The Mil Mi-6 (NATO reporting name "Hook") was a Soviet/Russian heavy transport helicopter designed by the Mil design bureau and built in large numbers for both military and civil roles. At the time of its introduction (1960) it was the largest, heaviest and fastest helicopter in the world.The Mil Mi-6 have been used on several occasion in the zone, although they are never seen in actual duty and all of them are found crashed.
A single Mil Mi-6 flew around Yantar sometime after the events of Clear Sky as it is only seen in Shadow of Chernobyl. It crashed near the lake, most likely due to the psychic emissions coming from the Yantar factory complex. The corpse of an Ecologist named Vasiliev lies near the wreck.
Another single Mil Mi-6 can be seen near the road to the Red Forest in Shadow of Chernobyl. It most likely crashed due to the Brain Scorcher.
Two Mil Mi-6 helicopters can be found in the Red Forest in Shadow of Chernobyl. One on the road leading to Pripyat and the second hidden in the woods south of the fenced pipeline running East to West. Both helicopters most likely crashed due to the Brain Scorcher.
The last ones are 2 of them around the courtyard inside the Chernobyl NPP. They are parked in a landing position so it can be assumed that they were left there sometime after the initial explosion of the CNPP.
During the disaster of 1986, several Mi-6's were used in firefighting operations.
All of the helicopters in game have the former Soviet Air Force markings (red star) on the fuselage, indicating they were all left behind in the Zone since about 1986 to 1992, much before the Second disaster.