Rostec starts assembling the first Mi-171A3 offshore helicopter Russian Helicopters Press Release | December 15, 2020 Estimated reading time 2 minutes, 40 seconds. Russian Helicopters holding company (part of Rostec State Corporation) has started assembling the first prototype of Mi-171A3 offshore helicopter. Equipment for assembling the fuselage was put into operation at the Ulan-Ude Aviation Plant. The Mi-171A3 comes with several significant upgrades when compared to Mi-171A2.The model also features widespread use of composite materials, which significantly reduce its weight. Russian Helicopters Photo Mi-171A3 comes with several significant upgrades when compared to Mi-171A2: a new airframe that integrates a crash-resistant fuel system into the cargo bay floor and modernized avionics, upgraded for offshore operations and flights in the Arctic. The model also features widespread use of composite materials, which significantly reduce its weight.