FAA Issues Revision to AC 43.13-2

On July 29, 2026, the Federal Aviation Administration issued Advisory Circular 43.13-2C, Acceptable Methods, Techniques, and Practices—Aircraft Alterations. The new edition supersedes and cancels AC 43.13-2B, dated March 3, 2008. 

The AC provides acceptable methods, techniques, and practices for alterations to nonpressurized areas of civil aircraft with a gross weight of 12,500 pounds or less. Although primarily intended for mechanics, repair stations, and other certificated entities, it is also an important reference for aviation maintenance technician education. 

Key changes include:

• New guidance for larger-tire installations. Chapter 14 addresses the evaluation, documentation, testing, and maintenance of larger wheel-and-tire installations, commonly called tundra-tire modifications.
• Corrected structural load values. The structural-data chapter now lists a 1.5g normal/utility occupant sideward value, resolving an inconsistency in the prior edition. The seven-pound equipment example now uses a 6.6g downward factor and a 46.2-pound test load instead of the 6.0g/42-pound value in AC 43.13-2B.
• Renumbered chapters and paragraphs. A new introductory Chapter 1 shifts each former technical chapter forward by one number. Paragraphs now use chapter-based decimal numbering, so citations carried over from AC 43.13-2B generally will no longer point to the correct location.
• Guidance on performance-based Part 23 certification. The AC explains that legacy prescriptive standards may remain suitable for traditional aircraft designs but may be insufficient for some modern designs certificated under performance-based rules.
• Modernized references and terminology. FAA organizational terminology, regulatory citations, military specifications, Technical Standard Orders, approval guidance, and cross-references were updated.

Educational institutions should ensure that references to the AC are updated throughout their curricula.

The FAA has also stated that it is revising AC 43.13-1, Acceptable Methods, Techniques, and Practices—Aircraft Inspection and Repair, but has not provided an estimated timeline for publication.