What information does the filed True Airspeed (TAS) determine in Flight Plan Aided Tracking?

Filed True Airspeed (TAS) is essential in calculating the ground speed of an aircraft during a flight plan aided tracking scenario. TAS represents the speed of the aircraft relative to the surrounding air and is crucial for understanding how quickly the aircraft is moving over the ground. This is particularly important for air traffic controllers and pilots as it enables them to anticipate the aircraft’s arrival at waypoints and manage its trajectory accurately.

When an aircraft is in motion, wind conditions can significantly affect its ground speed. By knowing the TAS, one can account for headwinds or tailwinds, which in turn allows for precise predictions of the aircraft's path over the Earth's surface. Therefore, the correct answer highlights the role of TAS in determining how fast the aircraft is actually traveling with respect to the ground, which is vital for effective navigation and traffic management.

The other options, while related to flight dynamics, do not directly stem from TAS. Altitude is independent of airspeed; the rate of climb pertains to vertical speed, which involves vertical navigation more than horizontal tracking; and heading changes primarily relate to changes in direction rather than speed calculations.