Flight 778 departed Moscow Domodedovo International Airport at 17:17 UTC. The flight was uneventful until it started its descent to Irkutsk at 22:17. At the time, the weather at Irkutsk was being affected the edge of a cyclone near Ulaanbaatar, resulting in a cold front sweeping over the area. Observers stated that the weather in Irkutsk was light precipitation with cumulonimbus clouds over the airport. Wind speed at ground level at the airport was roughly 5 m/s (11.1 MPH). If landing in Irkutsk was not possible, the flight would have to be diverted to Bratsk Airport. The plane contacted air traffic control and lined up perfectly with the runway.