Russia’s Mi-171A2 Helicopter Cleared for Flight 5,000m Above Sea Level

Russian Helicopters, a subsidiary of Rostec has completed flight tests of the Mi-171A2 multi-purpose helicopter on Elbrus, the highest peak of the Caucasus Mountains.

During flights in various modes, specialists collected and analyzed information about the operation of the main components and assemblies of the rotorcraft in the highlands. As a result, the current certificate for flights from 3,500 to 5,000 meters above sea level will be extended for this type of helicopter.

The Mi-171A2 helicopter carried out test flights with a takeoff weight of up to 13 tons. Experts checked the work in the highlands of the main systems: engines, auxiliary power unit, and oxygen equipment. In addition, as part of the tests, the controllability, maneuverability and rate of climb of the helicopter were evaluated at sites of various altitudes.

The Mi-171A2 is a multi-purpose heavy-class helicopter certified in Category A, which confirms that it meets the highest flight safety requirements for civil helicopters. At the same time, the Mi-171A2 surpasses mass-produced Mi-8/17 helicopters in terms of key flight performance characteristics - cruising and maximum speeds are 10% higher, and the payload is 25% higher. The Mi-171A2 has a more efficient X-shaped tail rotor, as well as a new main rotor with composite blades and an improved aerodynamic layout.

“The performance characteristics of the Mi-171A2 helicopter ensure the reliability and efficiency of its operation in high-altitude areas. According to the current certificate, the Mi-171A2 can take off and land at an altitude of up to 3,500 meters above sea level. Tests have proven that this figure can be significantly increased - the helicopter can be used to transport passengers and cargo in the highlands, at an altitude of up to 5000 meters. Extending the operational characteristics of a helicopter is a very urgent task that meets the needs of our customers. At present, the holding has begun issuing an addendum to the type certificate documenting the possibility of taking off and landing on the Mi-171A2 at an altitude of up to 5,000 meters,” said Oleg Gulyaev, First Deputy General Director of the Russian Helicopters holding.

As part of certification tests at an altitude of up to 5,000 meters, specialists from the National Center for Helicopter Engineering named after M.L. Mil and N.I. Kamov worked out a variety of maneuvers, including those with imitation of emergency situations. For example, the so-called aborted landings, when one of the engines fails and the helicopter is forced to continue flying, entering the second circle, as well as continued take-offs, when one of the engines suddenly loses power on takeoff and the car continues to climb on one of them. In addition, the possibility of landing with the engines turned off was worked out - in autorotation mode.

“We confidently performed takeoffs and landings with maximum takeoff weight, the helicopter showed high power-to-weight ratio, stability and controllability in rarefied air, which had the best effect on flight safety, allowing us to expand operating conditions and remove a number of restrictions. The Mi-171A2 is a real mountain helicopter,” commented Alexander Klimov, head of flight tests Hero of Russia, Honored Test Pilot of the Russian Federation.

The helicopter is equipped with VK-2500PS-03 engines manufactured by the United Engine Corporation with a digital control system. High-power engines with a BARK digital control system give helicopters fundamentally new opportunities for operation in high-mountainous areas and in areas with a hot climate.