If an aircraft is modified, what is required for installation of parts made under TSO?

When an aircraft is modified with parts that are made under Technical Standard Order (TSO), it is essential to recognize that these parts have been manufactured in accordance with FAA standards and have undergone rigorous testing and evaluation to ensure they meet specified performance criteria. Because TSO'd parts are pre-certified for their safety and airworthiness, once they are incorporated into the aircraft, no further approval is required specifically for the installation of those parts.

This principle allows for streamlined processes when upgrading or modifying existing aircraft. It reflects the FAA's intent to facilitate modifications while maintaining safety standards since TSO parts have already demonstrated compliance with industry requirements. Therefore, the emphasis on the pre-existing approval of TSO parts underscores their reliability and the confidence the FAA places in their manufacturing processes.

Other approaches, such as the need for supplemental approval, new certification, or merely verbal confirmation, would add unnecessary complexity to the installation process, contrary to the streamlined approach the TSO system embodies. By allowing modifications using TSO parts without requiring additional approvals, aviation stakeholders can effectively balance safety with operational efficiency.