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Comment by speakspokespok | Hacker News Reader

Speaking for the USA, the ADS-B data stream you see on FlightAware's commercial feeds has military and police aircraft data filtered, even if those aircraft are broadcasting that information. While ADS-B data reception is public, certain data types must be removed in your commercial offering per FAA.

Near me in Puget Sound / Seattle are two intl airports, several military bases including a nuclear sub base, plus we're near the US / Canadian border. Air traffic as you can imagine is very interesting and includes state police Cessna's at night cruising for people speeding on Highway 18, military transport through JBLM (military base) but no fighter jet ADS-B. There's commercial air traffic, hobby planes, private jets, hospital and news helicopters. There's flight paths and local flight patterns. My current mystery are the small, black, unmarked DHS (I think!) helicopters that cruise Discovery Park lighthouse every few hours. They don't show up on ADS-B at all. There's more but you get the idea of how cool this all is. SDR is just wild. All you need is a Pi 3 and the PiAware image, the antenna and the 1050 filter they suggest. PiAware has a local webinterface that shows everything it's picking up but will be filtered later by FlightAware.

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Sorry if I'm being pedantic, but a lot of people do think that all military and police aircraft are filtered by FlightAware, FlightRadar24, etc., and that's not true. Right now I can find several military and police aircraft flying in Southern California on both FA and FR24.

As far as I know, the FAA doesn't ask anyone to filter any types of aircraft or data. They do have a program, LADD[1]: "Aircraft owners or designated representative may request limiting aircraft data displayed (formally referred to as blocking) or unblocking of flight tracking data." If you use FAA data I believe you must honor the LADD list, but as far as I know owners have to submit every registration number or call sign that they want blocked (and that list has even been FOIAed[2]). It's always possible that a flight tracking site might decide they want to voluntarily block some type of aircraft, but so far there doesn't seem to be evidence of that that I know of.

[1] https://ladd.faa.gov [2] https://www.muckrock.com/foi/united-states-of-america-10/faa...

Thanks, good information.

>If you use FAA data

I was under the impression that FlightRadar24 uses crowd sourced data collected by users with radio receivers managed by Raspberry Pi if I recall correctly?

That doesn't mean that they don't use FAA data, I just don't know that they do. And that's only addressing one of the two services you mentioned, of course.

FR24 uses radars and multilat streams too in some countries iirc. Not all aircrafts have adsb but FR24 sees much more aircraft than ADSB adoption rate should show.

Unfiltered cooperatives like adsbexchange.com are also good ways to see what's up there that might be filtered on FR24 or FlightAware.

This, TLDR other comments. Others do filter data and the proof is in comparing in real-time all the sites along with actually seeing the vehicle and its location in the sky as some data can be delayed.

I do not claim to be a plane spotter but given where I live I have picked up interest in the last several years after U.S. president 45 was elected and even more now with 46. 46 goes home nearly every weekend and the FAA flight restriction circumference borders right over my house. I also have the locational benefit of being inline with the flight path and approach for Air Force N for 46s comings and goings by plane which I have seen multiple times and I did see 45s helicopter once flying over enroute to NYC.

Others may not be aware that there is the active deployment of fighter jets and air refueling tankers that support this FAA VIP air restriction. Since 46 has been elected and nearly every weekend he is home we experience non stop fighter jet thrust rumble at our location. One will not find these jets on any public data plane location stream yet the persistent presence of the air refueling tankers and the rumble from jets burning fuel on the ready makes it obvious of the jets presence for those in the know. Given the proximity to major airports the air refueling tanker is listed on adsbexchange and fly's in circles sun up to sun down topping off those jets.

A few Sundays back we had pristine clear skys for both PV collection as well as noob plane spotting. Using binoculars on a tripod and sky scanning based on the tankers locations I believe I saw the back side of a F22 coming in to top off. I did get a picture about an hour later of an unknown jet type refueling off the air tanker after months of trying, I just smiled.

As to the point of this "China" ban I personally know the value of such data in my own accomplishments as I see it akin to social engineering. Granted it is not war time so the tanker is broadcasting but I find it an oversight by those in charge to advertise where mother goose is as the goslings are never far behind.

Not just the tankers—the VC-20s themselves are usually visible on ADSBExchange if they’re flying over areas that support Mode-S multilateration[1]. You see some interesting things this way, e.g. President Obama’s last flight on AF1 immediately following President Trump’s inauguration left Joint Base Andrews for Palm Springs[2], but made an unscheduled diversion to fly over the city of Chicago a few times at about 3PM Eastern—perhaps a nice gesture from the flight crew? I never saw that reported anywhere.

[1]: http://www.multilateration.com/surveillance/multilateration....

[2]: https://www.dailynews.com/2017/01/20/ex-president-obamas-pla...

Have you tried ADS-B Exchange? They don’t use FAA data or apply their filters.

> Speaking for the USA, the ADS-B data stream you see on FlightAware's commercial feeds has military and police aircraft data filtered, even if those aircraft are broadcasting that information

I have seen military aircraft on FlightAware before. This one for example: https://flightaware.com/live/flight/SIKES85/

It was a pair of KC-46s practicing in-air re-fueling and were actually visible from the ground.

Some other examples: https://flightaware.com/live/flight/NITRO72/

https://flightaware.com/live/flight/BISON2/

Pretty sure these are fighter jets given the speed at which they are maneuvering:

https://flightaware.com/live/flight/COBRA66/history/20211108...

https://flightaware.com/live/flight/COBRA44/history/20211108...

https://flightaware.com/live/flight/COBRA52/history/20211108...

You can basically check the flightaware pages for Air Force bases and find these.

Not sure about those last three being fighters. One of them was going fast enough to be plausible, but the other two spent the flight in the 200-300 mph range. That's not much above stall speed for an F-16 or F-22, for example.

Agreed that COBRA66 and COBRA52 seem to be pretty slow for a fighter jet even though they were still flying loops at over 150 kts in one case. COBRA44 though seems to be in about the correct range.

COBRA44 is a T-38 (trainer used to train fighter pilots): https://globe.adsbexchange.com/?icao=ae00d6

COBRA51 and COBRA66 are thought to be Beech C-12C Hurons: https://twitter.com/SkyCirclesR2508/status/14577732869353062... https://twitter.com/SkyCirclesR2508/status/14577926990423859...

Cessna's looking for speeders. I wonder what the ROI on that is: I'm guessing that's not all they do.

Aren’t speeding tickets known to be really big income for local governments?

They can be hundreds of dollars; I’m sure it can work out financially if they can hand out enough, which seems likely from an airplane.

Can't give a specific driver a ticket from an airplane. I thought the main function of the planes was to follow extreme speeders, which has to be revenue negative -- just because there are so few and it takes so long -- but maybe a justified expense.

They are able to identify speeders without radar using fixed distance marks on the road and timing cars traveling between those marks. At that point, they are then able to give information about the car to the police on the ground for them to be pulled over.

These days they all pretty much have systems like the Churchill/Shotover Augmented Reality Mapping System (ARS) which will give them target vehicle speed automatically. Even news helicopters use similar systems[1].

1. https://shotover.com/videos/videos/kabc_tv_air7hd_with_xtrem...

That's a rather neat system. Things like overlay of the street map on the display - makes navigation for aviation more useful too.

https://youtu.be/rumcjbVzzLE

There are entire towns who can only afford to have a police department because of their ability to write traffic tickets.

They usually fly something like a 206 or 182 with a Flir gimbal and two people on board. Those types cost between $120 and $200 an hour to operate plus whatever the costs of the gimbal are (mind that the gimbal may cost as much or more than the host aircraft).

The pilot and sensor operator are paid so that's another $100+/hr after benefits and such are paid.

I'm guessing they just do it to subsidize the aircraft and give it something to do between calls when it's on station. The aircraft costs money just sitting in the hangar so it'll help justify the costs.

There's a "Portland Police Bureau" activity going on right now, using a C182. I think they are following a car on various local highways. https://globe.adsbexchange.com/?icao=a1d296

But that's misleading. I've been told that the FBI usually pilots that particular aircraft. So the ADSB "owner" could be someone else.

This also factors into economics. Stuff like FLIR might be expensive to local police agencies but that cost is totally irrelevant to the Federales. Same with salaries. The Feds are already getting paid. The incremental cost is $0.

Most of the time this particular aircraft is observing various intersections in Portland. E.g. pursuing fleeing perps or monitoring street racing. Gang violence in Portland is out of control and there has been a public announcement that the FBI is helping.

Even if they don't generate money from that, catching people speeding is a public service. If one disagrees with the idea that speeding is bad, then why don't we raise speed limits until the speeds deemed "reasonable" at under the limit.

Sure, but fixed cameras along the route must be a lot cheaper than the plane.

They're on Waze five minutes later.

Good. If it's actually important that people drive slower in that area, everybody knowing there are speed cameras will have that effect.

Looking at you:

- Crotch rockets (driven by dudes in jorts and a t-shirt flapping in the wind)

- Dodge chargers w/ aftermarket exhausts

- BMWs with iridescent vehicle wraps

- Lifted pickup trucks with massively oversized tires

This reads like a Reddit comment.

If everyone guns it right after passing the camera, you've potentially made things more dangerous.

Aircraft allow for a "you could get caught at any time" deterrent that cameras can't unless you put them literally everywhere.

They still increase the safety by limiting the speed in for example an exposed intersection.

On the other hand you can go the average speed route instead.

https://en.wikipedia.org/wiki/Speed_limit_enforcement#Averag...

The cameras are more effective if people have to expect them everywhere, because then they will (hopefully) stick to the speed limit everywhere.

This is such an insane take.

The speed limit is for everywhere for safety. They faster people go the more dangerous it is.

Actually, people tend to drive at the speed that is safe, and traffic engineers set the limit at about the 85th percentile of the observed speed. Maximum limits on safe roads are usually lower than the observed speed, and so serve no purpose from a safety perspective.

Traffic calming techniques like narrower lane widths and widths are shown to be more effective than police enforcement. The “downside” of these methods are that they’re actually effective at controlling speed, and thus are a revenue loss.

> Actually, people tend to drive at the speed that is safe,

That not remotely true in any part of the world I've visited so far.

Not the person you replied to, but I really feel like enforcement must be a pretty substantial part of what stops people from speeding and driving recklessly, given that traffic enforcement has been de-emphasized since the start of the pandemic and the number of road fatalities has gone up more than 7 percent, even though the actual number of miles driven has gone down.

https://www.nhtsa.gov/press-releases/2020-fatality-data-show...

If people drive at whatever speed they think is safe, then why would the aggregate number of people dying on roadways ever go up when miles driven by the same population goes down? Here are the possibilities:

1. Driving has become more risky due to external, uncontrollable factors, like weather or road changes that motorists can't account for or

2. People are modifying their behavior.

Why would they modify their behavior? The roads haven't changed. The speed limits haven't changed. What has changed? More people are dead because of extreme speed and reckless driving on roadways, which kind of suggests that traffic enforcement did at least prevent some of those deaths.

I'm not sure there's enough information to draw such a conclusion. For example, due to changes brought on by the pandemic, the makeup of vehicles, drivers, and reasons for driving may have been significantly different.

One interesting point from your link was a significant increase in drivers involved in fatal crashes testing positive for drugs including cannabis and alcohol, but especially opioids. It would take real research to quantify the relative effects of each of:

1. Increased speeding due to reduced enforcement

2. Increased DUI due to reduced enforcement

3. Increased DUI due to pandemic-related drug use

Also, is there actually any evidence of reduced traffic enforcement? Or are people just assuming this?

Except the road conditions totally changed. At the beginning of the pandemic, you had hardly any traffic anywhere. No more were people being slowed down to 25mph on the freeway by a traffic jam. You could easily cruise 60mph into the city for a long time. Suddenly, a morning wreck meant someone crashed at 60 instead of 25.

You need to stop equating speeding with driving recklessly.

Going 70-80 on a limited access highway when conditions permit is not reckless. Weaving through traffic at 20+ the prevailing speed with no margin for error is. A number on a sign does squat to effect either group.

> people tend to drive at the speed that is safe,

*at the speed they believe is safe. Most people also highly overestimate their driving skill.

When you start saying that everybody else is wrong on issues that are broadly defined by social consensus (e.g. what's a safe speed for this road, what's appropriate attire for the office, etc, etc) you're basically saying everyone is wrong except you but with extra steps.

Social consensus can be and often is wrong. Counterintuitive results like the Birthday Problem are widespread, people are shit at statistics and risk evaluation, etc.

The US national speed limit was imposed as a fuel economy measure not a safety measure.

Did states not have their own speed limits prior to that? Do they not set speed limits on state or county roads today?

If speed limits are about safety, when the states set theirs and the feds over-rode them, which one was used flawed safety data (or was it “both”)?

> The speed limit is for everywhere for safety.

Absolutely not. Speed limits that don't fit the roads they're on are not a safety measure. Outside of really blatant speeders, it's the road design that needs to make things safe or not and do the bulk of the work in guiding people to a reasonable speed.

But even separate from that issue, tons of speed limits are set for reasons like "people complained about noise, probably unreasonably" or "we want to make money off tricking drivers".

I'm a staunch privacy advocate, but we have thousands of people in my state dying a year from automobile accidents. (On par with gun deaths, a figure which includes 60+% suicides.)

I'm not sure I'd fight it if we lined the entire interstate highway system with plate detectors.

If your average speed is above a reasonable limit (80mph on low density straightaways?), then you receive a ticket at a rate multiplied by the duration of infraction.

Norway and Finland fines proportional to your yearly salary. Of course there are some problems with that, but in general I like that system more.

Where there’s a lot of speeding to catch is low density straightaways marked 35.

You can make these cameras so dense that there is very little opportunity for speeding in between two cameras.

No need for so many cameras. You only need two :-)

https://en.wikipedia.org/wiki/SPECS_(speed_camera)#Similar_s...

https://en.wikipedia.org/wiki/Speed_limit_enforcement#Averag...

(Sorry for the nerdy nitpick)

flashback to Calc 101 and the Mean Value Theorem!

This is essentially the way it works in Switzerland. On motorways there are speed cameras every few kilometers: even with an app to warn you, it’s not worth trying to speed between cameras.

Oh man I got so many speeding tickets in Switzerland (like 5 in two years). They were all super minor like $50 or something?

I heard it does not apply to all cantons, the Italian ones speeding is more OK.

All that being said I really dislike the US system where you can pass a police car driving 75 on the 101 and he doesn't care. There has to be some enforcement of the rules.

> All that being said I really dislike the US system where you can pass a police car driving 75 on the 101 and he doesn't care. There has to be some enforcement of the rules.

The US system is a probable cause generator.

Or revenue, or both.

When you travel in a country where limits are harshly enforced, driving is wayyy more relaxing because of the reduction in speed variation (most people travelling at the stated limit) and no crazy overtaking manoeuvres (idiots don’t just harm themselves). That said, I’m not a fan of draconian speed limits.

Not sure about the 101 but most places won’t pull you over unless you’re going 10+ over. They did a super speeder law in my state where 85+ on any road or 20+ over gives you a much harsher penalty. The state patrol will sometimes sit and wait for the super speeders and let the 15+ people pass.

$50 will be for a couple of km/h over the limit (after the 5 km/h "standard" deduction). At 20 km/h, it's CHF250; above that you're getting in front of a judge, will lose your driving license for a while and face thousands in fine and administrative fees.

So? Wouldn’t people that know the cameras are there drive slower than the people that don’t? From a public safety point of view, known cameras are more effective at limiting speed than unknown ones.

Reducing lane width is also shown to be a very effective speed control methodology, that does not require police enforcement.[0]

Or are you concerned about a loss of local and state revenue? Seriously, the use of police for revenue generation, rather than public safety is an open secret among police and local governments.[1][2][3]

[0] https://nacto.org/publication/urban-street-design-guide/stre...

[1] https://harvardlawreview.org/2015/04/policing-and-profit/

[2] https://www.policechiefmagazine.org/generating-new-revenue-s...

[3] https://www.theatlantic.com/national/archive/2014/12/the-ben...

That’s simple. Just do one camera at the beginning, one at the end and you can get average speed by simple math. While it allows you to go above the speed limit, you also have to slow down to “lose” that earned time so at the end it averages back to speed limit. Go ahead and advertise this speed trap well because the more people understand how this works the better.

They are illegal in a lot of states. I no small part because of the egalitarian nature of them. Government officials are getting ticketed and they get the same treatment as the rest of us.

Some states have ruled them unconstitutional.

OK, let's do that.

60 is plenty on Highway 18, especially during these wet fall and icy winter months

60 as a limit on any controlled access road is an absolute joke.

It turns out to be more difficult than people want.

to be certain, some speed limits are low for bad-science reasons. But the other issue is that the speed limit isn't set for the average case; it's set for the safety-limit case. As one highway engineer's blog put it colorfully (paraphrasing from memory): they aren't set to keep your decently-well-maintained 4-door sedan with tires installed this year on the road; they're set to keep the 18-wheeler driven by a sleep-deprived trucker at night during a light drizzle on the road when one of their tires blows.

Variable speed limits that adjust automatically with weather and lighting conditions can help, but the signage to indicate them costs money... Way more money than a static metal road sign.

The one place I've seen a Cessna on speeder patrol it certainly paid for itself. There was a spot where an interstate cut through an Indian reservation. The speed limit was set to 65 mph even though the road was better than that.

A bird in the sky plus more cops than I would have thought they had were a frequent occurrence there, pulling over basically everyone who wasn't aware of the speed trap. Certainly worth it.

One day they raised the limit to 75 which is far more appropriate--I've never seen the plane since, I've seen one cop a couple of times hiding behind the crest of a hill.

"Even though the road was better than that"

Where I live, people flying past you at 100+mph is a common occurrence on the autostrada. (Yeah not US.) Speed limit is 80ish.

The road was engineered for speeds higher than the 65 mph limit. Obviously so as no changes were made to the road when it was changed to 75 mph.

What’s the ROI on responding to domestic disturbances in low income neighborhoods?

What a silly way to look at safety money.

That depends on how much you think a human life is worth, disappointingly.

I would like to see some numbers for implied value of life by some of the decisions we make (driving at speed, extreme sports, anything fun but risky), especially the implied value for yourself versus others like pedestrians.

I used to live in a remote mountain village, located on one of the main highways across our central mountain range. 8km or so of the highway leading into the village was narrow and winding with no shoulder - the road lines were cut in the horse and coach days, so not designed for cars. It was surrounded by forest, often with bluffs on one side and a 20m drop on the other.

People crossing the centre line on blind corners because they were driving too fast were a real hazard on that section of road.

One summer (when the road was busiest) the Police ran an operation where a helicopter observed the road, and identified vehicles cutting corners, who were then pulled over outside the 8km stretch where it was safe to do so by waiting patrol cars.

They only ran it for a couple of weeks, but the calming effect of it on bad driving on that stretch lasted months, it was awesome.

So the Cessna might not be about making money, and more about the potential presence of the Cessna changing driving patterns increasing safety.

In Norway they put one of those radar boxes with a camera in places like this. They even put a sign a mile before saying there is going to be a box since the objective is not to catch people but to make the average traffic slow down.

In the US (at least in NY), traffic tickets are considered income -especially in Manhattan. Some jurisdictions actually plan budgets on it. The same with civil forfeiture.

Not to be outdone by NYC, this happened in Chicago, too:

> A Tribune examination of overturned red light tickets revealed evidence that the city of Chicago has quietly cast a wider net to snare drivers since switching camera vendors earlier this year amid a bribery scandal.

> A before-and-after analysis of photographic evidence and interviews with experts suggests the transition to a new vendor last spring was accompanied by a subtle but significant lowering of the threshold for yellow light times.

https://www.chicagotribune.com/news/ct-red-light-camera-yell...

This happened all over the US:

https://www.foxnews.com/politics/ohio-town-must-pay-back-mil...

The New York Times has been running a series on traffic stops focusing on reasons for the high death rate among motorists who are pulled over, but they also did this long and infuriating piece on the funding issue. It was actually somehow even worse than I expected: https://www.nytimes.com/2021/10/31/us/police-ticket-quotas-m...

"People will behave well if they think Big Brother is always watching so let's make them think that"

Remember when you could leave your house and not get recorded? I miss that.

Well, I'd prefer that they could drive safely on a dangerous road without a helicopter enforcing it, but human nature is what it is.

Far too many people seem to think that their wants and needs and beliefs are so important that fuck the rest of you.

(Could also be that old chestnut about 75% of drivers considering themselves above average)

I'm fine with that kind of enforcement for crossing the center line, but that's different from speed limits, and especially people that are going mildly over the speed limit on big close-to-straight roads.

If they use those planes for other reasons (search and rescue, fire, etc.) then the cost is minimal. If the pilot weren't out there catching speeders he would be doing touch-n-goes, etc. to maintain currency.

Pilots have a minimum number of hours / approaches per time period, and planes have high fixed operating costs (annual service, hanger, etc.), combined the marginal cost of catching speeders is low.

Are you feeding data to FlightAware for the free Enterprise Subscription?

By the way I'm in Ballard (near Discovery Park) and do notice those helicopters too. Whatever they are - they seem to usually originate at KBFI which is where I'm currently doing my PPL.

Can you pick up both ADS-B and VHF radio with your setup or would VHF require other hardware?

Different antenna. ADS-B is at 1090 MHz, and VHF air comms is more around 121-135 MHz. The same SDR radio can tune those two bands, but an antenna that works well for one would work poorly for the other.

Small world! I too live in Ballard and have been super curious what these have been up to, they fly pretty low and have a lot of hardware hanging underneath them.

> certain data types must be removed in your commercial offering per FAA.

Can you link to source if it? Afaik everything transmitted by ADS-B is public including military and le. FAA allows mil or le to turn off ADS-B out if it can compromise their mission [1].

[1] https://www.aviationtoday.com/2019/07/23/new-rule-allows-mil...

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