An app for tablet computers and smartphones allowed users to see the location and other flight data for so-called Japanese Air Force One, the government aircraft used by members of the Imperial family and the prime minister when they visit foreign countries, Defense Ministry officials said Wednesday.
In mid-August, the ministry asked the Swedish company that produces the application to withhold information on the aircraft for security reasons, the officials said, adding that the ministry later confirmed that such information was no longer available on the app.
The Flightradar24 service, accessible through software than can be used on portable devices, tracks flights using signals called ADS-B, which are broadcast by aircraft to avoid midair collisions. Information on the signals is supplied by aviation enthusiasts around the world.
The app's users can see the aircraft as a symbol moving on a map in near real time with such details as the carrier, flight number, altitude, heading, flight route, geographical coordinates and speed.
The government only discloses dates and airports when operating the official planes domestically. For overseas flights, only the destination is made public as a counterterrorism measure.
A pair of Boeing 747-400 aircraft are currently operated by the Air Self-Defense Force as the official government planes. They are based at Chitose Air Base in Hokkaido.