Radio equipment installations made in accordance with Supplemental Type Certificate data require approval for return to service by?

The requirement for approval for return to service after radio equipment installations made according to Supplemental Type Certificate (STC) data stems from the need to ensure compliance with aviation safety regulations. When radio equipment is installed under an STC, the work done must meet specific standards and procedures that have been assessed and approved by aviation authorities.

The holder of an inspection authorization is particularly qualified to approve such return to service because they have the necessary training, experience, and authority to conduct inspections and make determinations about the safety and airworthiness of the aircraft after such modifications. This authorization ensures that a qualified individual has reviewed the installation in accordance with the STC data and confirmed that it complies with all regulatory requirements.

The other choices do not provide the same level of assurance. While any certified technician may be skilled and knowledgeable, they may not possess the specialized inspection authority required to sign off on such complex modifications. A federal inspector is typically responsible for oversight and enforcement but may not be directly involved in the return to service process, and the equipment manufacturer, while knowledgeable about their products, does not inherently possess the authority to approve modifications on an aircraft. Thus, the only option that meets the necessary regulatory requirements for return to service in this context is the holder of an inspection authorization.