This was the second Mil V-12 twin-rotor helicopter. In 1969, carrying a payload of 40204 kg (88,448 lb.), it was flown to 2255 m (11,224 ft.) by V.P.Koloshenko.
Source: "Helicopters - Military, Civilian and Rescue Rotorcraft", General editor: Robert Jackson. The Aviation Factfile, (c) 2005 International Masters Publishers BV, ISBN 1-84013-812-2