PT REPORTS CHEST PAIN RM318

It's broadcast in the clear, unencrypted. Just like all non-military aircraft comms.

> It's broadcast in the clear, unencrypted.

But so were analog mobile phones and pagers, and in some countries, even receiving unencrypted voice ATC radio isn't legal.

The whole point of ATC is that everyone in the area is able to figure out what is going on by listening in.

What/how is making listening in on that illegal ok?

[delayed]

> Totally legal everywhere (except a few rare exceptions, like the UK).

And (after a cursory search) Spain, Portugal, Germany, Austria, maybe France... In other words, legal in some places, illegal in others.

> Text-based ATC communications is done over a different system called CPDLC (FANS-1/A)

ACARS is both an application and a (legacy) lower layer suite of protocols supporting it, but modern ACARS versions and CPDLC can use the same underlying digital channel, as far as I understand (i.e. VDL Mode 2).

As a result, many of these tracking sites can capture both, as well as presumably "legacy/analog" ACARS.

Not sure about the details, but I suspect it's more a consequence of laws on telecommunication privacy from analog days being very generic than a specific intention to make ATC listening illegal. Opt-out vs. opt-in by frequency and/or purpose, essentially.

That said, it's supposedly still being very much enforced against e.g. planespotters at airshows in some places – no idea what the point of that is.

Baffling to get downvoted for a suspicion about the origins of the status quo, as if that were an endorsement of it.

Forget it up Jake, it’s Chinatown

Explicitly legal. ECPA has an carve out for listening to aeronautical radio traffic:

18 U.S.C. § 2511(2)(g)(ii)(I/IV):

"It shall not be unlawful under this chapter or chapter 121 of this title for any person to intercept any radio communication which is transmitted by any station for the use of the general public, or that relates to ships, aircraft, vehicles, or persons in distress;... or by any marine or aeronautical communications system."

The ones recorded in the US probably are legal to listen to and the ones in the UK probably are not. I think I remember reading somewhere that it’s not legal to record ATC in the UK. IANAL SIUKRTCL