What does free track utilize in its operation?

Free track operates primarily by using radar data independently from flight plan information. This approach allows air traffic control to track aircraft movements based solely on the radar returns, which provide real-time positional data. The advantage of relying on radar data is that it can be utilized even when flight plans are not available or when discrepancies between the radar data and flight plan information exist. This capability enhances situational awareness and ensures that aircraft can be monitored effectively in real time, regardless of their compliance with previously filed flight plans.

In contrast, options that suggest free track relies on flight plan information or only utilizes flight plan data would limit its effectiveness and flexibility, as they could lead to situations where aircraft are not adequately tracked due to the absence of or errors in the filed flight plans. Additionally, the option mentioning visual instruments for tracking does not align with the primary operation of free track, which is fundamentally based on radar technology.