More Problems for the Russian PAK-FA T50

The PAK-FA T50 Fighter Jet continues to have problems. The single largest one the Russians will admit to is the engine. The current engine being used is not powerful enough for the performance desired from the aircraft. the Russians embarked on designing, building and testing a new one. Yet…that too has slipped. Sukhoi had been claiming the engine would start bench testing and sale through. However, ODK General Director Aleksandr Artyukhov just poured a bit of cold water on that.

ODK General Director Aleksandr Artyukhov has dampened the prospects for Russia’s developmental fifth generation fighter aircraft, the T-50 or PAK FA. Friday in Lukhovitsy at the presentation of the MiG-35, Artyukhov told RIA Novosti that R&D on PAK FA’s “second phase” engine won’t be complete until 2020. 

A Russian Website said that, What do we think is the likely problem? Has it been too long since the Russians did a fresh start engine design? Manufacturing problems? I’d thought they were fine with prototypical one offs, but had issues with mass manufacture only? Or is it purely monetary woes? Or something else?