Which of the following statements is true regarding enhancements made by mechanics on aircraft?

The statement regarding enhancements made by mechanics on aircraft that is true is that mechanics must have specific authorizations for different types of work. This reflects the regulatory requirements established by aviation authorities, such as the FAA, which ensure that mechanics are qualified to perform certain tasks on aircraft.

Each type of maintenance or alteration—whether minor or major—has different criteria and standards that must be met. Mechanics are required to have the appropriate certifications and authorizations based on their training and the nature of the work they are performing. This ensures safety and compliance within the aviation industry, as only qualified personnel should undertake specific types of repairs or modifications.

In the context of other statements: saying that all alterations require certification from the manufacturer overstates the requirement, as not all alterations need direct manufacturer certification. Minor alterations do not require FAA approval, meaning that while they may still need documentation, they are not subject to the same rigorous review process as major alterations. Furthermore, major alterations cannot simply be delegated to any technician without the necessary qualifications, as this could compromise safety standards.