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United States Department of Transportation United States Department of Transportation

AC 20-188 - Compatibility of Changes to Type Design Installed on Aircraft

Document Information

Number
20-188
Title
Compatibility of Changes to Type Design Installed on Aircraft
Status
Active
Date issued
2016-12-09
Office of Primary Responsibility
AIR-1
Description
Federal Aviation Administration (FAA) Order 8110.4C, Type Certification, paragraph 4-19(f)(2), requires the Limitations and Conditions section of a multiple STC to include the statement: “The installer must determine whether this design change is compatible with previously approved modifications.” This advisory circular (AC) provides engineering guidance to installers on determining the compatibility of the installation of approved changes to type design where previously approved changes to type design are installed on aircraft. Previously approved changes include other major or minor changes to type design approved under Title 14 of the Code of Federal Regulations (14 CFR) part 21, Certification Procedures for Products and Parts. Alterations or repairs to aircraft approved pursuant to part 43, Maintenance, Preventive Maintenance, Rebuilding, and Alteration should also be considered. Although this AC focuses on the installation of changes to type design approved via supplemental type certificate (STC) or amended type certificate where previously approved changes exist, the principles and guidance are applicable to alterations approved in a manner other than STC or amended type certificate where previously approved changes exist.
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