AD Issued for Lycoming O-540 and IO-540 Piston Pins - National Agricultural Aviation Association

The FAA has adopted a new airworthiness directive (AD 2026-17-10) for certain Lycoming O-235, O-540 and IO-540 engines with a certain piston pin installed. This AD was prompted by several reports of piston pin failure that resulted in metal particulate contamination in the engine oil and engine failure. This AD requires replacement of the affected piston pin with a part eligible for installation and, for all affected 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.

Affected piston pins are those having part number LW-13445 and one of the following:

An FAA Form 8130-3 from the original equipment manufacturer (OEM) for production dated between January 7, 2021 through December 15, 2025
An FAA Form 8130-3 from the OEM for which the production date on the Form 8130-3 cannot be determined
An FAA Form 8130-3 that is not available

For more information, see Lycoming Service Bulletin No. 667A, dated March 12, 2026.

AD 2026-17-20 is effective September 14, 2026.