before further flight, following the Required Action of Lycoming MSB 667A dated March 12, 2026, as applicable to engine model. For Group 1 engines with pins manufactured January 7, 2021 to March 22, 2023, where the inspection found no particulates, replacement is due at the next maintenance event that requires removing a cylinder assembly with an affected pin. The alternative trigger is the next engine overhaul not exceeding the time between overhaul in Lycoming Service Instruction No. 1009BF, dated July 20, 2026, and whichever comes first after November 24, 2026 governs.
Group 2 engines with 150 or more hours time in service as of November 24, 2026 must have the pin replaced before further flight. Group 2 engines with fewer than 150 hours must be replaced within 25 hours time in service after that date, and in any case before or upon reaching 150 total hours since pin installation, whichever comes first. Across the AD, the FAA sets compliance times at 25 hours time in service or earlier after the effective date, depending on engine model.
The AD allows special flight permits for airplanes with affected engines under 14 CFR 21.197 and 21.199, provided no metal particulates are found during the required inspection. For Group 2 engines not covered by the inspection step, an oil change showing no metal particulates is required before a permit is issued.
The FAA says Lycoming reported metal particulates in engine oil during oil changes, along with two non-detectable engine failures, and the AD aims to prevent piston pin failure. According to the FAA, leaving the condition unaddressed could result in engine failure, loss of thrust control, in-flight shutdown, airplane damage and loss of control of the airplane. The agency adopted the rule without prior notice and comment, finding good cause. It says pin microcracks and inclusions are hard to detect before failure and can cause internal engine damage, in-flight shutdown and loss of control, and that the compliance time is shorter than the time needed for public comment and publication of a final rule.
The FAA invites comments on AD 2026-22-13, which must be received by December 24, 2026. They can be sent under Docket No. FAA-2026-13797 through regulations.gov, fax, mail or hand delivery, and the agency may amend the rule because of comments received by the closing date. The Director of the Federal Register approved incorporation by reference of Lycoming Service Instruction No. 1009BF as of November 24, 2026, and of Lycoming MSB 667A as of September 14, 2026. Lycoming material is available from Lycoming Engines in Williamsport, PA, and at lycoming.com/contact/knowledge-base/publications, and both documents can be viewed at the FAA Airworthiness Products Section in Burlington, MA, and at regulations.gov under the docket.
