TASS reported yesterday that the first production Su-57 stealth fighter will be delivered to the Akhtubinsk flight test center for testing and, presumably, integration of the Khinzhal hypersonic air-launched missile. At the present time, only a single regiment equipped with the Mig-31K based in the Southern Military District is capable of carrying the Khinzhal. A source told TASS that one production aircraft has been delivered to an air base in the southern district, while an additional four production Su-57’s are to be delivered in 2021.