From 1976 this TU-144 was often used for test flights to test operation, payload and kerosene consumption on long distances, with the result that distances of over 6,000 kilometers were practicable. In 1977 she made her first flights on the route between the Soviet capital Moscow and the provincial capital Khabarovsk in the Far East. The flights in both directions were on average under three and a half hours for the 6,300 kilometer route.