On 14th December 1977 there was made a test flight of a heavy transport helicopter Mi-26. Its construction consisted of eight-blade main lift rotor and tail rotor. It could carry 120 passengers in civilian variant or 68 parachutist in military purposes. Mi-28 is adjusted to carry 20 t of load in cargo space or under the fuselage. The total production run of those aircrafts was 316 and are in the possession of Russia, Greece, Laos, Mexico, Peru and North Korea.