Who or what determines “good engineering and good amateur practice,” as applied to the operation of an amateur station in all respects not covered by the Part 97 rules?

The FCC (Federal Communications Commission) is the regulatory body that creates and enforces the rules for amateur radio in the United States (Part 97). When a specific rule does not cover a particular operational scenario, Part 97 explicitly states that stations must be operated in accordance with "good engineering and good amateur practice." Because the FCC is the ultimate authority over these regulations, they are also the sole legal entity that interprets and determines what actually constitutes these good practices. While organizations like the IEEE or ITU set standards or international treaties, and the control operator implements practices locally, the FCC holds the legal jurisdiction to make the final determination in the US.