Inside Flightradar24, the website that tracks every plane in the sky

(CNN) – On average, more than 200,000 flights take off and land around the world a day. This includes commercial, cargo and charter aircraft – which account for about half of the total – as well as business jets, private aircraft, helicopters, air ambulances, government and military aircraft, drones, hot air balloons and gliders.

Most of them are equipped with a transponder, a device that communicates aircraft position and other flight data to air traffic control, and an inexpensive receiver based on a technology called ADS-B for automatic dependent surveillance-broadcasting that signal. can be captured with That’s what flight-tracking websites do in a nutshell, providing users with a real-time snapshot of everything in the sky (minus a few exceptions).

An ADS-B receiver manufactured by Flightradar24.

Courtesy Flightradar24

It is now reaching far beyond aviation enthusiasts. When the US Air Force plane carrying House Speaker Nancy Pelosi landed in taiwan In early August, more than 700,000 people watched the event as it happened, via a flight-tracking service. flightradar24,

The aircraft, a military version of the Boeing 737, called the C-40, took off from Kuala Lumpur in Malaysia to avoid encounters with the Chinese military, before embarking on a winding route to Taiwan, adding hours to the flight time. left for It was not immediately clear what the final destination would be, sparking online conversations as the plane slowly headed north toward the island. As a result, it was the most tracked flight ever on Flightradar24, with 2.92 million people following at least a portion of the seven-hour journey.

Part of a group of flight-tracking services popular with FlightAware and PlaneFinder, the website was founded in Sweden in 2006 “completely by accident,” says Ian Petchenik, communications director for Flightradar24, to track traffic for a flight. Price comparison service as a way to run.

It first gained global recognition in 2010, when an Icelandic volcano erupted. thousands of flights suspended and attracted four million visitors: “This was certainly our first foray into international events, and how displaying air traffic to the public in real time could affect how people were thinking about world news.” ,” says Petechnik. “With the number of visitors we got, the website would have crashed, so our saving grace was that there was nothing but a hole to show.”

interest is rising

Prior to Pelosi’s flight, the record for the most tracked flight on Flightradar 24 was held by Russian opposition leader Alexei Navalny on his return trip to Russia, where he was to be imprisoned. The January 2021 flight was tracked by 550,000 people, breaking an earlier record in April 2020, when nearly 200,000 users flew a Boeing 777 with the Turkish national flag in the skies over Ankara to celebrate Turkey’s 100th anniversary. Saw the crescent and star symbols. Sovereignty.

Earlier, in September 2017, thousands watched a brave Delta Boeing 737 land directly in Puerto Rico in Hurricane Irma, and 40 minutes later for JFK to carefully position itself in the gap between the storm’s arms .

Outside of major events, however, the number of people tracking flights continues to grow: “We see many people using the site to track down a loved one, track their flight, or visit the site.” They find the flight they’re going to be on later that day, to make sure the plane is arriving,” says Petchenik.

“Another use case is people who are very interested in aviation, or really like to follow certain types of aircraft. They can even go to the airport, pull up the app and see what happens. What’s coming. Then you have people who are professionally invested in the aviation industry, because they have a plane and they rent it, or because they have a fleet of planes and they want to keep an eye on them. Finally, there are people who are professionally invested in holding a lot of flight data. It’s airlines, airports, aircraft manufacturers who are using large data sets to gain industry insights.”

how data is harvested

To gather the data, Flightradar has built its own network of ADS-B receivers, which they now say is the largest in the world at around 34,000 units, covering even remote areas such as Antarctica. Is.

Flightradar24 has receivers all over the world, including in remote places like Antarctica.

Flightradar24 has receivers all over the world, including in remote places like Antarctica.

Courtesy Flightradar24

About a quarter of the receivers were built by Flightradar24 itself, but most are assembled by enthusiasts who provide data on a voluntary basis. Because the receiver is relatively cheap to make—the components cost around $100—many have signed up since Flightradar24 began opening its network to the public in 2009.

Tracking flights on a global scale requires a denser array of receivers, but there is an obvious problem with oceans, where networks tend to be sparse. So how do you get coverage on open water?

“By finding islands wherever we can and making sure we have receivers,” says Petchenik. “But recently we have turned to satellite-based ADS-B receivers to better track aircraft over the ocean. However, the most prominent source of data is still our own terrestrial network.”

Having such a fine-grained and localized amount of data can be useful for getting early information about emergencies and accidents: “We store everything that comes in our servers and if necessary we return to a specific receiver.” and extract the raw data. This is usually only done if an accident has occurred or if we have a request from an air navigation service provider or accident investigation branch,” says Petchenic.

Sometimes, the data may reveal the cause of the accident before an official investigation. In the case of Germanwings Flight 9525which was deliberately blown up into a mountain by the co-pilot on March 24, 2015, the data suggested a very clear picture: “One of the parameters that comes in the full set of data, which we obtained in this case The Germanwings flight, called the MCP ALT – is the knob that is turned to tell the aircraft’s autopilot at what altitude to fly. Looking at that aircraft’s data, the value for that altitude is zero. was set.”

However, not all data is available for each aircraft, as it depends on the type of transponder and the receiver involved.

Aircraft owners or operators may also decide to prevent their data from being publicly displayed, usually for military, government or private aircraft. For example, they can sign up for a program like LADD for “Limiting Aircraft Data Display,” which is maintained by the Federal Aviation Administration: “We follow that list,” says Petchenik.

“This allows operators to have their data displayed individually, anonymously or in some instances, not displayed at all. We account for approximately 3% of the total number of aircraft tracked on a daily basis. There is kind of data display regulation.”

Top image: A Boeing C-40C flight carrying US House Speaker Nancy Pelosi takes off from Taipei Songshan on August 3, 2022, a day after SPAR19 became Flightradar24’s most-tracked flight ever.