Russia's latest fighter jet aircraft is to undertake its first test flight on Friday, according to agency reports.

The first prototype of the Sukhoi T-50 PAK-FA is scheduled to make its first flight from Sukhoi's KNAPPO facility at Komsomolsk-on-Amur in Russian Far East. A Sukhoi spokesman told the RIA Novosti news agency that the flight was originally scheduled for Thursday but was postponed to Friday. The aircraft successfully completed two taxiing tests just before Christmas.

Sukhoi T-50

The single-seat T-50 is the first Russian 5th generation fighter, and the first all-new Russian combat jet since the collapse of the Soviet Union. The aircraft is intended to replace the Su-27 and MiG-29 (pictured) in Russian Air Force service. There is little detailed information about the aircraft's specifications or capabilities, but it is designed to be a swing-role combat aircraft capable of carrying multiple weapons systems for air-to-air and air-to-surface roles. It is also believed the Sukhoi T-50 has stealthy characteristics and the ability to supercruise, in common with other 5th generation combat aircraft like the F-22A Raptor and the forthcoming F-35 Lightning II.

PAK-FA

The designation PAK-FA, translated, is "Prospective (Promising) Aircraft Complex (System) of Front line Aviation"). The aircraft has been in gestation for a long time. The Russian AF first started investigations into the project as long ago as the early 1990s. Technology developed for the Su-47 Berkut and Mikoyan 1.44 projects during the 1990s has apparently been used in the development of PAK-FA.

The aircraft is not expected to enter Russian AF service until 2015 at the earliest, Russian defence analyst Alexander Khramchikhin told Reuters. However, he added that the history of development delays with other major Russian defence equipment projects - including new submarines and the Su-35 fighter - make this date somewhat optimistic. Another analyst, Konstantin Makiyenko, deputy head of the Moscow-based Centre for Analysis of Strategies and Technologies (CAST) think tank, last year told the same agency that "there could be at least 10 years between the first flight of the fifth-generation prototype and commercial production."

Indeed, even the PAK-FA's first flight is delayed. The original plan called for the aircraft to make its first flight in late 2008. This was postponed until August 2009, but engine issues delayed development and put back the maiden flight until now.