What regulations govern the terms and conditions of a Standard Airworthiness Certificate?

The terms and conditions of a Standard Airworthiness Certificate are specifically governed by Parts 21, 43, and 91 of the Federal Aviation Regulations (FARs). Part 21 details the certification procedures for products and parts, including the standards necessary for aircraft to receive an airworthiness certificate. Part 43 addresses the maintenance, preventive maintenance, and alteration of aircraft, ensuring they are kept airworthy in accordance with the prescribed standards after they receive their certificate. Part 91 outlines the general operating and flight rules that apply to all aircraft operating in the U.S. airspace, including those with a Standard Airworthiness Certificate.

The other options do not contain the appropriate regulations for Standard Airworthiness Certificates. For instance, Parts 25, 61, and 135 relate to aircraft certification for transport category airplanes, pilot certification, and commuter and on-demand operations, respectively, which do not directly govern airworthiness certificates. The remaining options deal with regulations that pertain to other aviation aspects, making them unsuitable in this context. Therefore, the combination of Parts 21, 43, and 91 is crucial for understanding the framework governing Standard Airworthiness Certificates.