It's the second fatal incident with a military Mi-8 helicopter in a week. On May 19, another Mi-8 crash-landed near the town of Klin, 90 kilometers (56 miles) from Moscow, killing all three crew members.
Officials said at the time that crash was probably caused by a technical malfunction. The Mi-8 is a multipurpose, medium twin-turbine helicopter, originally designed in the Soviet Union and now produced by Russia. It is one of the most common helicopters in the Russian armed forces.