[3] 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.

[10] 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.

[1] The MiG-31 replaced the Tu-128 as the Soviet Union's dedicated long-range interceptor,[11] with far more advanced sensors and weapons,[12] while its range is almost double that of the MiG-25.

[18] Russian Federation Defence Ministry chief Colonel Yuri Balyko has claimed that the upgrade will increase the combat effectiveness of the aircraft several times over.

The aircraft would be called PAK-DP (ПАК ДП, Перспективный авиационный комплекс дальнего перехвата – Prospective Air Complex for Long-Range Interception).

[citation needed] In March 2014, Russian test pilot Anatoly Kvochur said that work began on a Mach 4 capable MiG-41 based on the MiG-31.

[25][needs update] Like the MiG-25, the MiG-31 is a large twin-engine aircraft with side-mounted air intake ramps, a shoulder-mounted wing with an aspect ratio of 2.94, and twin vertical tailfins.

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 A-50 AEW aircraft and MiG-31 can automatically exchange aerial and terrestrial radar target designation,[32] as well as air defense.

[61][62] As of 8 September 2024, three MiG-31BMs have been visually confirmed as lost, with two being destroyed by Ukrainian missile strike on Belbek airfield in occupied Crimea on 15th of May 2024, and third crashed during takeoff on the same airfield on 1 October 2022, with satellite images showing clear visible wreck, with jet having run off the end of the runway and fell off a cliff before exploding.

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".

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.

[69][70][71] On 15 May 2024, Russian-installed officials in Crimea claimed that a missile attack caused explosions and fires near the Belbek airfield.

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.

[121] 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.

[122] This occurred during a training exercise over the Telemba proving ground in Buryatia; both crew members ejected successfully.

[123] 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 2 December 2022, a MiG-31 of the Russian Aerospace Forces crashed during a training flight in the far eastern Primorsky Region.[127][importance?]