The Mil Mi-8 (Russian: ??-8, NATO reporting name: Hip) is a medium twin-turbine helicopter, originally designed by the Soviet Central Aerohydrodynamic Institute (TsAGI) in the 1960s and introduced into the Soviet Air Force in 1968. Russian production of the aircraft model still continues as of 2024. In addition to its most common role as a transport helicopter, the Mi-8 is also used as an airborne command post, armed gunship, and reconnaissance platform. The Mi-8 is the world's most-produced helicopter, with over 17,000 units used by over 50 countries. As of 2015, when combined with the related Mil Mi-17, the two helicopters are the third most common operational military aircraft in the world.