The stealth jets first flew in 2010, but due to delays in production until 2018, the 10 SU-57 prototypes were marred with “inadequate and incomplete sensors, incomplete fire-control systems and self-protection suites, no operational integrated avionics and unreliable engines,” aviation expert Tom Cooper writes.
The twin-engine for SU-57 is built at the Komsomolsk-on-Amur aircraft plant in the Russian Far East. According to a report in Forbes by David Axe, Sukhoi originally planned to hand over the first two production-standard SU-57s in late 2019 and two more in 2020. But the December 2019 crash of one of the jets compelled the company to halt the work on the program.
Earlier, Russian Minister of Industry, Denis Manturov, had confirmed that a contract for the acquisition of 76 Sukhoi Su-57 aircraft, Russia’s first indigenously designed and built fifth-generation stealth fighter jet, has been concluded between Moscow and United Aircraft Corporation.
Last year, Russia deployed pairs of SU-57s to Syria for what it claimed were combat trials. However, there’s no evidence to prove that the fighters actually flew front-line missions.