Which of the following is NOT one of the three relevant parts involved in aircraft fundamentals?

The pilot is not considered one of the three relevant parts involved in aircraft fundamentals. Instead, the study of aircraft fundamentals typically focuses on the atmospheric conditions, the aircraft itself, and the relative wind.

The atmospheric sensor measures various parameters of the environment, such as temperature, pressure, and humidity, which are crucial for understanding how the aircraft will perform. The relative wind refers to the airflow relative to the aircraft, which is vital for analyzing lift, drag, and other aerodynamic forces acting on the aircraft.

While the pilot is essential to the operation of the aircraft, in the context of aircraft fundamentals, the primary focus is on the physical principles and components that affect flight. This distinction helps streamline the understanding of how aircraft function independently of the human factors involved in their operation.