Flight monitoring knowledge is a crucial instrument in open supply analysis, however with 100,000 every day flights, it may be troublesome to contextualise what a selected plane’s actions point out.
Bellingcat has developed a instrument referred to as Turnstone to make it simpler to visualise historic developments in flight knowledge and spot uncommon patterns. It additionally permits customers to filter by parameters reminiscent of plane kind or a geographic area of curiosity.
This instrument primarily makes use of Computerized Dependent Surveillance–Broadcast (ADS-B) knowledge, the expertise that permits open supply investigators and lovers to trace flights.
Most plane are outfitted with transmitters that broadcast ADS-B knowledge to adjust to world aviation rules, although rules differ by jurisdiction, and army plane won’t all the time transmit. ADS-B knowledge contains details about an plane’s id and kind, in addition to its exact place, pace and altitude.
In style flight-tracking web sites reminiscent of Flightradar24 and ADS-B Trade sometimes show historic knowledge for a selected time or plane. Nonetheless, Turnstone aggregates ADS-B knowledge for a number of plane over time, and permits customers to seek for flights throughout two areas of curiosity directly. These options present extra context for open supply investigators to raised perceive flight behaviour.
Watch the video for an indication of how the instrument works, utilizing the instance of Black Hawk helicopter patrols close to one of many borders between the US and Canada:
You possibly can view Turnstone’s supply code and details about internet hosting it your self on Bellingcat’s GitHub.
We even have a web-based occasion of the instrument that journalists and teachers can entry. On account of knowledge internet hosting and processing prices, we are able to solely grant entry on a selective foundation. If you want to use, please fill in this type. Precedence will likely be given to researchers conducting open supply investigations aligned with Bellingcat’s objectives.
Learn on for extra examples of how Turnstone can be utilized for investigations, in addition to some limitations of the instrument.
Recognizing Unusually Excessive US Tanker Exercise Earlier than Iran Strikes
The US and Israel launched joint air strikes throughout Iran on Feb. 28, 2026, reportedly killing greater than 1,000 individuals, together with members of the Iranian management, in 5 days.
This marked a dramatic escalation because the US and Israel bombed three Iranian nuclear websites in June 2025.
Flight knowledge earlier than each the June 2025 and February 2026 strikes confirmed a lot of American aerial tankers leaving the US and crossing the Atlantic in direction of Iran. Aerial tankers such because the KC-135 and KC-46A can refuel army plane in-flight, making them important for many long-range fight missions.
The 9 KC-46As that went to Ben Gurion.
All got here direct from the jap U.S. pic.twitter.com/izANyrqi4Q
— Evergreen Intel (@vcdgf555) February 27, 2026
With Turnstone, it’s potential to interrogate the baseline stage of motion and see how uncommon this exercise is.
To do that, three filters are set on the search: a geographic area of curiosity, set to the North Atlantic, a filter on the plane kind, to go looking just for tankers, and a filter on the plane heading, to go looking just for eastbound site visitors.
[Note: For the aircraft category designations, Bellingcat used a custom-prompted large language model (LLM), Claude Sonnet 4.0, to assign a category label using aircraft type code data. There may be some inaccuracies in the classifications, as LLMs are prone to hallucinations. We discuss this further in the “Limitations of the Data” section of this piece.]
This search finds over 40,000 plane areas that match these filter queries. Nonetheless, a take a look at the abstract desk reveals that this knowledge contains non-American tankers as properly.
We are able to filter this knowledge to incorporate solely plane related to the US by typing “United States” into the search field within the desk. Notice that possession knowledge shouldn’t be 100% correct – it might be old-fashioned, particularly for privately owned plane, and new plane won’t have any knowledge in any respect. Nonetheless, particularly when evaluating developments over time or looking for analysis leads, this knowledge can nonetheless be helpful.
The graph of matching detections over time now reveals that whereas there’s a giant baseline stage of transatlantic motion for American tankers, there was a notably increased variety of American tankers heading eastward from the US throughout the North Atlantic detected within the week of June 15, 2025, in addition to within the final two weeks of February 2026.
Per week after the elevated eastbound site visitors in June 2025, early within the morning on June 22, the US struck a number of nuclear websites in Iran. And on Feb. 28, 2026, the US and Israel launched over 900 strikes in opposition to Iran.
Altering the search question to search for westbound tankers as a substitute of eastbound tankers, we are able to additionally see a larger-than-normal variety of American tankers heading within the route of the US in the course of the week of July 13, 2025, bookending the summer season airstrikes in Iran. No such return motion is but seen following the latest strikes.
Discovering Deportation Flights to Guantanamo Bay
Turnstone additionally means that you can seek for plane detected throughout two totally different geographic areas of curiosity (ROIs).
Shortly after US President Donald Trump introduced the opening of a migrant detention centre at Guantanamo Bay in Cuba on the finish of January 2025, the US army reportedly flew about 100 immigrants from El Paso, Texas, to the US naval base to await deportation. By choosing the areas round each Guantanamo Bay and El Paso, we are able to discover flights between these cities that broadcast ADS-B knowledge.
When two ROIs are chosen, you may as well enter the utmost time distinction between an plane’s presence within the two areas.
Within the instance beneath, we have now entered 36,000 seconds (10 hours), that means that the plane will need to have crossed by way of each areas inside 10 hours of one another. We have now additionally set the utmost altitude to fifteen,000 ft (4.57km) to search for planes touchdown and taking off. This restrict is ready comparatively excessive as there aren’t any ADS-B receivers at Guantanamo Bay, and solely the preliminary method is captured.
After 5 months with no tracked flights between the 2 areas, this search reveals an uptick in flights within the few months from February 2025.
Outcomes for this search question from Jan. 26, 2026, embody a number of passenger plane operated by firms identified to run deportation flights from the US, reminiscent of Omni Air Worldwide and International Crossing Airways.
Mapping US Customs and Border Patrol Plane
Turnstone additionally helps importing an inventory of Worldwide Civil Aviation Group (ICAO) addresses, informally known as plane “hex codes”, that are distinctive identifiers assigned to plane by ICAO member states.
For instance, to discover knowledge associated to Division of Homeland Safety (DHS) exercise and search for patterns associated to the US immigration enforcement and border safety operations, we are able to copy and paste the hex codes from a checklist of US Customs and Border Patrol (CBP) plane (used throughout the DHS) right into a textual content file, and add that file. Now, we are able to search amongst these plane with any of the identical filters demonstrated within the earlier case research. Alternatively, we are able to additionally deselect the entire filters to trace the latest exercise by these plane.
Let’s attempt that with the CBP checklist, this time with a really giant variety of outcomes chosen: 500,000. Notice that rising the variety of outcomes will increase the search time and requires extra browser reminiscence.
When many factors are displayed, the map is simplified, and hover options are disabled.
By the California-Mexico border, Eurocopter AS350 (kind “AS50”) will be seen on frequent patrol missions over the land border. Over the Pacific Ocean, Black Hawk helicopters (“H60”) will be seen patrolling the worldwide waters boundary off the Mexican coast, whereas CBP Sprint-8s (“DH8B” and “DH8C”) journey farther offshore.
In distinction, by the Minnesota-Canada border, CBP makes extra energetic use of one in all its MQ-9 Reaper drones, as seen from the prevalence of purple dots that correspond to “Q9”, the sort code of those drones, within the outcomes map.
Let’s take a better take a look at these drones by filtering the outcomes with the textual content “Q9”. Now the displayed plane solely embody MQ-9 Reaper drones.
Now we are able to take a better take a look at the patterns of drones, particularly among the many search outcomes.
Whereas total CBP flight exercise was comparatively steady, drone flights appear to have intensified in December 2025 and January 2026, in contrast with earlier weeks.
Limitations of the Information
In open supply analysis, it’s all the time vital to be alert to the constraints of a selected knowledge supply, and ADS-B knowledge isn’t any exception.
For instance, some plane do not need ADS-B transponders and use older transponders to transmit flight data, which can lead to monitoring instruments reminiscent of Turnstone exhibiting inaccurate place knowledge.
Within the earlier case examine of CBP plane, the Turnstone outcomes appeared to indicate an MQ-9 Reaper drone in Canada on Jan. 20, 2026.
Is that this proof of covert DHS missions in Canadian airspace? Doubtless not: a cross-check of the drone’s hex code on that date with ADS-B Trade reveals that the plane’s place monitor shouldn’t be easy, however jumps forwards and backwards between a line within the US and a number of other factors many kilometres away in Canada.
This occurs as a result of when ADS-B place knowledge shouldn’t be obtainable, flight trackers usually use multilateration (MLAT), which estimates the placement of the plane utilizing the time variations between alerts transmitted from identified websites, in its place. The flight monitoring data on ADS-B Trade reveals that the place was calculated utilizing MLAT, which is much less correct than place knowledge instantly transmitted by way of ADS-B. ADSB.lol, which is the info supply utilized by Turnstone, makes use of MLAT when ADS-B place knowledge shouldn’t be obtainable.
ADS-B knowledge can be restricted by the place floor antennas can be found to obtain radio alerts from plane and by when plane select to transmit the info.
Different datasets which Bellingcat has used to allow the filters obtainable on Turnstone every have their very own limitations.
There is no such thing as a single supply of knowledge on plane possession. ADS-B knowledge identifies an plane solely utilizing its ICAO deal with or hex codes, however doesn’t include different data that instantly specifies the kind of plane or its registration.
As an alternative, flight-tracking web sites reference plane registration databases, reminiscent of these maintained by the US Federal Aviation Administration, to correlate ICAO addresses with registration data. The possession knowledge displayed on Turnstone is from tar1090-db, a community-maintained undertaking which has produced probably the most complete freely obtainable world plane registration database. Nonetheless, since possession knowledge is collected from many jurisdictions, with totally different privateness and disclosure necessities, it might typically be out-of-date or deceptive.
Possession data displayed in Turnstone or another flight-tracking software program ought to nonetheless be verified independently utilizing a number of sources.
For instance, one of many plane that got here up within the seek for flights between El Paso and Guantanamo Bay had a hex code of a6b0f5. This confirmed up in Turnstone’s outcomes as being owned by Financial institution of Utah Trustee, which matches the operator listed for this flight on ADS-B Trade. However a few of the flight codes utilized by this plane, beginning with “GXA”, are utilized by International Crossing Airways (GlobalX). The Financial institution of Utah is identified to legally personal plane below a belief relationship, whereas leasing the plane and operational management to 3rd events reminiscent of GlobalX.
The “Class” label and “Army” flag, which give a handy approach to filter plane, are pre-generated by a custom-prompted giant language mannequin, Claude Sonnet 4.0, based mostly on the make and mannequin of an plane.
For instance, the LLM might take a kind code of A321, which refers to an Airbus A321 passenger jet, as enter and assign the corresponding plane the class of “airliner”.
Bellingcat manually verified over 80 per cent of plane, comparable to the most typical plane varieties. However as we all know, LLMs are liable to hallucinations, and categorisation could also be inaccurate for extra obscure plane. Moreover, some plane, such because the V-22 Osprey, fall between classes and are inherently ambiguous.
To stop errors brought on by the potential miscategorisation of plane, you could need to search by kind code, which can draw from the uncooked tar1090-db knowledge, fairly than class. All plane registration, kind, and proprietor data must be independently verified.
Ideas and Additional Data
As we’ve seen on this information, Turnstone searches historic ADS-B knowledge to permit researchers to discover flight patterns over time and in particular areas. Whereas flight-tracking knowledge has inherent limitations, Turnstone can present helpful leads for researchers seeking to incorporate flight monitoring of their investigations.
In case you have solutions for bettering the instrument, you’ll be able to submit a pull request on Bellingcat’s GitHub. Extra technical data can be discovered within the instrument’s README.
For extra demos and details about the historical past of this instrument, watch a chat that Bellingcat gave about it on the What Hackers Yearn (WHY) 2025 hacker camp:
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