production Serial production of the MiG-31 began in 1979. 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 . The MiG-31 was designed to fulfill the following mission objectives: Intercept cruise missiles and their launch aircraft by reaching missile launch range in the shortest possible time after departing the loiter area; Detect and destroy low flying cruise missiles, UAVs and helicopters; Long range escort of strategic bombers; Provide strategic air defense in areas not covered by ground-based air defense systems. MiG-31 production ended in 1994. 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. Upgrades and replacement Some upgrade programs have found their way into the MiG-31 fleet, like the MiG-31BM multirole version with upgraded avionics, new multimode radar, hands-on-throttle-and-stick (HOTAS) controls, liquid crystal (LCD) color multi-function 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 are to be upgraded to MiG-31BM standard by 2020. Russian Federation Defence Ministry chief Colonel Yuri Balyko has claimed that the upgrade will increase the combat effectiveness of the aircraft several times over. 18 MIG-31BMs were delivered in 2014. The Russian military will receive more than 130 upgraded MiG-31BMs, and the first 24 aircraft have already been delivered, Russian Deputy Defense Minister Yuri Borisov told reporters on 9 April 2015. Russia plans to start development of a replacement for the MiG-31 by 2019. The aircraft will be called PAK-DP (ПАК ДП, Перспективный авиационный комплекс дальнего перехвата – 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,