First, thank you for your support and contributions over the years. We now have (just shy of) 7,500 ground stations sharing data and growing faster than ever. If you haven’t heard, we recently released PiAware 3.0 (>25% better receiver performance, native WiFi support, new maps, and more) and are also open sourcing our Android feeder so the community can benefit from the code even though we are discontinuing support for it.
I’m writing today to discuss an issue with the FlightAware multilateration (MLAT) network. As many of you know, FlightAware not only operates a free MLAT network (currently using 136 top-of-the-line Xeon CPUs covering 113 geographic regions) for all PiAwares and FlightFeeders, but FlightAware also feeds back all the MLAT calculations that you’ve contributed to. This means that you can view the data locally on your dump1090 web interface or any other tools you have connected to your receiver. We’re the only ones that do this and it’s awesome.
Unfortunately, a very small percentage of users are re-distributing and aggregating FlightAware’s MLAT calculations, often for the purpose of tracking aircraft that have specifically requested not to be tracked and are on one or more “block lists” used by the flight tracking industry.
As a result, we have come under pressure from aircraft operators with legitimate security concerns to stop feeding MLAT data back or remove their aircraft from the feed. Specifically, a lot of the concern originates from law enforcement, military, and other government operators that appreciate our cooperation, but will otherwise solve the problem with legislation and law enforcement, impacting FlightAware and everyone else, possibly criminalizing this otherwise fun and harmless activity
We would like to solve this together as a community rather than have the government solve it for us. So, we’ve come up with a better alternative – for the small number of aircraft on this list (less than 1% of flights, most of which are in the US, and none of which are airline flights), we’ll continue to feed MLAT results to PiAware & FlightFeeder, but with an anonymized Mode S code and no ident. This means your maps will look the same and this has no impact on ADS-B flights or other Mode S data you’re tracking locally, which are decoded and displayed entirely within your device, without the involvement of FlightAware’s servers. We’ll also ask that people limit their use of the FlightAware MLAT results to themselves.
In summary, the specifics:
Starting today, less than 1% of MLAT flights will have anonymized mode S codes. You’ll need PiAware 3 or FlightFeeder 7 to see the anonymized MLAT results since it will not be displayed on older versions.
This doesn’t affect ADS-B flight tracking or your local Mode S data, which your receiver does on its own without our involvement.
We’ll be releasing a new license that continues to give you unlimited personal use of the MLAT data, but does not allow for redistribution. We are asking for your cooperation, support, and understanding to ensure this is honored.
Thank you for your continued support. We are expanding our efforts on ADS-B projects and are excited about the new opportunities and types of information and tools that we’ll be releasing in the coming weeks and months.