The Kh-58 (; NATO:AS-11 'Kilter') is a Soviet anti-radiation missile with a range of 120 km. the Kh-58U variant was still the primary anti-radiation missile of Russia and its allies. It is being superseded by the Kh-31. The NATO reporting name is "Kilter". Development The Bereznyak design bureau had developed the liquid-fuelled Kh-28 (AS-9 ‘Kyle’) and the KSR-5P (AS-6) anti-radiation missiles. They merged with Raduga in 1967, so Raduga was given the contract in the early 1970s to develop a solid-fuel successor to the Kh-28 to equip the new Su-24M 'Fencer-D' attack aircraft. Consequently, the project was initially designated the Kh-24, before becoming the Kh-58. During the 1980s a longer-range variant was developed, the Kh-58U, with lock-on-after-launch capability. Since the fall of the Soviet Union, Raduga have offered several versions for export. Design It was designed to be used in conjunction with the Su-24's L-086A "Fantasmagoria A" or L-086B "Fantasmagoria B" target acquisition system. The range achieved depends heavily on the launch altitude, thus the original Kh-58 has a range of 36 km from low level, 120 km from , and 160 km from . Like other Soviet missiles of the time, the Kh-58 could be fitted with a range of seeker heads designed to target specific air defence radars such as MIM-14 Nike-Hercules or MIM-104 Patriot. Operational history The Kh-58 was deployed in 1982 on the Su-24M 'Fencer D' in Soviet service. The Kh-58U entered service in 1991 on the Su-24M and MiG-25BM 'Foxbat-F'. The Kh-58E version can be carried on the Su-22M4 and Su-25TK as well, while the Kh-58UShE appears to be intended for Chinese Su-30MKK's. Variants Kh-58 (Izdeliye 112) - original version for the Su-24M. Kh-58U - improved version with longer range and lock-on-after-launch. Kh-58E - export version of Kh-58U, first offered in 1991. Kh-58EM - another version offered for export in the 1990s. Kh-58UShE (Uluchshennaya Shirokopolosnaya Exportnaya meaning 'Improved, Wideband, Export') - new wideband seeker in new radome, intended for Su-30MK. Kh-58UShKE - version with folding fins for internal carriage in the Sukhoi Su-57, first unveiled at MAKS 2007. Kh-58UShKE(TP) - version with added imaging infrared UV seeker, first unveiled at MAKS 2015. Some Western sources have referred to a Kh-58A that is either optimised for naval radars or has an active seeker head for use as an anti-shipping missile - it probably represents another name for the Kh-58U. Operators Current operators Algerian Air Force Belarusian