What is required to act as pilot in command of a complex airplane?

To act as pilot in command of a complex airplane, the requirement involves receiving training and obtaining a one-time endorsement from a Certified Flight Instructor (CFI). A complex airplane is defined as one that has retractable landing gear, flaps, and a controllable pitch propeller, featuring systems and operations that can be more demanding than those of a standard airplane.

The endorsement serves as formal recognition from a CFI that the pilot has received the necessary training on the specific systems and operations associated with complex airplanes and demonstrates proficiency in flying them. This training ensures that the pilot understands the aircraft's advanced systems and can manage them safely during flight.

Other options, while they might pertain to general flight requirements or other aircraft types, do not specifically address the nuanced requirements for complex aircraft operation as established by the FAA. Therefore, the emphasis on training and endorsement is paramount for safe and competent piloting of complex airplanes.