FlightAware Discussions

Flight track log - missed updates shows estimated

Hi,

What does the solid white line in this flight path mean?

Is there any documentation explaining all these different scenarios?

Thanks.

The white line is an estimated track while the aircraft was out of range of terrestrial ADS-B coverage. If you look at the track log, you will notice a “gap in available data” between approx 1450Z and 1750Z - this is the part of the track that corresponds to the white line.

Thank you @obj. What does terrestrial ADS-B coverage mean ? Are those known areas where we always show white solid line ?

Terrestrial = land based.
Data received by land based receivers and fed to FA.

In contrast: space-based receivers: https://flightaware.com/commercial/aireon/

There is a coverage map:
https://flightaware.com/adsb/coverage#data-coverage

And terrestrial coverage is where there will be data.
As normal user you don’t get access to the space-based data, so you are shown an estimation of where the plane was. The white line is not actual data but a best guess.

To add to what wiedehopf said, ADS-B is essentially limited to line-of-sight reception, limited by the horizon, so in areas where there are no nearby terrestrial (i.e. Earth-based) receivers that can see the aircraft - notably over the oceans away from the coastline - we don’t receive ADS-B data from the terrestrial network. That’s what the coverage map reflects.

Thank you again @obj and @wiedehopf.