The MiG-31 (NATO - Foxhound) is a two-seater long-range supersonic interceptor fighter. The MiG-31 was developed in the 1970s and completed Its maiden flight in September 1975. The MiG-31 set several world records by reaching an altitude of 37,650 meters (123,523 ft) in 1977 as well as setting a time-to-altitude record of 35,000 meters (114,829 ft) in 4 minutes 11.78 seconds. The MiG-25 “Foxbat” was the basis for the MiG-31 “Foxhound” but equipped with the latest digital avionics that allows it to operate in all weather conditions and the first Soviet aircraft to have look-down shoot-down capability. “B” variant In 1990 the upgraded second production of the MiG-31 was put in service. It had an in-flight refueling probe, new radar, improved ECM and EW equipment and improved R-33S missiles as well as Long Range navigation facilities. MIG-31B (1990s) : weapons similar to MIG-25 (R60, R40) “BM” variant was approved in 2008 with 50 of the MiG-31Bs being modified to the BM ((Bolshaya Modernizatsiya/Deep Modernization) standards. The upgraded improved the detection range to 320 km (200 miles) and could track up to 10 targets and was increased to 24 targets capable of engaging 8 targets in newer releases. This variant could carry R-33S missiles and later R-37 anti-radar, air to ship and air to ground missiles. A multi-role aircraft with a refueling probe. MIG-31BM (after2008) : same as “B” (adding rear mirror), use more modern weapons (R77, R33, R37) “BSM” In 2014 a contract to upgrade 60 aircraft. The BSM variant has a refueling probe, New heat resistant glass for the canopy made it possible to fly faster and further, new rear-view periscope above the front cockpit canopy. New multi-function computers, new navigation systems. Multi-role capability can use anti-radar, anti-ship and air-to-ground missiles. MIG-31BSM (after 2014) : hidden refueling probe, use more modern weapons (R77, R33, R37) “K” This variant is capable of carrying the Kh-17M2 Kinzhal ALBM. By 2018 10 aircraft were modified to this variant. MIG-31K : same as BM, carries Kh-17M2