Originally Posted by
henra
Fair point, the question at the end simply is: Is the FR24/WEBTRAK picture completely off or not?! So far I see no reason to assume that we were shown a false picture neither in the video nor in the posted WEBTRAK chart.
As a general rule, FR24 positioning (except when they do their dumb extrapolation and unfeasible joining-the-dots) is reasonably accurate provided that the aircraft's ADS-B is GNSS-sourced. As long as you disregard any abrupt track changes, what's left is probably OK. Timings can be subject to some latency because the data is being sent to FR24 over the Internet and isn't timestamped at source, so probably shouldn't be taken as gospel.
WebTrak data originates from the FAA's radars, so what you see is what the TRACON is seeing. Timings should be pretty accurate and the granularity will depend on how many radars are currently tracking the target.