What is considered a "complex" aircraft?

A complex aircraft is defined as one that is equipped with certain advanced features that require additional training and proficiency to operate safely. The characteristics that define a complex aircraft include retractable landing gear, flaps, and moveable stabilizer surfaces, such as a horizontal stabilizer that can be adjusted in flight.

Retractable landing gear reduces drag and increases performance, while flaps allow for better control during takeoff and landing phases. A moveable stabilizer enhances the ability to control pitch, which becomes crucial during various flight conditions. Given these features, pilots must possess a more extensive set of skills compared to those flying simpler aircraft, as these systems can significantly affect the aircraft's handling and performance.

Therefore, the presence of retractable landing gear, flaps, and moveable stabilizers is what classifies an aircraft as "complex" and necessitates further training to operate it safely.