United Nations representatives are mandating the carriage of terrain-awareness and ground-proximity warning systems on helicopters operating under its banner.
The mandate takes effect from 1 December, according to a UN communication dated 28 June.
It says the requirement covers all rotorcraft operating under long-term UN air charter agreements and letter-of-assist programmes.
Russian federal air transport regulator Rosaviatsia has formally notified operators of Mil Mi-8 and Mi-26 helicopters, registered in the UN database, of the requirement.
Helicopters must be fitted with a forward-looking terrain-avoidance system as well as a ground-proximity warning system, says the UN.
The decision is based, it says, on an ICAO recommendation that helicopters with more than nine seats, operating instrument flights, should carry such equipment.
It adds that the UN's Department of Field Support has reviewed technical and contractual arrangements to "further reduce the risk associated with controlled flight into terrain".