Which of the following is NOT listed as one of the four parts of an aircraft?

• A. Landing Gear
• B. Engine
• C. Wings
• D. Horizontal Stabilizer

Answer: (A)

Think about the four primary structural components that define an airplane: the wings, the fuselage, the propulsion system (engine), and the tail assembly (empennage), which includes the horizontal and vertical stabilizers. The engine provides thrust, the wings generate lift, and the horizontal stabilizer is part of the tail assembly that helps control pitch and stability. The landing gear, while essential for takeoff, landing, and ground handling, is a separate support system rather than one of these main parts. Therefore, landing gear is not among the four main parts, making it the correct choice. The engine, wings, and horizontal stabilizer all fit within that four-part framework.