Russia has grounded all of its MiG-31 interceptors after one crashed. The 200 or so in service will be examined to see if there is a common defect that might cause others to crash. MiG aircraft in general have a reputation for these kinds of problems. Mig-21s, MiG-23/27s and MiG-29 all have had these design defect and quality control issues. Now the curse comes to the MiG-31.
Three years ago, Russia completed testing of the latest version of its MiG-31 interceptor. 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), 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 latest version, the MiG-31M, is actually an accumulation of upgrades. This works has been under way since the Soviet Union collapsed in 1991. But since then, about 200 of the remaining 350 MiG-31s have been upgraded, or are in line for the work. Originally, 500 MiG-31s were built in the 1980s. 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, and some 360 MiG-31s are 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). Russia is hoping that there's an export market for the MiG-31M, although it's unlikely that they will resume production. There are a hundred MiG-31s in storage, which can be refurbished and upgraded to MiG-31M standards.