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Shop Talk: "Minor Change" and "Type Design".Shop Talk: "Minor Change" and "Type Design".

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: 14 CFR 21.93 defines a “minor change” in type design as one that has no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, or other characteristics affecting the airworthiness of the product. What is a “type design”?

Answer:  Type design is defined in 14 CFR 21.31.

Section 21.31 states that the type design consists of:

(a) The drawings and specifications, and a listing of those drawings and specifications, necessary to define the configuration and the design features of the product shown to comply with the requirements of that part of this subchapter applicable to the product;

(b) Information on dimensions, materials, and processes necessary to define the structural strength of the product;

(c) The Airworthiness Limitations section of the Instructions for Continued Airworthiness as required by Parts 23, 25, 27, 29, 31, 33, and 35 of this chapter, or as otherwise required by the Administrator; and as specified in the applicable airworthiness criteria for special classes of aircraft defined in § 21.17(b); and

(d) For primary category aircraft, if desired, a special inspection and preventive maintenance program designed to be accomplished by an appropriately rated and trained pilot-owner.

(e) Any other data necessary to allow, by comparison, the determination of the airworthiness, noise characteristics, fuel venting, and exhaust emissions (where applicable) of later products of the same type.

Submit your own question via e-mail.

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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