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Shop Talk: Avionics installations

Wish you had a better understanding of the regulations when talking to your mechanic or the avionics shop? Aircraft Electronics Association Vice President of Government/Industry Affairs Ric Peri answers your frequently asked questions.


Question: How can you install an antenna without the alteration to the fuselage being considered a major alteration?

Answer: The answer to this question actually dates back to 1958 and the Civil Aeronautics Administration (CAA). In the 1958 printing of the Civil Aeronautics Manual 18 (CAM 18), the CAA published an interpretation of major alterations, which included the root of the language that was transferred into the FARs in 1964. In this document, the CAA states the criteria for an airframe major alteration include “Major changes to the basic design or external configuration of any structural component such as: … fuselage ….” It is clear that the intent of this regulation is focused on major changes to the basic design of the fuselage or major changes in the external configuration of the fuselage. A basic communication or navigation antenna seldom, if ever, would constitute a major change.

Why is the CAM 18 interpretation still valid?

In 1961 the Federal Aviation Agency announced the initiation of a project to recodify the Civil Air Regulations and related regulatory materials. In the notice the FAA claimed that it proposed no substantive changes in the regulations and therefore it was not a notice of proposed rulemaking subject to the Administrative Procedure Act. The program would not result in any new regulatory requirements. Nor would it change any of the regulatory requirements in the present system, with the exception that some obviously obsolete rules possibly could be eliminated. The FAA claimed that most of the current rules and regulatory materials had been inherited from predecessor organizations and were promulgated by them over a period of more than 20 years. As a result, the regulatory system in 1961, which embraced the Civil Air Regulations, Civil Aeronautics Manuals, Regulations of the Administrator, etc. did not reflect the consolidation of rulemaking authority affected by the Federal Aviation Act of 1958.

Since the words used in today’s Part 43 Appendix A date back to the original recodification of the regulations, the CAA interpretation is still valid.

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Note: AEA offers this column in order to foster greater understanding of the Federal Aviation Regulations and the rules that govern the industry. AEA strives to make them as accurate as possible at the time they are written, but rules change so you should verify the information. AEA disclaims any warranty for the accuracy of the information provided. This information is not meant to serve as legal advice.

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