Question: Byelka was devoped for an aircraft which was a product of what?
Sentence (from "Sukhoi Su-57"): The aircraft is the product of the PAK FA (Russian: ПАК ФА , Russian: Перспективный авиационный комплекс фронтовой авиации , "Perspektivny Aviatsionny Kompleks Frontovoy Aviatsii", literally "Prospective Airborne Complex of Frontline Aviation"), a fifth-generation fighter programme of the Russian Air Force.
Relevant evidence: Yes