Flightradar24 has conquered the skies – but how does it work?

No one seems interested. But I am.

As the Airbus A320 begins its final approach to Heathrow, it’s running about five minutes late, travelling around 185 knots and at 4,000 feet. I wonder who’s on board and what awaits them once they arrive in west London.

Unfortunately, that’s one thing Flightradar24 can’t tell me. Everything else the aircraft-tracking website has covered – the registration number of the aircraft, model, time spent in the air, distance to destination (a subscription fee unlocks even more info, including aircraft age, wind speed and temperature).

I look at the planes on my computer screen then watch them pass overhead. Another BA flight, this time from Marseilles, appears through the clouds.

I’m just one of two million people around the world who use Flightradar24 to follow any of the 16,000 flights that are flying through the air at any given moment.

Head to the site now and you’ll see Ireland, the UK, Europe, North America, the whole world, awash with tiny, yellow planes of various shapes and sizes. There’s something satisfying about spotting an A380, the world’s largest passenger jet, as it completes a seven-hour flight from Doha. It may seem dull, but it’s oddly addictive.

CEO Fredrik Lindahl remembers how the site was born.

It was 2006 and internet entrepreneurs Mikael Robertsson and Olov Lindberg had just launched Flygresor.se - a Swedish flight comparison website, not dissimilar to the likes of Skyscanner, which still exists - and they needed a way to drive traffic to it from Google.

“Back then - and to a certain extent still today - getting a lot of other websites to link to your website was important to rank well,” says Fredrik.

“Mikael and Olov saw that these ADS-B receivers (flight tracking technology) were available and decided that making a website showing what air traffic looks like at any given time would be something that would attract a lot of links.”

Though it was only intended to support Flygresor, the tracking site soon overtook its maker in popularity.

“To avoid Google starting to think that Flygresor was about flight tracking over Sweden rather than finding the cheapest plane tickets to New York, the flight tracking component was moved to a separate domain,” says Fredrik, and Flightradar24 was born.

But it was in 2010 that the site got its big break: the Icelandic ash cloud.

The April eruption of Eyjafjallajokull (below) led to the grounding of some 100,000 flights across Europe and North America - as many as 19,000 a day - throwing thousands of holiday plans, and the profit margins of airlines, into disarray. It also drove people online to look at how the volcanic dust was affecting their holiday.

Since then, Flightradar24 has grown inordinately, increasing the number of data receivers it uses around the world from 500 to 15,000 and launching an app.

Based predominantly in Stockholm, it employs more than 30 people around the world, several of whom manage its Twitter account, which has helped highlight the site’s uses to the social media savvy.

Earlier this month, Boeing drew a massive outline of a Dreamliner in the sky over the course of a 17-hour flight, starting and finishing in Seattle, the manufacturer’s headquarters. Such a stunt would not have been possible without Flightradar24, which monitored the 787’s progress. Boeing later used the website for a “playback” of the flight’s route in a tweet which has since been retweeted 3,500 times.

Flightradar24’s Twitter account, which boasts 375,000 followers, splits its time between genuine aviation updates (storms, drones, emergencies and delays), airline activity (deliveries of new aircraft) and quirky content (bizarre holding patterns, interesting planes or mesmerising air traffic flows).

Who knew aviation could be so fun?

Fredrik breaks down users of the site into four categories: professionals, aviation enthusiasts, laymen tracking the flight of a loved one, or people like me, who spot a plane overhead and want to know where it’s going.

“Whenever media reports on a specific flight, there’s a spike in traffic,” he says. “For example, whenever the Pope is going somewhere on a plane, that tends to draw a big crowd.”

Additionally, when there is a crash or an emergency diversion, the public flocks to the website to see the details, while sometimes crash investigation teams request data from the site.

In the wake of a number of high-profile incidents (MH370, for example), the media is increasingly ready to report on any issues affecting aircraft, with Flightradar24 providing minute-by-minute details of where a plane is at any given time.

But on a daily basis, it’s more fun for glancing at the sky and instead of wondering where that jet is going, knowing.

How does Flightradar24 work?

Flightradar24 uses a number of data sources to track planes, including ADS-B, MLAT and radar. Broadly speaking, it is GPS navigation sources used by aircraft, sent from satellites to receivers around the world that feed into Flightradar24.

Accordingly, there are some parts of the world where the receivers cannot pick up signals for aircraft. Flightradar24 estimates it tracks around 70 per cent of all commercial passenger aircraft using ADS-B through some 10,000 receivers. It says that 100 per cent of Europe and the US is covered, with good coverage across a host of nations, including much of Asia and South America.

When an aircraft is out of radar, its position is estimated (for up to two hours).

Some aircraft without ADS-B transponders do not appear on Flightradar24, especially light aircraft in general aviation. Many private jets, military aircraft and helicopters do not appear, while some aircraft - like Air Force One - have their paths blocked for security reasons.

For more information visit flightradar24.com/how-it-works.