Russia's fifth-generation jet fighter, the T-50, will start a standard flight test program in April, a source at the Sukhoi aircraft maker said on Monday.
He said it would take "several years" to complete the testing program.
A prototype of the fighter made a 47-minute maiden flight in Russia's Far East on January 29.
Russia has been developing its newest fighter since the 1990s. The current prototype was designed by the Sukhoi design bureau and built at a plant in Komsomolsk-on-Amur, in Russia's Far East.
It will be delivered to the Russian Air Force from 2015 onwards.
Russian officials have already hailed the fighter as "a unique warplane" that combines the capabilities of an air superiority fighter and attack aircraft.
MOSCOW, March 1 (RIA Novosti)