Earlier this summer, Malaysian Prime Minister Najib Razak was forced to admit that he had used federal funds for a four-day trip to Milan, Italy, with his wife. The revelation came after a member of the Malaysian parliament presented evidence from air traffic website FlightRadar24 that the official plane thought to be bringing the prime minister back from Washington, D.C. made stops in Milan and Dubai (for refueling) before landing in Kuala Lumpur.
That was one of the more unexpected uses of the site, which incorporates GPS data from five continents to create a real-time visualization of air traffic, says FlightRadar24 CEO Fredrik Lindahl. Built by Lindahl and a fellow aviation enthusiast in Stockholm, Sweden as a hobby in 2006, FlightRadar24 opened to the public in 2009 and now employs a small team of developers.
Using technology called Automatic Dependent Surveillance-Broadcast (ADS-B), FlightRadar24 has established a network of more than 500 ADS-B receivers around the world, installed and operated by volunteer plane spotters. During flight, an aircraft gets its GPS location from satellites, and many use an onboard ADS-B unit to transmit a signal containing that location and other information. The receiver picks up the signal and, using custom FlightRadar24 software, feeds the data into the company’s MySQL open source database.
Roughly 60 percent of all passenger planes are equipped with an ADS-B transponder, but that percentage will increase as ADS-B replaces less precise radar as the primary aircraft surveillance method, says Lindahl. The U.S., for example, will require the majority of aircraft operating within its airspace to be equipped with some form of ADS-B by 2020. Coverage for a receiver varies, based on height of the antenna and visibility, but typically extends about 250 kilometers in all directions with 400 kilometers possible, Lindahl says.
FlightRadar24 has integrated aircraft location data from the U.S. Federal Aviation Administration to provide coverage for all commercial air traffic in the U.S. and Canada, not just those with ADS-B. But the FAA data have a five-minute delay due to U.S. regulations. To account for that, FlightRadar24 displays FAA-provided location data as orange planes and real-time ADS-B data as yellow planes. The site presents the data on a Google Map. The map’s blue pins indicate major airports within FlightRadar24’s coverage areas.
Clicking on a plane brings up a window with information including airline, flight number, origin, destination, aircraft type, a photo of the plane model, altitude, speed, and squawk (or transponder code). It also displays the aircraft’s route, with the variegated trail color indicating the aircraft’s altitude along the way. That route is not transmitted by the aircraft, but drawn from FlightRadar24’s own database based on the flight’s call sign, and data integrity issues do arise. A pilot may enter the wrong call sign, for example.
Users with the Google Earth plug-in can check out the view from the cockpit. And FlightRadar24 provides access to air traffic data for the previous thirty days. In April 2010, ITOWorld, a U.K.-based provider of web-based transportation services, used that historical data to create a video visualization of air traffic returning to European skies following a shutdown due to volcanic ash from Iceland.
FlightRadar24 offers its service for iOS and Android devices, including a professional version of each for $2.99. Lindahl says more than 2 million apps have been downloaded so far. The company also earns revenues from the advertising that appears on the site and apps, making a premium, ad-free version of the site, with additional features like not timing out when the user is inactive, for free to the hosts of its receivers.
While FlightRadar24 has a following among aviation enthusiasts and industry professionals, like pilots, it has proven useful to individual travelers as well. Users of the Lonley Planet travel forums have noted its utility in getting real-time updates on flights unavailable elsewhere.
This summer, Lindahl signed a deal with Swedish air traffic management software vendor Avtech Sweden to incorporate FlightRadar24’s data into applications where flight efficiency and wake vortex generation are analyzed.
“Flightradar24 started as a fun project seven years ago, but as we went forward we realized how valuable this data is and how it can be used in different applications,” says Lindahl, who wants to increase the site’s coverage. “Getting more [data] feeders has been and is the biggest challenge,” he says. “That’s our number one focus.”
A partial embedded view of FlightRadar24’s real-time visualization is below.
Stephanie Overby is a Boston-based freelance writer. Follow her on Twitter: @stephanieoverby.