The Sukhoi Su-57 (Russian: Сухой Су-57; NATO reporting name: Felon) is a stealth, single-seat, twin-engine multirole fifth-generation jet fighter being developed since 2002 for air superiority and attack operations. The aircraft is the product of the PAK FA (Russian: ПАК ФА, short for: Перспективный авиационный комплекс фронтовой авиации, romanized: Perspektivny Aviatsionny Kompleks Frontovoy Aviatsii, lit. ”prospective aeronautical complex of front-line air forces”), a fifth-generation fighter programme of the Russian Air Force. Sukhoi’s internal name for the aircraft is T-50. The Su-57 is the first aircraft in Russian military service to use stealth technology. Its maiden flight took place on 29 January 2010 and it entered service on 25 December 2020. The fighter is the world’s fourth operational fifth-generation stealth fighter aircraft after the F-22, F-35, and J-20.According to Sukhoi Company, the fighter is designed to have supercruise, supermaneuverability, stealth, and advanced avionics to overcome the previous generation fighter aircraft as well as ground and naval defences.The Su-57 is intended to succeed the MiG-29 and Su-27 in the Russian Air Force.The prototypes and initial production batch are to be delivered with a highly upgraded Lyulka AL-31 variant, the AL-41F1, as an interim powerplant, while an advanced clean-sheet design engine, currently designated the Izdeliye 30, is in final stages of development, expected to be available after mid-2020s. The aircraft is expected to have a service life of up to 35 years.