Flight Tracking

[Mendel]

Public flight tracking sites like Flight Radar 24 collect ADS-B data from aircraft all around the world. (There are also sites tracking AIS data from ships, and sites that archive aviation weather reports called METARs for most major airports.) There are apps that let you identify a flight by pointing your smartphone at it. The flight tracking sites also have an archive, but the free version usually only goes back a few days, and you need a paid subscription to access it. That's where this comes in handy:

In case you didn't know ADSB Exchange now offers 1 year of flight data playback. It displays some military flights that FlightRadar24 does not. You can access the replay function at https://globe.adsbexchange.com/?r .

Anyway... I've checked for the time of this sighting, and there's nothing showing on ADBSExchange that isn't on FR24.

View attachment 47137

Also they offer the download of kmls (click on the plane, button "Export KML" appears bottom left.)

View attachment 47138

 

[jarlrmai]

Does anyone else have this issue with ADSB Exchange I click on a plane icon to select it, then when i click elsewhere on the map that plane vanishes from the view.

 

[Trailspotter]

Does anyone else have this issue with ADSB Exchange I click on a plane icon to select it, then when i click elsewhere on the map that plane vanishes from the view.

I experienced something similar, but not today. Usually, this happens when the connection to ADSB server was lost temporarily.

 

[Giddierone]

• Does anyone know how to access historical flight data, say from as far back as the 1970s?
• Do vintage aircraft at contemporary airshows feature in flight tracking datasets?

 

[jarlrmai]

Flight tracking as we know it (ADS-B) only goes back as far as mid 2000's and then it took a while to become ubiquitous and then for things like FR24 etc to come online.

Anything that far back (70's) would basically be paper flight logs or flight plans and is probably not gettable unless historically interesting and in a museum or library, enthusiasts possession and also would not have the accuracy and resolution of ADS-B and may also be wrong based on plan not matching actual flight etc.

Yes vintage aircraft at contemporary airshows would have to have an ADS-B transmitter, if part of a formation probably only the lead aircraft would have the transmitter enabled.

Public ADS-B platforms provide only 3 years of data.

 

[Duke]

• Do vintage aircraft at contemporary airshows feature in flight tracking datasets?

Probably depends on the individual a/c. There is a Stearman based at a small airport nearby that I see frequently, but I've never seen on Flightradar24 or ADS-B Exchange. Conversely, I've seen a/c from the Collins Foundation and the Commemorative Air Force show up on numerous occasions. I've also watched warbirds at both Oshkosh and Fun 'n Sun on Flightradar24.

 

[Mendel]

Probably depends on the individual a/c.

Article:

However, 14 CFR 91.225(e)—which provides comparable exemptions to the ADS-B Out requirement—specifies "any aircraft that was not originally certificated with an electrical system, or that has not subsequently been certified with such a system installed, including balloons and gliders."

Source: https://www.aopa.org/news-and-media/all-news/2017/january/19/ads-b-requirement-clarified-for-nonelectrical-aircraft

If you don't have an alternator on the aircraft, you can fly without ADS-B and go untracked. (Or take a battery-powered transponder for safety.)

There are also other exceptions, e.g. for flying low outside of class B and class C airspace, or a one-time permission thing for a specific flight.

 

[Giddierone]

Yesterday there was a small single-prop aircraft doing a slow snaking pattern, like an aerial survey path, above us for a good hour but it didn't show on Flightradar24. Do you need a subscription to track small aircraft? Is there another tool that can be used?

 

[Mick West]

Yesterday there was a small single-prop aircraft doing a slow snaking pattern, like an aerial survey path, above us for a good hour but it didn't show on Flightradar24. Do you need a subscription to track small aircraft? Is there another tool that can be used?

Not all small planes have ADS-B transponders, they are not required outside of controlled airspace. It's also possible it was simply not working.

 

[Giddierone]

It was on Saturday around midday (clear cloudless sky) over the blue spot on the NATS map below, which I think is controlled airspace. It was really slow moving.

Source: Guide to Visual Flight Rules (VFR) in the UKhttps://www.bfgc.co.uk › VFR_Guide

Source: NATS Airspace Exporer App on iOS.

 

[Mendel]

It was on Saturday around midday (clear cloudless sky) over the blue spot on the NATS map below, which I think is controlled airspace.

That's LTMA-1 (class A), from 2500 ft. upward.
It's uncontrolled below.

From https://helispot.be/hs/documents/heli/olympics_airspace_guide_june_26.pdf p.16:

Though I think the inner area with the orange lines is the airport airspace, that would probably be controlled down to the ground?

 

[Giddierone]

Though I think the inner area with the orange lines is the airport airspace, that would probably be controlled down to the ground

If that's so can a small plane, like the one below, (which I think is flying just outside of the more controlled airspace North of me) turn their transponder off in such controlled airspace? Is OGN/FLARM the same device or is it independent to ADS-B? Meaning, can a plane fly with them both off?
We're right under the flightpath to London heliport (south of the blue dot) and often see helicopters at around 1,700ft. I estimate the plane I saw was above that (est. 2,000-2,500ft) circling back and forth it passed directly overhead - but it didn't show up on FR24.

 

[Mendel]

If that's so can a small plane, like the one below, (which I think is flying just outside of the more controlled airspace above me) turn their transponder off in such controlled airspace?

No. But I don't think they're in controlled airspace.

Is OGN/FLARM the same device or is it independent to ADS-B?

FLARM is independent and not meant to be picked up by ground stations, so I don't think FR24 would show it.

Article:

FLARM (an acronym based on 'flight alarm') is the proprietary name for an electronic device which is in use as a means of alerting pilots of small aircraft, particularly gliders, to potential collisions with other aircraft which are similarly equipped. [...] The 'problem' with FLARM is, however, that it does not transmit any signal detectable by ACAS or ADS-B.

Source: https://www.skybrary.aero/articles/flarm

Meaning, can a plane fly with them both off?

Sure, why not? or turn ADS-B off and leave FLARM on.

We're right under the flightpath to London heliport (south of the blue dot) and often see helicopters at around 1,700ft. I estimate the plane I saw was above that (est. 2,000-2,500ft) circling back and forth it passed directly overhead - but it didn't show up on FR24.

Watford is at ~200 ft elevation, as long as they're not higher than 2300 ft. AGL (for a total altitude of 2500 ft), they're good.

 

[Giddierone]

I don't think they're in controlled airspace.

I'm referring to the blue dot in the images above as the location of the plane I saw. The plane near Watford was just used as an example of the kind of plane I'd seen circling above my location, but which didn't show up on any tracker I could find.

FLARM is independent and not meant to be picked up by ground stations, so I don't think FR24 would show it.

The FR24 app shows it.

 

[Mendel]

The FR24 app shows it.

Yes, but a) the reach of FLARM is limited due to its low power, and b) I don't believe the FR24 volunteer receivers pick it up. That's why FLARM coverage may be limited.

I don't know the rules for London CTR, if that's where it is.

Note also that FR24 suppresses tracks of certain aircraft, e.g. military.

 

[Giddierone]

Flight tracking being new to me, how common is it to see aircraft in controlled airspace over a city but not be able to see them on a tracker?

 

[Giddierone]

What appears to be the same single engine fixed wing plane described in #8 has been doing loops overhead for 30 mins from around 21:30pm, was slightly cloudy, now totally overcast. Doesn't appear on Flightradar 24 or the NATS Airspace Explorer app. Military? ¯\_(ツ)_/¯

 

[flarkey]

What appears to be the same single engine fixed wing plane described in #8 has been doing loops overhead for 30 mins from around 21:30pm, was slightly cloudy, now totally overcast. Doesn't appear on Flightradar 24 or the NATS Airspace Explorer app. Military? ¯\_(ツ)_/¯

Have you looked on https://globe.adsbexchange.com/ ? It sometimes shows planes that aren't in Flightradar24.

 

[Giddierone]

Have you looked on https://globe.adsbexchange.com/ ? It sometimes shows planes that aren't in Flightradar24.

Thanks. Does it allow you to scroll back or is it just live data?

 

[flarkey]

Flight tracking being new to me, how common is it to see aircraft in controlled airspace over a city but not be able to see them on a tracker?

Depends what they are doing. There are some planes that fly out of Northolt that won't appear over London for security reasons.

Thanks. Does it allow you to scroll back or is it just live data?

This should let you view replay data...

https://globe.adsbexchange.com/?replay

 

[Giddierone]

This should let you view replay data...

Thanks again. So the plane I saw doesn't appear here. These are the tracks for the time period it was overhead. I've annotated it (red circle) with what I think was the approximate loop it flew repeatedly. I watched with binoculars for a while. Given its position within the flight corridors to Heathrow is it some kind of spotter plane for air traffic control?

 

[Duke]

Thanks again. So the plane I saw doesn't appear here. These are the tracks for the time period it was overhead. I've annotated it (red circle) with what I think was the approximate loop it flew repeatedly. I watched with binoculars for a while. Given its position within the flight corridors to Heathrow is it some kind of spotter plane for air traffic control? View attachment 56206

Were you able to identify the a/c type, or at least see it well enough to describe it? High wing? Low wing? Fixed landing gear?

 

[flarkey]

Given its position within the flight corridors to Heathrow is it some kind of spotter plane for air traffic control?

I think that's unlikely.

From my aviation enthusiast* experience there's two likely options for what this might be....

A P68 of the National Police Air Service used to watch criminals and events.

A Britten-Norman Islander (although these may be out of service now), used by the RAF for watching and listening to naughty people.

Did it look like any of these?

Edit: Probably not, if it was a single prop aircraft....

Yesterday there was a small single-prop aircraft doing a slow snaking pattern, like an aerial survey path, above us for a good hour but it didn't show on Flightradar24. Do you need a subscription to track small aircraft? Is there another tool that can be used?

*Plane spotter.

 

[Duke]

I think that's unlikely.

From my aviation enthusiast* experience there's two likely options for what this might be....

A P68 of the National Police Air Service used to watch criminals and events.

View attachment 56218
A Britten-Norman Islander (although these may be out of service now), used by the RAF for watching and listening to naughty people.

View attachment 56219

Did it look like any of these?

Edit: Probably not, if it was a single prop aircraft....

That's exactly what I was thinking. I saw those Islanders very frequently over Belfast when they were operated by the Army Air Corps.

*Plane spotter.

Did you have a blue anorak?

 

[flarkey]

That's exactly what I was thinking. I saw those Islanders very frequently over Belfast when they were operated by the Army Air Corps.

Me too.

Did you have a blue anorak?

No. It was grey.

 

[Giddierone]

Did it look like any of these?

No. We saw it again this morning on the school run. My son (sporting his bergundy anorak) said it was a Cessna. To my eye it was the same kind of plane I watched last night. They fly them at North London Flight school directly North of us, but on the trackers they only appear close to their airport, never directly above us.

 

[Giddierone]

I managed to get a couple of shots (taken through binoculars with an iPhone). Not sure if this is the same plane but it's typical of the kind of aircraft I see regularly flying in a wide circle. Again they don't show on the trackers. Now i'm not even sure if it's a single prop or not...

 

[flarkey]

Looks like a Cessna 150 series...

https://en.wikipedia.org/wiki/Cessna_150

 

[flarkey]

Hey @Mendel (oops, I mean @Topbunk 2.0 ) I posted your pic and FR24 track on a London Plane Spotters page, and the suggestion was it it was likely a rather sneaky Islander, registration G-BJOH that flies out of Northolt. It wouldn't appear on flight trackers due to the nature of it's work supporting Police operations.

Your image

Spylander

 

[Giddierone]

G-BJOH

Nice one! I saw this on YouTube. He describes it doing exactly what I saw twice a day for over a week now. Especially the part where he remarks how slowly it was flying. I saw it fly directly overhead and it looked like it was barely moving.
Source: https://www.youtube.com/watch?v=GwjqzmPBSMg

 

[Easy Muffin]

ADS-B Exchange has been acquired by private equity firm Jetnet, itself a subsidiary of PE firm Silversmith Capital Partners.

Article:

JetNet acquires flight tracker ADS-B Exchange

Friday, 27 January 2023

JetNet's resources will accelerate the growth of ADS-B Exchange while allowing it to maintain its enthusiast roots and unfiltered data. This is the first of several anticipated acquisitions by the intelligence provider.

Aviation data and market intelligence provider JetNet has acquired ADS-B Exchange, one of the world's largest networks of ADS-B/Mode S/MLAT feeders and providers of real-time and historical flight data. The acquisition is the second of what the company anticipates will be several future acquisitions as JetNet expands its data-driven product offerings for the aviation industry.
Founded in 2016 by Dan Streufert, ADS-B Exchange aggregates approximately 750,000 messages per second worldwide via receivers hosted by aviation enthusiasts around the world. The acquisition of ADS-B Exchange will enable JetNet to expand its flight data solutions with real-time information.
"ADS-B Exchange was founded as the go-to resource for aviation and flight-data enthusiasts," says president and founder Dan Streufert. "Joining forces with JetNet is the perfect match as we look to meet the business needs of our users while maintaining our enthusiast roots and unfiltered data. With a long history of providing highly valuable data to the aviation industry, JetNet offers the resources we need to accelerate our growth."
Like JetNet, ADS-B Exchange serves numerous constituents across the aviation industry, including MRO, airport operations and aircraft leasing. In addition, its real-time data is used by dozens of commercial customers across numerous end markets, including aerospace and defence, government, research and academia, and financial services.
"We are committed to providing our customers with innovative product offerings that provide the information and intelligence they rely on to make critical business decisions," says JetNet CEO Derek Swaim. "We've long admired ADS-B Exchange and know how strategic the company's real-time data offerings are to the aviation industry. Dan has done an incredible job building a fast-growing business that customers love. We believe he and the ADS-B Exchange platform will bring significant value to our customers."

Source: https://www.businessairnews.com/mag_story.html?ident=26872

This casts some doubts on its future, since a) the investors likely didn't do this out of the kindness of their hearts and will want to see a return on their investments, which seems at odds with the platform's current 'all the data for free' format, and b) the platform sources its data from a large number of volunteers, and by the sound of things many of them are not willing to keep feeding it for free to what's now essentially a hobbyist's project turned business enterprise, and if this picks up steam then the new owners will eventually have barely any data to display.

In fact, a lot of feeders have already gone elsewhere. The software itself is open source and a non-monetised replacement has sprung up at https://globe.adsb.fi - I don't know who's behind this, how many people will eventually upload their feed there or if it will even exist for the longer term but this appears to be the most promising alternative for the time being. As you can probably imagine, things are in a state of flux right now. Another site to keep an eye on is https://app.airframes.io.

 

[Mendel]

I'm adding this note on weather balloon tracking sites here to make it more findable.

Slightly off thread.... I often post links to plane tracking and satellite tracking websites on here but did you know that you can track Weather Balloons all around the world....

https://sondehub.org/

View attachment 57746

Amateur balloons can be tracked here
https://amateur.sondehub.org/

Root page is https://habhub.org/

 

[Giddierone]

This company/initiative Aerocene makes balloons - what they call Aerosolar sculptures - from old plastic bags and floats them around the world.

Some of them look like black triangles.

Extract from their website.

AEROCENE SCULPTURES ARE SOLAR POWERED AND CAN EASILY REACH ALTITUDES OF OVER 16 KM, HEATED ONLY BY THE SUN, CARRIED ONLY BY THE WINDS.

They have an app for tracking them.
Source: https://aerocene.org/

 

[Giddierone]

Hey @Mendel (oops, I mean @Topbunk 2.0 ) I posted your pic and FR24 track on a London Plane Spotters page, and the suggestion was it it was likely a rather sneaky Islander, registration G-BJOH that flies out of Northolt. It wouldn't appear on flight trackers due to the nature of it's work supporting Police operations.

Your image
View attachment 56321

Spylander
View attachment 56320

This plane (or one of the same kind, I couldn't see the tail number) has been flying in a circle over north west London all. day. long. No tracking data.

 

[Giddierone]

Can anyone recommend a tool/method to convert Two-Line Element Sets (TLE) data to a KML file for the purpose of illustrating a satellite ground track on Google Earth?

 

[Mick West]

Can anyone recommend a tool/method to convert Two-Line Element Sets (TLE) data to a KML file for the purpose of illustrating a satellite ground track on Google Earth?

I'll see if I can add it to Sitrec later.

 

[Giddierone]

A question about TLE flight/orbital tracking data.
Why do simulators show objects continuing to orbit beyond their decay date?
For example the ATV 1 that was filmed burning up. (
Source: https://youtu.be/OhBw5yaR_SU?si=Rib3DE7khjqz0Ndh
)
The TLE data for ATV-1 is
1 32686U 08008A 08273.04186473 .00037110 00000-0 19651-3 0 9991
2 32686 051.6395 202.3391 0011327 317.2751 152.9367 15.80097592 32156
Source:https://www.space-track.org/basicsp...ORAD_CAT_ID/32686/format/tle/emptyresult/show
The final deorbit time (decay date/time) was 14:58 CEST on 29 September 2008
If you enter the data into Flightclub.io or Sitrec it will show an object orbiting long after the decay date.
Questions.
Is the TLE data a projection of where the obejct would be if it hadn't been destroyed on reentry?
What defines "orbital decay" exactly? Is it where the object falls below a certain Radio Cross Section size as it's destroyed? Are the extra revolutions particle matter from the craft (or perhaps they don't correspond to an object at all if the object no longer exists)?

 

[flarkey]

A question about TLE flight/orbital tracking data.
Why do simulators show objects continuing to orbit beyond their decay date?
For example the ATV 1 that was filmed burning up. (
Source: https://youtu.be/OhBw5yaR_SU?si=Rib3DE7khjqz0Ndh
)
The TLE data for ATV-1 is
1 32686U 08008A 08273.04186473 .00037110 00000-0 19651-3 0 9991
2 32686 051.6395 202.3391 0011327 317.2751 152.9367 15.80097592 32156
Source:https://www.space-track.org/basicsp...ORAD_CAT_ID/32686/format/tle/emptyresult/show
The final deorbit time (decay date/time) was 14:58 CEST on 29 September 2008
If you enter the data into Flightclub.io or Sitrec it will show an object orbiting long after the decay date.
Questions.
Is the TLE data a projection of where the obejct would be if it hadn't been destroyed on reentry?
What defines "orbital decay" exactly? Is it where the object falls below a certain Radio Cross Section size as it's destroyed? Are the extra revolutions particle matter from the craft (or perhaps they don't correspond to an object at all if the object no longer exists)?

yes. the number 08273 in the first line of the TLE shows the date that the TLE was created. 08 is the year and 273 is the day of the year September 29 (2008 was a leap year). If you have a number of TLE for the same object in a simulator set to predict the orbit at a particular time it will take the nearest one, or the last one. There's no 'validity' flag saying if the data is accurate or not.

https://en.wikipedia.org/wiki/Two-line_element_set

 

[Mendel]

What defines "orbital decay" exactly?

Article:

Orbital decay is a gradual decrease of the distance between two orbiting bodies at their closest approach (the periapsis) over many orbital periods. These orbiting bodies can be a planet and its satellite, a star and any object orbiting it, or components of any binary system. If left unchecked, the decay eventually results in termination of the orbit when the smaller object strikes the surface of the primary; or for objects where the primary has an atmosphere, the smaller object burns, explodes, or otherwise breaks up in the larger object's atmosphere;

Source: https://en.m.wikipedia.org/wiki/Orbital_decay

Obviously (as you noticed), the validity of TLEs for objects undergoing orbital decay is limited.
But this may also be true for satellites that are still actively correcting their course.

Perhaps sitrec could display a warning if an out-of-date TLE is used?

 

[Easy Muffin]

Old, as in more than a few days, TLEs are not very useful for reentry prediction purposes. See for example this comparison here,

(from https://analyticalgraphics.my.sales...s/HowTo/Can-TLEs-be-used-for-Decay-Estimation)

It's data for Iridium 96
set 1 - black/green - apogee/perigee from Jan 2020 to Jun 2020 derived from TLE valid Jan 1
set 2 - blue/purple - apogee/perigee from Jan 2020 to Jun 2020 derived from most current TLE
actual reentry occured on May 30, about where set 2 takes the rapid plunge

The de-facto TLE propagator for satellites in usual orbits is SGP4 - there exist other propagators such as HPOP that model atmospheric drag in more detail but even those are limited since the actual conditions are quite chaotic.

For an example of how fuzzy reentry predictions are see for example this blog post here - https://sattrackcam.blogspot.com/2023/11/delfi-c3-reentry-forecast-updates.html
The author keeps updating predicted reentry times for a small cubesat. It's expected to come down in the next few days but the uncertainty period is still greater than one day (albeit down from the +/- 1 week uncertainty of a month ago).