Which action is most authoritative when determining if a modification to a product is compatible with existing installation?

Which action is most authoritative when determining if a modification to a product is compatible with existing installation?

• A. Type Certificate Data Sheet
• B. Advisory Circular
• C. Form 337
• D. Manufacturer's Manual

Answer: (A)

The most authoritative source for determining if a modification to a product is compatible with the existing installation is the Type Certificate Data Sheet for that product. The TCDS is the FAA-approved record of the approved design, and it specifies the configuration that is legally recognized, along with installation limitations, limits of use, and any data required for approved changes. When you evaluate a proposed modification, you must check the TCDS (and any FAA-approved data such as an STC or PMA) to see whether the modification is included in the approved design or if additional FAA-approved data is required. If the modification isn’t covered or conflicts with the installation limits, it isn’t approved for that product through normal FAA routes. Advisory Circulars provide guidance but aren’t authoritative for approval. Form 337 is a documentation tool used to record alterations after the fact for FAA acceptance, but it does not define what is and isn’t approved for installation. The Manufacturer’s Manual offers recommended procedures from the manufacturer, but those procedures aren’t FAA-approved design data and don’t determine compatibility with the type design.

The most authoritative source for determining if a modification to a product is compatible with the existing installation is the Type Certificate Data Sheet for that product. The TCDS is the FAA-approved record of the approved design, and it specifies the configuration that is legally recognized, along with installation limitations, limits of use, and any data required for approved changes. When you evaluate a proposed modification, you must check the TCDS (and any FAA-approved data such as an STC or PMA) to see whether the modification is included in the approved design or if additional FAA-approved data is required. If the modification isn’t covered or conflicts with the installation limits, it isn’t approved for that product through normal FAA routes.

Advisory Circulars provide guidance but aren’t authoritative for approval. Form 337 is a documentation tool used to record alterations after the fact for FAA acceptance, but it does not define what is and isn’t approved for installation. The Manufacturer’s Manual offers recommended procedures from the manufacturer, but those procedures aren’t FAA-approved design data and don’t determine compatibility with the type design.