FAA Inspection Authorization Practice Test 2026 – The All-in-One Guide to Mastering Your Exam!

For a major alteration, you must base the work on FAA-approved data. Approved data are the design data the FAA has reviewed and authorized for use in that modification. The sources that count as approved data include the Type Certificate Data Sheet, which outlines the approved configuration of the aircraft; previously approved data such as a FAA-accepted 337 form; and manufacturer data that has been approved through an FAA process (for example, an STC or PMA package). Advisory Circulars, while valuable for guidance on compliance, do not themselves authorize changes or establish an approved basis for an alteration. They explain acceptable methods but are not substitute approval data. So for a major alteration, advisory circulars would typically not be used as the approved data basis, whereas the other options can be, depending on their approved-data status.