Before passengers can be carried in an aircraft that has been altered in a manner that may have appreciably changed its flight characteristics, it must be flight tested by an appropriately-rated pilot who holds at least

• A. Private Pilot Certificate
• B. Commercial Pilot Certificate
• C. Instrument Rating
• D. Airline Transport Pilot Certificate

Answer: (A)

When an aircraft has been altered in a way that could appreciably change how it flies, it must be flight tested by someone with enough piloting experience to judge the handling and safety of the modification. The minimum qualification for that test is a private pilot certificate. This level ensures the tester has solid basic piloting skills and a solid understanding of flight characteristics without implying authority for commercial operations or specialized instrument flight rules.

The requirement isn’t about having the ability to operate commercially or under IFR, or about airline-level credentials. A commercial certificate or an instrument rating would represent capabilities beyond what’s necessary to verify the altered aircraft’s safety in normal and basic operating conditions, and an airline transport pilot certificate is far beyond what’s required for this specific testing task. The key point is that the test confirms that the modified aircraft remains controllable and safe to carry passengers before it enters service.