Which feature defines a complex aircraft?

• A. An aircraft with fixed landing gear, flaps, and a fixed-pitch propeller.
• B. An aircraft with two engines.
• C. An aircraft with retractable landing gear, flaps, and a controllable-pitch propeller.
• D. An aircraft with a turbojet.

Answer: (C)

A complex aircraft is defined by having retractable landing gear, flaps, and a controllable-pitch propeller. This combination requires the pilot to manage gear operation, adjust flap settings for different phases of flight, and control the propeller pitch to optimize performance, which adds the level of complexity beyond basic fixed-gear, fixed-pitch airplanes. The option that includes all three of these features satisfies this definition, so it is the best choice. A plane with two engines isn’t by itself complex under this standard, since complexity centers on gear, flaps, and propeller control, not the number of engines. A turbojet alone doesn’t define complexity unless the other features are present, and a fixed landing gear with a fixed-pitch propeller lacks the elements that increase operational intricacy.