February 8, 2012: The Russian Air Force recently revealed that about 16 percent of its 188 MiG-31 interceptors are on alert at any time, ready to take off and confront aerial intruders. A larger number of the 240 Su-27s are on alert as well. The high-flying and extremely fast MiG-31s are able to catch just about any type of aircraft. The Su-27 comes along to back up the Mig-31s and protect them from any fighters. The MiG-31 is optimized for quick interception, not prolonged air combat.
Russia is covering 20,000 kilometers of land borders with fewer than 600 fighters. Worse yet, most of the Cold War era radars along the borders are elderly or off-line. The radar system is being rebuilt, but that will be taken care of more quickly than rebuilding the jet interceptor force. Actually, Russia will probably never have the Cold War size interceptor force (2,300 fighters) that existed in 1991. The only survivors of that are the MiG-31s and Su-27s.
Meanwhile, Russia is in the process of upgrading its MiG-31 jet interceptors to the new MiG-31BM standard, a process that will take about eight years to complete. The upgrade will include a new radar with a range of 320 kilometers and the ability to simultaneously track up to 10 targets.
These upgrades come just in time, as the remaining MiG-31s are in bad shape. 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. But only about 180 MiG-31s remain flyable.
About 500 MiG-31s were 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 if need be.