MOSCOW (Reuters) - Most countries keep national aircraft registries, which are publicly available databases with details of every plane registered in the country.
The registers give an aircraft’s manufacturer’s serial number (MSN), a unique code that stays with it throughout its lifetime; the registration number, also known as the tail number, assigned by the country where it is registered; and details of the plane’s owner and operator.
That is how Reuters was able to track the path of aircraft from locations including the United States, Ireland, Russia and Ukraine.
After Ukraine, however, many of the aircraft that Reuters reporters tracked went to Iran, Afghanistan or Syria. None of those countries keeps a publicly available aircraft register.
Tracking planes to those countries requires a different resource: flight-tracking websites, which pick up and record the physical movement of civil aircraft.
In essence, they crowd-source aircraft data.
A vast network of people on the ground, often amateur enthusiasts, use commercially available equipment to pick up real-time data emitted by airliners flying overhead. They then share that data with nonofficial websites that collate it and make it publicly available.
The data includes the aircraft’s location when in the air, the MSN, the tail number and the call sign, which contains a code identifying the company operating the aircraft.
Reuters drew on data primarily from three flight-tracking websites:
www.flightradar24.com, www.planefinder.net and usii.qsl.udm.ru/VirtualRadar
Each flight was checked across the three sites to ensure the data was accurate. In almost all cases, the data matched across the three sites, although there were a handful of discrepancies. In one case, two of the sites gave different Syrian destinations for a flight, possibly because the spotters picking up and sharing the data inside Syria are thinner on the ground than elsewhere.
An extra layer of corroboration was provided by amateur plane-spotters who post photographs of aircraft, with their tail numbers, on the tarmac at airports. Those photographs are shared on sites such as jetphotos.com, and on the personal social media pages of plane-spotters.