Russian Helicopters, a subsidiary of Oboronprom, a Rostec State Corp., announced the delivery that was made under a contract signed in 2012 by Poly Technologies and Rosoboronexport.
Under the contract, Russian Helicopters is supplying 52 Mi-171E transport helicopters to China.
The latest consignment of four brings the number delivered to 32, with the final batch expected to be transferred in 2014, Russian Helicopters said in a statement.
Russian Helicopters said it has worked with Poly Technologies, a subsidiary of China Poly Group Corp., since 2009 when they signed a previous deal for 32 Mi-171E helicopters, all of which were delivered by 2011.
The new Mi-171Es are produced at the Russian Helicopters plant Ulan-Ude Aviation in Ulan-Ude, capital of the Russian Federation's southeastern republic of Buryatia.
China's latest Mi-171Es are adapted for operation in mountainous terrain and are fitted with enhanced Klimov VK-2500 turboshaft engines and Safir auxiliary power plants. They also have upgraded transmissions, searchlights, internal fuel tanks and landing seats.
A cargo loading ramp and an additional sliding door on the right-hand side make for faster flight turnarounds, Russian Helicopters said.
The Ulan-Ude Aviation factory manufactures the medium-lift helicopters Mi-171, Mi-171A1 and Mi-171Sh helicopters and produces prototypes of attack aircraft, including the Su-25UBM and Su-39.
The plant also makes accessories and spare parts, participates in cooperative programs, services the aircraft it manufactures and offers training and retraining to pilots and technical staff at its own certified training centers.
The statement by Russian Helicopters didn't specify the final user of the Mi-171Es, although Mi-171Es already operating in China are carrying out a wide range of cargo work, including delivery of medicine, humanitarian aid and construction materials.
Mi-171 helicopters also support rescue operations including the ones following the earthquake in China's Sichuan province in April, Russian Helicopters said.
Chinese crews have been training on Mi-171 flight simulators at the Ulan-Ude Aviation plant which installed a new Mi-171 flight simulator produced by CSTS Dinamika in February.
The simulator is capable of simulating emergency situations and in-flight failures due to pilot errors and adverse environmental conditions including severe weather, CSTS said.
The simulator's visual system is a multichannel direct-projection complex with a partial dome that enables a field of view FOV 240°H x 70°V.
The Raduga CD IG, made by Constanta-Design, provides a detailed and realistic underlying surface with moving 3D objects. This includes special effects such as atmospheric light dispersion, soft dynamic shadows, 3D fogs and clouds, dust and snow vortices.
The simulator's projectors are made by Norwegian firm Projectiondesign whose F32 projector series feature brightness and contrast characteristics sufficient for highly realistic day and night scenes, a CSTS statement said.