mh,
If you have a mode S transponder, the identification of the aircraft already makes it not anonymous. It does not need to be ADS-B Out.
In the US, pilots who use a Mode A/C transponder (not mode S) and install a UAT ADS-B Out system have an option called anonymous mode. It supports aircraft not receiving ATC services and squawking VFR (1200 in the US) to broadcast a user selected identifier which is a semi random value. It only applies for a single flight. It allows all the data but the N number and aircraft ICAO ID to be transmitted by the ADS-B Out system, so the aircraft can be tracked, but not identified.
Anonymous mode is not supported for 1090ES as the transponder already emits the ICAO identifier in response to secondary radar interrogations or TAS/TCAS interrogations.
I would think that if doing something illegal or semi-illegal or plain simply NIMBY-controversial, turning off the thing is understandable (but why do illegal things anyway?). Busting CAS is really dumb and busting CAS with Mode C turned off is incredibly dumb.
What is IMHO pointless is being invisible all the time, enroute, in the circuit, etc. I see people every time I fly whose planes are obviously equipped but who turn it off for no good reason.
BTW I doubt FR24 makes millions. Also FR24 doesn’t show most VFR traffic. They filter it out.
Anyway, this only confirms what I am saying about people wanting “privacy”, when so many say I am making it up 
Peter wrote:
busting CAS with Mode C turned off is incredibly dumb
Turning off mode C after busting CAS is even more dumb. I was told it happens frequently enough by the then (shift?) supervisor at Paris Orly when I phoned them to apologise for having bust their airspace (and potentially delayed some arrivals). He specifically thanked me for not having turned the transponder off. I never heard anything else about it (and it’s been 5years) but, from the conversation we had, i had the impression that had I turned off my transponder, the police might have been waiting for me on arrival, or I could have head later from some legal department.
NCYankee wrote:
If you have a mode S transponder, the identification of the aircraft already makes it not anonymous. It does not need to be ADS-B Out.
I know, but unless FR and similar sites triangulate the position, it is still doesn’t show the flight. The concern is not to be visible for other aircraft or ATC, the concern is being visible to literary anyone, with what intentions ever.
Peter wrote:
I would think that if doing something illegal or semi-illegal or plain simply NIMBY-controversial, turning off the thing is understandable (but why do illegal things anyway?). Busting CAS is really dumb and busting CAS with Mode C turned off is incredibly dumb.
The point is not doing something illegal, the point is that my flight route is not of anyone’s business, unless I am flying through your airspace or you want to fly at the same place at the same time. But getting reported while doing something completely legal because some nitwit ga-enemy doesn’t know any rules just creates unnecessary work for everyone – and yes, that has happened and it’s a PITA.
There is a history in Germany that every pilot’s name had to be noted in the airfields logbook. A certain late German aviation journalist was caught cheating on his missus with these logs and fought hard to remove those requirements – and won. As much as I disagree with the cheating, it’s none of my business and his privacy ranks higher as someone’s curiosity.
I don’t want people asking “how has he the money to fly xyz hours in his aircraft?” or “He should be in the office right now” or “Look, he’s flying to this and that contractor” or whatever. These are data that are not meant for public display and they don’t belong there.
If you WANT to be tracked, fine. You could just register your Mode-S or ADS-B ID and everything is fine. But I have never agreed to the use of my data, and me not wanting to be displayed should be enough not to display my data. I don’t want to search all day for new platforms, despite having the time for this stuff. Nor do I want to send them my documents (License, Passport and registration(!)) to be removed. So I am using the only means I have: turn the stuff OFF and only have it ON, when it is required for some airspaces or VFR at night (bad enough… ).
Peter wrote:
BTW I doubt FR24 makes millions. Also FR24 doesn’t show most VFR traffic. They filter it out.
Well, the numbers are public… http://forum.flightradar24.com/threads/7020-Flightradar24-soars-high-posts-%E2%82%AC2-9-million-turnover. I guess our Swedish members will find the balance sheets of flightradar24 AB easier than me.
Peter wrote:
Anyway, this only confirms what I am saying about people wanting “privacy”, when so many say I am making it up
Of course, if people are forced to give up their privacy (and many times without their knowledge) so that others can built a business model on their data, many will refuse to deliver if they can. And they have all right to do so, IMHO.
mh wrote:
Of course, if people are forced to give up their privacy (and many times without their knowledge) so that others can built a business model on their data, many will refuse to deliver if they can. And they have all right to do so, IMHO.
I agree entirely, and even more so when it is government employees building their careers on an arguably unethical ‘business’ that pays their salary with taxpayer money.
NCYankee wrote:
In the US, pilots who use a Mode A/C transponder (not mode S) and install a UAT ADS-B Out system have an option called anonymous mode. It supports aircraft not receiving ATC services and squawking VFR (1200 in the US) to broadcast a user selected identifier which is a semi random value. It only applies for a single flight. It allows all the data but the N number and aircraft ICAO ID to be transmitted by the ADS-B Out system, so the aircraft can be tracked, but not identified
I think that reason that exists in the US is because a difference to international practice was necessary to make the US ADS-B rule legal – a lesson learned years ago from the failed mandatory Mode S saga. Unfortunately I think few people will either understand that or act on it because 1090ES will be easier, and as a result non-technical people will have been carefully manipulated into being tracked.
Silvaire wrote:
I think that reason that exists in the US is because a difference to international practice was necessary to make the US ADS-B rule legal – a lesson learned years ago from the failed mandatory Mode S saga. Unfortunately I think few people will either understand that or act on it because 1090ES will be easier, and as a result non-technical people will have been carefully manipulated into being tracked.
I don’t understand your comment. Here in the US, the dual frequency decision was driven primarily by the density of 1090 MHz traffic. UAT can be less expensive than a transponder. Also, since UAT was a new clean sheet technology, AOPA lobbied for an anonymous mode and the FAA agreed. The US ADS-B rule followed the normal rule making process, so it was always legal.
We now have two threads running on the “privacy” issue (this one and the journey log) and I can’t think of a better example of chucking the baby out with the bathwater because for collision avoidance and TCAS alerting you need only Mode C which doesn’t give away your identity.
All other methods, potentially better e.g. ADS-B, will have privacy concerns because anybody can receive the data with a dirt cheap receiver which will work over a radius of hundreds of miles. I have seen a demo of one covering most of Europe, though I doubt it was the £10 USB-TV type.
And Mode S owners turn off the transponder completely because you can’t turn off Mode S (and the emission of the 24-bit code) without turning off the whole thing.
So we are well and truly buggered for the future.
NCYankee wrote:
Also, since UAT was a new clean sheet technology, AOPA lobbied for an anonymous mode and the FAA agreed.
What I understand is that AOPA and NBAA lobbied to prevent mandatory aircraft tracking by Government, and ID broadcast to anybody interested, under the ADS-B regulation. They had a good argument because it is unethical in many people’s mind and arguably illegal in the US. FAA agreed because it’s also proved politically impossible in the past (during the prior failed effort to make Mode S mandatory for GA in certain US airspace). I see no logical connection between ‘new clean sheet technology’ and lobbying efforts for autonomy, that strikes me as a hopelessly naive or ‘politically correct’ explanation.
NCYankee wrote:
The US ADS-B rule followed the normal rule making process, so it was always legal.
No argument there, and I think that’s why in the end, we have the UAT option as it is – because it adds pilot selected autonomy in the US, which makes ADS-B more resistant to legal challenges. UAT autonomy does have features I find offensive, like the requirement under the regulation that tracking be automatically turned on and manually turned off, but its better than nothing. I hope anybody with an interest in autonomy considers their ADS-B options before spending their money.
Peter wrote:
I can’t think of a better example of chucking the baby out with the bathwater because for collision avoidance and TCAS alerting you need only Mode C which doesn’t give away your identity.
Agreed! I don’t think anybody with a legitimate interest in your position really needs automatic identification. The motivations for it are either stupid, ill considered or (probably IMO) illegitimate.
We now have two threads running on the “privacy” issue (this one and the journey log)
Well noone will post your logs all over the internet without your consent, I guess.
So we are well and truly buggered for the future.
Patrick Ky had put it very nice recently: “Sometimes, more safety is the enemy of safety.”
because for collision avoidance and TCAS alerting you need only Mode C which doesn’t give away your identity.
Yes, any anonymous random ID would do the trick, I guess. Or we have to ask if relying on the “other aircraft” to emitt signals is good idea in the first place …
mh wrote:
I know, but unless FR and similar sites triangulate the position
