When modifying an aircraft, what is required according to FAA regulations?

When modifying an aircraft, it is essential to document all changes as required by FAA regulations. This documentation serves multiple purposes, including tracking the modification history of the aircraft, ensuring that safety and compliance standards are upheld, and providing a clear record for future maintenance or inspections. Proper documentation also aids in maintaining the aircraft's airworthiness, as it shows regulatory compliance and verifies that the modifications meet required safety standards.

The other options do not align with FAA guidelines. The lack of requirement for approval on wing modifications can lead to unsafe conditions if such changes are not certified for airworthiness. Furthermore, operational checks after modifications ensure that the aircraft performs as intended and that the modifications do not negatively impact safety. Lastly, while some minor changes might be less involved, they still need to be reported to maintain a comprehensive record of the aircraft’s modifications. Thus, proper documentation is a fundamental aspect of ensuring safety and regulatory compliance in aircraft modifications.