The Russian prototype fifth-generation fighter jet has broken the sound barrier for the first time during a test flight.
The supersonic flight for the PAK FA took place last week at the test range near Komsomolsk-on-Amur in Siberia and was deemed a success by engineers.
The characteristics of the PAK FA are not being disclosed by the Defense Ministry. It is expected to have a maximum speed over Mach-2 and an ability to super-cruise, i.e. to fly at supersonic speed for a long time.
The Sukhoi aircraft company has so far built two prototypes of the advanced combat vehicle for flight tests, which are scheduled to be complete by 2012. The jet will be produced in series starting in 2015, with some 150 units total to be supplied to the Air Force.