Regarding the statements about STC data and TSO installations, which is true?

Regarding the statements about STC data and TSO installations, which is true?

• A. Only No. 2 is true
• B. Both are true
• C. Neither is true
• D. Only No. 1 is true

Answer: (D)

STC data establishes the approved installation method for a modification on a specific aircraft model, including the required procedures, alterations, and any operating limitations. It is the authoritative basis you must follow to legally perform that change. Technical Standard Order (TSO) installations involve parts that carry a TSO approval, meaning those parts are designed to be installed under the TSO’s conditions, often without a unique STC for each airframe. However, that doesn’t automatically waive the need for appropriate documentation or approvals for the overall installation if the modification extends beyond what the TSO covers. In this item, the first statement aligns with the concept that the STC data provides the approved installation path, while the second statement about TSO installations is not generally correct in isolation. The key takeaway is that STC data defines a specific, authorized way to modify and install something on a given aircraft, and while TSOs offer standardized parts, proper approvals still govern how those parts are installed in practice.

STC data establishes the approved installation method for a modification on a specific aircraft model, including the required procedures, alterations, and any operating limitations. It is the authoritative basis you must follow to legally perform that change. Technical Standard Order (TSO) installations involve parts that carry a TSO approval, meaning those parts are designed to be installed under the TSO’s conditions, often without a unique STC for each airframe. However, that doesn’t automatically waive the need for appropriate documentation or approvals for the overall installation if the modification extends beyond what the TSO covers. In this item, the first statement aligns with the concept that the STC data provides the approved installation path, while the second statement about TSO installations is not generally correct in isolation. The key takeaway is that STC data defines a specific, authorized way to modify and install something on a given aircraft, and while TSOs offer standardized parts, proper approvals still govern how those parts are installed in practice.