FAA Airworthiness Directive

Response to Inquiry: FAA Airworthiness Directive AD 2024-21-02

On October 31, 2024, at Lycoming Engines’ request, the FAA issued Airworthiness Directive (AD) 2024-21-02, which requires enhanced visual inspection during regularly scheduled oil changes to detect indications of deterioration of certain connecting rod bushings. The AD also directs follow-on maintenance activities to replace potentially non-conforming connecting rod bushings.

By issuing AD 2024-21-02, the FAA now requires operators to follow guidance that has been contained in Lycoming Engines’ Service Bulletins 630 and Service Bulletin 480F since 2017. This action will help ensure continued airworthiness for those operators who were not already following Lycoming Engines’ recommended maintenance procedures. 

This AD is the latest in a series of long-standing, comprehensive steps taken by Lycoming Engines and the FAA to address safety concerns created when a former Lycoming Engines supplier manufactured non-conforming connecting rod bushings. In 2017, Lycoming Engines issued Service Bulletins 632 to protect customers from potentially non-conforming bushings, and the FAA made Service Bulletin 632 mandatory in AD 2017-16-11. That same year, Lycoming Engines issued Service Bulletin 630 to ensure that non-conforming bushings were not reinstalled during maintenance or overhaul activities. Lycoming Engines also amended Service Bulletin 480F to expand inspection guidance to all engines potentially containing bushings manufactured by Lycoming Engines’ former bushing supplier.

Customers should utilize Lycoming Engines’ Engine Serial Number History Search to see if their engine was shipped during the date range specified in AD 2024-21-02. Technical questions related to the applicability of Lycoming Engines’ service literature can be directed to the company’s
Technical Support team at 1-800-258-3279
or Technicalsupport@lycoming.com .