January 21, 2012:
Russia is in the process of upgrading 60 of its MiG-31 jet interceptors to the new MiG-31BM standard. This will take about eight years to complete. The upgrade includes new avionics, digital data links, improved multimode radar, a class cockpit (color multi-function displays), and a new powerful fire-control system that enables the use of the latest smart bombs, anti-aircraft, and anti-radar missiles. The new radar has a range of 320 kilometers and can simultaneously track up to 10 targets.
These upgrades come just in time. Fourteen months ago Russia grounded all its MiG-31s after one crashed. The 200 or so in service were examined to see if there was a common defect that might cause others to crash. There wasn't. MiG aircraft in general have a reputation for these kinds of problems. Mig-21s, MiG-23/27s, and MiG-29 all have had design defect and quality control issues.
The MiG-31 is itself an upgrade of the MiG-25, which was developed to deal with the American B-70 bomber. When the United States cancelled the B-70 in 1967 (too expensive, and a decision to go with bombers that come in low and fast rather than high and fast), the Russians kept going with the MiG-25 and switched its role to reconnaissance. The MiG-25 turned out to be an excellent recon aircraft, able to fly higher and faster than other fighters used for this job, although not as high as the American U-2 or SR-71. But the United States did not sell those aircraft to anyone, while Russia made a lot of money selling MiG-25s to anyone with enough cash. Russia also made a lot of money training the two man crew required for each aircraft.
The MiG-31 fixed a long list of MiG-25 problems and was turned into a very impressive interceptor. The 46 ton aircraft has passive sensors (which have a range of 200 kilometers), and radar guided R33 missiles, with a range of 150 kilometers. Other missiles are carried, as well as smart bombs. The MiG-31 is not very maneuverable, but it is fast (able to sprint at up to 3,200 kilometers an hour). Like the original MiG-25, it does not have much range (720 kilometers combat radius). The current version, the MiG-31M, is actually an accumulation of upgrades that have been under way since the Soviet Union collapsed in 1991. Since then, about 200 of the remaining 350 MiG-31s have been upgraded, or are in line for the work. In the last few years, the MiG-31 fleet has gotten a lot more money, and readiness (for combat) has gone from under 25 percent, to over 75 percent.
About 500 MiG-31s have been built in the 1980s and these aircraft remain the mainstay of Russian air defenses, at least as far as interceptors go. But the MiG-31 fleet is spread thin across Russia's vast borders, and squadrons tend to be concentrated in areas where they might encounter high performance intruders (China and Europe). There are a hundred MiG-31s in storage, which can be refurbished and upgraded to MiG-31M or 31BM standards.