A few points I wanted to make, specific to the HN context (and a lot
of this is in the "nerd mode" donation page at
https://skycircl.es/donate-nerd-mode/):
1. This seems like a classic "low effort, high impact" project. It's
super easy to detect aircraft flying in circles, in real-time, and
post it to twitter. But it turns out to be an entry-point into a
"strangely interesting" (according to pg) world of aircraft activity.
The current #1 comment sadly only gets to see general aviation pilots
practicing, but my bots have tweeted military aerial refueling, STOL
practice in the wilderness, float-planes practicing on rivers and
lakes, military drones flying over the desert, planes dropping sterile
fruit flies as a way to reduce the fruit fly population, news
helicopters following a highway pursuit, U.S. Forest Service AH-1Z
Viper attack helicopters fighting fires, helicopters dropping mosquito
pesticide, aerial tankers over Manhattan for the president's combat
air patrol, FBI surveillance planes registered to front companies,
Coast Guard helicopters doing search & rescue, crop dusters,
scientists observing sea life over the ocean, planes doing Gorgon
Stare-style persistent surveillance over Baltimore, sheriff's
helicopters rescuing hikers, power line inspections, pipeline
inspections, military aircraft doing surveillance over protestors,
stealth jet test flights, a Grumman HU-16 Albatross seaplane that
belongs to the USAF over the Mojave desert, a U-2 test flight, and a
B-29. That is not even close to a complete list.
3. As far as I know, this comment on HN is the first time anyone
published any significant detail about the FBI's secret aerial
surveillance program: https://news.ycombinator.com/item?id=9508812
The FAA uses the term "advisory circular" to share information with pilots and aircraft operators, using "circular" in the way of "bulletin" or "newsletter" [1]
I was really confused at first by your use of the phrase.
I also think it is pretty funny if you didn't intend it. I would have thought what you're doing is better described as a "circular advisory" rather than "advisory circular". Cool project :)
> my bots have tweeted [...] U.S. Forest Service AH-1Z Viper attack helicopters fighting fires
I had to Google that. I'll await a correction from a more knowledgeable HNer, but as far as I can tell the US Forest Service does not have AH-1Z Viper attack helicopters.
I don't care enough to dig deeply into it, but it seems that basically there is a very long line of Bell helicopters called "AH-1", going all the way back to the original AH-1 Cobra in 1965. There have been many variants over the decades, and two of these have been been retrofitted into "FireWatch" helicopters for the US Forest Service, after being retired from military service.
The AH-1Z Viper is a modern attack helicopter, a variant of the SuperCobra, itself based on the AH-1 Cobra. It went into service in 2000, whereas the USFS two FireWatch Cobra's were originally built in 1969 and 1983: https://wildfiretoday.com/2010/06/27/firewatch-cobra-helicop...
I have a flight tracking app for my phone and see aircraft flying in circles over where I live all the time. Dozens and dozens of times each day.
They're people in small planes practicing.
Also, I live near several military bases. The interesting and loud stuff that I see flying by out my window NEVER shows up on any app. I expect this web site is similarly, deliberately, incomplete.
As a current student pilot, I have been doing a whole lot of circling. Hope no one thinks I'm the FBI in a ratty old C172. :)
When it comes to military aircraft, the situation there is kind of interesting. There's no general exception for the military, military aircraft are generally "required" to transmit ADS-B unless they have a specific reason not to (and I believe this requires authorization from somewhere up the chain of command). I put "required" in scare quotes though as many military aircraft are simply not equipped... the DoD has drug its feet on installing ADS-B out and the FAA has basically relented by setting very lax objectives. FAA requested DoD to have ADS-B installed on 21% of aircraft by the first of this year and I believe they met that goal... but it's still less than a quarter.
Over time more and more military aircraft should be appearing in ADS-B data, but I suspect it's going to be some years before it's almost all of them.
> I expect this web site is similarly, deliberately, incomplete.
Perhaps less incomplete than you think (and certainly more complete than the standard tracking websites, which outside of hiding planes also must honor a 5-minute data delay requested by the FAA).
The advisory circular bots the author runs link to https://tar1090.adsbexchange.com/ , which is run from a home-grown network of SDRs. It makes a point of not hiding anything that reports its position with ADS-B -- which all aircraft (over a certain size) must report by law. I've even seen Air Force One and its escorts on this service, something that is always absent from other flight tracking services.
Things flying near an airport are excluded ("The centroid of the last 3 minutes worth of positions must be more
than 2.5 km away from all known airports."). I've never seen it tweet about planes doing obvious pattern practice.
>> The interesting and loud stuff that I see flying by out my window NEVER shows up on any app.
The slightly interesting stuff doesn't show up, the loud jets, but the really interesting stuff does. CIA rendition flights, police spying on protests, Air Force One, rich people flagrantly violating COVID rules ... they all squawk ADS-B.
If you're on iOS you want the "OpenADSB" app. I think I paid $10 for it but it's awesome. It doesn't filter out the military planes like FlightRadar24 does. But, sometimes FlightRadar24 has data that OpenADSB doesn't have, so both are still useful.
A few weeks ago I was watching an F-35 off the coast of Southern California... so cool to see that stuff. It seems to also pick up weather balloons (or some kind of balloons that are above 60,000ft). Anyway, it's fun to see what's out there.
Reminds me of a program I read about a while ago in Iraq. Planes would circle cities with a camera and some huge hard drives installed. If an IED went off they would rewind the tapes, and watch every stop the people who planted it went through before and after planting the bomb. From that they could unwind very complex networks of insurgent activity. The equipment was mostly off the shelf, and relatively cheap.
"In Iraq" - they did it over US cities as well [0]. To be fair, I read that link a long time ago and don't remember the specifics of how long it ran and if it ran in more cities.
This is a good example of the "boomerang" effect[1] in which control techniques and developed for and used on imperial colonies, and are eventually brought back and used in the homeland.
[1] sometimes called the imperial boomerang, the colonial boomerang, or Foucault's boomerang
To those who notices planes flying in circles, it doesn't have to be anything sinister. Those might be planes calibrating avionics or ground/airport equipment or doing test flights after maintenance. I have agencies in the region doing both, so you can sometimes find planes doing strange patterns which are their clients.
Definitely agree! That's why the author has explicitly filtered out patternwork by excluding "circles" that are particularly close to an airport. It doesn't mean anything is sinister, but this project is definitely aware of and disinterested in just finding student pilots beating up the pattern.
When I was tracking flights some years ago (use case was determining whether speed monitoring aircraft were in the air, and a prediction model of their schedule) I learned that the ADS-B transmitters didn't need to broadcast GPS co-ordinates below a certain ceiling. You could get the signal that a given tail number was in the air, but if it stayed below a certain altitude, you couldn't always receive its location.
I lost interest in it because I just don't speed that much and I don't have a sport bike fast enough for it to matter, but useful to know that ADS-B doesn't cover all aircraft.
The regulations around ADS-B are pretty weird, basically because the FAA wants to require it of all aircraft but all the aircraft owners object because it's pretty expensive to install it. So the FAA has kind of been taking a "death by a thousand cuts" approach where they never quite "mandate" ADS-B but they require it in more and more situations...
So aircraft are perfectly allowed to not transmit ADS-B as long as they stay out of certain types of airspaces and outside of a certain distance of other types of airspaces and etc. So the effective result is pretty much that you need to have ADS-B if you ever want to land at a controlled airport but the details get a little weird.
These rules have also been changing reasonably quickly in federal terms. The current set of ADS-B requirements only took effect the first of this year. Among other things, these rules require that any aircraft equipped with ADS-B out have it turned on at all times... but that's only been the rule as of recently (not sure if this revision or the previous one), so not that long ago it was acceptable to turn it on and off if you were outside of areas where it was required.
> You could get the signal that a given tail number was in the air, but if it stayed below a certain altitude, you couldn't always receive its location.
I believe trackers (like ADS-B exchange) will estimate location using mutlilateration. IE: enough receivers with GPS-sync’d time and knowing where they are can estimate origin with the differences in receipt timing.
With good enough equipment, even one ground station might be able to tell a lot with Doppler shifts. Unsure if that’s don’t in practice though.
Oh that's interesting, I actually thought about that recently when I saw a "speed monitored by aircraft" sign on a highway. I wondered if an ADS-B receiver would pick it up. But... indeed, it's quite often that I see an aircraft and observe that it is not being picked up by my ADS-B receiver. Not sure whether due to low altitude , or that they are simply not transmitting..
I ended up using some lockdown time to put together a Pi-based ADS-B receiver, as I live close to the main low-flying helicopter route through London. I've chosen to feed data to a mix of services, including ADSBexchange which powers those bots, so some of the data there comes from my receiver; which has a surprisingly long range with a decent antenna: I'm regularly tracking aircraft 190 or so miles away...
You can set up a system for under $120 with a good antenna and a 1090MHz-filtered software defined radio stick. I use the Piaware distribution, which sets up the basic software needed to feed data and to generate your own maps. An added bonus of being a feeder is that you can get free access to commercial ADS-B networks like Flightradar...
it seem cool but it bothers me that this is a link to a donation page and that its been obviously made to request money, rather than show the service provided
I find it oddly satisfying to be able to use an app on my phone to identify planes above me. Do it all the time. I live across the Puget Sound from Seattle and I occasionally end up spotting a Boeing plane clearly on a test flight based on the route it has flown (geometric shapes, circles, take-off and return same airport).
Also had an interesting occurrence when I awoke to the sound of a plane dive-bombing my house. We happened to be located in an area designated to be sprayed for some sort of moth. The plane was just about scraping the tops of trees. But I was able to track and see the pattern it flew to spray our area and other areas it had visited that morning.
TIL about iOS shortcuts. This shortcut is pretty cool. But the nearest airplane comes up as private and now I’m paranoid it is an FBI surveillance plane when it is probably just going to/from the local small field airport.
Recently we had a suspect run through the yard. It was terrifying and had I not been hanging out on the back room I would not have been able to lock the door before he got in. The initial tip off that something was off was the CHP plane flying in circles above.
Now when I hear the aircraft above us I instantly check its pattern and lock all the doors.
I love what you're doing, but where's your website? You've got Twitter bots, but I'm not on Twitter, and a Siri integration but I don't own AAPL products. It makes me sad to see such useful data siloed in closed platforms.
Oh my goodness, Mr. literal over here. There are currently 3 continents covered by Advisory Circular bots. There are actually more Australian cities than American cities covered.
Maybe a link to the actual bots in the page rather than to a tweet with a twitter list that doesn’t seem to work would be helpful to, you know, actually see what’s going on?
hey, in the slide there was a part that says that surveillance planes typically flight in a couterclockwise circle. does anybody know why and can explain to me?
thanks
[+] [-] jjwiseman|5 years ago|reply
A few points I wanted to make, specific to the HN context (and a lot of this is in the "nerd mode" donation page at https://skycircl.es/donate-nerd-mode/):
1. This seems like a classic "low effort, high impact" project. It's super easy to detect aircraft flying in circles, in real-time, and post it to twitter. But it turns out to be an entry-point into a "strangely interesting" (according to pg) world of aircraft activity.
The current #1 comment sadly only gets to see general aviation pilots practicing, but my bots have tweeted military aerial refueling, STOL practice in the wilderness, float-planes practicing on rivers and lakes, military drones flying over the desert, planes dropping sterile fruit flies as a way to reduce the fruit fly population, news helicopters following a highway pursuit, U.S. Forest Service AH-1Z Viper attack helicopters fighting fires, helicopters dropping mosquito pesticide, aerial tankers over Manhattan for the president's combat air patrol, FBI surveillance planes registered to front companies, Coast Guard helicopters doing search & rescue, crop dusters, scientists observing sea life over the ocean, planes doing Gorgon Stare-style persistent surveillance over Baltimore, sheriff's helicopters rescuing hikers, power line inspections, pipeline inspections, military aircraft doing surveillance over protestors, stealth jet test flights, a Grumman HU-16 Albatross seaplane that belongs to the USAF over the Mojave desert, a U-2 test flight, and a B-29. That is not even close to a complete list.
2. All the code is open source. See https://gitlab.com/jjwiseman/advisory-circular/ and https://gitlab.com/jjwiseman/whatsoverhead
3. As far as I know, this comment on HN is the first time anyone published any significant detail about the FBI's secret aerial surveillance program: https://news.ycombinator.com/item?id=9508812
[+] [-] schmookeeg|5 years ago|reply
I was really confused at first by your use of the phrase.
I also think it is pretty funny if you didn't intend it. I would have thought what you're doing is better described as a "circular advisory" rather than "advisory circular". Cool project :)
[1] https://www.faa.gov/regulations_policies/advisory_circulars/
[+] [-] vosper|5 years ago|reply
I had to Google that. I'll await a correction from a more knowledgeable HNer, but as far as I can tell the US Forest Service does not have AH-1Z Viper attack helicopters.
I don't care enough to dig deeply into it, but it seems that basically there is a very long line of Bell helicopters called "AH-1", going all the way back to the original AH-1 Cobra in 1965. There have been many variants over the decades, and two of these have been been retrofitted into "FireWatch" helicopters for the US Forest Service, after being retired from military service.
The AH-1Z Viper is a modern attack helicopter, a variant of the SuperCobra, itself based on the AH-1 Cobra. It went into service in 2000, whereas the USFS two FireWatch Cobra's were originally built in 1969 and 1983: https://wildfiretoday.com/2010/06/27/firewatch-cobra-helicop...
[+] [-] DaftDank|5 years ago|reply
[+] [-] reaperducer|5 years ago|reply
They're people in small planes practicing.
Also, I live near several military bases. The interesting and loud stuff that I see flying by out my window NEVER shows up on any app. I expect this web site is similarly, deliberately, incomplete.
[+] [-] jcrawfordor|5 years ago|reply
When it comes to military aircraft, the situation there is kind of interesting. There's no general exception for the military, military aircraft are generally "required" to transmit ADS-B unless they have a specific reason not to (and I believe this requires authorization from somewhere up the chain of command). I put "required" in scare quotes though as many military aircraft are simply not equipped... the DoD has drug its feet on installing ADS-B out and the FAA has basically relented by setting very lax objectives. FAA requested DoD to have ADS-B installed on 21% of aircraft by the first of this year and I believe they met that goal... but it's still less than a quarter.
Over time more and more military aircraft should be appearing in ADS-B data, but I suspect it's going to be some years before it's almost all of them.
[+] [-] nja|5 years ago|reply
Perhaps less incomplete than you think (and certainly more complete than the standard tracking websites, which outside of hiding planes also must honor a 5-minute data delay requested by the FAA).
The advisory circular bots the author runs link to https://tar1090.adsbexchange.com/ , which is run from a home-grown network of SDRs. It makes a point of not hiding anything that reports its position with ADS-B -- which all aircraft (over a certain size) must report by law. I've even seen Air Force One and its escorts on this service, something that is always absent from other flight tracking services.
[+] [-] jmwilson|5 years ago|reply
Things flying near an airport are excluded ("The centroid of the last 3 minutes worth of positions must be more than 2.5 km away from all known airports."). I've never seen it tweet about planes doing obvious pattern practice.
[+] [-] mastazi|5 years ago|reply
This is what the standard training circuit looks like (it's basically a rectangular-ish shape)[1]
This is the type of orbit pattern that is used for search and rescue (SAR) or surveillance (a near-perfect circle, like the ones in the OP) [2]
[1] http://www.ppl-flight-training.com/circuits-briefing.html
[2] page 127 of this pdf ("Creating an Orbit Pattern") https://static.garmin.com/pumac/190-01007-03_r.pdf
[+] [-] sandworm101|5 years ago|reply
The slightly interesting stuff doesn't show up, the loud jets, but the really interesting stuff does. CIA rendition flights, police spying on protests, Air Force One, rich people flagrantly violating COVID rules ... they all squawk ADS-B.
[+] [-] LargoLasskhyfv|5 years ago|reply
Don't know if there is an "app", but regarding the interesting stuff, it's the most complete, IMO/E.
[+] [-] throwanem|5 years ago|reply
Most of the helicopters belong to either TV stations or city/county/state police. There's also medevac, but they don't circle much.
[+] [-] bonestamp2|5 years ago|reply
A few weeks ago I was watching an F-35 off the coast of Southern California... so cool to see that stuff. It seems to also pick up weather balloons (or some kind of balloons that are above 60,000ft). Anyway, it's fun to see what's out there.
[+] [-] minitoar|5 years ago|reply
[+] [-] mysterydip|5 years ago|reply
[+] [-] Shivetya|5 years ago|reply
Are there several? If so what was the key features you were looking for?
[+] [-] beamatronic|5 years ago|reply
[+] [-] WrongThinkerNo5|5 years ago|reply
[deleted]
[+] [-] rhacker|5 years ago|reply
1. Not move there because of flight training schools.
2. Lobby to get the flight training school to practice over unpopulated areas.
[+] [-] swalsh|5 years ago|reply
[+] [-] avh02|5 years ago|reply
[0] - https://www.bloomberg.com/features/2016-baltimore-secret-sur...
[+] [-] exhilaration|5 years ago|reply
[+] [-] JoblessWonder|5 years ago|reply
https://www.pss-1.com/
[+] [-] SaberTail|5 years ago|reply
[1] sometimes called the imperial boomerang, the colonial boomerang, or Foucault's boomerang
[+] [-] kanobo|5 years ago|reply
[+] [-] salex89|5 years ago|reply
[+] [-] spyspy|5 years ago|reply
This video is a really cool example: https://www.youtube.com/watch?v=SdfVIdsufI8
[+] [-] nickmooney|5 years ago|reply
[+] [-] flyinghamster|5 years ago|reply
[+] [-] MrZongle2|5 years ago|reply
[+] [-] motohagiography|5 years ago|reply
The FAA has guidelines on what kind of data you can receive: https://www.faa.gov/nextgen/equipadsb/research/airspace/
I lost interest in it because I just don't speed that much and I don't have a sport bike fast enough for it to matter, but useful to know that ADS-B doesn't cover all aircraft.
[+] [-] jcrawfordor|5 years ago|reply
So aircraft are perfectly allowed to not transmit ADS-B as long as they stay out of certain types of airspaces and outside of a certain distance of other types of airspaces and etc. So the effective result is pretty much that you need to have ADS-B if you ever want to land at a controlled airport but the details get a little weird.
These rules have also been changing reasonably quickly in federal terms. The current set of ADS-B requirements only took effect the first of this year. Among other things, these rules require that any aircraft equipped with ADS-B out have it turned on at all times... but that's only been the rule as of recently (not sure if this revision or the previous one), so not that long ago it was acceptable to turn it on and off if you were outside of areas where it was required.
[+] [-] Scoundreller|5 years ago|reply
I believe trackers (like ADS-B exchange) will estimate location using mutlilateration. IE: enough receivers with GPS-sync’d time and knowing where they are can estimate origin with the differences in receipt timing.
With good enough equipment, even one ground station might be able to tell a lot with Doppler shifts. Unsure if that’s don’t in practice though.
[+] [-] amatecha|5 years ago|reply
[+] [-] zymhan|5 years ago|reply
[+] [-] sbisson|5 years ago|reply
You can set up a system for under $120 with a good antenna and a 1090MHz-filtered software defined radio stick. I use the Piaware distribution, which sets up the basic software needed to feed data and to generate your own maps. An added bonus of being a feeder is that you can get free access to commercial ADS-B networks like Flightradar...
[+] [-] zobzu|5 years ago|reply
[+] [-] shanecleveland|5 years ago|reply
Also had an interesting occurrence when I awoke to the sound of a plane dive-bombing my house. We happened to be located in an area designated to be sprayed for some sort of moth. The plane was just about scraping the tops of trees. But I was able to track and see the pattern it flew to spray our area and other areas it had visited that morning.
[+] [-] gentleman11|5 years ago|reply
[+] [-] irrational|5 years ago|reply
[+] [-] EvRev|5 years ago|reply
Now when I hear the aircraft above us I instantly check its pattern and lock all the doors.
[+] [-] bengotow|5 years ago|reply
[+] [-] arkanciscan|5 years ago|reply
[+] [-] bhaile|5 years ago|reply
[+] [-] shruubi|5 years ago|reply
Last I counted, four of those five are in the same country. The world does not begin and end in America.
[+] [-] jjwiseman|5 years ago|reply
You can see the complete list of bots here: https://twitter.com/i/lists/1263724487435890688/members
[+] [-] iNerdier|5 years ago|reply
[+] [-] ShradhaSingh|5 years ago|reply
[+] [-] pps43|5 years ago|reply
[+] [-] linhchi|5 years ago|reply