What system on an aircraft is primarily responsible for steering the aircraft on the ground?

The system primarily responsible for steering the aircraft on the ground is the nose wheel steering. This system allows the pilot to control the direction of the aircraft while taxiing, which is crucial for maneuvering on the airport surface. Nose wheel steering is typically controlled by the pilot using the aircraft's control yoke or rudder pedals, allowing for precise directional changes.

Other aircraft control surfaces, such as the rudder, elevator, and ailerons, serve different primary functions. The rudder assists in controlling the aircraft's yaw during flight and can help with slight directional adjustments during ground operations, but it is not the primary system used for steering on the ground. The elevator primarily controls the pitch of the aircraft, affecting its ascent and descent. Ailerons are responsible for roll control during flight, allowing the aircraft to turn left or right. Thus, while these surfaces have important roles during flight, they are not designed for steering the aircraft during ground operations.