FAA issues directive for Lycoming engines due to potential piston pin failure

The Federal Aviation Administration (FAA) has issued Airworthiness Directive 2026-17-10 regarding specific Lycoming O-235, O-540, and IO-540 engines. The directive, effective September 14, 2026, affects approximately 957 engines registered in the United States.

The measure follows reports from Lycoming of metallic particles in oil and two engine failures. Investigations revealed that certain thin-wall piston pins (P/N LW-13445) contained microfissures and metal inclusions due to manufacturing process changes. If these pins fail, debris can enter the lubrication system, potentially damaging bearings and cylinders, obstructing oil passages, and causing total engine failure.

Initial requirements include an oil change and visual inspections of the filter, pressure screen, and suction screen for metallic debris. Depending on the engine's history, inspections must occur either before the next flight or within the first five hours of service after the directive takes effect. If metallic residue is found, the affected pins must be replaced before further flight.