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Proposed Advisory Circular (AC) No. 21.101-1 Change 1, Advisory Material for the Establishment of the Certification Basis of Changed Aeronautical Products

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Information about this document as published in the Federal Register.

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This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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Federal Aviation Administration (FAA), DOT.


Notice of availability and request for comments.


This notice announces the availability of and request for comments on Draft Advisory Circular (AC) 21.101-1 Change 1,dated April 3, 2002, Advisory Material for the Establishment of the Certification Basis of Changed Aeronautical Products. This AC provides guidance for establishing the certification basis for changes made to aeronautical products. The FAA has issued a final rule, Type Certification Procedures for Changed Products, that amends the procedural regulations for the certification of changes made to type certification of aeronautical products. These amendments affect changes accomplished through either an amended type certificate or a supplemental type certificate. This proposal AC provides guidance for determining compliance with those amended procedural regulations for the certification of all aircraft, aircraft engines, and propellers.


Comments must be received on or before June 5, 2002.


Address your comments to the Docket Management System. U.S. Department of Transportation, Room Plaza 401, 400 Seventh St., SW., Washington, DC 20590-0001. You must identify the docket number at the beginning of your comments, and you should submit two copies of your comments.

You may also submit comments through the Internet to http://dms/​ You may review the public docket containing comments to these proposed AC in person in the Dockets Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Dockets Office is on the plaza level at the Department of Transportation building at the address above. Also, you may review public dockets on the Internet at

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Randall Petersen, Certification Procedures Branch, AIR-110, Aircraft Engineering Division, Aircraft Certification Service, Federal Aviation Administration, 800 Independence Ave., SW., Washington, DC 20591; telephone number: (202) 267-9583, fax (202) 278-5340.

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Comments Invited

The FAA invites you to participate in this action by submitting written data, views, or arguments. In your comments, identify AC 21-101-1 Change 1, Advisory Material for the Establishment of the Certification Basis of Changed Aeronautical Products, and the regulatory docket number specified previously. Submit them in duplicate to the DOT Rules Docket address specified above.

The FAA will consider all comments received on or before the closing date for comments before issuing the final AC. The docket is available for public inspection before and after the comments closing date.

Availability of Rulemaking Documents

You can get an electronic copy of this document from the Internet by taking the following steps:

(1) Go to the search function of the Department of Transportation's electronic Docket Management System (DMS) web page (​search).

(2) On the search page, type in the last four digits of the docket number shown at the beginning of this document. Click on “search.”

(3) On the next page, which contains the docket summary information, click on the item you want to see.

You can also get an electronic copy using the Internet through the FAA's web page at​avr/​arm/​nprm/​htm or the Federal Register's web page at​su_​docs/​aces/​aces/​140.html.


Final Rule

On June 7, 2000, the Type Certification Procedures for Changed Products final rule (65 FR 36244, June 7, 2000) became effective. The FAA established a mandatory compliance date of December 10, 2001, for transport category airplanes and restricted category airplanes that have been certificated using transport category standards; and a date of December 9, Start Printed Page 197942002, for all other category aircraft, engines, and propellers. The rule requires, among other things, that an applicant for a change to a type certificate must show the changed product complies with the certification requirements in effect on the date of application. (14 CFR 21.101(a)). The rule also states the applicant may show the changed product complies with an earlier amendment of a regulation if the Administrator determines the change is “not-significant.” (14 CFR 21.101(b)(1)). Specifically, determining the appropriate certification basis for each design change requires an assessment against the automatic criteria of “significant” as stated in the rule, coupled with the Administrator's discretionary right to consider the extent of the changes and related revisions to the regulations. (14 CFR 21.101(b)(1)(i) and (ii)).

On August 8, 2001, the FAA also published AC 21.101-1, providing guidance for the applicant to comply with the amended regulations for the certification of changes to transport category airplanes and restricted category airplanes that have been certified using transport category regulations.

During the fifteen months since publishing the rule, FAA, Transport Canada Civil Aviation, European Joint Aviation Authorities, and industry developed guidance material in the form of an advisory circular, a draft FAA Notice, and related training materials. The aviation industry has questioned the ability to standardize administrative procedures, raising a concern that implementation of the rule may not be uniform among the aviation manufacturing communities, both domestic and international. Based on this concern, FAA wants to ensure the implementation procedures for the rule provide for an equal and balanced application for all manufacturers, both domestic and international, and do not place an undue burden on FAA Aircraft Certification Offices and other civil aviation authorities. Accordingly, the FAA published a delay of all the compliance dates in the rule (66 FR 56989, November 14, 2001) to June 10, 2003.

Advisory Circular (AC)

To ensure a uniform application of this rule as it pertains to FAA's determination of “significant” and “not-significant” design changes, FAA has worked closely with the Joint Aviation Authorities and Transport Canada Civil Aviation to develop AC 21.101-1 Change 1. This advisory circular addresses the standardization concerns that precipitated the delay in implementing the rule until June 10, 2003, for all categories of aircraft, engines, and propellers.

AC 21.101-1 Change 1, will provide guidance for the applicant to comply with the amended regulations for the certification of changes to all aeronautical products. This AC will supercede Advisory Circular 21.101-1, dated August 8, 2001.

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Issued in Washington, DC, on April 12, 2002.

David W. Hempe,

Manager, Aircraft Engineering Division.

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[FR Doc. 02-9935 Filed 4-18-02; 2:31 pm]