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Comment by nja | Hacker News Reader

> 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.

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> must honor a 5-minute data delay requested by the FAA

This only applies to FAA-provided data. And I'd not be surprised if it's simply enforced by the FAA only providing 5-minute delayed data.

Tracking sites that use ADS-B are definitely realtime. My kids and I sit outside on the patio sometimes and track the planes coming at our house (we're pretty close to one of the standard ingress routes to PDX).

> 5-minute data delay requested by the FAA

Can you expand on this for the noobs in the subject?

so you cannot trivially go hit something with a ground-to-air missile.

why the downvotes? this was the actual stated reason when this was requested

Which is silly, because ground-to-air ordinance could just listen on ADS-B RF itself for the target (you too can listen in with a software defined radio if you're in the vicinity or have gear that can listen in the area). It's security theater, not an actual mitigation against a threat actor with access to an anti aircraft weapon.

For anything not broadcasting ADS-B, you can use multilateration (time difference of arrival) to determine positioning of dumb transponders. Flightaware does this [1].

[1] https://flightaware.com/adsb/mlat/

Umm, well, there is this issue that you can actually see the plane without a delay, so...

Requiring a line of site makes it much more difficult than giving real-time tracking data away

That's why The Rurists (Terrorists) try to hit a plane when it takes off or lands. Easier to hit. Even with a stinger. Just hang out by the airport with your favourite Stinger Launcher and you're good to go. No need to hit it at 30,000 feets. I'd hit it at landing takeoof the ground taxiing etc. Works for me.

No wonder that’s why 9/10 of the weekly terrorist takedowns of aircraft I read about are near airports.

Not sure why an answer to the question would be downvoted.

Anyway, it's possible that the reason was no so much ground-to-air missiles but rather ground-to-air weapons. In other words, idiots trying to shooting guns at airplanes or put up balloons in their path.

I suspect people downvoted it as a seemingly low effort post - ambiguous about whether it's a joke and no citation to indicate it isn't

I tried briefly googling, but while it's easy to find others talking about the delay [1], I didn't find a why confirmation

[1] https://aviation.stackexchange.com/questions/3052/is-there-a...

I had not heard of this rule before, but I'm guessing data sourced from the FAA is delayed by five minutes.

Most data on FlightAware, for instance, is from ADS-B feeders run by average folks. FlightAware takes this data and turns around to sell it for a boatload of money to people that manage fleets and want to know exactly where their plains are at. In order to ensure there isn't dropouts in coverage, FlightAware pays the FAA to feed them data that they can't get from ADS-B feeders, for example when a plane is not in range of any feeder. As a condition of the FAA giving them access to this data they must abide by the FAA's rules, one of which is filtering planes in which the owner has requested their tracking data not be made public.

Interesting fact, if you feed then you like contribute to FlightAware locating the position of an aircraft not emitting ADS-B, but with a Mode S (?) transponder. This is known as M-LAT, or multilateration. Because of FlightAware getting FAA data and being bound by FAA terms they won't return the position of the plane that you helped them locate, assuming the owner of that aircraft requested privacy. So essentially you help provid them the data that they can sell access to the owner of that aircraft, but you don't get to see that same data. Sites like ADSBExchange, which the OP app uses, do not source FAA data, and so are not bound by such crappy terms.

There's a side-effect of having a big array of receivers; if you get the basic Mode S data that all aircraft (including military) transmit from their transponders, a little math lets you quickly plot their location using a technique called multilateration (MLAT) using time of flight data and a bit of trigonometry.

> must honor

Is this true? Seems like an unambiguous violation of the first amendment. Someone can't report on raw data that they can receive with an SDR? Has this been litigated?

FlightRadar24 certainly doesn't have a delay.

They also hide certain aircrafts.

In most cases I've personally witnessed (I have an RTL-SDR decoding ADS-B transmissions in the vicinity of my home) the interesting aircraft (e.g. fighters) are not operating an ADS-B transmitter at all, so there's nothing to hide. Some sites (adsbexchange.com comes to mind) do not filter anything.

About the only thing that's gone past me without any transponders are the civilian marked up Dauphin II used by the SAS...

ADSB Exchange does not. https://tar1090.adsbexchange.com/

As another commenter noted, not every aircraft advertises itself using ADS-B, but the majority do - even military. I’m no expert here, but I think the distinction is that military aircraft operating outside of civilian airspace don’t need to. But some do anyway - I’ve seen a U-2 flying at 62k feet over the Southwestern US show up on ADS-B exchange. There’s no need for it to do so, as no civilian aircraft flies at altitudes that high.

A lot of the commercial flight tracking services allow opt-outs. But some stay true to their mission.

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