When a position symbol changes from FLAT Track to Free Track, what does that signify?

When a position symbol changes from FLAT Track to Free Track, what does that signify?

• A. It is exactly on course
• B. If aircraft is in lateral tolerance but out of longitudinal tolerance
• C. It has left the airspace
• D. It indicates worsening signal

Answer: (B)

The symbol change shows how accurately the radar is tracking the aircraft in two dimensions. When it shifts from FLAT Track to Free Track, it means the lateral position (sideways from the track) is still within the allowed margin, but the longitudinal position (along the flight path) has exceeded the permitted tolerance. So the target is still considered within side-to-side bounds, but its along-track data is not reliable enough to be within the longitudinal tolerance. This isn’t about being exactly on course, leaving the airspace, or signal quality. It’s about the two tolerance dimensions for track accuracy; losing longitudinal tolerance while keeping lateral tolerance is what triggers Free Track.

The symbol change shows how accurately the radar is tracking the aircraft in two dimensions. When it shifts from FLAT Track to Free Track, it means the lateral position (sideways from the track) is still within the allowed margin, but the longitudinal position (along the flight path) has exceeded the permitted tolerance. So the target is still considered within side-to-side bounds, but its along-track data is not reliable enough to be within the longitudinal tolerance.

This isn’t about being exactly on course, leaving the airspace, or signal quality. It’s about the two tolerance dimensions for track accuracy; losing longitudinal tolerance while keeping lateral tolerance is what triggers Free Track.