speed. Specifications required the functioning in day, night and poor weather as well as carrying eight soldiers (the design achieved seven in practice), eight stretchers or large external loads. An emphasis was placed on survivability with a focus on redundancy, IR suppression and special shock absorbers for the crew to increase the maximum "safe" crash velocity. The design incorporated a 23 mm rotary cannon (most likely GSh-23L) for defense in the forward hemisphere and a 12.7 mm heavy machine gun (most likely Yak-B) for defense in the rear. Fuselage fairings containing fuel replaced stub wings with missiles mounted above on special hardpoints. Its design borrowed much from the Mil Mi-36 developed over the previous two years, and was itself replaced after a year by the Mil Mi-42 project. Although the Mi-40 design was resurrected for a short period in the 1990s, with optimization studies being completed, it did not reach the prototype stage. Operators Current Algerian Air Force Iraqi Army Aviation Russian Air Force 90 Mi-28N, 12 Mi-28UB Ugandan Air Force Notable accidents On 2 August 2015, an Mi-28 of the Berkut squadron crashed while performing in an aerobatics display with other helicopters in Ryazan. Of the crew, the pilot Lieutenant Colonel Igor Butenko died as a result of the crash while the co-pilot Senior Lieutenant Alexander Kletnov survived. While the specific cause of the crash remains undetermined, the co-pilot indicated in his report that the aircraft suffered a hydraulics failure. As a result, the Russian military grounded all Mi-28s during the investigation. Specifications (Mi-28N) See also References Citations Bibliography External links Mi-28 page on army-technology.com Mi-28 page on helis.com Mi-28 on globalsecurity.org Russian Mi-28Ns to receive N025 radars in 2016 Jane's Information Group, IHS Jane's Defence Weekly, 27 August 2015, Nikolai Novichkov, Moscow. 1980s Soviet attack aircraft 1990s Soviet and Russian attack aircraft Attack helicopters Mil aircraft 1980s Soviet helicopters 1990s Soviet and Russian helicopters Twin-turbine helicopters Aircraft first flown in 1982