Part 39 Interpretation Raises AD Compliance Questions

 - April 27, 2011, 11:00 AM

The FAA is seeking comments on a proposed legal interpretation of Airworthiness Directive (AD) regulations. The interpretation comes from the FAA’s Organization/Procedures Working Group of the Airworthiness Directive Implementation Aviation Rulemaking Committee (ARC). Issues identified by the ARC are mostly a result of the FAA’s 2002 plain-language revision of 14 CFR Part 39, which governs the AD process. The ARC raised four key questions about interpretation of Part 39. The first addresses the continuing obligation to maintain an AD-mandated configuration and how that affects ongoing compliance. The second covers whether compliance with all of an AD’s actions is mandatory or just the portion necessary to resolve the unsafe condition. In the third question, the ARC questioned the use of the term “applicable.” The fourth question addressed the issue of impossibilities in ADs, actions that cannot be done because, for example, a component to which the AD applies has been modified or removed during a modification. This seems to raise serious issues, because the FAA interpretation suggests that even if an AD cannot apply because the modified item is completely different from the item called out in the AD, the FAA will still require FAA approval via an alternative method of compliance. Interested parties may comment on the interpretation through May 16.