Which system aids in aircraft navigation?

The flight control system plays a crucial role in aircraft navigation by ensuring the aircraft maintains the desired flight path. It includes various components that help manage the aircraft's attitude, altitude, and direction. When pilots navigate, they rely on the flight control system to execute their intended maneuvers and to respond to adjustments made during flight based on navigational data.

While other systems mentioned contribute to the aircraft's operation, they do not directly aid in navigation in the same way. For example, the landing gear system is primarily focused on takeoff and landing performance. The radio communication system facilitates communication between the aircraft and air traffic control, which is essential for navigation but not a navigation aid itself. The weather radar system helps pilots avoid adverse weather conditions but does not assist with navigational tasks directly. Therefore, the flight control system is identified as the key system that aids in navigation.