The Mikoyan MiG-31 (; NATO reporting name: Foxhound) is a supersonic interceptor aircraft developed for the Soviet Air Forces by the Mikoyan design bureau as a replacement for the MiG-25 "Foxbat", on which it is based and shares design elements.
The MiG-31 is the fastest known operational combat aircraft, with a top speed around . It continues to be operated by the Russian Aerospace Forces following the end of the Cold War and the collapse of the Soviet Union in 1991. The other operator, the Kazakh Air Defence Forces, retired the type in 2023. The Russian Defence Ministry expects the MiG-31 to remain in service until at least 2030; that was confirmed in 2020 when an announcement was made to extend the service lifetime of the existing airframes from 2,500 to 3,500 hours. The MiG-31K variant carries the Kh-47M2 Kinzhal conventional or nuclear warhead-capable air-launched ballistic missile.
The single-seat MiG-25 could achieve high speed, altitude, and rate of climb, but it lacked manoeuvrability at interception speeds and was difficult to fly at low altitudes. The MiG-25's speed was normally limited to Mach 2.83, but it could reach a maximum speed of at least Mach 3.2 with the risk of engine damage.
Development of the MiG-25's replacement began with the Ye-155MP () prototype, which first flew on 16 September 1975. Although it bore a superficial resemblance to the MiG-25, it had a longer fuselage to accommodate the radar operator's cockpit, and was in many respects a new design. An important development was the MiG-31's advanced radar, capable of both look-up and look-down/shoot-down engagement, as well as multiple target tracking. This gave the Soviet Union an interceptor with the capability to engage the most likely Western intruders (low-flying cruise missiles and bombers) at long range. The MiG-31 replaced the Tu-128 as the Soviet Union's dedicated long-range interceptor, with far more advanced sensors and weapons, while its range is almost double that of the MiG-25.
Like that of its MiG-25 predecessor, the introduction of the MiG-31 was surrounded by early speculation and misinformation concerning its design and abilities. The West learned of the new interceptor from Lieutenant Viktor Belenko, a pilot who defected to Japan in 1976 with his MiG-25P. Belenko described an upcoming "Super Foxbat" with two seats and an ability to intercept cruise missiles. According to his testimony, the new interceptor was to have air intakes similar to the Mikoyan-Gurevich MiG-23, which the MiG-31 does not have, at least in production variants.
Serial production of the MiG-31 began in 1979. The first production batch of 519 MiG-31s including 349 "baseline models" was produced at the Sokol plant between 1976 and 1988. The second batch of 101 MiG-31DZs was produced from 1989 to 1991. The final batch of 69 MiG-31B aircraft was produced between 1990 and 1994. From the final batch, 50 were retained by the Kazakhstan Air Force after the dissolution of the Soviet Union. Of the "baseline models", 40 airframes were upgraded to MiG-31BS standard.
Some upgrade programs have found their way into the MiG-31 fleet, such as the MiG-31BM multirole version with upgraded avionics, new multimode radar, hands-on-throttle-and-stick (HOTAS) controls, liquid crystal (LCD) colour multifunction displays (MFDs), ability to carry the R-77 missile and various Russian air-to-ground missiles (AGMs) such as the Kh-31 anti-radiation missile (ARM), a new and more powerful computer, and digital data links. A project to upgrade the Russian MiG-31 fleet to the MiG-31BM standard began in 2010; 100 aircraft were to be upgraded to the MiG-31BM standard by 2020. Russian Federation Defence Ministry chief Colonel Yuri Balyko has claimed that the upgrade would increase the combat effectiveness of the aircraft several times over. 18 MIG-31BMs were delivered in 2014. The Russian military was to receive more than 130 upgraded MiG-31BMs, with the first 24 aircraft already delivered according to Russian Deputy Defence Minister Yuri Borisov in his press briefing on 9 April 2015.
Russia planned to start development of a replacement for the MiG-31 by 2019. The aircraft would be called PAK-DP (ÃÂÃÂàÃÂÃÂ, ÃÂõÃÂÃÂÿõúÃÂøòýÃÂù ðòøðÃÂøþýýÃÂù úþüÿûõúàôðûÃÂýõóþ ÿõÃÂõàòðÃÂð â Prospective Air Complex for Long-Range Interception). Development of the new aircraft, designated MiG-41, began in April 2013. Such development is favored over restarting MiG-31 production. In March 2014, Russian test pilot Anatoly Kvochur said that work began on a Mach 4 capable MiG-41 based on the MiG-31. Later reports stated that the development of the MiG-31 replacement was to begin in 2017, with the first aircraft expected to be delivered in 2020, and the replacement entering service in 2025.This has currently yet to happen.
Like the MiG-25, the MiG-31 is a large twin-engined aircraft with side-mounted air intake ramps, a shoulder-mounted wing with an aspect ratio of 2.94, and twin vertical tailfins. Unlike the MiG-25, it has two seats, with the rear occupied by a dedicated weapon systems officer.
The MiG-31 was designed to fulfill these mission objectives:
The MiG-31 is limited to five g when travelling at supersonic speeds. While flying under combat weight, its wing loading is marginal and its thrust-to-weight ratio is favorable. The MiG-31 is not designed for close combat or rapid turning.
The wings and airframe of the MiG-31 are stronger than those of the MiG-25, permitting supersonic flight at low altitudes. Like the MiG-25, its flight surfaces are built primarily of nickel-steel alloy, enabling the aircraft to tolerate kinetic heating at airspeeds approaching Mach 3. The MiG-31 airframe comprises 49% arc-welded nickel steel, 33% light metal alloy, 16% titanium, and 2% composites. Its D30-F6 jet engines, each rated at 152 kN thrust, allow a maximum speed of Mach 1.23 at low altitude. High-altitude speed is temperature-redlined to Mach 2.83 â the thrust-to-drag ratio is sufficient for speeds in excess of Mach 3, but such speeds pose unacceptable hazards to engine and airframe life in routine use.
The MiG-31 was among the first aircraft with a phased-array radar. Its maximum range against fighter-sized targets is about , and it can track up to 10 targets and simultaneously attack four of them with its Vympel R-33 missiles. The radar is matched with an infrared search and track system in a retractable under-nose fairing.
The aircraft was equipped with RK-RLDN and APD-518 digital secure datalinks. The RK-RLDN datalink is for communication with ground-control centers. The APD-518 datalink enables a flight of four MiG-31s to automatically exchange radar-generated data within of each other. It also enables other aircraft with less sophisticated avionics, such as MiG-23s, 25s, and 29s and Su-15s and 27s, to be directed to targets spotted by MiG-31 (a maximum of four (long-range) for each MiG-31 aircraft). The A-50 AEW aircraft and MiG-31 can automatically exchange aerial and terrestrial radar target designation, as well as air defense. The MiG-31 is equipped with ECM of radar and infrared ranges.
The flight-navigation equipment of the MiG-31 includes a complex of automatic control system SAU-155ÃÂP and sighting-navigation complex KN-25 with two inertial systems and IP-1-72A with digital computer, electronic long-range navigation system Radical NP (312) or A-331, electronic system of the long-range navigation A-723. Distant radio navigation is carried out by means of two systems: Chayka (similar to the system of Loran) and ëRouteû (similar to the system of Omega).
Similarly to the complex S-300 missile system, aircraft group with APD-518 can share data obtained by various radars from different directions (active or passive scanning of radiation) and summarize the data. The target can be detected passively (via its emissions of jamming or use of its radar) and/or actively simultaneously from many different directions (with the MiG-31 using its radar). Every aircraft with the APD-518 will have the exact data, even if it is not involved in the search.
A group of four MiG-31 interceptors is able to control an area of air space across a total length of ; its radar possessing a maximum detection range of in distance (radius) and the typical width of detection along the front of .
Adopted in 1981, RP-31 N007 backstop (Russian: Zaslon).
The basic differences between other versions and the MiG-31BM are:
The aircraft is a two-seater with the rear seat occupant controlling the radar. Although cockpit controls are duplicated across cockpits, it is normal for the aircraft to be flown only from the front seat. The pilot flies the aircraft by means of a centre stick and left hand throttles. The rear cockpit has only two small vision ports on the sides of the canopy. The presence of the WSO (weapon systems operator) in the rear cockpit improves aircraft effectiveness since the WSO is entirely dedicated to radar operations and weapons deployment, thus decreasing the workload of the pilot and increasing efficiency. Both cockpits are fitted with zero/zero ejection seats which allow the crew to eject at any altitude and airspeed.
The MiG-31's main armament is four R-33 air-to-air missiles (NATO codename AA-9 'Amos') carried under the belly.
Serial production of the MiG-31 began in 1979. The MiG-31 entered operational service with the Soviet Air Defence Forces (PVO) in 1981.
During the 2022 Russian invasion of Ukraine, MiG-31s reportedly shot down several Ukrainian aircraft, mainly by using the long range R-37 air-to-air missile. By remaining at high speed and high altitude, MiG-31s have been able to operate virtually unopposed due to Ukrainian fighters lacking range, speed, or altitude necessary to engage the MiG-31.
As of 8 September 2024, three MiG-31BMs have been visually confirmed as lost, with two being destroyed by Ukrainian missile strikes on Belbek airfield in occupied Crimea on 15 May 2024. The third crashed during takeoff on the same airfield on 1 October 2022, with satellite images showing clear visible wreckage, with the jet having run off the end of the runway, falling off a cliff before exploding.
The R-37M has, since October 2022, been the main threat against the Ukrainian Air Force. The Ukrainian Air Force has a significant lack of fire-and-forget missiles. They relied on the R-27 missiles, both the R-27ER and R-27ET; the R-27ER's range is . A Ukrainian pilot must illuminate a Russian aircraft with radar to guide the missile to the target. Russian pilots firing the active-radar, fire-and-forget R-77 give them the ability to launch their missiles and then take evasive action. Ukrainian pilots were forced to "exploit ground clutter and terrain-masking to get close enough to fire before being engaged". During the first three days of the war both sides lost aircraft. The Ukrainians replaced them with older airframes that were made flyable. The Russian Aerospace Forces turned to the MiG-31 with the R-37M missile that has a range of . Combined with the superior radar on the MiG-31, the Ukrainian Air Force has started losing more aircraft. A report by the Royal United Services Institute states that in October some six R-37Ms were being fired at the Ukrainian Air Force a day. Four MiG-31s were also deployed to Crimea. To avoid R-37M missiles, Ukraine has had to attempt to destroy MiG-31s while they are still on the ground, such as the attack on the Belbek airbase and an attempted drone attack in August.
On the early morning of 4 May 2023, a Kh-47M2 Kinzhal missile was intercepted by the Patriot air defense system according to the commander of the Ukrainian Air Force, general Mykola Oleschuk. The missile was fired from a MiG-31K in Russian airspace. Ukraine confirmed the intercept, saying it used the Patriot missile system protecting the Kyiv region.
On 15 May 2024, Russian-installed officials in Crimea claimed that a missile attack caused explosions and fires near the Belbek airfield. Some missiles (possibly ATACMS) struck dropping cluster munitions on the airfield, and according to photographic evidence and satellite imagery, at least two Russian ground-based air defense systems destroyed, likely destroying two MiG-31s, destroyed a fuel farm and damaged one Su-27.
On the morning of 16 May 2023, six Kh-47M2 Kinzhal missiles were fired at Kyiv. Ukrainian Air Force spokesperson said that they were launched from six MiG-31Ks. Ukraine claims that all Kinzhals were intercepted but one may have damaged a Patriot battery launcher according to US officials, although there is limited evidence.
After they were intercepted by Finnish aircraft over the Gulf of Finland on 19 September 2025, three MiG-31s entered Estonian airspace. The Russians had not presented a flight plan, the aircraft's transponders were switched off and they ignored radio calls. They stayed inside Estonian airspace for 12 minutes before being intercepted by Italian F-35 and escorted back to Russia. Estonia reacted to the incident by calling NATO for Article 4 consultations.
On 18 December 2025 Ukraine claimed it had destroyed a MiG-31 at Belbek airfield and provided video footage that appeared to support the claim.
Kazakhstan inherited it's MiG-31s from the Soviet Union and used them up till 2023, when they were finally retired and put up for auction. Reports emerged that these aircraft were sold to the United States, but this was refuted.
Algeria was allegedly offered MiG-31s from the MiG corporation in exchange for its older MiG-25s which would be scrapped for parts to supply other MiG-25 users. Nothing came of this, and Algeria was the last operator of the MiG-25, also being the first to receive them in 1979.
In 1992 Russia offered the MiG-31 to Finland, which had a selection programme ongoing for a new fighter, but the offer was not submitted to the program, where Russia had submitted the MiG-29. Finland did not accept the offer, and chose the new fighter from the selection programme.
Russia was seeking to sell MiG-31 interceptors to the Islamic Republic of Iran Air Force (IRIAF) in response to Iranian calls to modernise their Airforce, with the first attempt occurring in the 1990-1992 time frame as a follow on to the MiG-29 and Su-24 purchase that Iran had made, the deal was also to include large numbers of other platforms and missile systems and would have included 24 airframes. The second attempt was in the 2001, with Iran reportedly paying in advance for the aircraft, but the deal was cancelled in both instances due to American pressure on the Russian government.
India was also offered the MiG-25 for MiG-31 trade deal that Algeria was. Indian pilots flew the MiG-31 in Russia, and the Foxhound was pitched to the IAF multiple times as a capable platform with multiple mission uses and it's capable long-range engagement radar and missiles. The IAF has rejected the MiG-31s as a replacement for it's MiG-25s (retired in 2006) as it's focus was on acquiring more Multi-role aircraft (through the MMRCA) and it's other roles could be fulfilled by other platforms (UAVs and Satellites for reconnaissance, Su-30MKIs for air-to-air combat).
Syria is reported to have ordered between five and eight MiG-31E aircraft in 2007 for the Syrian Air Force, allegedly partially funded by Iran. A Russian foreign ministry spokesperson - Mikhail Kamiynin - denied these reports stating that no such order had been placed. An order was placed again in 2008 or 2009, but suspended in May 2009 reportedly either due to Israeli pressure or lack of Syrian funds.
On 4 April 1984, a MiG-31 crashed while on a test flight, killing Mikoyan chief test pilot Aleksandr Vasilyevich Fedotov and his navigator V. Zaitsev.
On 26 April 2017, a MiG-31 crashed after it was accidentally hit by "friendly fire" during a training session near the Telemba proving ground in the Russian Far East. This occurred during a training exercise over the Telemba proving ground in Buryatia; both crew members ejected successfully. While Russian state media did not offer any details, independent investigators discovered from a leaked government document that the aircraft was shot down by an R-33 missile fired from another MiG-31 and that pilot error from both airplanes was at fault. The report also suggested problems with the Zaslon-AM radar and Baget-55 fire control system that might increase the risk of more accidental shootdowns.
On 16 April 2020, a MiG-31 interceptor of the Kazakh Air Force crashed in the country's Karaganda region.
On 8 April 2022, a MiG-31 of the Russian Aerospace Forces crashed in the Leningrad region.
On 2 December 2022, a MiG-31 of the Russian Aerospace Forces crashed during a training flight in the far eastern Primorsky Region.
On 26 April 2023, a MiG-31 of the Russian Aerospace Forces crashed during a training flight in northern Murmansk. The pilots reportedly ejected and survived.
On 4 July 2023, a MiG-31 of the Russian Aerospace Forces crashed during a training flight over Avacha Bay.