Thanks for the info about the PIA. Great idea.
NCYankee wrote:
The FAA is also allowing what is known as Privacy ICAO Address (PIA) to be assigned for Mode S transponders. The PIA is a 24 bit value that is not associated with a US tail number but within the ICAO code range assigned to the US
Bizjets who cary big corporate boss have used this but now with plane spotters everywhere they probably have to fly commercial 2nd class ticket on their middle name 
Incredible! But not really. This is the FR24 version of what is known in the crypto business as “traffic analysis”. Quite a good pun actually
A lot of bizjets are blocked on FR24 but there are other sites, plus anybody can set up their own receiver.
What the US has done for ADS-B anonymity is very interesting and very good, and as usual a total contrast with Europe…
Ibra, nothing new really, OSINT (https://en.wikipedia.org/wiki/Open-source_intelligence), just another source
Ibra wrote:
Bizjets who cary big corporate boss have used this but now with plane spotters everywhere they probably have to fly commercial 2nd class ticket on their middle name
The PIA is only available for flights totally within US airspace. International flights currently need to have the standard ICAO address loaded into the transponder.
Got it, outside US ADSB-OUT is not mandated yet but will be mandatory in Europe this June, so I expect some privacy angle to come in as well, in the meantime, no way to turn off ADSB-OUT off without having transponder OFF (but most serious bizjets have two transponders 
)
but will be mandatory in Europe this June
I don’t think so… so far there appears to be no initiative like the US has done.
I meant for complex & fast (>6T, >250kts), our stuff is exempt but may have to remain OCAS
Does the US have any TMZs / ADS-B mandatory zones, which are not normal controlled airspace?
Yes. The 30nm mode-C veil (or probably now renamed the ADS-B veil) requires it even if you’re in class G airspace and not within the lateral limits of class B above you. I think it’s also required if you’re flying underneath class C airspace now, but without diving into the FAR/AIM, I’m not 100% sure on that.
